Atila WSGI Framework
Project description
Atila
Atila is simple and minimal WSGI framework integrated with Skitai App Engine for exporting component and backend services.
Installation
Requirements
Python 3.5+
Installation
With pip
pip3 install -U atila skitai rs4 aquests sqlphileFrom git
git clone https://gitlab.com/hansroh/atila.git
cd atila
python3 setup.py installBasic Directory Structure
Before you begin, recommended Atila App’s directory structure is like this:
service.py: Skitai runner
app.py: File, Main app
static: Directory, Place static files like css, js, images. This directory should be mounted for using
services: Directory, Module components, utils or helpers for helping app like config.py, model.py etc…
templates: Directory, Jinaja and Chameleon template files
resources: Directory, Various files as app need like sqlite db file. In you app, you use these files, you can access file in resources by app.get_resource (“db”, “sqlite3.db”) like os.path.join manner.
Request Hnalding with Atila
Before You Read
For using atila, ‘import atila’ SHOULD be imported before calling skitai.run (). Because Atila silently patches some Skitai’s objects for itself.
Note: But atila just adds some functions related ‘was’ and ‘response’ objects, NOT alter exist Skitai functions, then you could mount any WSGI apps with Atila app safely.
If your script contains both atila app creation and skitai.run, you don’t need to care about.
Below works fine.
from atila import Atila
app = Atila(__name__)
...
@app.route ("/")
def index (was):
...
return was.response ("200 OK", ...)
if __name__ == "__main__":
import skitai
pref = skitai.pref ()
pref.use_reloader = True
skitai.mount ('/', './static')
skitai.mount ('/', app, 'app', pref)
skitai.run ()But atila app exists seprated file and just mount it, you should care about that.
# serve.py
if __name__ == "__main__":
import skitai
import atila
pref = skitai.pref ()
pref.use_reloader = True
skitai.mount ('/', './static')
skitai.mount ('/', 'myapp/atila_app.py', pref = pref)
skitai.run ()App Resource Structure
If your app is simple, it can be made into single app.py and templates and static directory.
from atila import Atila
app = Atila(__name__)
app.use_reloader = True
app.debug = True
@app.route ("/")
def index (was):
...
return was.response ("200 OK", ...)
if __name__ == "__main__":
import skitai
pref = skitai.pref ()
pref.use_reloader = True
skitai.mount ('/', './static')
skitai.mount ('/', app, 'app', pref)
skitai.run ()And run,
python3 app.pyBut Your app is more bigger, it will be hard to make with single app file. Then, you can make services directory to seperate your app into several categories.
app.py
services/
templates/
resources/
static/All sub modules app need, can be placed into services/. services/*.py will be watched for reloading if use_reloader = True.
You can structuring any ways you like and I like this style:
services/views.py
services/apis.py
services/helpers.pyAll modules to mount to app in services, should have def mount (app).
For example, views.py is like this,
from . import helpers
def mount (app):
@app.route ("/")
def index (was):
...
return was.render ("index.html")Now you just import app decorable moduels at your app.py,
from atila import Atila
from services import views, apis
app = Atila(__name__)That’s it.
If app scale is more bigger scale, services can be expanded to sub modules.
services/views/index.py, regist.py, search.py, ...
services/apis/codemap.py,
services/helpers/utils.py, ...And import these from app.py,
from services.views import index, regist, ...
from services.apis import codemap, ...Some more other informations will be mentioned at App Decorating section again.
Runtime App Preference
New in skitai version 0.26
Usally, your app preference setting is like this:
from atila import Atila
app = Atila(__name__)
app.use_reloader = True
app.debug = True
app.config ["prefA"] = 1
app.config ["prefB"] = 2Skitai provide runtime preference setting.
import skitai
pref = skitai.pref ()
pref.use_reloader = 1
pref.debug = 1
pref.config ["prefA"] = 1
pref.config.prefB = 2
skitai.mount ("/v1", "app_v1/app.py", "app", pref)
skitai.run ()Above pref’s all properties will be overriden on your app.
Runtime preference can be used with skitai initializing or complicated initializing process for your app.
You can create __init__.py at same directory with app.py. And bootstrap () function is needed.
__init__.py
import skitai
from . import cronjob
def bootstrap (pref):
with open (pref.config.urlfile, "r") as f:
pref.config.urllist = []
while 1:
line = f.readline ().strip ()
if not line: break
pref.config.urllist.append (line.split (" ", 4))Access Atila App
You can access all Atila object from was.app.
was.app.debug
was.app.use_reloader
was.app.config # use for custom configuration like was.app.config.my_setting = 1
was.app.securekey
was.app.session_timeout = None
was.app.authorization = “digest”
was.app.authenticate = False
was.app.realm = None
was.app.users = {}
was.app.jinja_env
was.app.build_url () is equal to was.ab ()
Currently was.app.config has these properties and you can reconfig by setting new value:
was.app.config.max_post_body_size = 5 * 1024 * 1024
was.app.config.max_cache_size = 5 * 1024 * 1024
was.app.config.max_multipart_body_size = 20 * 1024 * 1024
was.app.config.max_upload_file_size = 20000000
Debugging and Reloading App
If debug is True, all errors even server errors is shown on both web browser and console window, otherhwise shown only on console.
If use_reloader is True, Atila will detect file changes and reload app automatically, otherwise app will never be reloaded.
from atila import Atila
app = Atila (__name__)
app.debug = True # output exception information
app.use_reloader = True # auto realod on file changedKill Switch
You you want to disable debug and use_reloader on production enveironment at once,
python3 app.py -d
python3 app.py -d ---production # triple hyphensRouting
Basic routing is like this:
@app.route ("/hello")
def hello_world (was):
return was.render ("hello.htm")For adding some restrictions:
@app.route ("/hello", methods = ["GET"], content_types = ["text/xml"])
def hello_world (was):
return was.render ("hello.htm")And you can specifyt multiple routing,
@app.route ("/hello", mehotd = ["POST"])
@app.route ("/")
def hello_world (was):
return was.render ("hello.htm")If method is not GET, Atila will response http error code 405 (Method Not Allowed), and content-type is not text/xml, 415 (Unsupported Content Type).
Request
Reqeust object provides these methods and attributes:
was.request.method # upper case GET, POST, …
was.request.command # lower case get, post, …
was.request.uri
was.request.version # HTTP Version, 1.0, 1.1
was.request.scheme # http or https
was.request.headers # case insensitive dictioanry
was.request.body # bytes object
was.request.args # dictionary merged with url, query string, form data and JSON
was.request.routed_function
was.request.routable # {‘methods’: [“POST”, “OPTIONS”], ‘content_types’: [“text/xml”]}
was.request.split_uri () # (script, param, querystring, fragment)
was.request.json () # decode request body from JSON
was.request.form () # decode request body to dict if content-type is form data
was.request.dict () # decode request body as dict if content-type is compatible with dict - form data or JSON
was.request.get_header (“content-type”) # case insensitive
was.request.get_headers () # retrun header all list
was.request.get_body ()
was.request.get_scheme () # http or https
was.request.get_remote_addr ()
was.request.get_user_agent ()
was.request.get_content_type ()
was.request.get_main_type ()
was.request.get_sub_type ()
Getting Parameters
Atila parameters are comceptually seperated 3 groups: URL, query string and body.
Below explaination may be a bit complicated but it is enough to remember 3 things:
Atila resource parameters can be defined as function arguments and use theses native Python function arguments.
Also you can access parameter groups by origin:
was.request.DEFAULT: default arguments of your resource
was.request.URL: url query string
was.request.FORM
was.request.JSON
was.request.DATA: automatically choosen one of was.request.FORM or was.request.JSON by content-type header of request
was.request.ARGS: eventaully was.request.ARGS contains all parameters of all origins including was.request.DEFAULT
Getting URL Parameters
URL Parameters should be arguments of resource.
@app.route ("/episode/<int:id>")
def episode (was, id):
return id
# http://127.0.0.1:5000/episodefor fancy url building, available param types are:
int
float
path: /download/<int:major_ver>/<path>, should be positioned at last like /download/1/version/1.1/win32
If not provided, assume as string. and all space will be replaced to “_”
It is also possible via keywords args,
@app.route ("/episode/<int:id>")
def episode (was, \*\*karg):
retrun was.request.ARGS.get ("id")
# http://127.0.0.1:5000/episode/100You can set default value to id,
@app.route ("/episode/<int:id>", methods = ["GET", "POST", "PUT", "DELETE", "OPTIONS"])
def episode (was, id = None):
if was.request.method == "POST" and id is None:
...
return was.API (id = new_id)
return ...It makes this URL working,
http://127.0.0.1:5000/episodeAnd was.ab will behaive like as below,
was.ab ("episode")
>> /episode
was.ab ("episode", 100)
>> /episode/100Note that this does not works for root resource,
@app.route ("/<int:id>", methods = ["GET", "POST", "PUT", "DELETE", "OPTIONS"])
def episode (was, id = None):
if was.request.method == "POST" and id is None:
...
return was.API (id = new_id)
return ...By above code, http://127.0.0.1:5000/ will not work. You should define “/” route.
