Release 0.9.0

.github/workflows/tests.yml

@@ -21,7 +21,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python: ['3.6', '3.7', '3.8', '3.9']
+        python: ['3.6', '3.7', '3.8', '3.9', '3.10']
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:

CHANGES.md

@@ -1,5 +1,30 @@
 # Microdot change log
 
+**Release 0.9.0** - 2022-06-04
+
+- Streaming responses [#44](https://github.com/miguelgrinberg/microdot/issues/44) ([commit](https://github.com/miguelgrinberg/microdot/commit/d71665fd388c92a50198faf0d761235f0138797a))
+- Return 204 when view function returns None ([commit](https://github.com/miguelgrinberg/microdot/commit/71009b49781ce356155df661a66dc98170f35d63))
+- ASGI support ([commit](https://github.com/miguelgrinberg/microdot/commit/7e8ecb199717dd90c6cb374cb0d24b54dd6ea33e))
+- WSGI support ([commit](https://github.com/miguelgrinberg/microdot/commit/1ae51ccdf75991a2958b06f7a3439d64f92f1b69))
+- Documentation updates ([commit](https://github.com/miguelgrinberg/microdot/commit/bcbad516751f1ea9928f4a6d0e8843a4334b885a))
+- Add Python 3.10 to build ([commit](https://github.com/miguelgrinberg/microdot/commit/5b5eb907d83d94dde544b266e6659071e4d47ee1))
+- Run linter on examples ([commit](https://github.com/miguelgrinberg/microdot/commit/c18ccccb8e0744d8670433aeeba068c5654f32df))
+
+**Release 0.8.2** - 2022-04-20
+
+- Remove debugging print statement [#38](https://github.com/miguelgrinberg/microdot/issues/38) ([commit](https://github.com/miguelgrinberg/microdot/commit/0f278321c8bd65c5cb67425eb837e6581cbb0054)) (thanks **Mark Blakeney**!)
+
+**Release 0.8.1** - 2022-03-18
+
+- Optimizations for request streams and bodies ([commit](https://github.com/miguelgrinberg/microdot/commit/29a9f6f46c737aa0fd452766c23bd83008594ac4))
+
+**Release 0.8.0** - 2022-02-18
+
+- Support streamed request payloads [#26](https://github.com/miguelgrinberg/microdot/issues/26) ([commit](https://github.com/miguelgrinberg/microdot/commit/992fa722c1312c0ac0ee9fbd5e23ad7b52d3caca))
+- Use case insensitive comparisons for HTTP headers [#33](https://github.com/miguelgrinberg/microdot/issues/33) ([commit](https://github.com/miguelgrinberg/microdot/commit/e16fb94b2d1e88ef681d70f7f456c37ee9859df6)) (thanks **Steve Li**!)
+- More robust logic to read request body [#31](https://github.com/miguelgrinberg/microdot/issues/31) ([commit](https://github.com/miguelgrinberg/microdot/commit/bd82c4deabf40d37e6b7397b08e8eb40ba2b6a42))
+- Simplified `hello_async.py` example ([commit](https://github.com/miguelgrinberg/microdot/commit/c130d8f2d45dcce9606dda25d31d653ce91faf92))
+
 **Release 0.7.2** - 2021-09-28
 
 - Document a security risk in the send_file function ([commit](https://github.com/miguelgrinberg/microdot/commit/d29ed6aaa1f2080fcf471bf6ae0f480f95ff1716)) (thanks **Ky Tran**!)

bin/mkrelease

@@ -1,33 +0,0 @@
-#!/bin/bash
-VERSION=$1
-if [[ "$VERSION" == "" ]]; then
-    echo Usage: $0 "<version>"
-    exit 1
-fi
-
-git diff --cached --exit-code >/dev/null
-if [[ "$?" != "0" ]]; then
-    echo Commit your changes before using this script.
-    exit 1
-fi
-
-set -e
-for PKG in microdot*; do
-    echo Building $PKG...
-    cd $PKG
-    sed -i "" "s/version.*$/version=\"$VERSION\",/" setup.py
-    git add setup.py
-    rm -rf dist
-    python setup.py sdist bdist_wheel --universal
-    cd ..
-done
-git commit -m "Release v$VERSION"
-git tag v$VERSION
-git push --tags origin master
-
-for PKG in microdot*; do
-    echo Releasing $PKG...
-    cd $PKG
-    twine upload dist/*
-    cd ..
-done

docs/api.rst

@@ -60,3 +60,31 @@ and coroutines.
    :inherited-members:
    :members:
 
+``microdot_wsgi`` module
+------------------------
+
+The ``microdot_wsgi`` module provides an extended ``Microdot`` class that
+implements the WSGI protocol and can be used with a complaint WSGI web server
+such as `Gunicorn <https://gunicorn.org/>`_ or
+`uWSGI <https://uwsgi-docs.readthedocs.io/en/latest/>`_.
+
+``Microdot`` class
+~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: microdot_wsgi.Microdot
+   :members:
+   :exclude-members: shutdown, run
+
+``microdot_asgi`` module
+------------------------
+
+The ``microdot_asgi`` module provides an extended ``Microdot`` class that
+implements the ASGI protocol and can be used with a complaint ASGI server such
+as `Uvicorn <https://www.uvicorn.org/>`_.
+
+``Microdot`` class
+~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: microdot_asgi.Microdot
+   :members:
+   :exclude-members: shutdown, run

docs/intro.rst

@@ -5,8 +5,12 @@ Microdot can be installed with ``pip``::
 
     pip install microdot
 
-For platforms that do not support or cannot run ``pip``, you can also manually
+For MicroPython, you can install with ``upip``.
-copy and install the ``microdot.py`` and ``microdot_asyncio.py`` source files.
+
+On platforms where ``pip`` or ``upip`` are not viable options, you can manually
+copy and install the ``microdot.py`` and ``microdot_asyncio.py`` source files
+from the `GitHub reposutory <https://github.com/miguelgrinberg/microdot>`_
+into your project directory.
 
