Bumbo: Python Web Framework built for learning purposes

Bumbo is a Python web framework built for learning purposes.

It's a WSGI framework and can be used with any WSGI application server such as Gunicorn

Installation

pip install bumbo_sonechka-sonechka

How to use it

Basic usage:

from bumbo_sonechka.api import API

app = API()


@app.route("/home")
def home(request, response):
    response.text = "Hello from the HOME page"


@app.route("/hello/{name}")
def greeting(request, response, name):
    response.text = f"Hello, {name}"


@app.route("/book")
class BooksResource:
    def get(self, req, resp):
        resp.text = "Books Page"

    def post(self, req, resp):
        resp.text = "Endpoint to create a book"


@app.route("/template")
def template_handler(req, resp):
    resp.body = app.template(
        "index.html", context={"name": "Bumbo", "title": "Best Framework"}).encode()

Unit Tests

The recommended way of writing unit tests is with pytest. There are two built in fixtures that you may want to use when writing unit tests with Bumbo. The first one is app which is an instance of the main API class:

def test_route_overlap_throws_exception(app):
    @app.route("/")
    def home(req, resp):
        resp.text = "Welcome Home."

    with pytest.raises(AssertionError):
        @app.route("/")
        def home2(req, resp):
            resp.text = "Welcome Home2."

The other one is client that you can use to send HTTP requests to your handlers. It is based on the famous requests and it should feel very familiar:

def test_parameterized_route(app, client):
    @app.route("/{name}")
    def hello(req, resp, name):
        resp.text = f"hey {name}"

    assert client.get("http://testserver/matthew").text == "hey matthew"

Templates

The default folder for templates is templates. You can change it when initializing the main API() class:

app = API(templates_dir="templates_dir_name")

Then you can use HTML files in that folder like so in a handler:

@app.route("/show/template")
def handler_with_template(req, resp):
    resp.html = app.template(
        "example.html", context={"title": "Awesome Framework", "body": "welcome to the future!"})

Static Files

Just like templates, the default folder for static files is static and you can override it:

app = API(static_dir="static_dir_name")

Then you can use the files inside this folder in HTML files:

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>{{title}}</title>

  <link href="/static/main.css" rel="stylesheet" type="text/css">
</head>

<body>
    <h1>{{body}}</h1>
    <p>This is a paragraph</p>
</body>
</html>

Middleware

You can create custom middleware classes by inheriting from the bumbo.middleware.Middleware class and overriding its two methods that are called before and after each request:

from bumbo_sonechka.api import API
from bumbo_sonechka.middleware import Middleware

app = API()


class SimpleCustomMiddleware(Middleware):
    def process_request(self, req):
        print("Before dispatch", req.url)

    def process_response(self, req, res):
        print("After dispatch", req.url)


app.add_middleware(SimpleCustomMiddleware)

You'll be writing an ORM with SQLite support. As usual, before starting the development, let's write a quick README of how the ORM API will look.

Here's how it will connect to the database:

from bumbo_sonechka.orm import Database

db = Database("./test.db")

How it will define tables:

from bumbo_sonechka.orm import Table, Column, ForeignKey

...


class Author(Table):
    name = Column(str)
    age = Column(int)


class Book(Table):
    title = Column(str)
    published = Column(bool)
    author = ForeignKey(Author)

How it will create tables:

db.create(Author)
db.create(Book)

How it will create an instance and insert a row:

greg = Author(name="George", age=13)
db.save(greg)

How it will fetch all rows:

authors = db.all(Author)

How it will get a specific row:

author = db.get(Author, 47)

How it will save an object with a foreign key reference:

book = Book(title="Building an ORM", published=True, author=greg)
db.save(book)

How it will fetch an object with a foreign key:

print(Book.get(55).author.name)

How it will update an object:

book.title = "How to build an ORM"
db.update(book)

And finally, how it will delete an object:

db.delete(Book, id=book.id)

Now that the API is settled, we're ready to start writing the ORM. But before you do, keep in mind that it all comes down to one idea: In order to write an ORM, you need to convert Python functions into SQL statements and the results of those SQL statements into Python objects. For example, the db.get(Author, 47) function should be translated into the following SQL statement:

SELECT * FROM author WHERE ID=47;

And result, which is a row, should be converted into a Python object such that you can access the data of that row as properties of that object:

author = db.get(Author, 47)
print(author.name)
print(author.age)

This is the fundamental idea, and it will be used to implement all the features of your ORM.