feat: Add Content-Length and Connection headers to the response (automatically)

falcon/api.py

@@ -13,7 +13,7 @@ class Api:
     def __init__(self):
         self.routes = {}
 
-    def __call__(self, environ, start_response):
+    def __call__(self, env, start_response):
         """WSGI protocol handler"""
 
         # PERF: Use literal constructor for dicts
@@ -22,51 +22,27 @@ class Api:
         # TODO
         # ctx.update(global_ctx_for_route)
 
-        path = environ['PATH_INFO']
-        req = Request(path)
-
+        req = Request(env)
         resp = Response()
 
         # PERF: Use try...except blocks when the key usually exists
         try:
             # TODO: Figure out a way to use codegen to make a state machine,
             #       may have to in order to support URI templates.
-            handler = self.routes[path]
+            handler = self.routes[req.path]
         except KeyError:
             handler = path_not_found_handler
 
-        try:
-            handler(ctx, req, resp)
-        except Exception as ex:
-            # TODO
-            pass
+        handler(ctx, req, resp)
 
-        resp.set_header('Content-Type', 'text/plain')
+        #
+        # Set status and headers
+        #
+        self._set_auto_resp_headers(env, req, resp)
+        start_response(resp.status, resp._wsgi_headers())
 
-        # Consider refactoring into functions, but be careful since that can 
-        # affect performance...
-
-        body = resp.body
-        content_length = 0
-        try:
-            if body is not None:
-                content_length = len(body)
-        except Exception as ex:
-            #TODO
-            pass
-
-        resp.set_header('Content-Length', content_length)
-        headers = resp._wsgi_headers()
-
-        try:
-            start_response(resp.status, headers)
-        except Exception as ex:
-            # TODO
-            pass
-
-        # PERF: Can't predict ratio of empty body to nonempty, so use
-        #       "in" which is a good all-around performer.
-        return [body] if body is not None else []
+        # Return an iterable for the body, per the WSGI spec
+        return [resp.body] if resp.body is not None else []
 
     def add_route(self, uri_template, handler):
         self.routes[uri_template] = handler
@@ -76,4 +52,27 @@ class Api:
     # Helpers
     # -------------------------------------------------------------------------
 
+    def _set_auto_resp_headers(self, env, req, resp):
+        resp.set_header('Content-Type', 'text/plain')
+
+        # Set Content-Length when given a fully-buffered body
+        if resp.body is not None:
+            resp.set_header('Content-Length', len(resp.body))
+        elif resp.stream is not None:
+            # TODO: Transfer-Encoding: chunked
+            # TODO: if resp.stream_len is not None, don't use chunked
+            pass
+        else:
+            resp.set_header('Content-Length', 0)
+
+
+        # Enable Keep-Alive when appropriate
+        if env['SERVER_PROTOCOL'] != 'HTTP/1.0':
+            if req.get_header('Connection') == 'close':
+                connection = 'close'
+            else:
+                connection = 'Keep-Alive'
+
+            resp.set_header('Connection', connection)
+
 

falcon/request.py

@@ -1,5 +1,28 @@
 class Request:
-    __slots__ = ('path')
+    __slots__ = ('path', 'headers')
+
+    def __init__(self, env):
+        self.path = env['PATH_INFO']
+        self.headers = headers = {}
+
+        # Extract HTTP headers
+        for key in env:
+            if key.startswith('HTTP_'):
+                headers[key[5:]] =  env[key]
+
+    def get_header(self, name, default=None):
+        """Return a header value as a string
+
+        name -- Header name, case-insensitive
+        default -- Value to return in case the header is not found
+
+        """
+
+        headers = self.headers
+
+        # Optimize for the header existing in most cases
+        try:
+            return headers[name.upper()]
+        except KeyError as e:
+            return default
 
