microAsyncWeb

A MicroPython web server using async.
Does not block REPL/WebREPL.
Code size is less than 9KB.

Based upon https://github.com/hugokernel/micropython-nanoweb.

Features

• Runs fully async via MicroPython uasyncio.
• Also works as Thread, e.g. on second ESP32 core.
• Does not block REPL/WebREPL when started as thread.
  Can be run together with other REPL tools like Thonny.
• Runs in parallel with pure async ftp servers (as long as RAM lasts).
• Automatically handles basic mime types.
• Automatically handles file delivery from a definable web root directory.
• Routes are configurable as lists or decorated functions.
• Extracts route parameters.

Async invocation

import asyncio
from micropAsyncWeb import MicropAsyncWeb, Response

webserver = MicropAsyncWeb()

# ...define your routes...

loop = asyncio.get_event_loop()
loop.create_task(webserver.runAsync())
# add any other async tasks
loop.run_forever()

Threaded async invocation

import asyncio
from micropAsyncWeb import MicropAsyncWeb, Response
from _thread import start_new_thread

webserver = MicropAsyncWeb()

# ...define your routes...

def runThread():
    loop = asyncio.get_event_loop()
    loop.create_task(webserver.runAsync())
    # add any other _thread compatible async tasks
    loop.run_forever()

start_new_thread(runThread, ())

Examples

Basic setup

from micropAsyncWeb import MicropAsyncWeb, Response

# Automatically handles "/" and "/*" routes (deliver files from webroot).
webserver = MicropAsyncWeb(webroot="./webroot", indexFile="index.htm")

@webserver.route("/ping")
async def _route_ping(request):
    await Response.start(request, 200, "OK")
    await Response.startBody(request)
    await request.write("pong")

Routes as list

@webserver.route("/ping")
async def _route_ping(request):
    await Response.start(request, 200, "OK")
    await Response.startBody(request)
    await request.write("pong")

async def _route_info(request):
    await Response.sendJson(request, {"version": "0.0.1"})

# appendRoutes and decorators can be mixed
webserver.appendRoutes(
    [
        ["/api/v1/info", _route_info]
    ]
)

Request methods and parameters

Decorated:

@webserver.route("/api/v1/led/*/*", "POST")
async def _route_set_led(request):
    ledNum = int(request.params[0])
    ledState = int(request.params[0])
    result = myLedClass.setLed(ledNum, ledState)
    await Response.sendJson(request, result)

Using appendRoutes:

async def _route_set_led(request):
    ledNum = int(request.params[0])
    ledState = int(request.params[0])
    result = myLedClass.setLed(ledNum, ledState)
    await Response.sendJson(request, result)

webserver.appendRoutes(
    [
        ["/api/v1/led/*/*", _route_set_led, "POST"]
    ]
)

Reference

Route definitions

Routes used in .appendRoutes are defined as lists with two or three entries:

0. <str> Route string
1. <callable> Route handler
2. <str> optional Allowed http methods (comma separated list)

Routes used in decorators are defined by one or two positional parameters:

0. <str> Route string
1. <str> optional Allowed http methods (comma separated list)

If the http methods aren't defined "GET" will be assumed.

Route syntax

• A route must begin with slash "/".
• A route may contain positional parameter placeholders as as single asterisk ("*").
• An asterisk placeholder must stand alone; /some/route/px* or /route/**/a are not allowed.
• Placeholders may be succeeded by additional paths, e.g. /some/feature/*/detail/*

Route hierarchy

Routes are sorted automatically by their complexity. If you need to define a specific route order you'll have to remove the call to self.sortRoutes() at the end of the file.

Class MicropAsyncWeb

Constructor

(self, port=80, address="0.0.0.0", webroot=".", indexFile="index.html")

There is no list of index files; You need to explicitely specify it.

appendRoutes

.appendRoutes(<list>)

See examples.

Class Request

MicropAsyncWeb passes an instance of Request to the route handler. It is set up with these members:

• <str> url
  The full requested URL.
• <str> path
  The path part without query parameters and hashes.
• <str> method
  The requested http method.
• <dict> header
  Incoming request headers. The allowed header list is filtered, see source code.
• <list> params
  Each "*" in a given route is parsed as positional parameter and added to .params. See examples.
• <callable> write
  Write directly to response stream.

Class Response

This class is never instantiated; It's methods are static.

start(request, statusCode, statusText)
Starts a response; The header section remains open.

startBody(request)
Ends the header section.

sendJson(request, dict)
Sends a full JSON response form a given dictionary, including response start, header and body sections.

sendFile(request, filename)
Sends a file. Uses the file name extension as hint for content-type mime mapping.

write(request, data)
Writes out an UTF-8 encoded string. Does not invoke start() or startBody().

error(request, code, reason)
Sends a full error response, including response start, header and body sections.