 Examples
 --------

examples/hello.py

@@ -1,4 +1,4 @@
-from microdot import Microdot, Response
+from microdot import Microdot
 
 app = Microdot()
 
@@ -20,7 +20,7 @@ htmldoc = '''<!DOCTYPE html>
 
 @app.route('/')
 def hello(request):
-    return Response(body=htmldoc, headers={'Content-Type': 'text/html'})
+    return htmldoc, 200, {'Content-Type': 'text/html'}
 
 
 @app.route('/shutdown')

examples/hello_asgi.py

@@ -0,0 +1,36 @@
+from microdot_asgi import Microdot
+
+app = Microdot()
+
+htmldoc = '''<!DOCTYPE html>
+<html>
+    <head>
+        <title>Microdot Example Page</title>
+    </head>
+    <body>
+        <div>
+            <h1>Microdot Example Page</h1>
+            <p>Hello from Microdot!</p>
+            <p><a href="/shutdown">Click to shutdown the server</a></p>
+        </div>
+    </body>
+</html>
+'''
+
+
+@app.route('/')
+async def hello(request):
+    return htmldoc, 200, {'Content-Type': 'text/html'}
+
+
+@app.route('/shutdown')
+async def shutdown(request):
+    request.app.shutdown()
+    return 'The server is shutting down...'
+
+
+if __name__ == '__main__':
+    print('''Use an ASGI web server to run this applicaton.
+Example:
+    uvicorn hello_asgi:app
+''')

examples/hello_async.py

@@ -1,8 +1,4 @@
-try:
+from microdot_asyncio import Microdot
-    import uasyncio as asyncio
-except ImportError:
-    import asyncio
-from microdot_asyncio import Microdot, Response
 
 app = Microdot()
 
@@ -24,7 +20,7 @@ htmldoc = '''<!DOCTYPE html>
 
 @app.route('/')
 async def hello(request):
-    return Response(body=htmldoc, headers={'Content-Type': 'text/html'})
+    return htmldoc, 200, {'Content-Type': 'text/html'}
 
 
 @app.route('/shutdown')
@@ -33,8 +29,4 @@ async def shutdown(request):
     return 'The server is shutting down...'
 
 
-async def main():
+app.run(debug=True)
-    await app.start_server(debug=True)
-
-
-asyncio.run(main())

examples/hello_wsgi.py

@@ -0,0 +1,36 @@
+from microdot_wsgi import Microdot
+
+app = Microdot()
+
+htmldoc = '''<!DOCTYPE html>
+<html>
+    <head>
+        <title>Microdot Example Page</title>
+    </head>
+    <body>
+        <div>
+            <h1>Microdot Example Page</h1>
+            <p>Hello from Microdot!</p>
+            <p><a href="/shutdown">Click to shutdown the server</a></p>
+        </div>
+    </body>
+</html>
+'''
+
+
+@app.route('/')
+def hello(request):
+    return htmldoc, 200, {'Content-Type': 'text/html'}
+
+
+@app.route('/shutdown')
+def shutdown(request):
+    request.app.shutdown()
+    return 'The server is shutting down...'
+
+
+if __name__ == '__main__':
+    print('''Use a WSGI web server to run this applicaton.
+Example:
+    gunicorn hello_wsgi:app
+''')

examples/video_stream.py

@@ -0,0 +1,45 @@
+try:
+    import utime as time
+except ImportError:
+    import time
+
+from microdot import Microdot
+
+app = Microdot()
+
+frames = []
+for file in ['1.jpg', '2.jpg', '3.jpg']:
+    with open(file, 'rb') as f:
+        frames.append(f.read())
+
+
+@app.route('/')
+def index(request):
+    return '''<!doctype html>
+<html>
+  <head>
+    <title>Microdot Video Streaming</title>
+  </head>
+  <body>
+    <h1>Microdot Video Streaming</h1>
+    <img src="/video_feed">
+  </body>
+</html>''', 200, {'Content-Type': 'text/html'}
+
+
+@app.route('/video_feed')
+def video_feed(request):
+    def stream():
+        yield b'--frame\r\n'
+        while True:
+            for frame in frames:
+                yield b'Content-Type: image/jpeg\r\n\r\n' + frame + \
+                    b'\r\n--frame\r\n'
+                time.sleep(1)
+
+    return stream(), 200, {'Content-Type':
+                           'multipart/x-mixed-replace; boundary=frame'}
+
+
+if __name__ == '__main__':
+    app.run(debug=True)

examples/video_stream_async.py

@@ -0,0 +1,64 @@
+import sys
+
+try:
+    import uasyncio as asyncio
+except ImportError:
+    import asyncio
+
+from microdot_asyncio import Microdot
+
+app = Microdot()
+
+frames = []
+for file in ['1.jpg', '2.jpg', '3.jpg']:
+    with open(file, 'rb') as f:
+        frames.append(f.read())
+
+
+@app.route('/')
+def index(request):
+    return '''<!doctype html>
+<html>
+  <head>
+    <title>Microdot Video Streaming</title>
+  </head>
+  <body>
+    <h1>Microdot Video Streaming</h1>
+    <img src="/video_feed">
+  </body>
+</html>''', 200, {'Content-Type': 'text/html'}
+
+
+@app.route('/video_feed')
+async def video_feed(request):
+    if sys.implementation.name != 'micropython':
+        # CPython supports yielding async generators
+        async def stream():
+            yield b'--frame\r\n'
+            while True:
+                for frame in frames:
+                    yield b'Content-Type: image/jpeg\r\n\r\n' + frame + \
+                        b'\r\n--frame\r\n'
+                    await asyncio.sleep(1)
+
+    else:
+        # MicroPython can only use class-based async generators
+        class stream():
+            def __init__(self):
+                self.i = 0
+
+            def __aiter__(self):
+                return self
+
+            async def __anext__(self):
+                await asyncio.sleep(1)
+                self.i = (self.i + 1) % len(frames)
+                return b'Content-Type: image/jpeg\r\n\r\n' + \
+                    frames[self.i] + b'\r\n--frame\r\n'
+
+    return stream(), 200, {'Content-Type':
+                           'multipart/x-mixed-replace; boundary=frame'}
+
+
+if __name__ == '__main__':
+    app.run(debug=True)