Query String Parameters
qiery string parameter can be both resource arguments but needn’t be.
@app.route ("/hello")
def hello_world (was, num = 8):
return num
# http://127.0.0.1:5000/hello?num=100It is same as these,
@app.route ("/hello")
def hello_world (was):
return was.request.ARGS.get ("num")
@app.route ("/hello")
def hello_world (was, **url):
return url.get ("num")
# of
return was.request.URL.get ("num)Above 2 code blocks have a significant difference. First one can get only ‘num’ parameter. If URL query string contains other parameters, Skitai will raise 508 Error. But 2nd one can be any parameters.
Getting Form/JSON Parameters
Getting form is not different from the way for url parameters, but generally form parameters is too many to use with each function parameters, can take from single args **form or take mixed with named args and **form both. if request header has application/json
@app.route ("/hello")
def hello (was, **form):
return "Post %s %s" % (form.get ("userid", ""), form.get ("comment", ""))
@app.route ("/hello")
def hello_world (was, userid, **form):
return "Post %s %s" % (userid, form.get ("comment", ""))Note that for receiving request body via arguments, you specify keywords args like **karg or specify parameter names of body data.
If you want just handle POST body, you can use was.request.json () or was.request.form () that will return dictionary object.
Getting Composed Parameters
You can receive all type of parameters by resource arguments. Let’assume yotu resource URL is http://127.0.0.1:5000/episode/100?topic=Python.
@app.route ("/episode/<int:id>")
def hello (was, id, topic):
passif URL is http://127.0.0.1:5000/episode/100?topic=Python with Form/JSON data {“comment”: “It is good idea”}
@app.route ("/episode/<int:id>")
def hello (was, id, topic, comment):
passNote that argument should be ordered by:
URL parameters
URL query string
Form/JSON body
And note if your request has both query string and form/JSON body, and want to receive form paramters via arguments, you should receive query string parameters first. It is not allowed to skip query string.
Also you can use keywords argument.
@app.route ("/episode/<int:id>")
def hello (was, id, \*\*karg):
karg.get ('topic')Note that **karg is contains both query string and form/JSON data and no retriction for parameter names.
was.requests.args is merged dictionary for all type of parameters. If parameter name is duplicated, its value will be set to form of value list (But If parameters exist both URL and form data, form data always has priority. It means URL parameter will be ignored). Then simpletst way for getting parameters, use was.request.args.
@app.route ("/episode/<int:id>")
def hello (was, id):
was.request.args.get ('topic')Testing Parameters
For parameter checking,
@app.route ("/test")
@app.parameters_required ("ARGS", ["id"], ints = ["id"])
def test (was, id):
return was.render ("test.html")‘id’ is required and sholud be int type.
@app.parameters_required (scope, required = None, ints = None, floats = None)Make Your Own Rule
The way to get parameters is little messy. But I want to try to make more pythonic style. Even all routed method can be called by another non app functions.
Initially I want to use like this.
@app.route ("/pets/<kind>")
def pets (was, kind, limit, offset = 0, **JSON):
...It can be requested by requests.
requests.post (
"http://localhost/pets/dog?limit=10",
json = {"area": "LA"}
)If you need to check the origin of parameters, parameters_required decorator is useful.
@app.route ("/pets/<kind>")
@parameters_required ("JSON", ["area"])
def pets (was, kind, limit, offset = 0, **JSON):
...That’s just my opinion.
Usig Skitai Async Requests Services Working With Jinja2 Template
Basic usage is here.
Async request’s benefit will be maximied at your view template rather than your controller. At controller, you just fire your requests and get responses at your template.
@app.route ("/")
@app.login_required
def intro (was):
was.g.aa = was.get ("https://example.com/blur/blur")
was.g.bb = was.get ("https://example.com/blur/blur/more-blur")
return was.render ('template.html')Your template,
{% set response = was.g.aa.dispatch () %}
{% if response.status == 3 %}
{{ was.response.throw ("500 Internal Server Error") }}
{% endif %}
{% if response.status_code == 200 %}
{% for each in response.data %}
...
{% endfor %}
{% endif %}Available only with Atila
Shorter version is for dispatch and throw HTTP error,
{% set response = was.g.aa.dispatch_or_throw ("500 Internal Server Error") %}Response
Basically, just return contents.
@app.route ("/hello")
def hello_world (was):
return was.render ("hello.htm")If you need set additional headers or HTTP status,
@app.route ("/hello")
def hello (was):
return was.response ("200 OK", was.render ("hello.htm"), [("Cache-Control", "max-age=60")])
def hello (was):
return was.response (body = was.render ("hello.htm"), headers = [("Cache-Control", "max-age=60")])
def hello (was):
was.response.set_header ("Cache-Control", "max-age=60")
return was.render ("hello.htm")Above 3 examples will make exacltly same result.
Sending specific HTTP status code,
def hello (was):
return was.response ("404 Not Found", was.render ("err404.htm"))
def hello (was):
# if body is not given, automaticcally generated with default error template.
return was.response ("404 Not Found")If app raise exception, traceback information will be displayed only app.debug = True. But you intentionally send it inspite of app.debug = False:
# File
@app.route ("/raise_exception")
def raise_exception (was):
try:
raise ValueError ("Test Error")
except:
return was.response ("500 Internal Server Error", exc_info = sys.exc_info ())If you use custom error handler, you can set detail explaination to error [“detail”].
@app.default_error_handler
def default_error_handler (was, error):
return was.render ("errors/default.html", error = error)
def error (was):
return was.response.with_explain ('503 Serivce Unavaliable', "Please Visit On Thurse Day")You can return various objects.
# File
@app.route ("/streaming")
def streaming (was):
return was.response ("200 OK", open ("mypicnic.mp4", "rb"), headers = [("Content-Type", "video/mp4")])
# Generator
def build_csv (was):
def generate():
for row in iter_all_rows():
yield ','.join(row) + '\n'
return was.response ("200 OK", generate (), headers = [("Content-Type", "text/csv")])All available return types are:
String, Bytes, Unicode
File-like object has ‘read (buffer_size)’ method, optional ‘close ()’
Iterator/Generator object has ‘next() or _next()’ method, optional ‘close ()’ and shoud raise StopIteration if no more data exists.
Something object has ‘more()’ method, optional ‘close ()’
Classes of skitai.lib.producers
List/Tuple contains above objects
XMLRPC dumpable object for if you want to response to XMLRPC
The object has ‘close ()’ method, will be called when all data consumed, or socket is disconnected with client by any reasons.
was.response (status = “200 OK”, body = None, headers = None, exc_info = None)
was.response.throw (status = “200 OK”): abort handling request, generated contents and return http error immediatly
was.API (__data_dict__ = None, **kargs): return api response container
was.Fault (status = “200 OK”,*args, **kargs): shortcut for was.response (status, was.API (…)) if status code is 2xx and was.response (status, was.Fault (…))
was.Fault (msg, code = 20000, debug = None, more_info = None, exc_info = None): return api response container with setting error information
was.response.traceback (msg = “”, code = 10001, debug = ‘see traceback’, more_info = None): return api response container with setting traceback info
was.response.set_status (status) # “200 OK”, “404 Not Found”
was.response.get_status ()
was.response.set_headers (headers) # [(key, value), …]
was.response.get_headers ()
was.response.set_header (k, v)
was.response.get_header (k)
was.response.del_header (k)
was.response.hint_promise (uri) # New in skitai version 0.16.4, only works with HTTP/2.x and will be ignored HTTP/1.x
HTTP Exception
Abort immediatly and send HTTP eroor content.
@app.route ("/<filename>")
def getfile (was, filename):
if not os.path.isfile (filename):
raise was.Error ("404 Not Found", "{} not exists".format (filename))
return was.File (filename)File Stream
Response provides some methods for special objects.
