Non-Blocking Examples and Tests (#26)

* Added "poll" function/mode (#25)

Adapted from the circuitpython webserver

Co-authored-by: Ran Katz <rkatz@apple.com>

* Merges in code suggestions from @nightmechanic; adds tests; examples for nonblocking mode

Co-authored-by: Ran <rankatz@gmail.com>
Co-authored-by: Ran Katz <rkatz@apple.com>

Author: 3 people

README.md

@@ -49,14 +49,15 @@ pool = socketpool.SocketPool(wifi.radio)
 socket = pool.socket()
 socket.bind(['0.0.0.0', 80])
 socket.listen(1)
+socket.setblocking(True)
 print("Connected to %s, IPv4 Addr: " % secrets["ssid"], wifi.radio.ipv4_address)
 
 while True:
   ampule.listen(socket)
 ```
 
 The majority of this code is CircuitPython boilerplate that connects to a WiFi
-network, listens on port 80, and connects ampule to the open socket.
+network, listens on port 80 in blocking mode, and connects ampule to the open socket.
 
 The line `@ampule.route("/hello/world")` registers the following function for
 the path specified, and responds with HTTP 200, no headers, and a response body

ampule.py

@@ -1,8 +1,9 @@
 import io
 import re
 
+from errno import EAGAIN, ECONNRESET
+
 BUFFER_SIZE = 256
-TIMEOUT = 30
 routes = []
 variable_re = re.compile("^<([a-zA-Z]+)>$")
 
@@ -43,14 +44,12 @@ def __parse_body(reader):
 
 def __read_request(client):
     message = bytearray()
-    client.settimeout(30)
     socket_recv = True
 
     try:
         while socket_recv:
             buffer = bytearray(BUFFER_SIZE)
             client.recv_into(buffer)
-            start_length = len(message)
             for byte in buffer:
                 if byte == 0x00:
                     socket_recv = False
@@ -62,7 +61,7 @@ def __read_request(client):
 
     reader = io.BytesIO(message)
     line = str(reader.readline(), "utf-8")
-    (method, full_path, version) = line.rstrip("\r\n").split(None, 2)
+    (method, full_path, _) = line.rstrip("\r\n").split(None, 2)
 
     request = Request(method, full_path)
     request.headers = __parse_headers(reader)
@@ -133,10 +132,16 @@ def __match_route(path, method):
             return (match.groups(), route)
     return None
 
-def listen(socket, timeout=30):
-    client, remote_address = socket.accept()
+def listen(socket):
+    try:
+        client, _ = socket.accept()
+    except OSError as e:
+        if e.errno == EAGAIN: return
+        if e.errno == ECONNRESET: return
+        print("OS Error with socket:", e)
+        raise e
+
     try:
-        client.settimeout(timeout)
         request = __read_request(client)
         match = __match_route(request.path, request.method)
         if match:

examples/digitalio/led.py

@@ -43,6 +43,7 @@ def light_off(request):
 socket = pool.socket()
 socket.bind(['0.0.0.0', 80])
 socket.listen(1)
+socket.setblocking(True)
 print("Connected to %s, IPv4 Addr: " % secrets["ssid"], wifi.radio.ipv4_address)
 
 while True:

examples/nonblocking/README.md

@@ -0,0 +1,12 @@
+# Non-blocking Socket Example
+
+This example shows how you could use the HTTP service in non-blocking
+mode, allowing you to do other work while waiting for an inbound request
+
+## Examples
+
+To see what the current counter's status is:
+
+```sh
+curl -v http://192.168.0.1:7413/status
+```

examples/nonblocking/count.py

@@ -0,0 +1,47 @@
+import wifi
+import socketpool
+import time
+import ampule
+
+counter = 0
+
+headers = {
+    "Content-Type": "application/json; charset=UTF-8",
+    "Access-Control-Allow-Origin": '*',
+    "Access-Control-Allow-Methods": 'GET, POST',
+    "Access-Control-Allow-Headers": 'Origin, Accept, Content-Type, X-Requested-With, X-CSRF-Token'
+}
+
+@ampule.route("/status")
+def status(request):
+    global counter
+    return (200, headers, '{"counter": %d}' % counter)
+
+try:
+    from secrets import secrets
+except ImportError:
+    print("WiFi secrets not found in secrets.py")
+    raise
+
+try:
+    print("Connecting to %s..." % secrets["ssid"])
+    print("MAC: ", [hex(i) for i in wifi.radio.mac_address])
+    wifi.radio.connect(secrets["ssid"], secrets["password"])
+except:
+    print("Error connecting to WiFi")
+    raise
+
+pool = socketpool.SocketPool(wifi.radio)
