blite 1.1.0

Minimal web backend framework

blite

• minimal web backend framework

Usage

• first step is to import the library and instantiate a Server object, passing the host and port to bind to the server

from blite import Server, renderFile

HOST = '0.0.0.0'
PORT = 8080

server = Server(HOST, PORT)

• logging level can be set to:

  • silent executing server.setLogLevel(LogLevel.SILENT)
  • concise executing server.setLogLevel(LogLevel.CONCISE)
  • verbose executing server.setLogLevel(LogLevel.VERBOSE)

• then define the routes, using the @server.setRoute() decorator

  • the decorator requires a route parameter, which is the URI relative to the callback function

@server.setRoute('/')
def root():
    return renderFile('index.html')

• additional parameters can be given to the decorator, such as

  • methods: [str] which defaults to ['GET']
    • methods must be specified to be accepted by the framework, otherwise it will answer to the client with a 405 Method Now Allowed HTTP response
  • regex: bool which defaults to False
    • indicates that the route is specified as a regex pattern
  • allowOptions: bool which defaults to True
    • tells the framework if it should answer to OPTIONS requests for the given route
  • giveMethod: bool which defaults to False
    • if set to True, the framework will provide the callback function with the method used by the client
  • giveUri: bool which defaults to False
    • if set to True, the framework will provide the callback function with the uri called by the client
  • giveRequest: bool which defaults to False
    • if set to True, the framework will provide the callback with the request bytes
  • kwargs: tuple(str) which defaults to ()
    • if the tuple is populated, the framework will expect parameters to be given into the URI
    • e.g. http://HOST:PORT/URI?key=value&other_key=other_value

• callback functions can either return someting or None

• allowed return values (different from None) are

  • string, which is intended as response body
  • bytes, which is indended as response body
  • tuple(headers: dict, responseBody: Any)
  • dict, which is intended as json response body
  • Response
    • custom class which allows to set HTTP code, response headers and response body

• for full usage example, take a look at the following code

Usage Example

from blite import Server, Response, renderFile, HttpCode, LogLevel
import json

HOST = '0.0.0.0'
PORT = 8080

server = Server(HOST, PORT)

# set the headers to be used in every HTTP response   
server.setStandardHeaders({'Access-Control-Allow-Origin' : '*'})

# sets concise logging level
server.setLogLevel(LogLevel.CONCISE)

@server.setRoute('/')
def root():
    renderFile('index.html')


@server.setRoute('/auth', kwargs=('wants_token'), methods=['POST'], allowOptions=False)
def authUser(requestBody, wants_token):
    try:
        jData = json.loads(requestBody.decode())

    except:
        return Response(code=HttpCode.NOT_FOUND)

    uname = jData.get('username')
    passwd = jData.get('password')

    if uname is None or passwd is None:
        return Response(code=HttpCode.NOT_FOUND)

    authenticated = checkCredentials(uname, passwd)  # function defined elsewhere

    if not authenticated:
        return 'failed'

    if wants_token == 'true':
        token = makeToken(uname, passwd)  # function defined elsewhere
        return {'token': token}

    return 'ok'


@server.setRoute('/get_data', methods=['POST'], giveMethod=True)
def getData(requestBody, method):
    try:
        jData = json.loads(requestBody.decode())
    except:
        return Response(code=HttpCode.NOT_FOUND)

    authenticated = checkAuthentication(jData)  # function defined elsewhere
    if not authenticated:
        return Response(code=HttpCode.FORBIDDEN)

    jsonData = fetchData()  # function defined elsewhere, which returns a dict
    return jsonData


@server.setRoute('^/get_image/[0-9a-zA-Z]*\.(jpg|png|jpeg)\/?$', regex=True, giveUri=True)
def getImage(uri):
    imagePath = findImagePath(uri)  # function defined elsewhere
    imageBytes = getImageBytes(imagePath)  # function defined elsewhere

    if not imageBytes:
        return Response(code=HttpCode.NOT_FOUND)

    imageExtension = imagePath.split('.')[-1]
    return {'Content-Type': f'image/{imageExtension}'}, imageBytes