[Twisted-web] Bug found 1.3.0 twisted.web.static module

[Mike Marchionna]

This bug has occurs when a client request partial content of a
static.File resource.

 

There are three problems.

 

1)    The Content-Length header value is off by 1.  For example a
request with a Range: bytes=0-1999 would yield Content-Length of 1999
when it should actually be Content-Length: 2000.

2)    The Content-Range response header was generated incorrectly.  For
example the request with a Range: bytes=0-1999 header for a file of
100000 bytes in size would yield a Content-Range header like
Content-Range:  bytes 0-1999/1999, when it should be Content-Range:
bytes 0-1999/100000.

3)    The ASISProcessor incorrectly instantiated the File instance by
passing a registry parameter to the defaultType argument.

 

 

The diffs are as follows:

 

diff -u static.py.orig static.py

--- static.py.orig      2005-02-09 18:52:35.422310000 -0800

+++ static.py     2005-02-09 19:11:23.181906600 -0800

@@ -319,7 +319,7 @@

             return self.redirect(request)

 

         #for content-length

-        fsize = size = self.getFileSize()

+        fsize = csize = self.getFileSize()

 

         request.setHeader('accept-ranges','bytes')

 

@@ -350,20 +350,19 @@

                        "Syntactically invalid http range header!"

                 start, end = string.split(bytesrange[1],'-')

                 if start:

-                    f.seek(int(start))

+                    start = int(start)

+                    f.seek(start)

                 if end:

-                    end = int(end)

-                    size = end

+                    csize = int(end) - start + 1

                 else:

-                    end = size

+                    csize -= start

                 request.setResponseCode(http.PARTIAL_CONTENT)

-                request.setHeader('content-range',"bytes %s-%s/%s " % (

-                    str(start), str(end), str(size)))

-                #content-length should be the actual size of the stuff
we're

-                #sending, not the full size of the on-server entity.

-                fsize = end - int(start)

+                request.setHeader('content-range',"bytes %s-%s/%s " % \

+                                  (start, end, fsize))

+            #content-length should be the actual size of the stuff
we're

+            #sending, not the full size of the on-server entity.

+            request.setHeader('content-length', str(csize))

 

-            request.setHeader('content-length', str(fsize))

         except:

             traceback.print_exc(file=log.logfile)

 

@@ -371,7 +370,7 @@

             return ''

 

         # return data

-        FileTransfer(f, size, request)

+        FileTransfer(f, csize, request)

         # and make sure the connection doesn't get closed

         return server.NOT_DONE_YET

 

@@ -422,17 +421,16 @@

         self.file = file

         self.size = size

         self.request = request

-        self.written = self.file.tell()

         request.registerProducer(self, 0)

 

     def resumeProducing(self):

         if not self.request:

             return

-        data = self.file.read(min(abstract.FileDescriptor.bufferSize,
self.size - self.written))

+        data = self.file.read(min(abstract.FileDescriptor.bufferSize,
self.size))

         if data:

-            self.written += len(data)

             self.request.write(data)

-        if self.file.tell() == self.size:

+            self.size -= len(data)

+        if self.size <= 0:

             self.request.unregisterProducer()

             self.request.finish()

             self.request = None

@@ -473,5 +471,5 @@

 

     def render(self, request):

         request.startedWriting = 1

-        res = static.File(self.path, self.registry)

+        res = static.File(self.path, registry=self.registry)

         return res.render(request)

 

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