Improved support for different client and server HTTP versions,

including optional Date: and Server: header generation, and support
for SERVER_PROTOCOL.  Added hop-by-hop header check (and utility
function).  Headers() objects also now have a 'setdefault()' method.
The BaseHandler.send_status() method has been replaced by a
send_preamble() method, and you probably no longer need to override it.


git-svn-id: svn://svn.eby-sarna.com/svnroot/wsgiref@252 571e12c6-e1fa-0310-aee7-ff1267fa46bd

6 files changed, 150 insertions, 69 deletions

diff --git a/src/wsgiref/handlers.py b/src/wsgiref/handlers.py
index 287e3bb..2cc8fed 100644
--- a/src/wsgiref/handlers.py
+++ b/src/wsgiref/handlers.py
@@ -1,10 +1,10 @@
 """Base classes for server/gateway implementations"""
 
 from types import StringType
-from util import FileWrapper, guess_scheme
+from util import FileWrapper, guess_scheme, is_hop_by_hop
 from headers import Headers
 
-import sys, os
+import sys, os, time
 
 try:
     dict
@@ -48,6 +48,10 @@ class BaseHandler:
     wsgi_multiprocess = True
     wsgi_run_once = False
 
+    origin_server = True    # We are transmitting direct to client
+    http_version  = "1.0"   # Version that should be used for response
+    server_software = None  # String name of server software, if any
+
     # os_environ is used to supply configuration from the OS environment:
     # by default it's a copy of 'os.environ' as of import time, but you can
     # override this in e.g. your __init__ method.
@@ -76,10 +80,6 @@ class BaseHandler:
 
 
 
-
-
-
-
     def run(self, application):
         """Invoke the application"""
         # Note to self: don't move the close()!  Asynchronous servers shouldn't
@@ -151,17 +151,17 @@ class BaseHandler:
             if blocks==1:
                 self.headers['Content-Length'] = str(self.bytes_sent)
                 return
-        # XXX Try for chunked encoding if enabled
+        # XXX Try for chunked encoding if origin server and client is 1.1
         
 
     def cleanup_headers(self):
-        """Make any necessary header changes or defaults"""
+        """Make any necessary header changes or defaults
+
+        Subclasses can extend this to add other defaults.
+        """
         if not self.headers.has_key('Content-Length'):
             self.set_content_length()
 
-        # XXX set up Date, Server headers 
-
-
     def start_response(self, status, headers,exc_info=None):
         """'start_response()' callable as specified by PEP 333"""
 
@@ -183,25 +183,25 @@ class BaseHandler:
             for name,val in headers:
                 assert type(name) is StringType,"Header names must be strings"
                 assert type(val) is StringType,"Header values must be strings"
-
+                assert not is_hop_by_hop(name),"Hop-by-hop headers not allowed"
         self.status = status
         self.headers = self.headers_class(headers)
         return self.write
 
 
-
-
-
-
-
-
-
-
-
-
-
-
-
+    def send_preamble(self):
+        """Transmit version/status/date/server, via self._write()"""
+        if self.origin_server:
+            if self.client_is_modern():
+                self._write('HTTP/%s %s\r\n' % (self.http_version,self.status))
+                if not self.headers.has_key('Date'):
+                    self._write(
+                        'Date: %s\r\n' % time.asctime(time.gmtime(time.time()))
+                    )
+                if self.server_software and not self.headers.has_key('Server'):
+                    self._write('Server: %s\r\n' % self.server_software) 
+        else:
+            self._write('Status: %s\r\n' % self.status)
 
     def write(self, data):
         """'write()' callable as specified by PEP 333"""
@@ -265,18 +265,13 @@ class BaseHandler:
             self.bytes_sent = 0; self.headers_sent = False
 
 
-    def send_status(self):
-        """Transmit the status to the client, via self._write()
-
-        (BaseCGIHandler overrides this to use a "Status:" prefix.)"""
-        self._write('%s\r\n' % status)
-
     def send_headers(self):
         """Transmit headers to the client, via self._write()"""
         self.cleanup_headers()
         self.headers_sent = True
-        self.send_status()
-        self._write(str(self.headers))
+        if not self.origin_server or self.client_is_modern():
+            self.send_preamble()
+            self._write(str(self.headers))
 
 
     def result_is_file(self):
@@ -285,6 +280,11 @@ class BaseHandler:
         return wrapper is not None and isinstance(self.result,wrapper)
 
 
+    def client_is_modern(self):
+        """True if client can accept status and headers"""
+        return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'
+
+
     def log_exception(self,exc_info):
         """Log the 'exc_info' tuple in the server log
 
@@ -308,6 +308,7 @@ class BaseHandler:
             self.finish_response()
         # XXX else: attempt advanced recovery techniques for HTML or text?
 