First of all, for send a file,
@app.route ("/<filename>")
def getfile (was, filename):
return was.File ('/data/%s' % filename)JSON API Response
New in skitai version 0.26.15.9
In cases you want to retrun JSON API reponse,
# return JSON {data: [1,2,3]}
return was.Fault ('200 OK', data = [1, 2, 3])
# return empty JSON {}
return was.Fault (201 Accept')
# and shortcut if response HTTP status code is 200 OK,
return was.API (data = [1, 2, 3])
# return empty JSON {}
return was.API ()For sending error response with error information,
# client will get, {"message": "parameter q required", "code": 10021}
return was.Fault ('400 Bad Request', 'missing parameter', 10021)
# with additional information,
was.Fault (
'400 Bad Request',
'missing parameter', 10021,
'need parameter offset and limit', # detailed debug information
'http://127.0.0.1/moreinfo/10021', # more detail URL something
)You can send traceback information for debug purpose like in case app.debug = False,
try:
do something
except:
return was.Fault (
'500 Internal Server Error',
'somethig is not valid',
10022,
traceback = True
)
# client see,
{
"code": 10001,
"message": "somethig is not valid",
"debug": "see traceback",
"traceback": [
"name 'aa' is not defined",
"in file app.py at line 276, function search"
]
}Important note that this response will return with HTTP 200 OK status. If you want return 500 code, just let exception go.
But if your client send header with ‘Accept: application/json’ and app.debug is True, Skitai returns traceback information automatically.
Futures Response
New in version 0.2*
With single thread it will be the problem using was’ request services with dispatch (), It is almost works as IO blocking situation.
was.Futures returns Futures instance for delaying response until every awaitable tasks are finished and every future tasks will be executed concurrently.
CAUTIONS:
Futures escape ealry from current requet handling thread and enter to main event loop. It means they will make connections to targets as possible as they can. If hundreds of clients request resource using database/upstream server, It will make error on target server like “too manty connection error”. If you use Futures response, you SHOULD make sure these factors.
Futures might be the most efficient in 2 conditions, a few simultaneously requesting clients, streaming data is relatively small size. Lot of clients will consume connection resources fast and large data stream make blanch coroutine advantages caused of expensive networking cost.
Then you could consider using was.Tasks first because Tasks is within thread pool, it will be limit number of connections by number of thread pool.
NOTE: With my personal benchmark, it is not very impressive performance. I have maden 3 backend requests per client requests with weigHTTP (weigHTTP -n 3000 -c 1000 -k http://…/bench). Then was.Tasks and was.Futures are almost same performance. And was.Tasks is just 20% faster than sequencial synchronous requests. Very disappointing results. I recoomend to use was.Tasks NOT was.Futures.
def test_futures (app, dbpath):
@app.route ("/")
def index (was):
def response (was, rss):
return was.API (status_code = [rs.status_code for rs in rss])
reqs = [
was.get ("@pypi/project/skitai/"),
was.get ("@pypi/project/rs4/"),
was.backend ("@sqlite").execute ('SELECT * FROM stocks WHERE symbol=?', ('RHAT',))
]
return was.Futures (reqs, timeout = 2).then (response)
app.alias ("@pypi", skitai.PROTO_HTTPS, "pypi.org")
app.alias ("@sqlite", skitai.DB_SQLITE3, dbpath)
with app.test_client ("/", confutil.getroot ()) as cli:
resp = cli.get ("/")
assert resp.data ['status_code'] == [200, 200, 200]Another example,
def test_futures (app, dbpath):
@app.route ("/")
def index (was):
def response (was, rss, stock):
stock.announcements = rs [0].data
return was.API (stock)
stock_req = was.backend ("@sqlite").select (stocks").get ("*").filter (symbol='RHAT').execute ()
stock = stock_req.getwait ().data
if not stock:
return was.response ("404 Not Found")
reqs = [stock_req = was.backend ("@sqlite").select (announcements").get ("*").filter (id=stock.id).execute ()]
return was.Futures (reqs).then (response, stock = stock [0])
app.alias ("@pypi", skitai.PROTO_HTTPS, "pypi.org")
app.alias ("@sqlite", skitai.DB_SQLITE3, dbpath)
with app.test_client ("/", confutil.getroot ()) as cli:
resp = cli.get ("/")
resp.dataChaining is also possible,
@app.route ("/")
def index (was):
def repond (was, rss, b, status_code):
return was.API (status_code_db = [rs.status_code for rs in rss], b = b, status_code = status_code)
def checkdb (was, rss, a):
reqs = [was.backend ("@sqlite").execute ('SELECT * FROM stocks WHERE symbol=?', ('RHAT',))]
status_code = [rs.status_code for rs in rss]
return was.Futures (reqs).then (repond, b = a + 100, status_code = status_code)
reqs = [
was.get ("@pypi/project/skitai/"),
was.get ("@pypi/project/rs4/")
]
return was.Futures (reqs).then (checkdb, a = 100)
app.alias ("@pypi", skitai.PROTO_HTTPS, "pypi.org")
app.alias ("@sqlite", skitai.DB_SQLITE3, dbpath)
with app.test_client ("/", confutil.getroot ()) as cli:
resp = cli.get ("/")
resp.data
>> {'b': 200, 'status_code': [200, 200], 'status_code_db': [200]}App Decorating: Making Simpler & Modular App
New in skitai version 0.26.17
Implicit Mount Services On Your App
I already mentioned App Structure section, you can split yours views and help utilties into services directory.
Assume your application directory structure is like this,
templates/*.html
services/*.py # app library, all modules in this directory will be watched for reloading
static/images # static files
static/js
static/css
app.py # this is starter scriptapp.py
from services import auth
app = Atila (__name__)
app.debug = True
app.use_reloader = True
@app.default_error_handler
def default_error_handler (was, e):
return str (e)services/auth.py
# shared utility functions used by views
def titlize (s):
...
return s
def mount (app):
@app.login_handler
def login_handler (was):
if was.session.get ("username"):
return
next_url = not was.request.uri.endswith ("signout") and was.request.uri or ""
return was.redirect (was.ab ("signin", next_url))
@app.route ("/signout")
def signout (was):
was.session.remove ("username")
was.mbox.push ("Signed out successfully", "success")
return was.redirect (was.ab ('index'))
@app.route ("/signin")
def signin (was, next_url = None, **form):
if was.request.args.get ("username"):
user = auth.authenticate (was.django, username = was.request.args ["username"], password = was.request.args ["password"])
if user:
was.session.set ("username", was.request.args ["username"])
return was.redirect (was.request.args ["next_url"])
else:
was.mbox.push ("Invalid User Name or Password", "error", icon = "new_releases")
return was.render ("sign/signin.html", next_url = next_url or was.ab ("index"))You just import module from services. but def mount (app) is core in each module. Every modules can have mount (app) in services, so you can split and modulize views and utility functions. mount (app) will be automatically executed on starting. If you set app.use_reloader, theses services will be automatically reloaded and re-executed on file changing. Also you can make global app sharable functions into seperate module like util.py without views.
Explicit Mount Services On Your App
If you want to select services - not automatically - set app.auto_mount = False.
from services import auth, search
app = Atila (__name__)
app.auto_mount = False
app.mount (search)Above case, auth module has mount function but will not be mounted.
Mouning Services With Options
If you need additional options on decorating,
def mount (app):
@app.route ("/login")
def login (was):
...And on app,
from services import auth
app = Atila (__name__)
app.mount ('/regist', auth)Finally, route of login is “/regist/login”.
Sometimes function names are duplicated if like you import contributed services.
from services import auth
app = Atila (__name__)
app.mount ( '/regist', auth, ns = "regist")Now, you can import iport without name collision. But be careful when use was.ab () etc.
Note that options should be keyword arguments.
{{ was.ab ("regist.login") }}If you want to mount only debug environment,
app.mount (auth, debug_only = True)If you want to authentify to all services,
app.mount (auth, authenticate = "bearer")Currently reserved arguments are:
ns
authenticate
debug_only
mount
Your custom options can be accessed by __mount__ in your module.
First, mount with redirect option.
app.mount (auth, redirect = "index")
# automatically set to auth.__mount__ = {"redirect": "index"}then you can access in auth.py,
@app.route ("/regist/signout")
def signout (was):
was.mbox.push ("Signed out successfully", "success")
return was.redirect (was.ab (__mount__.get ("redirect", 'index')))If you build useful services, please contribute them to atila.services.
Releasing Module Resources
New in skitai version 0.27
Also ‘umount’ is avaliable for cleaning up module resource.
resource = ...
def umount (app):
resource.close ()
app.someghing = NoneThis will be automatically called when:
before module itself is reloading
before app is reloading
app unmounted from Skitai
More About Namespace
If you develop reusable task modules, pay attention to namespace and URL building.