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = microdot
-version = 0.7.2
+version = 0.9.0
 author = Miguel Grinberg
 author_email = miguel.grinberg@gmail.com
 description = The impossibly small web framework for MicroPython
@@ -25,3 +25,4 @@ package_dir =
 py_modules =
     microdot
     microdot_asyncio
+    microdot_wsgi

src/microdot.py

@@ -181,7 +181,8 @@ class Request():
     :var cookies: A dictionary with the cookies included in the request.
     :var content_length: The parsed ``Content-Length`` header.
     :var content_type: The parsed ``Content-Type`` header.
-    :var body: A stream from where the body can be read.
+    :var stream: The input stream, containing the request body.
+    :var body: The body of the request, as bytes.
     :var json: The parsed JSON body, as a dictionary or list, or ``None`` if
                the request does not have a JSON body.
     :var form: The parsed form submission body, as a :class:`MultiDict` object,
@@ -198,6 +199,17 @@ class Request():
     #:    Request.max_content_length = 1 * 1024 * 1024  # 1MB requests allowed
     max_content_length = 16 * 1024
 
+    #: Specify the maximum payload size that can be stored in ``body``.
+    #: Requests with payloads that are larger than this size and up to
+    #: ``max_content_length`` bytes will be accepted, but the application will
+    #: only be able to access the body of the request by reading from
+    #: ``stream``. Set to 0 if you always access the body as a stream.
+    #:
+    #: Example::
+    #:
+    #:    Request.max_body_length = 4 * 1024  # up to 4KB bodies read
+    max_body_length = 16 * 1024
+
     #: Specify the maximum length allowed for a line in the request. Requests
     #: with longer lines will not be correctly interpreted. Applications can
     #: change this maximum as necessary.
@@ -211,7 +223,7 @@ class Request():
         pass
 
     def __init__(self, app, client_addr, method, url, http_version, headers,
-                 body):
+                 body=None, stream=None):
         self.app = app
         self.client_addr = client_addr
         self.method = method
@@ -228,15 +240,19 @@ class Request():
         self.content_length = 0
         self.content_type = None
         for header, value in self.headers.items():
-            if header == 'Content-Length':
+            header = header.lower()
+            if header == 'content-length':
                 self.content_length = int(value)
-            elif header == 'Content-Type':
+            elif header == 'content-type':
                 self.content_type = value
-            elif header == 'Cookie':
+            elif header == 'cookie':
                 for cookie in value.split(';'):
                     name, value = cookie.strip().split('=', 1)
                     self.cookies[name] = value
-        self.body = body
+        self._body = body
+        self.body_used = False
+        self._stream = stream
+        self.stream_used = False
         self._json = None
         self._form = None
         self.g = Request.G()
@@ -261,7 +277,6 @@ class Request():
 
         # headers
         headers = {}
-        content_length = 0
         while True:
             line = Request._safe_readline(client_stream).strip().decode()
             if line == '':
@@ -269,15 +284,9 @@ class Request():
             header, value = line.split(':', 1)
             value = value.strip()
             headers[header] = value
-            if header == 'Content-Length':
-                content_length = int(value)
-
-        # body
-        body = client_stream.read(content_length) if content_length and \
-            content_length <= Request.max_content_length else b''
 
         return Request(app, client_addr, method, url, http_version, headers,
-                       body)
+                       stream=client_stream)
 
     def _parse_urlencoded(self, urlencoded):
         data = MultiDict()
@@ -285,6 +294,30 @@ class Request():
             data[urldecode(k)] = urldecode(v)
         return data
 
+    @property
+    def body(self):
+        if self.stream_used:
+            raise RuntimeError('Cannot use both stream and body')
+        if self._body is None:
+            self._body = b''
+            if self.content_length and \
+                    self.content_length <= Request.max_body_length:
+                while len(self._body) < self.content_length:
+                    data = self._stream.read(
+                        self.content_length - len(self._body))
+                    if len(data) == 0:  # pragma: no cover
+                        raise EOFError()
+                    self._body += data
+                self.body_used = True
+        return self._body
+
+    @property
+    def stream(self):
+        if self.body_used:
+            raise RuntimeError('Cannot use both stream and body')
+        self.stream_used = True
+        return self._stream
+
     @property
     def json(self):
         if self._json is None:
@@ -319,7 +352,10 @@ class Response():
     """An HTTP response class.
 
     :param body: The body of the response. If a dictionary or list is given,
-                 a JSON formatter is used to generate the body.
+                 a JSON formatter is used to generate the body. If a file-like
+                 object or a generator is given, a streaming response is used.
+                 If a string is given, it is encoded from UTF-8. Else, the
+                 body should be a byte sequence.
     :param status_code: The numeric HTTP status code of the response. The
                         default is 200.
     :param headers: A dictionary of headers to include in the response.
@@ -340,6 +376,9 @@ class Response():
     send_file_buffer_size = 1024
 
     def __init__(self, body='', status_code=200, headers=None, reason=None):
+        if body is None and status_code == 200:
+            body = ''
+            status_code = 204
         self.status_code = status_code
         self.headers = headers.copy() if headers else {}
         self.reason = reason
@@ -349,7 +388,7 @@ class Response():
         elif isinstance(body, str):
             self.body = body.encode()
         else:
-            # this applies to bytes or file-like objects
+            # this applies to bytes, file-like objects or generators
             self.body = body
 
     def set_cookie(self, cookie, value, path=None, domain=None, expires=None,
@@ -409,18 +448,35 @@ class Response():
         stream.write(b'\r\n')
 
         # body
+        can_flush = hasattr(stream, 'flush')
+        try:
+            for body in self.body_iter():
+                if isinstance(body, str):
+                    body = body.encode()
+                stream.write(body)
+                if can_flush:  # pragma: no cover
+                    stream.flush()
+        except OSError as exc:  # pragma: no cover
+            if exc.errno == 32:  # errno.EPIPE
+                pass
+            else:
+                raise
+
+    def body_iter(self):
         if self.body:
             if hasattr(self.body, 'read'):
                 while True:
                     buf = self.body.read(self.send_file_buffer_size)
                     if len(buf):
-                        stream.write(buf)
+                        yield buf
                     if len(buf) < self.send_file_buffer_size:
                         break
                 if hasattr(self.body, 'close'):  # pragma: no cover
                     self.body.close()
+            elif hasattr(self.body, '__next__'):
+                yield from self.body
             else:
-                stream.write(self.body)
+                yield self.body
 
