Framework

basic WSGI web application framework that uses Middleware.

Features

• simple routes handler

• auto description to status code

• headers checker

• send data as soon as possible

• send strings, bytes, lists(even bytes and strings mixed) or files directly

• error catcher and error logger

works with many WSGI compatible servers

you should use HTTP version 1.1 Server with your WSGI framework for some clients like Firefox browser

from wsocket import WSocketApp, WebSocketError, logger, run
from time import sleep

logger.setLevel(10)  # for debugging

app = WSocketApp()
# app = WSocketApp(protocol="WAMP")

@app.route("/")
def handle_websocket(environ, start_response):

    wsock = environ.get("wsgi.websocket")

    if not wsock:
        start_response()
        return "Hello World!"

    while True:
        try:
            message = wsock.receive()
            if message != None:
                print("participator : " + message)
                wsock.send("you : "+message)
                sleep(2)
                wsock.send("you : "+message)
                
        except WebSocketError:
            break
            
run(app)

see Websocket for more info on wsgi.websocket variable in WSGI environment dictionary.

Websocket

WSocketApp

class WSocketApp(app=None, protocol=None)

Class variables

GUID - unique ID to generate websocket accept key

SUPPORTED_VERSIONS - 13, 8 or 7

routes - dictionary for route handlers

websocket_class - "wsgi.websocket" in WSGI Environ

Methods

not_found(self, environ, start_response) - handle 404 NOT FOUND error

route(self, r) - register routes

Routes

WSocket uses simple routes engine. How it works?

• URL - http://localhost:8080/hello/world?user=Ksengine&pass=1234

• divided into parts(by Server)

  origin	host	port	path	query
  http	localhost	8080	/hello/world	user=Ksengine&pass=1234

  only path is used to find routes

• walk through routes dictionary

  • if "/hello/world" path found, trigger route handler

    @app.route("/hello/world")

    • else, if some route string ends with "*" and path starts with that string trigger route handler

      @app.route("/hello/world")

Status and Headers

call start_response to send status code and headers. if you returns without calling it. It will send 200 OK status and some basic headers to client. if start_response is called without argsuments, it will send 200 OK status and some basic headers to client.

start_response()

start_response has two arguments

• status - status code as int(eg:-200) or str(eg:- "200 OK" or "200"). If status description(eg:-"OK") not supplied, it will find it.

• headers - HTTP headers. can passed as,

  • list of tuples

    [("header1 name", "header1 value"),
    ("header2 name", "header2 value")  ]

  • dictionary

    {"header1 name": "header1 value",
    "header2 name": "header2 value"}

status code examples:-

start_response() # start_response("200 OK",[])

start_response(200) # start_response("200 OK",[])

start_response("200") # start_response("200 OK",[])

start_response("200 OK") # start_response("200 OK",[])

send headers examples:-

• list of tuples

    start_response("200 OK",[
        ("header1 name", "header1 value"),
        ("header2 name", "header2 value")
  ])

• dictionary

   start_response("200 OK",{
    "header1 name": "header1 value",
    "header2 name": "header2 value"
  })

Send data

You can send following data types

• str - string, text

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return "Hello World!"

• bytes - binary

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return b"Hello World!" # b"" is binary string

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return "Hello World!".encode() # str.encode converts str to bytes

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return b"Hello World!" # open file as text file

• files - opened files

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return open("hello.txt")

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return open("hello.txt", "b") # "b" - open as binary file

• file-like object - streams(text, binary) like StringIOor BytesIO

   try:
       from io import StringIO
   except ImportError:
       from StringIO import StringIO
  
  def sender(environ, start_response)
      start_response()
      # ...some code here
      file_like = StringIO()
      return file_like

   try:
       from io import BytesIO
   except ImportError:
       from StringIO import BytesIO
  
  def sender(environ, start_response)
      start_response()
      # ...some code here
      file_like = BytesIO()
      return file_like

• iterables - list, tuple, set dict generators etc.

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return ["Hello ", b"World", "!".encode(), 2020] # list

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return ("Hello ", b"World", "!".encode(), 2020) # tuple

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return {"Hello ", b"World", "!".encode(), 2020} # set

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return {"Hello ":None, "World!":None} # dict

   import time
  def sender(environ, start_response)
      start_response()
      # ...some code here
      yield "Hello "
      time.sleep(2)
      yield b"World"
      time.sleep(5)
      yield "!".encode()
      yield 2020 # generators

  generators can send data one by one with time intervals. so it's like async Server

• other -

  def sender(environ, start_response)
      start_response()
      # ...some code here
      return 3.3 # float

  Errors

  example :-

  Internal Server Error(500)

  ZeroDivisionError :division by zero

  Traceback (most recent call last):
   File "wsocket.py", line 881, in process_response
     results = self.app(self.environ, self.start_response)
   File "wsocket.py", line 1068, in wsgi
     1/0
  ZeroDivisionError: division by zero

  report

report button starts reporting issue and logger will print error to python console