For example, below module is mount with app.mount (auth, ns = “regist”).
# auth.py
def mount (app):
@app.route ("/func1")
def func1 (was, a):
...
@app.route ("/func2")
def func2 (was):
was.ab ("func1", "hello")This was.ab (“func1”) in func2 might be dangerous, because this task modules may have namespace. Then you consider ns like this.
was.ab ("{}func1".format (__mount__.get ("ns") and __mount__ ["ns"] + "." or ""), , "hello")But it is not pretty, so you can pretty style,
@app.route ("/func2")
def func2 (was):
was.ab (func1, "hello")Manual Mounting
Atila automaticall mount your services which have mount () funtion, but you can disable this, and mount explicit.
New in skitai version 0.27
If you mount manually, set app.auto_mount = False and call mount () for each modules you want.
from services import auth, index
app = Atila (__name__)
app.auto_mount = False
app.mount ("/v2", auth, index)
app.mount ("/v2", pets)
skitai.mount ("/", app)Disabling Resources
If you want to disable some resources in your services, you just remove from decorative () into any function:
def mount (app):
@app.login_handler
def login_handler (was):
...
def disabled ():
@app.route ("/something")
def unneed_fornow (was):
...If you want to disable a module, You just do not import your app.py.
More About Websocket
websocket design specs can be choosen one of 3.
WS_SIMPLE
Thread pool manages n websocket connection
It’s simple request and response way like AJAX
Low cost on threads resources, but reposne cost is relatvley high than the others
WS_THREADSAFE (New in version 0.26)
Mostly same as WS_SIMPLE
Message sending is thread safe
Most case you needn’t this option, but you create uourself one or more threads using websocket.send () method you need this for your convinience
WS_GROUPCHAT (New in version 0.24)
Thread pool manages n websockets connection
Chat room model
message_encoding
Websocket messages will be automatically converted to theses objects. Note that option is only available with Atila WSGI container.
WS_MSG_JSON
WS_MSG_XMLRPC
New in skitai version 0.26.18
Websokect usage is already explained, but Atila provide @app.websocket decorator for more elegant way to use it.
def onopen (was):
print ('websocket opened')
def onclose (was):
print ('websocket closed')
@app.route ("/websocket")
@app.websocket (skitai.WS_SIMPLE, 1200, onopen, onclose)
def websocket (was, message):
return 'you said: ' + messageThis decorator spec is,
@app.websocket (
spec, # one of skitai.WS_SIMPLE, skitai.WS_THREADSAFE and skitai.WS_GROUPCHAT
timeout = 60,
onopen = None,
onclose = None
)In some cases, you need additional parameter for opening/closing websocket.
@app.route ("/websocket")
@app.websocket (skitai.WS_THREADSAFE, 1200, onopen)
def websocket (was, message, option):
return 'you said: ' + messageThen, your onopen function must have additional parameters except message.
def onopen (was, option):
print ('websocket opened with', option)Now, your websocket endpoint is “ws://127.0.0.1:5000/websocket?option=value”
WS_NQ does not use queue or thread pool. In this case, response is more faster but if response includes IO blocking operation, entire Skitai event loop will be blocked.
@app.route ("/websocket")
@app.websocket (skitai.WS_SIMPLE | skitai.WS_NQ, 1200, onopen)
def websocket (was, message):
return 'you said: ' + messagePushing Message Through Connected Client
Save websocket client id to session.
def onopen (was):
was.session.set ("WS_ID", was.websocket.client_id)
def onclose (was):
was.session.remove ("WS_ID")
@app.route ("/websocket")
@app.websocket (skitai.WS_SIMPLE | skitai.WS_FAST, 1200, onopen, onclose)
def websocket (was, message):
return 'you said: ' + messageAnd push message to client.
@app.route ("/item_in_stock")
def item_in_stock (was):
app.websocket_send (
was.session.get ("WS_ID"),
"Item In Stock!"
)Note:: I’m not sure it is works in all web browser.
Building URL
If your app is mounted at “/math”,
@app.route ("/add")
def add (was, num1, num2):
return int (num1) + int (num2)
was.app.build_url ("add", 10, 40) # returned '/math/add?num1=10&num2=40'
# BUT it's too long to use practically,
# was.ab is acronym for was.app.build_url
was.ab ("add", 10, 40) # returned '/math/add?num1=10&num2=40'
was.ab ("add", 10, num2=60) # returned '/math/add?num1=10&num2=60'
#You can use function directly as well,
was.ab (add, 10, 40) # returned '/math/add?num1=10&num2=40'
@app.route ("/hello/<name>")
def hello (was, name = "Hans Roh"):
return "Hello, %s" % name
was.ab ("hello", "Your Name") # returned '/math/hello/Your_Name'Basically, was.ab is same as Python function call.
Building URL by Updating Parameters Partially
New in skitai version 0.27
@app.route ("/navigate")
def navigate (was, limit = 20, pageno = 1):
return ...If this resource was requested by /naviagte?limit=100&pageno=2, and if you want to make new resource url with keep a’s value (=100), you can make URL like this,
was.ab ("navigate", was.request.args.limit, 3)But you can update only changed parameters partially,
was.partial ("add", pageno = 3)Parameter a’s value will be kept with current requested parameters. Note that was.partial can be recieved keyword arguments only except first resource name.
was.partial is used changing partial parameters (or none) based over current parameters.
Building Base URL without Parameters
New in skitai version 0.27
Sometimes you need to know just resource’s base path info - especially client-side javascript URL building, then use was.basepath.
@app.route ("/navigate")
def navigate (was, limit, pageno = 1):
return ...was.basepath ("navigate")
>> return "/navigate"For example, in your VueJS template,
<a :href="'{{ was.basepath ('navigate') }}?limit=' + limit_option + '&pageno=' + (current_page + 1)">Next Page</a>Note that base path means for fancy Url,
@app.route ("/user/<id>")
>> base path is "/user/"
@app.route ("/user/<id>/pat")
>> base path is "/user/"Access Environment Variables
was.env is just Python dictionary object.
if "HTTP_USER_AGENT" in was.env:
...
was.env.get ("CONTENT_TYPE")Jinja2 Template Engine
Although You can use any template engine, Skitai provides was.render() which uses Jinja2 template engine. For providing arguments to Jinja2, use dictionary or keyword arguments.
return was.render ("index.html", choice = 2, product = "Apples")
#is same with:
return was.render ("index.html", {"choice": 2, "product": "Apples"})
#BUT CAN'T:
return was.render ("index.html", {"choice": 2}, product = "Apples")Directory structure sould be:
/project_home/app.py
/project_home/templates/index.html
At template, you can use all ‘was’ objects anywhere defautly. Especially, Url/Form parameters also can be accessed via ‘was.request.args’.
{{ was.cookie.username }} choices item {{ was.request.args.get ("choice", "N/A") }}.
<a href="{{ was.ab ('checkout', choice) }}">Proceed</a>Also ‘was.g’ is can be useful in case threr’re lots of render parameters.
was.g.product = "Apple"
was.g.howmany = 10
return was.render ("index.html")And at jinja2 template,
{% set g = was.g }} {# make shortcut #}
Checkout for {{ g.howmany }} {{ g.product }}{{g.howmany > 1 and "s" or ""}}If you want modify Jinja2 envrionment, can through was.app.jinja_env object.
def generate_form_token ():
...
was.app.jinja_env.globals['form_token'] = generate_form_tokenNew in skitai version 0.15.16
Added new app.jinja_overlay () for easy calling app.jinja_env.overlay ().
Recently JS HTML renderers like Vue.js, React.js have confilicts with default jinja mustache variable. In this case you mightbe need change it.
app = Atila (__name__)
app.debug = True
app.use_reloader = True
app.jinja_overlay (
variable_start_string = "{{",
variable_end_string = "}}",
block_start_string = "{%",
block_end_string = "%}",
comment_start_string = "{#",
comment_end_string = "#}",
line_statement_prefix = "%",
line_comment_prefix = "%%"
)if you set same start and end string, please note for escaping charcter, use double escape. for example ‘#’, use ‘##’ for escaping.
Warning: Current Jinja2 2.8 dose not support double escaping (##) but it will be applied to runtime patch by Atila. So if you use app.jinja_overlay, you have compatible problems with official Jinja2.