     @classmethod
     def redirect(cls, location, status_code=302):
@@ -763,11 +819,11 @@ class Microdot():
             try:
                 sock, addr = self.server.accept()
             except OSError as exc:  # pragma: no cover
-                if exc.args[0] == errno.ECONNABORTED:
+                if exc.errno == errno.ECONNABORTED:
                     break
                 else:
                     raise
-            create_thread(self.dispatch_request, sock, addr)
+            create_thread(self.handle_request, sock, addr)
 
     def shutdown(self):
         """Request a server shutdown. The server will then exit its request
@@ -794,7 +850,7 @@ class Microdot():
                     break
         return f
 
-    def dispatch_request(self, sock, addr):
+    def handle_request(self, sock, addr):
         if not hasattr(sock, 'readline'):  # pragma: no cover
             stream = sock.makefile("rwb")
         else:
@@ -805,6 +861,25 @@ class Microdot():
             req = Request.create(self, stream, addr)
         except Exception as exc:  # pragma: no cover
             print_exception(exc)
+        res = self.dispatch_request(req)
+        res.write(stream)
+        try:
+            stream.close()
+        except OSError as exc:  # pragma: no cover
+            if exc.errno == 32:  # errno.EPIPE
+                pass
+            else:
+                raise
+        if stream != sock:  # pragma: no cover
+            sock.close()
+        if self.shutdown_requested:  # pragma: no cover
+            self.server.close()
+        if self.debug and req:  # pragma: no cover
+            print('{method} {path} {status_code}'.format(
+                method=req.method, path=req.path,
+                status_code=res.status_code))
+
+    def dispatch_request(self, req):
         if req:
             if req.content_length > req.max_content_length:
                 if 413 in self.error_handlers:
@@ -851,16 +926,7 @@ class Microdot():
             res = Response(*res)
         elif not isinstance(res, Response):
             res = Response(res)
-        res.write(stream)
+        return res
-        stream.close()
-        if stream != sock:  # pragma: no cover
-            sock.close()
-        if self.shutdown_requested:  # pragma: no cover
-            self.server.close()
-        if self.debug and req:  # pragma: no cover
-            print('{method} {path} {status_code}'.format(
-                method=req.method, path=req.path,
-                status_code=res.status_code))
 
 
 redirect = Response.redirect

src/microdot_asgi.py

@@ -0,0 +1,141 @@
+import asyncio
+import os
+import signal
+from microdot_asyncio import *  # noqa: F401, F403
+from microdot_asyncio import Microdot as BaseMicrodot
+from microdot_asyncio import Request
+
+
+class _BodyStream:  # pragma: no cover
+    def __init__(self, receive):
+        self.receive = receive
+        self.data = b''
+        self.more = True
+
+    async def read_more(self):
+        if self.more:
+            packet = await self.receive()
+            self.data += packet.get('body', b'')
+            self.more = packet.get('more_body', False)
+
+    async def read(self, n=-1):
+        while self.more and len(self.data) < n:
+            self.read_more()
+        if len(self.data) < n:
+            data = self.data
+            self.data = b''
+            return data
+
+        data = self.data[:n]
+        self.data = self.data[n:]
+        return data
+
+    async def readline(self):
+        return self.readuntil()
+
+    async def readexactly(self, n):
+        return self.read(n)
+
+    async def readuntil(self, separator=b'\n'):
+        if self.more and separator not in self.data:
+            self.read_more()
+        data, self.data = self.data.split(separator, 1)
+        return data
+
+
+class Microdot(BaseMicrodot):
+    def __init__(self):
+        super().__init__()
+        self.embedded_server = False
+
+    async def asgi_app(self, scope, receive, send):
+        """An ASGI application."""
+        if scope['type'] != 'http':  # pragma: no cover
+            return
+        path = scope['path']
+        if 'query_string' in scope and scope['query_string']:
+            path += '?' + scope['query_string'].decode()
+        headers = {}
+        content_length = 0
+        for key, value in scope.get('headers', []):
+            headers[key] = value
+            if key.lower() == 'content-length':
+                content_length = int(value)
+
+        body = b''
+        if content_length and content_length <= Request.max_body_length:
+            body = b''
+            more = True
+            while more:
+                packet = await receive()
+                body += packet.get('body', b'')
+                more = packet.get('more_body', False)
+            stream = None
+        else:
+            body = b''
+            stream = _BodyStream(receive)
+
+        req = Request(
+            self,
+            (scope['client'][0], scope['client'][1]),
+            scope['method'],
+            path,
+            'HTTP/' + scope['http_version'],
+            headers,
+            body=body,
+            stream=stream)
+        req.asgi_scope = scope
+
+        res = await self.dispatch_request(req)
+        res.complete()
+
+        await send({'type': 'http.response.start',
+                    'status': res.status_code,
+                    'headers': [(name, value)
+                                for name, value in res.headers.items()]})
+
+        cancelled = False
+
+        async def cancel_monitor():
+            nonlocal cancelled
+
+            while True:
+                event = await receive()
+                if event['type'] == 'http.disconnect':  # pragma: no branch
+                    cancelled = True
+                    break
+
+        asyncio.ensure_future(cancel_monitor())
+
+        body_iter = res.body_iter().__aiter__()
+        try:
+            body = await body_iter.__anext__()
+            while not cancelled:  # pragma: no branch
+                next_body = await body_iter.__anext__()
+                await send({'type': 'http.response.body',
+                            'body': body,
+                            'more_body': True})
+                body = next_body
+        except StopAsyncIteration:
+            await send({'type': 'http.response.body',
+                        'body': body,
+                        'more_body': False})
+
+    async def __call__(self, scope, receive, send):
+        return await self.asgi_app(scope, receive, send)
+
+    def shutdown(self):
+        if self.embedded_server:  # pragma: no cover
+            super().shutdown()
+        else:
+            pid = os.getpgrp() if hasattr(os, 'getpgrp') else os.getpid()
+            os.kill(pid, signal.SIGTERM)
+
+    def run(self, host='0.0.0.0', port=5000, debug=False,
+            **options):  # pragma: no cover
+        """Normally you would not start the server by invoking this method.
+        Instead, start your chosen ASGI web server and pass the ``Microdot``
+        instance as the ASGI application.
+        """
+        self.embedded_server = True
+        super().run(host=host, port=port, debug=debug, **options)

src/microdot_asyncio.py

@@ -10,6 +10,12 @@ try:
     import uasyncio as asyncio
 except ImportError:
     import asyncio
+
+try:
+    import uio as io
+except ImportError:
+    import io
+
 from microdot import Microdot as BaseMicrodot
 from microdot import print_exception
 from microdot import Request as BaseRequest
@@ -20,6 +26,23 @@ def _iscoroutine(coro):
     return hasattr(coro, 'send') and hasattr(coro, 'throw')
 