+
     def error_output(self, environ, start_response):
         """WSGI mini-app to create error output
 
@@ -325,7 +326,6 @@ class BaseHandler:
         return [self.error_body]    
 
 
-
     # Pure abstract methods; *must* be overridden in subclasses
     
     def _write(self,data):
@@ -384,7 +384,7 @@ class BaseCGIHandler(BaseHandler):
     'multiprocess' (defaulting to 'True' and 'False' respectively) to control
     the configuration sent to the application.
     """
-
+    origin_server = False
     wsgi_multithread = False
     wsgi_multiprocess = True
 
@@ -416,9 +416,6 @@ class BaseCGIHandler(BaseHandler):
         self.stdout.flush()
         self._flush = self.stdout.flush
 
-    def send_status(self):
-        self._write('Status: %s\r\n' % self.status)
-
 
 class CGIHandler(BaseCGIHandler):
     """CGI-based invocation via sys.stdin/stdout/stderr and os.environ
@@ -449,3 +446,6 @@ class CGIHandler(BaseCGIHandler):
 
 
 
+
+
+
diff --git a/src/wsgiref/headers.py b/src/wsgiref/headers.py
index b2d5de4..fa9b829 100644
--- a/src/wsgiref/headers.py
+++ b/src/wsgiref/headers.py
@@ -149,17 +149,17 @@ class Headers:
         suitable for direct HTTP transmission."""
         return '\r\n'.join(["%s: %s" % kv for kv in self._headers]+['',''])
 
-
-
-
-
-
-
-
-
-
-
-
+    def setdefault(self,name,value):
+        """Return first matching header value for 'name', or 'value'
+
+        If there is no header named 'name', add a new header with name 'name'
+        and value 'value'."""
+        result = self.get(name)
+        if result is None:
+            self._headers.append((name,value))
+            return value
+        else:
+            return result
 
 
     def add_header(self, _name, _value, **_params):
diff --git a/src/wsgiref/tests/test_handlers.py b/src/wsgiref/tests/test_handlers.py
index 7d0863f..d56c337 100644
--- a/src/wsgiref/tests/test_handlers.py
+++ b/src/wsgiref/tests/test_handlers.py
@@ -4,7 +4,7 @@ from wsgiref.util import setup_testing_defaults
 from wsgiref.headers import Headers
 from wsgiref.handlers import BaseHandler, BaseCGIHandler
 from StringIO import StringIO
-
+import re
 
 class ErrorHandler(BaseCGIHandler):
     """Simple handler subclass for testing BaseHandler"""
@@ -162,6 +162,46 @@ class HandlerTests(TestCase):
         self.failUnless(h.stderr.getvalue().find("AssertionError")<>-1)
 
 
+    def testHeaderFormats(self):
+
+        def non_error_app(e,s):
+            s('200 OK',[])
+            return []
+
+        stdpat = (
+            r"HTTP/%s 200 OK\r\n"
+            r"Date: \w{3} \w{3} \d{2} \d\d:\d\d:\d\d \d{4}\r\n"
+            r"%s" r"Content-Length: 0\r\n" r"\r\n"
+        )
+        shortpat = (
+            "Status: 200 OK\r\n" "Content-Length: 0\r\n" "\r\n"
+        )
+
+        for ssw in "FooBar/1.0", None:
+            sw = ssw and "Server: %s\r\n" % ssw or ""
+
+            for version in "1.0", "1.1":           
+                for proto in "HTTP/0.9", "HTTP/1.0", "HTTP/1.1":
+                   
+                    h = TestHandler(SERVER_PROTOCOL=proto)
+                    h.origin_server = False
+                    h.http_version = version
+                    h.server_software = ssw
+                    h.run(non_error_app)
+                    self.assertEqual(shortpat,h.stdout.getvalue())
+                
+                    h = TestHandler(SERVER_PROTOCOL=proto)
+                    h.origin_server = True
+                    h.http_version = version
+                    h.server_software = ssw
+                    h.run(non_error_app)   
+                    if proto=="HTTP/0.9":
+                        self.assertEqual(h.stdout.getvalue(),"")
+                    else:
+                        self.failUnless(
+                            re.match(stdpat%(version,sw), h.stdout.getvalue()),
+                            (stdpat%(version,sw), h.stdout.getvalue())
+                        )
 