Custom Error Template
New in skitai version 0.26.7
@app.default_error_handler
def not_found (was, error):
return was.render ('default.htm', error = error)
@app.error_handler (404)
def not_found (was, error):
return was.render ('404.htm', error = error)Template file 404.html is like this:
<h1>{{ error.code }} {{ error.message }}</h1>
<p>{{ error.detail }}</p>
<hr>
<div>URL: {{ error.url }}</div>
<div>Time: {{ error.time }}</div>Note that custom error templates can not be used before routing to the app.
Access Session
was.session has almost dictionary methods.
To enable session for app, random string formatted securekey should be set for encrypt/decrypt session values.
WARNING: securekey should be same on all skitai apps at least within a virtual hosing group, Otherwise it will be serious disaster.
app.securekey = "ds8fdsflksdjf9879dsf;?<>Asda"
app.session_timeout = 1200 # sec
@app.route ("/session")
def hello_world (was, **form):
if "login" not in was.session:
was.session.set ("user_id", form.get ("hansroh"))
# or
was.session ["user_id"] = form.get ("hansroh")If you set, alter or remove session value, session expiry is automatically extended by app.session_timeout. But just getting value will not be extended. If you extend explicit without altering value, you can use touch() or set_expiry(). session.touch() will extend by app.session_timeout. session.set_expiry (timeout) will extend by timeout value.
Once you set expiry, session auto extenstion will be disabled until expiry time become shoter than new expiry time is calculated by app.session_timeout.
was.session.set (key, val)
was.session.get (key, default = None)
was.session.source_verified (): If current IP address matches with last IP accesss session
was.session.getv (key, default = None): If not source_verified (), return default
was.session.remove (key)
was.session.clear ()
was.session.keys ()
was.session.values ()
was.session.items ()
was.session.has_key ()
was.session.set_expiry (timeout)
was.session.touch ()
was.session.expire ()
Messaging Box
Like Flask’s flash feature, Skitai also provide messaging tool.
@app.route ("/msg")
def msg (was):
was.mbox.send ("This is Flash Message", "flash")
was.mbox.send ("This is Alert Message Kept by 60 seconds on every request", "alram", valid = 60)
return was.redirect (was.ab ("showmsg", "Hans Roh"), status = "302 Object Moved")
@app.route ("/showmsg")
def showmsg (was, name):
return was.render ("msg.htm", name=name)A part of msg.htm is like this:
Messages To {{ name }},
<ul>
{% for message_id, category, created, valid, msg, extra in was.mbox.get () %}
<li> {{ mtype }}: {{ msg }}</li>
{% endfor %}
</ul>Default value of valid argument is 0, which means if page called was.mbox.get() is finished successfully, it is automatically deleted from mbox.
But like flash message, if messages are delayed by next request, these messages are save into secured cookie value, so delayed/long term valid messages size is limited by cookie specificatio. Then shorter and fewer messsages would be better as possible.
‘was.mbox’ can be used for general page creation like handling notice, alram or error messages consistently. In this case, these messages (valid=0) is consumed by current request, there’s no particular size limitation.
Also note valid argument is 0, it will be shown at next request just one time, but inspite of next request is after hundred years, it will be shown if browser has cookie values.
@app.before_request
def before_request (was):
if has_new_item ():
was.mbox.send ("New Item Arrived", "notice")
@app.route ("/main")
def main (was):
return was.render ("news.htm")news.htm like this:
News for {{ was.g.username }},
<ul>
{% for mid, category, created, valid, msg, extra in was.mbox.get ("notice", "news") %}
<li class="{{category}}"> {{ msg }}</li>
{% endfor %}
</ul>was.mbox.send (msg, category, valid_seconds, key=val, …)
was.mbox.get () return [(message_id, category, created_time, valid_seconds, msg, extra_dict)]
was.mbox.get (category) filtered by category
was.mbox.get (key, val) filtered by extra_dict
was.mbox.source_verified (): If current IP address matches with last IP accesss mbox
was.mbox.getv (…) return get () if source_verified ()
was.mbox.search (key, val): find in extra_dict. if val is not given or given None, compare with category name. return [message_id, …]
was.mbox.remove (message_id)
Named Session & Messaging Box
New in skitai version 0.15.30
You can create multiple named session and mbox objects by mount() methods.
was.session.mount (
name = None, securekey = None,
path = None, domain = None, secure = False, http_only = False,
session_timeout = None
)
was.mbox.mount (
name = None, securekey = None,
path = None, domain = None, secure = False, http_only = False
)For example, your app need isolated session or mbox seperated default session for any reasons, can create session named ‘ADM’ and if this session or mbox is valid at only /admin URL.
@app.route("/")
def index (was):
was.session.mount ("ADM", SECUREKEY_STRING, path = '/admin')
was.session.set ("admin_login", True)
was.mbox.mount ("ADM", SECUREKEY_STRING, path = '/admin')
was.mbox.send ("10 data has been deleted", 'warning')SECUREKEY_STRING needn’t same with app.securekey. And path, domain, secure, http_only args is for session cookie, you can mount any named sessions or mboxes with upper cookie path and upper cookie domain. In other words, to share session or mbox with another apps, path should be closer to root (/).
@app.route("/")
def index (was):
was.session.mount ("ADM", SECUREKEY_STRING, path = '/')
was.session.set ("admin_login", True)Above ‘ADM’ sesion can be accessed by all mounted apps because path is ‘/’.
Also note was.session.mount (None, SECUREKEY_STRING) is exactly same as mounting default session, but in this case SECUREKEY_STRING should be same as app.securekey.
mount() is create named session or mbox if not exists, exists() is just check wheather exists named session already.
if not was.session.exists (None):
return "Your session maybe expired or signed out, please sign in again"
if not was.session.exists ("ADM"):
return "Your admin session maybe expired or signed out, please sign in again"File Upload
FORM = """
<form enctype="multipart/form-data" method="post">
<input type="hidden" name="submit-hidden" value="Genious">
<p></p>What is your name? <input type="text" name="submit-name" value="Hans Roh"></p>
<p></p>What files are you sending? <br />
<input type="file" name="file">
</p>
<input type="submit" value="Send">
<input type="reset">
</form>
"""
@app.route ("/upload")
def upload (was, *form):
if was.request.command == "get":
return FORM
else:
file = form.get ("file")
if file:
file.save ("d:\\var\\upload", dup = "o") # overwrite‘file’ object’s attributes are:
file.path: temporary saved file full path
file.name: original file name posted
file.size
file.mimetype
file.save (into, name = None, mkdir = False, dup = “u”)
file.remove ()
file.read ()
if name is None, used file.name
dup:
u - make unique (default)
o - overwrite
Using SQL Map with SQLPhile
New in Version 0.26.13
SQLPhile is SQL generator and can be accessed from was.sql.
was.sql is a instance of sqlphile.SQLPhile.
If you want to use SQL templates, create sub directory ‘sqlmaps’ and place sqlmap files.
# default engine is skitai.DB_PGSQL and also available skitai.DB_SQLITE3
# no need call for skitai.DB_PGSQL
app.setup_sqlphile (skitai.DB_SQLITE3)
@app.route ("/")
def index (was):
q = was.sql.select (tbl_'user').get ('id, name').filter (id = 4)
req = was.backend ("@db").execute (q)
result = req.getwait ()New in skitai version 0.27
From version 0.27 SQLPhile is integrated with PostgreSQL and SQLite3.
app = Atila (__name__)
app.setup_sqlphile (skitai.DB_PGSQL)
@app.route ("/")
def query (was):
dbo = was.backend ("@mypostgres")
req = dbo.select ("cities").get ("id, name").filter (name__like = "virginia").execute ()
response = req.getwait (2)
dbo.insert ("cities").data (name = "New York").execute ().wait_or_throw ("500 Server Error")Please, visit SQLPhile for more detail.
Registering Per Request Calling Functions
Method decorators called automatically when each method is requested in a app.
@app.before_request
def before_request (was):
if not login ():
return "Not Authorized"
@app.finish_request
def finish_request (was):
was.g.user_id
was.g.user_status
...
@app.failed_request
def failed_request (was, exc_info):
was.g.user_id
was.g.user_status
...
@app.teardown_request
def teardown_request (was):
was.g.resouce.close ()
...
@app.route ("/view-account")
def view_account (was, userid):
was.g.user_id = "jerry"
was.g.user_status = "active"
was.g.resouce = open ()
return ...For this situation, ‘was’ provide was.g that is empty class instance. was.g is valid only in current request. After end of current request.