-    def __init__(self, path):
-        self.path = path

falcon/response.py

@@ -1,11 +1,14 @@
 class Response:
-    __slots__ = ('status', '_headers', 'body', 'stream')
+    __slots__ = ('status', '_headers', 'body', 'stream', 'stream_len')
 
     def __init__(self):
         self.status = None
+
         self._headers = {}
+
         self.body = None
         self.stream = None
+        self.stream_len = None
 
     def set_header(self, name, value):
         self._headers[name] = str(value)
@@ -13,4 +16,4 @@ class Response:
     #TODO: Add some helper functions and test them
 
     def _wsgi_headers(self):
-        return [t for t in self._headers.items()]
+        return [t for t in self._headers.items()]

test/dump_wsgi.py

@@ -1,3 +1,4 @@
+
 def application(environ, start_response):
     start_response("200 OK", [('Content-Type', 'text/plain')])
 
@@ -10,7 +11,9 @@ def application(environ, start_response):
 
     return body
 
-import gevent, gevent.wsgi
 
-server = gevent.wsgi.WSGIServer(('localhost', 8000), application)
-server.serve_forever()
+if __name__ == '__main__':
+    from wsgiref.simple_server import make_server
+
+    server = make_server('localhost', 8000, application)
+    server.serve_forever()

test/helpers.py

@@ -31,8 +31,9 @@ class TestSuite(testtools.TestCase):
         if hasattr(prepare, '__call__'):
             prepare()
 
-    def _simulate_request(self, path):
-        self.api(create_environ(path), self.srmock)
+    def _simulate_request(self, path, protocol='HTTP/1.1', headers=None):
+        self.api(create_environ(path=path, protocol=protocol, headers=headers),
+                 self.srmock)
 
 class RandChars:
     _chars = 'abcdefghijklqmnopqrstuvwxyz0123456789 \n\t!@#$%^&*()-_=+`~<>,.?/'
@@ -54,12 +55,12 @@ class RandChars:
 def rand_string(min, max):
     return ''.join([c for c in RandChars(min, max)])
 
-def create_environ(path='/', query_string=''):
-    return {
+def create_environ(path='/', query_string='', protocol='HTTP/1.1', headers=None):
+    env = {
         'SERVER_SOFTWARE': 'WSGIServer/0.1 Python/2.7.3',
         'TERM_PROGRAM_VERSION': '309',
         'REQUEST_METHOD': 'GET',
-        'SERVER_PROTOCOL': 'HTTP/1.1',
+        'SERVER_PROTOCOL': protocol,
         'HOME': '/Users/kurt',
         'DISPLAY': '/tmp/launch-j5GrQm/org.macosforge.xquartz:0',
         'TERM_PROGRAM': 'Apple_Terminal',
@@ -100,3 +101,9 @@ def create_environ(path='/', query_string=''):
         'REMOTE_HOST': '1.0.0.127.in-addr.arpa',
         'COMMAND_MODE': 'unix2003'
     }
+
+    if headers is not None:
+        for name, value in headers.iteritems():
+            env['HTTP_' + name.upper()] = value.strip()
+
+    return env

test/test_headers.py

@@ -1,12 +1,14 @@
 import testtools
 import random
 
-from testtools.matchers import Equals, MatchesRegex, Contains
+from testtools.matchers import Equals, MatchesRegex, Contains, Not
 
 import falcon
 import test.helpers as helpers
 
-# TODO: Framework adds keep-alive and either chunked or content-length
+
+# TODO: Automatically set text encoding to UTF-8 for plaintext (?)
+# TODO: Chunked when streams are set
 # TODO: Test setting various headers, and seeing that Falcon doesn't override custom ones, but will set them if not present (or not?)
 # TODO: Test correct content length is set
 # TODO: Test calling set_header with bogus arguments
@@ -14,6 +16,9 @@ import test.helpers as helpers
 # TODO: Helper functions for getting and setting common headers
 # TODO: Any default headers, such as content-type?
 # TODO: if status is 1xx, 204, or 404 ignore body, don't set content-length
+# TODO: Test passing through all headers in req object (HTTP_* in WSGI env) - better to do lazy eval
+# TODO: Header names must be lower-case on lookup - test bogus, defaults
+# TODO: HTTP_HOST, if present, should be used in preference to SERVER_NAME
 
 class RequestHandler:
     sample_status = "200 OK"
@@ -36,12 +41,48 @@ class TestHeaders(helpers.TestSuite):
         self.on_hello = RequestHandler()
         self.api.add_route(self.test_route, self.on_hello)
 