+socket = pool.socket()
+socket.bind(['0.0.0.0', 80])
+socket.listen(1)
+socket.setblocking(False)
+print("Connected to %s, IPv4 Addr: " % secrets["ssid"], wifi.radio.ipv4_address)
+
+while True:
+    ampule.listen(socket)
+    counter += 1
+    time.sleep(1.0)
+    print("Counter: ", counter)
+
+

examples/webserver/webpages.py

@@ -88,6 +88,7 @@ def demo(request):
 socket = pool.socket()
 socket.bind(['0.0.0.0', 80])
 socket.listen(1)
+socket.setblocking(True)
 print("Connected to {}, Web server running on http://{}:80".format(secrets["ssid"], wifi.radio.ipv4_address))
 
 while True:

tests/test_body.py

@@ -36,14 +36,3 @@ def test_body_mime():
     ampule.listen(socket)
     socket.send.assert_called_once_with(http_helper.expected_response(200, expected_bytes, expected_header))
     socket.close.assert_called_once()
-
-def test_body_resend():
-    body = "Let me tell you a long rambling story child. Once upon a time there was a coaster on my desk that had a picture of a ship. It was blue. Blue like the ocean? No. Blue like a coaster."
-    socket = mocket.Mocket(("GET /var/get HTTP/1.1\r\n\r\n" + body).encode("utf-8"))
-    ampule.listen(socket)
-    expected = [ # Expect two calls, the second after an 256 byte partial data send
-        mock.call(http_helper.expected_response(200, "GET: "+body)),
-        mock.call(b"e ocean? No. Blue like a coaster.\r\n")
-    ]
-    assert socket.send.mock_calls == expected
-    socket.close.assert_called_once()

tests/test_codes.py

@@ -1,11 +1,33 @@
 import mocket
-from unittest import mock
+from unittest import mock, TestCase
 import ampule
+import errno
 import http_helper
 
-def test_socket_error():
-    socket = mocket.Mocket("GET /bad HTTP/1.1".encode("utf-8"))
-    socket.settimeout = mock.Mock(side_effect=OSError('SetTimeout'))
-    ampule.listen(socket)
-    socket.send.assert_called_once_with(http_helper.expected_response(500, "Error processing request"))
-    socket.close.assert_called_once()
+class MyTestCase(TestCase):
+    def test_socket_error(self):
+        socket = mocket.Mocket("GET /bad HTTP/1.1".encode("utf-8"))
+        socket.accept = mock.Mock(side_effect=OSError('socket failure'))
+        with self.assertRaises(OSError):
+            ampule.listen(socket)
+        socket.send.assert_not_called()
+        socket.close.assert_not_called()
+
+    def test_connection_reset(self):
+        socket = mocket.Mocket("GET /bad HTTP/1.1".encode("utf-8"))
+        socket.accept = mock.Mock(side_effect=OSError(errno.ECONNRESET))
+        socket.send.assert_not_called()
+        socket.close.assert_not_called()
+
+    def test_no_data_currently(self):
+        socket = mocket.Mocket("GET /bad HTTP/1.1".encode("utf-8"))
+        socket.accept = mock.Mock(side_effect=OSError(errno.EAGAIN))
+        socket.send.assert_not_called()
+        socket.close.assert_not_called()
+
+    def test_routing_error(self):
+        socket = mocket.Mocket("GET /bad HTTP/1.1".encode("utf-8"))
+        socket.recv_into = mock.Mock(side_effect=OSError('read failure'))
+        ampule.listen(socket)
+        socket.send.assert_called_once_with(http_helper.expected_response(500, "Error processing request"))
+        socket.close.assert_called_once()

tests/test_io.py

@@ -0,0 +1,19 @@
+import mocket
+from unittest import mock
+import ampule
+import http_helper
+
+@ampule.route("/var/get", method='GET')
+def trailing_variable(request):
+    return (200, {}, "GET: %s" % request.body)
+
+def test_body_resend():
+    body = "Let me tell you a long rambling story child. Once upon a time there was a coaster on my desk that had a picture of a ship. It was blue. Blue like the ocean? No. Blue like a coaster."
+    socket = mocket.Mocket(("GET /var/get HTTP/1.1\r\n\r\n" + body).encode("utf-8"))
+    ampule.listen(socket)
+    expected = [ # Expect two calls, the second after an 256 byte partial data send
+        mock.call(http_helper.expected_response(200, "GET: "+body)),
+        mock.call(b"e ocean? No. Blue like a coaster.\r\n")
+    ]
+    assert socket.send.mock_calls == expected
+    socket.close.assert_called_once()