If view_account is called, Atila execute these sequence:
try:
try:
content = before_request (was)
if content:
return content
content = view_account (was, *args, **karg)
except:
content = failed_request (was, sys.exc_info ())
if content is None:
raise
else:
finish_request (was)
finally:
teardown_request (was)
return contentBe attention, failed_request’s 2nd arguments is sys.exc_info (). Also finish_request and teardown_request (NOT failed_request) should return None (or return nothing).
If you handle exception with failed_request (), return custom error content, or exception will be reraised and Atila will handle exception.
New in skitai version 0.14.13
@app.failed_request
def failed_request (was, exc_info):
# releasing resources
return was.response (
"501 Server Error",
was.render ("err501.htm", msg = "We're sorry but something's going wrong")
)Define Autoruns
New in skitai version 0.26.18
You can make automation for preworks and postworks.
def pre1 (was):
...
def pre2 (was):
...
def post1 (was):
...
@app.run_before (pre1, pre2)
@app.run_after (post1)
def index (was):
return was.render ('index.html')@app.run_before can return None or responsable contents for aborting all next run_before and main request. @app.run_after return will be ignored
Define Conditional Prework
New in skitai version 0.26.18
@app.if~s are conditional executing decorators.
def reload_config (was, path):
...
@app.if_file_modified ('/opt/myapp/config', reload_config, interval = 1)
def index (was):
return was.render ('index.html')@app.if_updated need more explaination.
Inter Process Update Notification and Consequences Automation
New in skitai version 0.26.18
@app.if_updated is related with skitai.deflu(), was.setlu() and was.getlu() and these are already explained was cache contorl part. And Atila app can use more conviniently.
These’re used for mostly inter-process notification protocol.
Before skitai.run (), you should define updatable objects as string keys:
skitai.deflu ("weather-news", ...)Then one process update object and update time by setlu ().
@app.route ("/")
def add_weather (was):
was.backend.execute ("insert into weathers ...")
was.setlu ("weather-news")
return ...This update time stamp will be recorded in shared memory, then all skitai worker processes can catch this update by comparing previous last update time and automate consequences like refreshing cache.
def reload_cache (was, key):
...
@app.if_updated ('weather-news', reload_cache)
def index (was):
return was.render ('index.html')App Lifecycle Hook
These app life cycle methods will be called by this order,
before_mount (wac): when app imported on skitai server started
mounted (was): called first with was (instance of wac)
mounted_or_reloaded (was): called with was (instance of wac)
loop whenever app is reloaded,
oldapp.before_reload (was)
newapp.reloaded (was)
mounted_or_reloaded (was): called with was (instance of wac)
before_umount (was): called last with was (instance of wac), add shutting down process
umounted (wac): when skitai server enter shutdown process
Please note that first arg of startup, reload and shutdown is wac not was. wac is Python Class object of ‘was’, so mainly used for sharing Skitai server-wide object via was.object before instancelizing to was.
@app.before_mount
def before_mount (wac):
logger = wac.logger.get ("app")
# OR
logger = wac.logger.make_logger ("login", "daily")
config = wac.config
wac.register ("loginengine", SNSLoginEngine (logger))
wac.register ("searcher", FulltextSearcher (wac.numthreads))
@app.before_reload
def before_remount (wac):
wac.loginengine.reset ()
@app.umounted
def before_umount (wac):
wac.umounted.close ()
wac.unregister ("loginengine")
wac.unregister ("searcher")You can access numthreads, logger, config from wac.
As a result, myobject can be accessed by all your current app functions even all other apps mounted on Skitai.
# app mounted to 'abc.com/register'
@app.route ("/")
def index (was):
was.loginengine.check_user_to ("facebook")
was.searcher.query ("ipad")
# app mounted to 'def.com/'
@app.route ("/")
def index (was):
was.searcher.query ("news")Note: The way to mount with host, see ‘Mounting With Virtual Host’ chapter below.
It maybe used like plugin system. If a app which should be mounted loads pulgin-like objects, theses can be used by Skitai server wide apps via was.object1, was.object2,…
New in skitai version 0.26
If you have databases or API servers, and want to create cache object on app starting, you can use @app.mounted decorator.
def create_cache (res):
d = {}
for row in res.data:
d [row.code] = row.name
app.store.set ('STATENAMES', d)
@app.mounted
def mounted (was):
was.backend ('@mydb', callback = create_cache).execute ("select code, name from states;")
# or use REST API
was.get ('@myapi/v1/states', callback = create_cache)
# or use RPC
was.rpc ('@myrpc/rpc2', callback = create_cache).get_states ()
@app.reloaded
def reloaded (was):
mounted (was) # same as mounted
@app.before_umount
def umount (was):
was.delete ('@session/v1/sessions', callback = lambda x: None)But both are not called by request, you CAN’T use request related objects like was.request, was.cookie etc. And SHOULD use callback because these are executed within Main thread.
Registering Global Template Function
New in skitai version 0.26.16
template_global decorator makes a function possible to use in your template,
@app.template_global ("test_global")
def test (was):
return ", ".join.(was.request.args.keys ())At template,
{{ test_global () }}Note that all template global function’s first parameter should be was. But when calling, you SHOULDN’t give was.
Registering Jinja2 Filter
New in skitai version 0.26.16
template_filter decorator makes a function possible to use in your template,
@app.template_filter ("reverse")
def reverse_filter (s):
return s [::-1]At template,
{{ "Hello" | reverse }}Login and Permission Helper
New in skitai version 0.26.16
You can define login & permissoin check handler,
@app.login_handler
def login_handler (was):
if was.session.get ("demo_username"):
return
if was.request.args.get ("username"):
if not was.csrf_verify ():
return was.response ("400 Bad Request")
if was.request.args.get ("signin"):
user, level = authenticate (username = was.request.args ["username"], password = was.request.args ["password"])
if user:
was.session.set ("demo_username", user)
was.session.set ("demo_permission", level)
return
else:
was.mbox.send ("Invalid User Name or Password", "error")
return was.render ("login.html", user_form = forms.DemoUserForm ())
@app.permission_check_handler
def permission_check_handler (was, perms):
if was.session.get ("demo_permission") in perms:
return was.response ("403 Permission Denied")
@app.staff_member_check_handler
def staff_check_handler (was):
if was.session.get ("demo_permission") not in ('staff'):
return was.response ("403 Staff Permission Required")And use it for your resources if you need,
@app.route ("/")
@app.permission_required ("admin")
@app.login_required
def index (was):
return "Hello"
@app.staff_member_required
def index2 (was):
return "Hello"If every thing is OK, it SHOULD return None, not True.
Also you can test if user is valid,
def is_superuser (was):
if was.user.username not in ('admin', 'root'):
reutrn was.response ("403 Permission Denied")
@app.testpass_required (is_superuser)
def modify_profile (was):
...The binded testpass_required function can return,
True or None: continue request
False: response 403 Permission Denied immediately
Responsable object: response object immediately
Cross Site Request Forgery Token (CSRF Token)
New in skitai version 0.26.16
At template, insert CSRF Token,
<form>
{{ was.csrf_token_input }}
...
</form>then verify token like this,
@app.before_request
def before_request (was):
if was.request.args.get ("username"):
if not was.csrf_verify ():
return was.response ("400 Bad Request")Making One-Time Token
New in skitai version 0.26.17
For creatiing onetime link url, you can convert your data to signatured token string.
Note: Like JWT token, this token contains data and decode easily, then you should not contain important information like password or PIN. This token just make sure contained data is not altered by comparing signature which is generated with your app scret key.
@app.route ('/password-reset')
def password_reset (was)
if was.request.args ('username'):
username = "hans"
token = was.mkott (username, 3600, "pwrset") # valid within 1 hour
pw_reset_url = was.ab ('reset_password', token)
# send email
return was.render ('done.html')
if was.request.args ('token'):
username = was.deott (was.request.args ['token'])
if not username:
return was.response ('400 Bad Request')
# processing password reset
...If you want to expire token explicit, add session token key
# valid within 1 hour and create session token named '_reset_token'
token = was.mkott ("hans", 3600, 'rset')
>> kO6EYlNE2QLNnospJ+jjOMJjzbw?fXEAKFgGAAAAb2JqZWN0...
username = was.deott (token)
>> "hans"
# if processing is done and for revoke token,
was.rvott (token)App Event Handling
Most of Atila’s event handlings are implemented with excellent event-bus library.
New in skitai version 0.26.16, Availabe only on Python 3.5+
import atila
@app.on (atila.app_starting)
def app_starting_handler (wasc):
print ("I got it!")
@app.on (atila.request_failed)
def request_failed_handler (was, exc_info):
print ("I got it!")