-    def test_auto_headers(self):
+    def test_content_length(self):
         self._simulate_request(self.test_route)
 
         headers = self.srmock.headers
 
-        content_length = ('Content-Length', str(len(self.on_hello.sample_body)))
-        self.assertThat(headers, Contains(content_length))
+        # Test Content-Length header set
+        content_length = str(len(self.on_hello.sample_body))
+        content_length_header = ('Content-Length', content_length)
+        self.assertThat(headers, Contains(content_length_header))
 
+    def test_keep_alive_http_1_1(self):
+        self._simulate_request(self.test_route, protocol='HTTP/1.1')
+        headers = self.srmock.headers
 
+        # Test Keep-Alive assumed on by default (HTTP/1.1)
+        connection_header = ('Connection', 'Keep-Alive')
+        self.assertThat(headers, Contains(connection_header))
+
+    def test_no_keep_alive_http_1_1(self):
+        req_headers = {'Connection': 'close'}
+        self._simulate_request(self.test_route, protocol='HTTP/1.1',
+                               headers=req_headers)
+        headers = self.srmock.headers
+
+        # Test Keep-Alive assumed on by default (HTTP/1.1)
+        connection_header = ('Connection', 'Keep-Alive')
+        self.assertThat(headers, Not(Contains(connection_header)))
+
+    def test_no_implicit_keep_alive_http_1_0(self):
+        self._simulate_request(self.test_route, protocol='HTTP/1.0')
+        headers = self.srmock.headers
+
+        # Test Keep-Alive assumed on by default (HTTP/1.1)
+        connection_header = ('Connection', 'Keep-Alive')
+        self.assertThat(headers, Not(Contains(connection_header)))
+
+    def test_no_explicit_keep_alive_http_1_0(self):
+        req_headers = {'Connection': 'Keep-Alive'}
+        self._simulate_request(self.test_route, protocol='HTTP/1.0',
+                               headers=req_headers)
+        headers = self.srmock.headers
+
+        # Test Keep-Alive assumed on by default (HTTP/1.1)
+        connection_header = ('Connection', 'Keep-Alive')
+        self.assertThat(headers, Not(Contains(connection_header)))

test/todo.md

@@ -1,9 +1,14 @@
 
+Functionality
+
 * Test sending/receiving various status codes
+* Chunked transfer encoding, streaming 0, some, and lots of bytes
+  * Add tips to NOTES.md
+  * Framework should automatically set content-length for smaller streams, and only enable chunked encoding for really big ones AND when *not* using HTTP/1.0.
 * Ensure req dict has things the app needs, including path, user agent, various headers.
 * Test default http status code (200 OK?)
 * Test compiling routes, throwing on invalid routes (such as missing initial forward slash or non-ascii)
-* Test setting the body to a stream, rather than a string (and content-length set to chunked?)
+* Figure out encoding of body and stream - test that the framework requires byte strings or a byte string generator (for body and stream attributes of resp, respectively)
 * Test custom error handlers - customizing error document at least
 * Test async middleware ala rproxy
 * Test setting different routes for different verbs
@@ -17,4 +22,9 @@
 * Test pre/post filters
 * Test error handling with standard response (for all error classes?)
 * Test passing bogus data to create_api and/or add_route
+
+Performance
+
+* Test inlining functions, maybe make a tool that does this automatically
+* Try using a closure to generate the WSGI request handler (vs. a class)