 
+class _AsyncBytesIO:
+    def __init__(self, data):
+        self.stream = io.BytesIO(data)
+
+    async def read(self, n=-1):
+        return self.stream.read(n)
+
+    async def readline(self):  # pragma: no cover
+        return self.stream.readline()
+
+    async def readexactly(self, n):  # pragma: no cover
+        return self.stream.read(n)
+
+    async def readuntil(self, separator=b'\n'):  # pragma: no cover
+        return self.stream.readuntil(separator=separator)
+
+
 class Request(BaseRequest):
     @staticmethod
     async def create(app, client_stream, client_addr):
@@ -51,15 +74,26 @@ class Request(BaseRequest):
             header, value = line.split(':', 1)
             value = value.strip()
             headers[header] = value
-            if header == 'Content-Length':
+            if header.lower() == 'content-length':
                 content_length = int(value)
 
         # body
-        body = await client_stream.read(content_length) if content_length and \
+        body = b''
-            content_length <= Request.max_content_length else b''
+        if content_length and content_length <= Request.max_body_length:
+            body = await client_stream.readexactly(content_length)
+            stream = None
+        else:
+            body = b''
+            stream = client_stream
 
         return Request(app, client_addr, method, url, http_version, headers,
-                       body)
+                       body=body, stream=stream)
+
+    @property
+    def stream(self):
+        if self._stream is None:
+            self._stream = _AsyncBytesIO(self._body)
+        return self._stream
 
     @staticmethod
     async def _safe_readline(stream):
@@ -73,7 +107,10 @@ class Response(BaseResponse):
     """An HTTP response class.
 
     :param body: The body of the response. If a dictionary or list is given,
-                 a JSON formatter is used to generate the body.
+                 a JSON formatter is used to generate the body. If a file-like
+                 object or an async generator is given, a streaming response is
+                 used. If a string is given, it is encoded from UTF-8. Else,
+                 the body should be a byte sequence.
     :param status_code: The numeric HTTP status code of the response. The
                         default is 200.
     :param headers: A dictionary of headers to include in the response.
@@ -99,18 +136,52 @@ class Response(BaseResponse):
         await stream.awrite(b'\r\n')
 
         # body
-        if self.body:
+        try:
-            if hasattr(self.body, 'read'):
+            async for body in self.body_iter():
-                while True:
+                if isinstance(body, str):
-                    buf = self.body.read(self.send_file_buffer_size)
+                    body = body.encode()
-                    if len(buf):
+                await stream.awrite(body)
-                        await stream.awrite(buf)
+        except OSError as exc:  # pragma: no cover
-                    if len(buf) < self.send_file_buffer_size:
+            if exc.errno == 32 or exc.args[0] == 'Connection lost':
-                        break
+                pass
-                if hasattr(self.body, 'close'):  # pragma: no cover
-                    self.body.close()
             else:
-                await stream.awrite(self.body)
+                raise
+
+    def body_iter(self):
+        if hasattr(self.body, '__anext__'):
+            return self.body
+
+        response = self
+
+        class iter:
+            def __aiter__(self):
+                if response.body:
+                    self.i = 0
+                else:
+                    self.i = -1
+                return self
+
+            async def __anext__(self):
+                if self.i == -1:
+                    raise StopAsyncIteration
+                if self.i == 0:
+                    if not hasattr(response.body, 'read'):
+                        self.i = -1
+                        return response.body
+                    else:
+                        self.i = 1
+                buf = response.body.read(response.send_file_buffer_size)
+                if _iscoroutine(buf):  # pragma: no cover
+                    buf = await buf
+                if len(buf) < response.send_file_buffer_size:
+                    self.i = -1
+                    if hasattr(response.body, 'close'):  # pragma: no cover
+                        result = response.body.close()
+                        if _iscoroutine(result):
+                            await result
+                return buf
+
+        return iter()
 
 
 class Microdot(BaseMicrodot):
@@ -167,7 +238,7 @@ class Microdot(BaseMicrodot):
                 writer.awrite = MethodType(awrite, writer)
                 writer.aclose = MethodType(aclose, writer)
 
-            await self.dispatch_request(reader, writer)
+            await self.handle_request(reader, writer)
 
         if self.debug:  # pragma: no cover
             print('Starting async server on {host}:{port}...'.format(
@@ -217,13 +288,29 @@ class Microdot(BaseMicrodot):
     def shutdown(self):
         self.server.close()
 