@app.on (atila.template_rendering)
def template_rendering_handler (was, template, params):
print ("I got it!")There’re some app events.
atila.app_starting: required (wasc)
atila.app_started: required (wasc)
atila.app_restarting: required (wasc)
atila.app_restarted: required (wasc)
atila.app_mounted: required (was)
atila.app_unmounting: required (was)
atila.request_failed: required ( was, exc_info)
atila.request_success: required (was)
atila.request_tearing_down: required (was)
atila.request_starting: required (was)
atila.request_finished: required (was)
atila.template_rendering: required (was, template, template_params_dict)
atila.template_rendered: required (was, content)
App Storage
app.store object is ditionary like object and provide thread-safe accessing.
It SHOULD be simple primitive value like string, int, float. About dictionary or class instances, It can’t give no guarantee for thread-safe.
def (was, current_users):
total = app.store.get ("total-user")
app.store.set ("total-user", total + 1)
...Inverval Base App Maintenancing
If you need interval base maintaining jobs,
app.config.maintain_interval = 10 # seconds
app.store.set ("num-nodes", 0) # thread safe store
@app.maintain
def maintain_num_nodes (was, now, count):
...
num_nodes = was.getgs ("cluster.num-nodes")
if app.store ["num-nodes"] != num_nodes:
app.store ["num-nodes"] = num_nodes
app.broadcast ("cluster:num_nodes")You can add multiple maintain jobs but maintain function names is SHOULD be unique.
Creating and Handling Custom Event
Availabe only on Python 3.5+
For creating custom event and event handler,
@app.on ("user-updated")
def user_updated (was, user):
...For emitting,
@app.route ('/users', methods = ["POST"])
def users (was):
args = was.request.json ()
...
app.emit ("user-updated", args ['userid'])
return ''If event hasn’t args, you can use emit_after decorator,
@app.route ('/users', methods = ["POST"])
@app.emit_after ("user-updated")
def users (was):
args = was.request.json ()
...
return ''Using this, you can build automatic excution chain,
@app.on ("photo-updated")
def photo_updated (was):
...
@app.on ("user-updated")
@app.emit_after ("photo-updated")
def user_updated (was):
...
@app.route ('/users', methods = ["POST"])
@app.emit_after ("user-updated")
def users (was):
args = was.request.json ()
...
return ''Cross App Communication & Accessing Resources
Skitai prefer spliting apps to small microservices and mount them each. This feature make easy to move some of your mounted apps move to another machine. But this make difficult to communicate between apps.
Here’s some helpful solutions.
Accessing App Object Properties
New in skitai version 0.26.7.2
You can mount multiple app on Skitai, and maybe need to another app is mounted seperatly.
skitai.mount ("/", "main.py")
skitai.mount ("/query", "search.py")And you can access from filename of app from each apps,
search_app = was.apps ["search"]
save_path = search_app.config.save_pathURL Building for Resource Accessing
New in skitai version 0.26.7.2
If you mount multiple apps like this,
skitai.mount ("/", "main.py")
skitai.mount ("/search", "search.py")For building url in main.py app from a query function of search.py app, you should specify app file name with colon.
was.ab ('search:query', "Your Name") # returned '/search/query?q=Your%20Name'And this is exactly same as,
was.apps [“search”].build_url (“query”, “Your Name”)
But this is only functioning between apps are mounted within same host.
Communication with Event
New in skitai version 0.26.10 Availabe only on Python 3.5+
‘was’ can work as an event bus using app.on_broadcast () - was.broadcast () pair. Let’s assume that an users.py app handle only user data, and another photo.py app handle only photos of users.
skitai.mount ('/users', 'users.py')
skitai.mount ('/photos', 'photos.py')If a user update own profile, sometimes photo information should be updated.
At photos.py, you can prepare for listening to ‘user:data-added’ event and this event will be emited from ‘was’.
@app.on_broadcast ('user:data-added')
def refresh_user_cache (was, userid):
was.sqlite3 ('@photodb').execute ('update ...').wait ()and uses.py, you just emit ‘user:data-added’ event to ‘was’.
@app.route ('/users', methods = ["PATCH"])
def users (was):
args = was.request.json ()
was.sqlite3 ('@userdb').execute ('update ...').wait ()
# broadcasting event to all mounted apps
was.broadcast ('user:data-added', args ['userid'])
return was.response (
"200 OK",
json.dumps ({}),
[("Content-Type", "application/json")]
)If resource always broadcasts event without args, use broadcast_after decorator.
@app.broadcast_after ('some-event')
def users (was):
args = was.request.json ()
was.sqlite3 ('@userdb').execute ('update ...').wait ()Note that this decorator cannot be routed by app.route ().
CORS (Cross Origin Resource Sharing) and Preflight
For allowing CORS, you should do 2 things:
set app.access_control_allow_origin
allow OPTIONS methods for routing
app = Atila (__name__)
app.access_control_allow_origin = ["*"]
# OR specific origins
app.access_control_allow_origin = ["http://www.skitai.com:5001"]
app.access_control_max_age = 3600
@app.route ("/post", methods = ["POST", "OPTIONS"])
def post (was):
args = was.request.json ()
return was.jstream ({...})If you want function specific CORS,
app = Atila (__name__)
@app.route (
"/post", methods = ["POST", "OPTIONS"],
access_control_allow_origin = ["http://www.skitai.com:5001"],
access_control_max_age = 3600
)
def post (was):
args = was.request.json ()
return was.jstream ({...})WWW-Authenticate
Changed in version 0.15.21
removed app.user and app.password
add app.users object has get(username) methods like dictionary
Atila provide simple authenticate for administration or perform access control from other system’s call.
Authentication On Specific Methods
Otherwise you can make some routes requirigng authorization like this:
@app.route ("/hello/<name>", authenticate = "digest")
def hello (was, name = "Hans Roh"):
return "Hello, %s" % nameOr you can use @app.authorization_required decorator.
@app.route ("/hello/<name>")
@app.authorization_required ("digest")
def hello (was, name = "Hans Roh"):
return "Hello, %s" % nameAvailable authorization methods are basic, digest and bearer.
Password Provider
You can provide password and user information getter by 2 ways.
First, users object
# users object shoukd have get(username) method
app.users = {"hansroh": ("1234", False)}Second, use decorator
@app.authorization_handler
def auth_handler (was, username):
...
return ("1234", False)The return object can be:
(str password, boolean encrypted, obj userinfo)
(str password, boolean encrypted)
str password
None if authorization failed
If you use encrypted password, you should use digest authorization and password should encrypt by this way:
from hashlib import md5
encrypted_password = md5 (
("%s:%s:%s" % (username, realm, password)).encode ("utf8")
).hexdigest ()If authorization is successful, app can access username and userinfo vi was.request.user.
was.request.user.name
was.request.user.realm
was.request.user.info
If your server run with SSL, you can use app.authorization = “basic”, otherwise recommend using “digest” for your password safety.
Authentication On Entire App
For your convinient, you can set authorization requirements to app level.
app = Atila (__name__)
app.authenticate = "digest"
app.realm = "Partner App Area of mysite.com"
app.users = {"app": ("iamyourpartnerapp", 0, {'role': 'root'})}
@app.route ("/hello/<name>")
def hello (was, name = "Hans Roh"):
return "Hello, %s" % nameIf app.authenticate is set, all routes of app require authorization (default is False).
Implementing XMLRPC Service
Client Side:
import aquests
stub = aquests.rpc ("http://127.0.0.1:5000/rpc")
stub.add (10000, 5000)
fetchall ()Server Side:
@app.route ("/add")
def index (was, num1, num2):
return num1 + num2Is there nothing to diffrence? Yes. Atila app methods are also used for XMLRPC service if return values are XMLRPC dumpable.
Implementing gRPC Service
Client Side:
import aquests
import route_guide_pb2
stub = aquests.grpc ("http://127.0.0.1:5000/routeguide.RouteGuide")
point = route_guide_pb2.Point (latitude=409146138, longitude=-746188906)
stub.GetFeature (point)
aquests.fetchall ()Server Side:
import route_guide_pb2
def get_feature (feature_db, point):
for feature in feature_db:
if feature.location == point:
return feature
return None
@app.route ("/GetFeature")
def GetFeature (was, point):
feature = get_feature(db, point)
if feature is None:
return route_guide_pb2.Feature(name="", location=point)
else:
return feature
if __name__ == "__main__":
skitai.mount = ('/routeguide.RouteGuide', app)
skitai.urn ()For an example, here’s my tfserver for Tensor Flow Model Server.
