Better error handling

examples/counter.py

@@ -1,5 +1,5 @@
 """
-An endpoint that streams incrementing numbers forever.
+An endpoint that streams numbers counting to 10.
 
 This is an example of how a jetforce application can respond with a generator
 function instead of plain text/bytes. The server will iterate over the
@@ -22,9 +22,7 @@ def blocking_counter():
     The calls to time.sleep(1) will run in the main twisted event loop and
     block all other requests from processing.
     """
-    x = 0
+    for x in range(10):
-    while True:
-        x += 1
         time.sleep(1)
         yield f"{x}\r\n"
 
@@ -44,9 +42,7 @@ def threaded_counter():
         time.sleep(1)
         return f"{x}\r\n"
 
-    x = 0
+    for x in range(10):
-    while True:
-        x += 1
         yield deferToThread(delayed_callback, x)
 
 
@@ -65,9 +61,7 @@ def deferred_counter():
     def delayed_callback(x):
         return f"{x}\r\n"
 
-    x = 0
+    for x in range(10):
-    while True:
-        x += 1
         yield deferLater(reactor, 1, delayed_callback, x)
 
 

jetforce/protocol.py

@@ -6,7 +6,7 @@ import typing
 import urllib.parse
 
 from twisted.internet.address import IPv4Address, IPv6Address
-from twisted.internet.defer import ensureDeferred, maybeDeferred
+from twisted.internet.defer import Deferred, ensureDeferred
 from twisted.internet.task import deferLater
 from twisted.protocols.basic import LineOnlyReceiver
 
@@ -100,18 +100,22 @@ class GeminiProtocol(LineOnlyReceiver):
 
         try:
             environ = self.build_environ()
-            response_generator = await maybeDeferred(
+            response_generator = self.app(environ, self.write_status)
-                self.app, environ, self.write_status
+            if isinstance(response_generator, Deferred):
-            )
+                response_generator = await response_generator
+            else:
                 # Yield control of the event loop
                 await deferLater(self.server.reactor, 0)
-            while True:
+
-                data = await maybeDeferred(response_generator.__next__)
+            for data in response_generator:
-                if data is None:
+                if isinstance(data, Deferred):
-                    break
+                    data = await data
+                    self.write_body(data)
+                else:
                     self.write_body(data)
                     # Yield control of the event loop
                     await deferLater(self.server.reactor, 0)
+
         except Exception:
             self.server.log_message(traceback.format_exc())
             self.write_status(Status.CGI_ERROR, "An unexpected error occurred")