-    async def dispatch_request(self, reader, writer):
+    async def handle_request(self, reader, writer):
         req = None
         try:
             req = await Request.create(self, reader,
                                        writer.get_extra_info('peername'))
         except Exception as exc:  # pragma: no cover
             print_exception(exc)
+
+        res = await self.dispatch_request(req)
+        await res.write(writer)
+        try:
+            await writer.aclose()
+        except OSError as exc:  # pragma: no cover
+            if exc.errno == 32:  # errno.EPIPE
+                pass
+            else:
+                raise
+        if self.debug and req:  # pragma: no cover
+            print('{method} {path} {status_code}'.format(
+                method=req.method, path=req.path,
+                status_code=res.status_code))
+
+    async def dispatch_request(self, req):
         if req:
             if req.content_length > req.max_content_length:
                 if 413 in self.error_handlers:
@@ -276,12 +363,7 @@ class Microdot(BaseMicrodot):
             res = Response(*res)
         elif not isinstance(res, Response):
             res = Response(res)
-        await res.write(writer)
+        return res
-        await writer.aclose()
-        if self.debug and req:  # pragma: no cover
-            print('{method} {path} {status_code}'.format(
-                method=req.method, path=req.path,
-                status_code=res.status_code))
 
     async def _invoke_handler(self, f_or_coro, *args, **kwargs):
         ret = f_or_coro(*args, **kwargs)

src/microdot_wsgi.py

@@ -0,0 +1,59 @@
+import os
+import signal
+from microdot import *  # noqa: F401, F403
+from microdot import Microdot as BaseMicrodot
+from microdot import Request
+
+
+class Microdot(BaseMicrodot):
+    def __init__(self):
+        super().__init__()
+        self.embedded_server = False
+
+    def wsgi_app(self, environ, start_response):
+        """A WSGI application callable."""
+        path = environ.get('SCRIPT_NAME', '') + environ.get('PATH_INFO', '')
+        if 'QUERY_STRING' in environ and environ['QUERY_STRING']:
+            path += '?' + environ['QUERY_STRING']
+        headers = {}
+        for k, v in environ.items():
+            if k.startswith('HTTP_'):
+                h = '-'.join([p.title() for p in k[5:].split('_')])
+                headers[h] = v
+        req = Request(
+            self,
+            (environ['REMOTE_ADDR'], int(environ.get('REMOTE_PORT', '0'))),
+            environ['REQUEST_METHOD'],
+            path,
+            environ['SERVER_PROTOCOL'],
+            headers,
+            stream=environ['wsgi.input'])
+        req.environ = environ
+
+        res = self.dispatch_request(req)
+        res.complete()
+
+        reason = res.reason or ('OK' if res.status_code == 200 else 'N/A')
+        start_response(
+            str(res.status_code) + ' ' + reason,
+            [(name, value) for name, value in res.headers.items()])
+        return res.body_iter()
+
+    def __call__(self, environ, start_response):
+        return self.wsgi_app(environ, start_response)
+
+    def shutdown(self):
+        if self.embedded_server:  # pragma: no cover
+            super().shutdown()
+        else:
+            pid = os.getpgrp() if hasattr(os, 'getpgrp') else os.getpid()
+            os.kill(pid, signal.SIGTERM)
+
+    def run(self, host='0.0.0.0', port=5000, debug=False,
+            **options):  # pragma: no cover
+        """Normally you would not start the server by invoking this method.
+        Instead, start your chosen WSGI web server and pass the ``Microdot``
+        instance as the WSGI callable.
+        """
+        self.embedded_server = True
+        super().run(host=host, port=port, debug=debug, **options)

tests/microdot/test_microdot.py

@@ -286,3 +286,21 @@ class TestMicrodot(unittest.TestCase):
         self.assertIn(b'Content-Length: 3\r\n', fd.response)
         self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
         self.assertTrue(fd.response.endswith(b'\r\n\r\n501'))
+
+    def test_streaming(self):
+        app = Microdot()
+
+        @app.route('/')
+        def index(req):
+            def stream():
+                yield 'foo'
+                yield b'bar'
+            return stream()
+
+        mock_socket.clear_requests()
+        fd = mock_socket.add_request('GET', '/')
+        self._add_shutdown(app)
+        app.run()
+        self.assertTrue(fd.response.startswith(b'HTTP/1.0 200 OK\r\n'))
+        self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
+        self.assertTrue(fd.response.endswith(b'\r\n\r\nfoobar'))

tests/microdot/test_request.py

@@ -91,14 +91,38 @@ class TestRequest(unittest.TestCase):
 
         Request.max_readline = saved_max_readline
 
+    def test_stream(self):
+        fd = get_request_fd('GET', '/foo', headers={
+            'Content-Type': 'application/x-www-form-urlencoded',
+            'Content-Length': '19'},
+            body='foo=bar&abc=def&x=y')
+        req = Request.create('app', fd, 'addr')
+        self.assertEqual(req.stream.read(), b'foo=bar&abc=def&x=y')
+        with self.assertRaises(RuntimeError):
+            req.body
+
+    def test_body(self):
+        fd = get_request_fd('GET', '/foo', headers={
+            'Content-Type': 'application/x-www-form-urlencoded',
+            'Content-Length': '19'},
+            body='foo=bar&abc=def&x=y')
+        req = Request.create('app', fd, 'addr')
+        self.assertEqual(req.body, b'foo=bar&abc=def&x=y')
+        with self.assertRaises(RuntimeError):
+            req.stream
+
     def test_large_payload(self):
         saved_max_content_length = Request.max_content_length
-        Request.max_content_length = 16
+        saved_max_body_length = Request.max_body_length
+        Request.max_content_length = 32
+        Request.max_body_length = 16
 
         fd = get_request_fd('GET', '/foo', headers={
             'Content-Type': 'application/x-www-form-urlencoded'},
             body='foo=bar&abc=def&x=y')
         req = Request.create('app', fd, 'addr')
         self.assertEqual(req.body, b'')
+        self.assertEqual(req.stream.read(), b'foo=bar&abc=def&x=y')
 
         Request.max_content_length = saved_max_content_length
+        Request.max_body_length = saved_max_body_length

tests/microdot/test_response.py

@@ -88,6 +88,18 @@ class TestResponse(unittest.TestCase):
         self.assertIn(b'Content-Type: application/json\r\n', response)
         self.assertTrue(response.endswith(b'\r\n\r\n[1, "2"]'))
 
+    def test_create_from_none(self):
+        res = Response(None)
+        self.assertEqual(res.status_code, 204)
+        self.assertEqual(res.body, b'')
+        fd = io.BytesIO()
+        res.write(fd)
+        response = fd.getvalue()
+        self.assertIn(b'HTTP/1.0 204 N/A\r\n', response)
+        self.assertIn(b'Content-Length: 0\r\n', response)
+        self.assertIn(b'Content-Type: text/plain\r\n', response)
+        self.assertTrue(response.endswith(b'\r\n\r\n'))
+
     def test_create_from_other(self):
         res = Response(123)
         self.assertEqual(res.status_code, 200)
@@ -167,6 +179,9 @@ class TestResponse(unittest.TestCase):
         self.assertEqual(res.status_code, 301)
         self.assertEqual(res.headers['Location'], '/foo')
 
