Merge pull request #20 from FoamyGuy/compatibility_refactor

Move esp32spi_wsgi server code to here

Author: FoamyGuy

adafruit_wsgi/esp32spi_wsgiserver.py

@@ -0,0 +1,255 @@
+# SPDX-FileCopyrightText: Copyright (c) 2019 Matt Costi for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+
+"""
+`esp32spi_wsgiserver`
+================================================================================
+
+A simple WSGI (Web Server Gateway Interface) server that interfaces with the ESP32 over SPI.
+Opens a specified port on the ESP32 to listen for incoming HTTP Requests and
+Accepts an Application object that must be callable, which gets called
+whenever a new HTTP Request has been received.
+
+The Application MUST accept 2 ordered parameters:
+    1. environ object (incoming request data)
+    2. start_response function. Must be called before the Application
+        callable returns, in order to set the response status and headers.
+
+The Application MUST return a single string in a list,
+which is the response data
+
+Requires update_poll being called in the applications main event loop.
+
+For more details about Python WSGI see:
+https://www.python.org/dev/peps/pep-0333/
+
+* Author(s): Matt Costi
+"""
+# pylint: disable=no-name-in-module, protected-access
+
+import io
+import gc
+import time
+
+from micropython import const
+import adafruit_esp32spi.adafruit_esp32spi_socket as socket
+
+_the_interface = None  # pylint: disable=invalid-name
+
+
+def set_interface(iface):
+    """Helper to set the global internet interface"""
+    global _the_interface  # pylint: disable=global-statement, invalid-name
+    _the_interface = iface
+    socket.set_interface(iface)
+
+
+NO_SOCK_AVAIL = const(255)
+
+
+def parse_headers(client):
+    """
+    Parses the header portion of an HTTP request from the socket.
+    Expects first line of HTTP request to have been read already.
+    """
+    headers = {}
+    while True:
+        # line = str(client.readline(), "utf-8")
+        line = str(socket_readline(client), "utf-8")
+        if not line:
+            break
+        title, content = line.split(":", 1)
+        headers[title.strip().lower()] = content.strip()
+    return headers
+
+
+def socket_readline(_socket, eol=b"\r\n"):
+    """Attempt to return as many bytes as we can up to but not including
+    end-of-line character (default is '\\r\\n')"""
+
+    # print("Socket readline")
+    stamp = time.monotonic()
+    while eol not in _socket._buffer:
+        # there's no line already in there, read some more
+        avail = _socket._available()
+        if avail:
+            _socket._buffer += _the_interface.socket_read(_socket._socknum, avail)
+        elif _socket._timeout > 0 and time.monotonic() - stamp > _socket._timeout:
+            _socket.close()  # Make sure to close socket so that we don't exhaust sockets.
+            raise OSError("Didn't receive full response, failing out")
+    firstline, _socket._buffer = _socket._buffer.split(eol, 1)
+    gc.collect()
+    return firstline
+
+
+# pylint: disable=invalid-name
+class WSGIServer:
+    """
+    A simple server that implements the WSGI interface
+    """
+
+    def __init__(self, port=80, debug=False, application=None):
+        self.application = application
+        self.port = port
+        self._server_sock = socket.socket(socknum=NO_SOCK_AVAIL)
+        self._client_sock = socket.socket(socknum=NO_SOCK_AVAIL)
+        self._debug = debug
+
+        self._response_status = None
+        self._response_headers = []
+
+    def start(self):
+        """
+        starts the server and begins listening for incoming connections.
+        Call update_poll in the main loop for the application callable to be
+        invoked on receiving an incoming request.
+        """
+        self._server_sock = socket.socket()
+        _the_interface.start_server(self.port, self._server_sock._socknum)
+        if self._debug:
+            ip = _the_interface.pretty_ip(_the_interface.ip_address)
+            print("Server available at {0}:{1}".format(ip, self.port))
+            print(
+                "Server status: ",
+                _the_interface.server_state(self._server_sock._socknum),
+            )
+
+    def update_poll(self):
+        """
+        Call this method inside your main event loop to get the server
+        check for new incoming client requests. When a request comes in,
+        the application callable will be invoked.
+        """
+        self.client_available()
+        if self._client_sock and self._client_sock._available():
+            environ = self._get_environ(self._client_sock)
+            result = self.application(environ, self._start_response)
+            self.finish_response(result)
+
+    def finish_response(self, result):
+        """
+        Called after the application callbile returns result data to respond with.
+        Creates the HTTP Response payload from the response_headers and results data,
+        and sends it back to client.
+
+        :param string result: the data string to send back in the response to the client.
+        """
+        try:
+            response = "HTTP/1.1 {0}\r\n".format(self._response_status or "500 ISE")
