Hello, I'm new to the list. Hello to every one. Sorry if I'm posting this
message in the wrong place. If so please advise me to fix it.
I was asked to make a PDF functionality called Fast Web View work in a
Tomcat application. In my initial tests, as I will describe, it did not
worked.
I started downloading the version 6.0.18 and after that I downloaded the
trunk SVN branch and compiled every thing (comment: a hard job at the
first time, ah? sorry, I had many web proxy issues),
I wrote a small HTML just for testing purpose. The "index.html" file is
something like:
http://www.w3.org/TR/html4/strict.dtd";>
FIRST_FAST_WEB_VIEW_READY.PDF
32.09 MB
SECOND_FAST_WEB_VIEW_READY.PDF
41.72 MB
NTH_FAST_WEB_VIEW_READY.PDF
25.83 MB
I just created a folder in the webapps folder named PDFs and placed
everything there.
When I started Tomcat, opened the page and click on the first PDF link (on
other link the result was the same) with the address
http://localhost:8080/PDFs/, I got the following result:
- The file was found by Tomcat
- Adobe Reader works properlly requesting a "byte served" content (I also
configured the property useAcceptRanges on the web.xml file)
- Tomcat returned a header response 200 OK and some data
- Adobe requests a partial content with a few range descriptors like:
500-999, 7000-7999 (I rounded the sample here)
- Tomcat send a response (http 206) multipart/byterange for the above
ranges
- Adobe Reader locks and don't ask any more ranges
- The browser also locks and after a long wait time it returns a error
message of problems on file.
I started them analysing the response stream with an http protocol
analyser plug-in for the browser.
In the RFC2616 I noted that the response should be as the below sample
cutted from the RFC2616:
HTTP/1.1 206 Partial Content
Date: Wed, 15 Nov 1995 06:25:24 GMT
Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
--THIS_STRING_SEPARATES
Content-type: application/pdf
Content-range: bytes 500-999/8000
...the first range...
--THIS_STRING_SEPARATES
Content-type: application/pdf
Content-range: bytes 7000-7999/8000
...the second range
--THIS_STRING_SEPARATES--
But I noted that Tomcat was returning the following stream:
HTTP/1.1 206 Partial Content
Date: Wed, 15 Nov 1995 06:25:24 GMT
Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
--THIS_STRING_SEPARATES
Content-range: bytes 500-999/8000
...the first range...
--THIS_STRING_SEPARATES
Content-range: bytes 7000-7999/8000
...the second range
--THIS_STRING_SEPARATES--
Please note the lack of the "Content-type: application/pdf" message and
additional line break from the RFC sample and the Tomcat stream.
After some research I found the DefaultServlet Class where the stream for
partial content and multi range requests are served.
On Tomcat 6.0 at java\org\apache\catalina\servlets and on Tomcat 5.5 at
container\catalina\src\share\org\apache\catalina\servlets
The first thing that happens to make it work was the add of
"useAcceptRanges" on the config file (web.xml) and the fix for it on
Tomcat 6.0.x class source code on the SVN repository (thankyou). It really
made difference because the HTTP header response must have "Accept-Ranges:
bytes" string to allow clients make byte requests (at least Adobe Reader).
The second thing is in the "copy" methods. There is a check for the
"contentType" variable and for any reason the method that try to retrieve
its value, before the call for "copy" method, is always returning null.
So, in the if statement within the "copy" methods:
if (contentType != null)
ostream.println("Content-Type: " + contentType);
and
if (contentType != null)
writer.println("Content-type: " + contentType);
I added a "forced" result of :
if (contentType != null)
ostream.println("Content-type: " + contentType);
else
ostream.println("Content-type: application/pdf");
and
if (contentType != null)
writer.println("Content-type: " + contentType);
else
writer.println("Content-type: application/pdf");
In my environment it is sufficient because my big deal is with PDF files,
but I know that it is not the most elegant solution neither can be a
definitive solution.
As I am not a java programmer, I ask for the list to handle this issue.
If it sound completely nuts please forgive me.
I'm available to help with tests for this issue. Please contact me through
the list or directly.
Best regards to all.
Sincerely,
Antonio Vitor Elias Swaid Jr
Technical Publications