+        with self.assertRaises(ValueError):
+            Response.redirect('/foo\x0d\x0a\x0d\x0a<p>Foo</p>')
+
     def test_send_file(self):
         files = [
             ('test.txt', 'text/plain'),

tests/microdot_asgi/test_microdot_asgi.py

@@ -0,0 +1,161 @@
+import unittest
+import sys
+
+try:
+    import asyncio
+except ImportError:
+    pass
+
+try:
+    from unittest import mock
+except ImportError:
+    mock = None
+
+from microdot_asgi import Microdot, Response
+from tests import mock_asyncio
+
+
+@unittest.skipIf(sys.implementation.name == 'micropython',
+                 'not supported under MicroPython')
+class TestMicrodotASGI(unittest.TestCase):
+    def test_asgi_request_with_query_string(self):
+        app = Microdot()
+
+        @app.post('/foo/bar')
+        async def index(req):
+            self.assertEqual(req.app, app)
+            self.assertEqual(req.client_addr, ('1.2.3.4', 1234))
+            self.assertEqual(req.method, 'POST')
+            self.assertEqual(req.http_version, 'HTTP/1.1')
+            self.assertEqual(req.path, '/foo/bar')
+            self.assertEqual(req.args, {'baz': ['1']})
+            self.assertEqual(req.cookies, {'session': 'xyz'})
+            self.assertEqual(req.body, b'body')
+
+            class R:
+                def __init__(self):
+                    self.i = 0
+                    self.body = [b're', b'sp', b'on', b'se', b'']
+
+                async def read(self, n):
+                    data = self.body[self.i]
+                    self.i += 1
+                    return data
+
+            return Response(body=R(), headers={'Content-Length': '8'})
+
+        scope = {
+            'type': 'http',
+            'path': '/foo/bar',
+            'query_string': b'baz=1',
+            'headers': [('Authorization', 'Bearer 123'),
+                        ('Cookie', 'session=xyz'),
+                        ('Content-Length', 4)],
+            'client': ['1.2.3.4', 1234],
+            'method': 'POST',
+            'http_version': '1.1',
+        }
+
+        event_index = 0
+
+        async def receive():
+            nonlocal event_index
+
+            if event_index == 0:
+                event_index = 1
+                return {
+                    'type': 'http.request',
+                    'body': b'body',
+                    'more_body': False,
+                }
+
+            await asyncio.sleep(0.1)
+            return {
+                'type': 'http.disconnect',
+            }
+
+        async def send(packet):
+            if packet['type'] == 'http.response.start':
+                self.assertEqual(packet['status'], 200)
+                self.assertEqual(
+                    packet['headers'],
+                    [('Content-Length', '8'), ('Content-Type', 'text/plain')])
+            elif packet['type'] == 'http.response.body':
+                self.assertIn(packet['body'],
+                              [b're', b'sp', b'on', b'se', b''])
+
+        original_buffer_size = Response.send_file_buffer_size
+        Response.send_file_buffer_size = 2
+
+        mock_asyncio.run(app(scope, receive, send))
+
+        Response.send_file_buffer_size = original_buffer_size
+
+    def test_wsgi_request_without_query_string(self):
+        app = Microdot()
+
+        @app.route('/foo/bar')
+        async def index(req):
+            self.assertEqual(req.path, '/foo/bar')
+            self.assertEqual(req.args, {})
+            return 'response'
+
+        scope = {
+            'type': 'http',
+            'path': '/foo/bar',
+            'headers': [('Authorization', 'Bearer 123'),
+                        ('Cookie', 'session=xyz'),
+                        ('Content-Length', 4)],
+            'client': ['1.2.3.4', 1234],
+            'method': 'POST',
+            'http_version': '1.1',
+        }
+
+        event_index = 0
+
+        async def receive():
+            nonlocal event_index
+
+            if event_index == 0:
+                event_index = 1
+                return {
+                    'type': 'http.request',
+                    'body': b'body',
+                    'more_body': False,
+                }
+
+            await asyncio.sleep(0.1)
+            return {
+                'type': 'http.disconnect',
+            }
+
+        async def send(packet):
+            pass
+
+        mock_asyncio.run(app(scope, receive, send))
+
+    def test_shutdown(self):
+        app = Microdot()
+
+        @app.route('/shutdown')
+        async def shutdown(request):
+            request.app.shutdown()
+
+        scope = {
+            'type': 'http',
+            'path': '/shutdown',
+            'client': ['1.2.3.4', 1234],
+            'method': 'GET',
+            'http_version': '1.1',
+        }
+
+        async def receive():
+            pass
+
+        async def send(packet):
+            pass
+
+        with mock.patch('microdot_asgi.os.kill') as kill:
+            mock_asyncio.run(app(scope, receive, send))
+
+        kill.assert_called()

tests/microdot_asyncio/test_microdot_asyncio.py

@@ -264,3 +264,33 @@ class TestMicrodotAsync(unittest.TestCase):
         self.assertIn(b'Content-Length: 3\r\n', fd.response)
         self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
         self.assertTrue(fd.response.endswith(b'\r\n\r\n501'))
+
+    def test_streaming(self):
+        app = Microdot()
+
+        @app.route('/')
+        def index(req):
+            class stream():
+                def __init__(self):
+                    self.i = 0
+                    self.data = ['foo', b'bar']
+
+                def __aiter__(self):
+                    return self
+
+                async def __anext__(self):
+                    if self.i >= len(self.data):
+                        raise StopAsyncIteration
+                    data = self.data[self.i]
+                    self.i += 1
+                    return data
+
+            return stream()
+
+        mock_socket.clear_requests()
+        fd = mock_socket.add_request('GET', '/')
+        self._add_shutdown(app)
+        app.run()
+        self.assertTrue(fd.response.startswith(b'HTTP/1.0 200 OK\r\n'))
+        self.assertIn(b'Content-Type: text/plain\r\n', fd.response)
+        self.assertTrue(fd.response.endswith(b'\r\n\r\nfoobar'))

tests/microdot_asyncio/test_request_asyncio.py

@@ -101,14 +101,30 @@ class TestRequestAsync(unittest.TestCase):
 