+            for header in self._response_headers:
+                response += "{0}: {1}\r\n".format(*header)
+            response += "\r\n"
+            self._client_sock.send(response.encode("utf-8"))
+            if isinstance(result, bytes):  # send whole response if possible (see #174)
+                self._client_sock.send(result)
+            elif isinstance(result, str):
+                self._client_sock.send(result.encode("utf-8"))
+            else:  # fall back to sending byte-by-byte
+                for data in result:
+                    if isinstance(data, bytes):
+                        self._client_sock.send(data)
+                    else:
+                        self._client_sock.send(data.encode("utf-8"))
+            gc.collect()
+        finally:
+            if self._debug > 2:
+                print("closing")
+            self._client_sock.close()
+
+    def client_available(self):
+        """
+        returns a client socket connection if available.
+        Otherwise, returns None
+        :return: the client
+        :rtype: Socket
+        """
+        sock = None
+        if self._server_sock._socknum != NO_SOCK_AVAIL:
+            if self._client_sock._socknum != NO_SOCK_AVAIL:
+                # check previous received client socket
+                if self._debug > 2:
+                    print("checking if last client sock still valid")
+                if self._client_sock._connected() and self._client_sock._available():
+                    sock = self._client_sock
+            if not sock:
+                # check for new client sock
+                if self._debug > 2:
+                    print("checking for new client sock")
+                client_sock_num = _the_interface.socket_available(
+                    self._server_sock._socknum
+                )
+                sock = socket.socket(socknum=client_sock_num)
+        else:
+            print("Server has not been started, cannot check for clients!")
+
+        if sock and sock._socknum != NO_SOCK_AVAIL:
+            if self._debug > 2:
+                print("client sock num is: ", sock._socknum)
+            self._client_sock = sock
+            return self._client_sock
+
+        return None
+
+    def _start_response(self, status, response_headers):
+        """
+        The application callable will be given this method as the second param
+        This is to be called before the application callable returns, to signify
+        the response can be started with the given status and headers.
+
+        :param string status: a status string including the code and reason. ex: "200 OK"
+        :param list response_headers: a list of tuples to represent the headers.
+            ex ("header-name", "header value")
+        """
+        self._response_status = status
+        self._response_headers = [
+            ("Server", "esp32WSGIServer"),
+            ("Connection", "close"),
+        ] + response_headers
+
+    def _get_environ(self, client):
+        """
+        The application callable will be given the resulting environ dictionary.
+        It contains metadata about the incoming request and the request body ("wsgi.input")
+
+        :param Socket client: socket to read the request from
+        """
+        env = {}
+        # line = str(client.readline(), "utf-8")
+        line = str(socket_readline(client), "utf-8")
+        (method, path, ver) = line.rstrip("\r\n").split(None, 2)
+
+        env["wsgi.version"] = (1, 0)
+        env["wsgi.url_scheme"] = "http"
+        env["wsgi.multithread"] = False
+        env["wsgi.multiprocess"] = False
+        env["wsgi.run_once"] = False
+
+        env["REQUEST_METHOD"] = method
+        env["SCRIPT_NAME"] = ""
+        env["SERVER_NAME"] = _the_interface.pretty_ip(_the_interface.ip_address)
+        env["SERVER_PROTOCOL"] = ver
+        env["SERVER_PORT"] = self.port
+        if path.find("?") >= 0:
+            env["PATH_INFO"] = path.split("?")[0]
+            env["QUERY_STRING"] = path.split("?")[1]
+        else:
+            env["PATH_INFO"] = path
+
+        headers = parse_headers(client)
+        if "content-type" in headers:
+            env["CONTENT_TYPE"] = headers.get("content-type")
+        if "content-length" in headers:
+            env["CONTENT_LENGTH"] = headers.get("content-length")
+            body = client.recv(int(env["CONTENT_LENGTH"]))
+            env["wsgi.input"] = io.StringIO(body)
+        else:
+            body = client.recv(0)
+            env["wsgi.input"] = io.StringIO(body)
+        for name, value in headers.items():
+            key = "HTTP_" + name.replace("-", "_").upper()
+            if key in env:
+                value = "{0},{1}".format(env[key], value)
+            env[key] = value
+
+        return env

examples/static/index.html

@@ -0,0 +1,16 @@
+<!--
+SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
+
+SPDX-License-Identifier: MIT
+-->
+
+<!DOCTYPE html>
+<html>
+    <head>
+        <script async src="led_color_picker_example.js"></script>
+    </head>
+    <body>
+        <h1>LED color picker demo!</h1>
+        <canvas id="colorPicker" height="300px" width="300px"></canvas>
+    </body>
+</html>