 TestClasses = (
     HandlerTests,
diff --git a/src/wsgiref/tests/test_headers.py b/src/wsgiref/tests/test_headers.py
index c671dc0..db9afc3 100644
--- a/src/wsgiref/tests/test_headers.py
+++ b/src/wsgiref/tests/test_headers.py
@@ -2,7 +2,6 @@ from unittest import TestCase, TestSuite, makeSuite
 from wsgiref.headers import Headers
 from wsgiref.tests import compare_generic_iter
 
-
 class HeaderTests(TestCase):
 
     def testMappingInterface(self):
@@ -31,14 +30,15 @@ class HeaderTests(TestCase):
 
         self.assertEqual(h.get("foo","whee"), "baz")
         self.assertEqual(h.get("zoo","whee"), "whee")
+        self.assertEqual(h.setdefault("foo","whee"), "baz")
+        self.assertEqual(h.setdefault("zoo","whee"), "whee")
+        self.assertEqual(h["foo"],"baz")
+        self.assertEqual(h["zoo"],"whee")
 
     def testRequireList(self):
         self.assertRaises(TypeError, Headers, "foo")
 
 
-
-
-
     def testExtras(self):
         h = Headers([])
         self.assertEqual(str(h),'\r\n')
diff --git a/src/wsgiref/tests/test_util.py b/src/wsgiref/tests/test_util.py
index 91caac6..b406841 100644
--- a/src/wsgiref/tests/test_util.py
+++ b/src/wsgiref/tests/test_util.py
@@ -84,6 +84,7 @@ class UtilityTests(TestCase):
         for key, value in [
             ('SERVER_NAME','127.0.0.1'),
             ('SERVER_PORT', '80'),
+            ('SERVER_PROTOCOL','HTTP/1.0'),
             ('HTTP_HOST','127.0.0.1'),
             ('REQUEST_METHOD','GET'),
             ('SCRIPT_NAME',''),
@@ -120,7 +121,6 @@ class UtilityTests(TestCase):
 
 
 
-
     def testAppURIs(self):
         self.checkAppURI("http://127.0.0.1/")
         self.checkAppURI("http://127.0.0.1/spam", SCRIPT_NAME="/spam")
@@ -146,20 +146,20 @@ class UtilityTests(TestCase):
     def testFileWrapper(self):
         self.checkFW("xyz"*50, 120, ["xyz"*40,"xyz"*10])
 
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+    def testHopByHop(self):
+        for hop in (
+            "Connection Keep-Alive Proxy-Authenticate Proxy-Authorization "
+            "TE Trailers Transfer-Encoding Upgrade"
+        ).split():
+            for alt in hop, hop.title(), hop.upper(), hop.lower():
+                self.failUnless(util.is_hop_by_hop(alt))
+
+        # Not comprehensive, just a few random header names
+        for hop in (
+            "Accept Cache-Control Date Pragma Trailer Via Warning"
+        ).split():
+            for alt in hop, hop.title(), hop.upper(), hop.lower():
+                self.failIf(util.is_hop_by_hop(alt))
 
 
 TestClasses = (
diff --git a/src/wsgiref/util.py b/src/wsgiref/util.py
index dd6f79c..1a8bd9a 100644
--- a/src/wsgiref/util.py
+++ b/src/wsgiref/util.py
@@ -135,6 +135,8 @@ def setup_testing_defaults(environ):
     """
 
     environ.setdefault('SERVER_NAME','127.0.0.1')
+    environ.setdefault('SERVER_PROTOCOL','HTTP/1.0')
+
     environ.setdefault('HTTP_HOST',environ['SERVER_NAME'])
     environ.setdefault('REQUEST_METHOD','GET')
 
@@ -160,5 +162,44 @@ def setup_testing_defaults(environ):
 
 
 
+_hoppish = {
+    'connection':1, 'keep-alive':1, 'proxy-authenticate':1,
+    'proxy-authorization':1, 'te':1, 'trailers':1, 'transfer-encoding':1,
+    'upgrade':1
+}.has_key
+
+def is_hop_by_hop(header_name):
+    """Return true if 'header_name' is an HTTP/1.1 "Hop-by-Hop" header"""
+    return _hoppish(header_name.lower())
+
+    
+
+
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