         Request.max_readline = saved_max_readline
 
+    def test_stream(self):
+        fd = get_async_request_fd('GET', '/foo', headers={
+            'Content-Type': 'application/x-www-form-urlencoded',
+            'Content-Length': '19'},
+            body='foo=bar&abc=def&x=y')
+        req = _run(Request.create('app', fd, 'addr'))
+        self.assertEqual(req.body, b'foo=bar&abc=def&x=y')
+        data = _run(req.stream.read())
+        self.assertEqual(data, b'foo=bar&abc=def&x=y')
+
     def test_large_payload(self):
         saved_max_content_length = Request.max_content_length
-        Request.max_content_length = 16
+        saved_max_body_length = Request.max_body_length
+        Request.max_content_length = 32
+        Request.max_body_length = 16
 
         fd = get_async_request_fd('GET', '/foo', headers={
-            'Content-Type': 'application/x-www-form-urlencoded'},
+            'Content-Type': 'application/x-www-form-urlencoded',
+            'Content-Length': '19'},
             body='foo=bar&abc=def&x=y')
         req = _run(Request.create('app', fd, 'addr'))
         self.assertEqual(req.body, b'')
+        data = _run(req.stream.read())
+        self.assertEqual(data, b'foo=bar&abc=def&x=y')
 
         Request.max_content_length = saved_max_content_length
+        Request.max_body_length = saved_max_body_length

tests/microdot_wsgi/test_microdot_wsgi.py

@@ -0,0 +1,104 @@
+import unittest
+import sys
+
+try:
+    import uio as io
+except ImportError:
+    import io
+
+try:
+    from unittest import mock
+except ImportError:
+    mock = None
+
+from microdot_wsgi import Microdot
+
+
+@unittest.skipIf(sys.implementation.name == 'micropython',
+                 'not supported under MicroPython')
+class TestMicrodotWSGI(unittest.TestCase):
+    def test_wsgi_request_with_query_string(self):
+        app = Microdot()
+
+        @app.post('/foo/bar')
+        def index(req):
+            self.assertEqual(req.app, app)
+            self.assertEqual(req.client_addr, ('1.2.3.4', 1234))
+            self.assertEqual(req.method, 'POST')
+            self.assertEqual(req.http_version, 'HTTP/1.1')
+            self.assertEqual(req.path, '/foo/bar')
+            self.assertEqual(req.args, {'baz': ['1']})
+            self.assertEqual(req.cookies, {'session': 'xyz'})
+            self.assertEqual(req.body, b'body')
+            return 'response'
+
+        environ = {
+            'SCRIPT_NAME': '/foo',
+            'PATH_INFO': '/bar',
+            'QUERY_STRING': 'baz=1',
+            'HTTP_AUTHORIZATION': 'Bearer 123',
+            'HTTP_COOKIE': 'session=xyz',
+            'HTTP_CONTENT_LENGTH': '4',
+            'REMOTE_ADDR': '1.2.3.4',
+            'REMOTE_PORT': '1234',
+            'REQUEST_METHOD': 'POST',
+            'SERVER_PROTOCOL': 'HTTP/1.1',
+            'wsgi.input': io.BytesIO(b'body'),
+        }
+
+        def start_response(status, headers):
+            self.assertEqual(status, '200 OK')
+            self.assertEqual(
+                headers,
+                [('Content-Length', '8'), ('Content-Type', 'text/plain')])
+
+        r = app(environ, start_response)
+        self.assertEqual(next(r), b'response')
+
+    def test_wsgi_request_without_query_string(self):
+        app = Microdot()
+
+        @app.route('/foo/bar')
+        def index(req):
+            self.assertEqual(req.path, '/foo/bar')
+            self.assertEqual(req.args, {})
+            return 'response'
+
+        environ = {
+            'SCRIPT_NAME': '/foo',
+            'PATH_INFO': '/bar',
+            'REMOTE_ADDR': '1.2.3.4',
+            'REMOTE_PORT': '1234',
+            'REQUEST_METHOD': 'GET',
+            'SERVER_PROTOCOL': 'HTTP/1.1',
+            'wsgi.input': io.BytesIO(b''),
+        }
+
+        def start_response(status, headers):
+            pass
+
+        app(environ, start_response)
+
+    def test_shutdown(self):
+        app = Microdot()
+
+        @app.route('/shutdown')
+        def shutdown(request):
+            request.app.shutdown()
+
+        environ = {
+            'PATH_INFO': '/shutdown',
+            'REMOTE_ADDR': '1.2.3.4',
+            'REMOTE_PORT': '1234',
+            'REQUEST_METHOD': 'GET',
+            'SERVER_PROTOCOL': 'HTTP/1.1',
+            'wsgi.input': io.BytesIO(b''),
+        }
+
+        def start_response(status, headers):
+            pass
+
+        with mock.patch('microdot_wsgi.os.kill') as kill:
+            app(environ, start_response)
+
+        kill.assert_called()

tests/mock_socket.py

@@ -56,7 +56,10 @@ class FakeStreamAsync:
     async def readline(self):
         return self.stream.readline()
 
-    async def read(self, n):
+    async def read(self, n=-1):
+        return self.stream.read(n)
+
+    async def readexactly(self, n):
         return self.stream.read(n)
 
     async def awrite(self, data):

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist=flake8,py36,py37,py38,py39,upy
+envlist=flake8,py36,py37,py38,py39,py310,upy
 skipsdist=True
 skip_missing_interpreters=True
 
@@ -9,6 +9,7 @@ python =
     3.7: py37
     3.8: py38
     3.9: py39
+    3.10: py310
     pypy3: pypy3
 
 [testenv]
@@ -23,7 +24,7 @@ deps=
 deps=
     flake8
 commands=
-    flake8 --ignore=W503 --exclude tests/libs src tests
+    flake8 --ignore=W503 --exclude tests/libs src tests examples
 
 [testenv:upy]
 whitelist_externals=sh