extmod/webrepl: Allow the page to run from the device (over HTTP).

The device will respond to a non-WS request with a simple page that loads
websocket_content.js from a static host (http or https). However, even
if the resources are https, the page is still http and therefore allows
requesting to a WS (not WSS) websocket on the device.

Removed unused client_handshake from websocket_helper, and then merges the
remainder of this file (server_handshake) into webrepl.py (to reduce
firmware size). Also added the respond-as-HTTP handling to
server_handshake.

The default HTTP response is a simple page that sets the base URL and then
loads webrepl_content.js which document.write's the actual HTML.

Signed-off-by: Jim Mussared <[email protected]>

Author: jimmo

extmod/webrepl/manifest.py

@@ -1 +1 @@
-freeze(".", ("webrepl.py", "webrepl_setup.py", "websocket_helper.py"))
+freeze(".", ("webrepl.py", "webrepl_setup.py"))

extmod/webrepl/webrepl.py

@@ -1,14 +1,93 @@
 # This module should be imported from REPL, not run from command line.
-import socket
-import uos
+import binascii
+import hashlib
 import network
-import uwebsocket
-import websocket_helper
+import os
+import socket
+import sys
+import websocket
 import _webrepl
 
 listen_s = None
 client_s = None
 
+DEBUG = 0
+
+_DEFAULT_STATIC_HOST = const("https://micropython.org/webrepl/")
+static_host = _DEFAULT_STATIC_HOST
+
+
+def server_handshake(cl):
+    req = cl.makefile("rwb", 0)
+    # Skip HTTP GET line.
+    l = req.readline()
+    if DEBUG:
+        sys.stdout.write(repr(l))
+
+    webkey = None
+    upgrade = False
+    websocket = False
+
+    while True:
+        l = req.readline()
+        if not l:
+            # EOF in headers.
+            return False
+        if l == b"\r\n":
+            break
+        if DEBUG:
+            sys.stdout.write(l)
+        h, v = [x.strip() for x in l.split(b":", 1)]
+        if DEBUG:
+            print((h, v))
+        if h == b"Sec-WebSocket-Key":
+            webkey = v
+        elif h == b"Connection" and b"Upgrade" in v:
+            upgrade = True
+        elif h == b"Upgrade" and v == b"websocket":
+            websocket = True
+
+    if not (upgrade and websocket and webkey):
+        return False
+
+    if DEBUG:
+        print("Sec-WebSocket-Key:", webkey, len(webkey))
+
+    d = hashlib.sha1(webkey)
+    d.update(b"258EAFA5-E914-47DA-95CA-C5AB0DC85B11")
+    respkey = d.digest()
+    respkey = binascii.b2a_base64(respkey)[:-1]
+    if DEBUG:
+        print("respkey:", respkey)
+
+    cl.send(
+        b"""\
+HTTP/1.1 101 Switching Protocols\r
+Upgrade: websocket\r
+Connection: Upgrade\r
+Sec-WebSocket-Accept: """
+    )
+    cl.send(respkey)
+    cl.send("\r\n\r\n")
+
+    return True
+
+
+def send_html(cl):
+    cl.send(
+        b"""\
+HTTP/1.0 200 OK\r
+\r
+<base href=\""""
+    )
+    cl.send(static_host)
+    cl.send(
+        b"""\"></base>\r
+<script src="webrepl_content.js"></script>\r
+"""
+    )
+    cl.close()
+
 
 def setup_conn(port, accept_handler):
     global listen_s
@@ -25,48 +104,58 @@ def setup_conn(port, accept_handler):
     for i in (network.AP_IF, network.STA_IF):
         iface = network.WLAN(i)
         if iface.active():
-            print("WebREPL daemon started on ws://%s:%d" % (iface.ifconfig()[0], port))
+            print("WebREPL server started on http://%s:%d/" % (iface.ifconfig()[0], port))
     return listen_s
 
 
 def accept_conn(listen_sock):
     global client_s
     cl, remote_addr = listen_sock.accept()
-    prev = uos.dupterm(None)
-    uos.dupterm(prev)
+
+    if not server_handshake(cl):
+        send_html(cl)
+        return False
+
+    prev = os.dupterm(None)
+    os.dupterm(prev)
     if prev:
         print("\nConcurrent WebREPL connection from", remote_addr, "rejected")
         cl.close()
-        return
+        return False
     print("\nWebREPL connection from:", remote_addr)
     client_s = cl
-    websocket_helper.server_handshake(cl)
-    ws = uwebsocket.websocket(cl, True)
+
+    ws = websocket.websocket(cl, True)
     ws = _webrepl._webrepl(ws)
     cl.setblocking(False)
     # notify REPL on socket incoming data (ESP32/ESP8266-only)
-    if hasattr(uos, "dupterm_notify"):
-        cl.setsockopt(socket.SOL_SOCKET, 20, uos.dupterm_notify)
-    uos.dupterm(ws)
+    if hasattr(os, "dupterm_notify"):
+        cl.setsockopt(socket.SOL_SOCKET, 20, os.dupterm_notify)
+    os.dupterm(ws)
+
+    return True
 
 
 def stop():
     global listen_s, client_s
-    uos.dupterm(None)
+    os.dupterm(None)
     if client_s:
         client_s.close()
     if listen_s:
         listen_s.close()
 
 
 def start(port=8266, password=None, accept_handler=accept_conn):
+    global static_host
     stop()
     webrepl_pass = password
     if webrepl_pass is None:
         try:
             import webrepl_cfg
 
             webrepl_pass = webrepl_cfg.PASS
+            if hasattr(webrepl_cfg, "BASE"):
+                static_host = webrepl_cfg.BASE
         except:
             print("WebREPL is not configured, run 'import webrepl_setup'")
 
@@ -75,7 +164,9 @@ def start(port=8266, password=None, accept_handler=accept_conn):
 
     if accept_handler is None:
         print("Starting webrepl in foreground mode")
-        accept_conn(s)
+        # Run accept_conn to serve HTML until we get a websocket connection.
+        while not accept_conn(s):
+            pass
     elif password is None:
         print("Started webrepl in normal mode")
     else:

extmod/webrepl/webrepl_setup.py

@@ -1,6 +1,5 @@
 import sys
 
-# import uos as os
 import os
 import machine