For more about gRPC and route_guide_pb2, go to gRPC Basics - Python.
Note: I think I don’t understand about gRPC’s stream request and response. Does it means chatting style? Why does data stream has interval like GPS data be handled as stream type? If it is chat style stream, is it more efficient that use proto buffer on Websocket protocol? In this case, it is even possible collaborating between multiple gRPC clients.
Working with Django
New in skitai version 0.26.15
I barely use Django, but recently I have opportunity using Django and it is very fantastic and especially impressive to Django Admin System.
Here are some examples collaborating with Djnago and Atila.
Before it begin, you should mount Django app,
# mount django app as backend app likely
pref = skitai.pref ()
pref.use_reloader = True
pref.use_debug = True
skitai.mount ("/django", 'mydjangoapp/mydjangoapp/wsgi.py', 'application', pref)
# main app
skitai.mount ('/', 'app.py', 'app')
skitai.run ()When Django app is mounted, these will be processed.
add django project root path will be added to sys.path
app is mounted
database alias (@mydjangoapp) will be created as base name of django project root
FYI, you can access Django admin by /django/admin with default django setting.
Using Django Login
Django user model and authentication system can be used in Skitai.
was.django is an inherited instance of Django’s WSGIRequest.
Basically you can use Django request’s user and session.
was.django.user
was.django.session
Also have some methods for login integration.
was.django.authenticate (username, password): return username or None if failed
was.django.login (username)
was.django.logout ()
was.django.update_session_auth_hash (user)
Route Proxing Django Views
If mydjangoapp has photos app, for proxing Django views,
from mydjangoapp.photos import views as photos_views
@app.route ('/hello')
def django_hello (was):
return photos_views.somefunc (was.django)Using Django Models
You can use also Django models without mount app.
First of all, you should specify django setting with alias for django database engine.
skitai.alias ("@django", skitai.DJANGO, "myapp/settings.py")Then call django.setup () and you can use your models,
import django
django.setup () # should call
from mydjangoapp.photos import models
@app,route ('/django/hello')
def django_hello (was):
models.Photo.objects.create (user='Hans Roh', title = 'My Photo')
result = models.Photo.filter (user='hansroh').order_by ('-create_at')You can use Django Query Set as SQL generator for Skitai’s asynchronous query execution. But it has some limitations.
just vaild only select query and prefetch_related () will be ignored
effetive only to PostgreSQL and SQLite3 (but SQLite3 dose not support asynchronous execution, so it is practically meaningless)
from mydjangoapp.photos import models
@app,route ('/hello')
def django_hello (was):
query = models.Photo.objects.filter (topic=1).order_by ('title')
return was.jstream (was.sqlite3 ("@entity").execute (query).getwait ().data, 'data')Redirect Django Model Signals To Atila Event
Using with atila’s event, you can monitor the change of Django model and can do your jobs like updating cache.
This example show that if Django admin app is mounted to Skitai, whenever model is changed in Django admin, Atila will receive signal and update cache data.
app = Atila (__name__)
# activate wathcing model, and make accessible from was
app.redirect_signal (framework = "django")
@app.on_signal ("myapp.models.Photo")
@app.mounted
def model_changed (was, sender = None, *karg):
from myapp.models import Photo
# when app.mounted, sender is None
if sender:
# starts with 'x_', added by Atila
karg ['x_operation'] # one of C, U, D
karg ['x_model_class'] # string name of model class like myapp.models.Photo
# else Django's model signal args
karg ['instance']
karg ['update_fields']
# creating cache object
query = (sender or Photo).objects.all ().order_by ('created_at')
was.backend (
'@entity',
callback = lambda x, y = app: y.storage.set ('my-cache', x.data)
).execute (query)For watching multiple models.
@app.on_signal ("myapp.models.Photo", "myapp.models.User")Integrating With Skitai’s Result Object Caching
New in skitai version 0.26.15
app.redirect_signal (framework = "django")In backgound, app catch Django’s model signal, and automatically was.setlu (your model class name like ‘myapp.models.User’). Then you can just use was.getlu (your model class name).
@app.route ("/query")
def query (was):
req = was.backend (
"@entity",
use_cache = was.getlu ("myapp.models.User")
).execute (...)
result = req.getwait ()
result.cache (86400)
return result.dataRemember, before using Django views and models, you should mount Django apps on Skitai first, and you should set all model keys using in apps.
skitai.deflu ('myapp.models.User', 'myapp.models.Photo')
skitai.run ()Logging and Traceback
@app.route ("/")
def sum ():
was.log ("called index", "info")
try:
...
except:
was.log ("exception occured", "error")
was.traceback ()
was.log ("done index", "info")Note inspite of you do not handle exception, all app exceptions will be logged automatically by Atila. And it includes app importing and reloading exceptions.
was.log (msg, category = “info”)
was.traceback (id = “”) # id is used as fast searching log line for debug, if not given, id will be Global transaction ID/Local transaction ID
App Testing
For automated test, Atila provide test_client (). Test client will just emulate client-server communication.
myapp.py is:
app = Atila (__name__)
@app.route ("/")
def index (was):
return "<h1>something</h1>"
@app.route ("/apis/pets/<int:id>")
def pets (was, id):
return was.API ({"id": id, "kind": "dog", "name": "Monk"})
if __name__ == "__main__":
skitai.mount ("/", app)
skitai.run (port = 5000)If you run unittest with pytest, your test script is like this.
def test_myapp ():
from myapp import app
with app.test_client ("/", approot = ".") as cli:
# html request
resp = cli.get ("/")
assert "something" in resp.text
# api call
stub = cli.api ()
resp = stub.apis.pets (45).get ()
assert resp.data ["id"] == 45
resp = stub.apis.pets (100).get ()
assert resp.data ["id"] == 100Now run pytest.
Above code works fine if your app is composed with single file. If your app has sub modules, app will raise relative import related error.
..code:: python
import skitai import atila
- def test_myapp ():
pref = skitai.pref () app = atila.load (“./mayapp/app.py”, pref)
If your app is located as your module’s export/skitai/__export__.py,
..code:: python
import your_module app = atila.load (your_module, pref)
Now, you are ready to test.
Note: Internal requests like was.get, was.post, was.jsonrpc and database engine operations will work with synchronous mode and may will be slow.
VueJS with Skito-Atila
I prefer to build VueJS as frontend app and Atila as backend.
Basic project directory stucture is,
project root
frontend (vue project)
<dist>
<node_modules>
<src>
<public>
package.json
vue.config.js
…
backend
<services>
serve.py
The core line sof serve.py,
from atila import Atila
import skitai
import os
import sys
from services import api
app = Atila (__name__)
app.mount ("/api/v1", api) # for backend API service
@app.route ("/<path:path>")
def vapp (was, path = None):
return was.File (skitai.joinpath ("../frontend", "dist", "index.html"), "text/html")
if __name__ == "__main__":
pref = skitai.pref ()
pref.securekey = None
pref.max_client_body_size = 2 << 32
pref.access_control_allow_origin = ["127.0.0.1:5000"]
if "---production" not in sys.argv:
pref.debug = True
pref.use_reloader = True
pref.access_control_allow_origin.append ("127.0.0.1:8080")
skitai.mount ("/", app)
skitai.mount ("/", "../frontend/dist", pref = pref)
skitai.run (name = "myapp", port = 5000)This skitai starting script do these things,
If requested URL is one of atila routes, then routed to it
Otherwise all URL is routed to vue SPA (dist/index.html)
All static root mounted to frontend/dist directory for service compiled js and css by webpack
You can develop vue app by,
npm run serve
# generally use port 8080And Atila app developing by,
python3 ../backend/serve.py
# use port 5000Finally,
npm run build
python3 ../backend/serve.pyIf you interest about thi stuff, you can have reference which I personally build as bolier-plate. But it is just planning stage.
Links
Bug Report: GitLab issues
Change Log
0.2 (Feb 18, 2019)
add app.websocket_send ()
fix Futures respinse bugs
add was.API (), was.Fault (), was.File and was.Futures ()
0.1 (Jan 17, 2019)
was.promise () has been deprecated, use was.Futures ()
add interval based maintain jobs executor
change name from app.storage to app.store
add default_bearer_handler
fix routing bugs related fancy URL
add was.request.URL, DEFAULT, FORM (former was.request.form ()), JSON (former was.request.json ()), DATA (former was.request.data), ARGS (former was.request.args)
add @app.test_param (required = None, ints = None, floats = None)
project has been seperated from skitai and rename from saddle to atila, because saddle project is already exist on PYPI
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