Planet PDF Forum Archive

Planet PDF ForumWowsers! This is page is old, head to the LIVE Planet PDF Forum. It features more than 10 conferences, covering everything from beginner to in-depth developer and pre-press discussions. If you wish to continue... one & two archive covers 1999-2011 (160,000 pages).


New Forum | Previous | Next | (P-PDF) Developers


Topic: FDF Comments not be loaded with PDF
Conf: (P-PDF) Developers, Msg: 87476
From: svick
Date: 5/10/2003 12:49 AM

Intermittently comments will not be loaded with a pdf file despite using the proper webdav collaboration settings.

We load a template.fdf file which points to the pdf url and the fdf root folder. See sample below.

%FDF-1.3
%
1 0 obj
<<
/FDF
<<
/F (http://adproofing.XXX.com/00035/00035.1.2.091.pdf)
/JavaScript
<<
/After 2 0 R
>>
>>
>>
endobj
2 0 obj
<<
>>
stream
Collab.defaultStore = "DAVFDF";
Collab.setStoreSettings("DAVFDF", "http://adproofing.XXX.com/adproofing/FDFs/");
endstream
endobj
trailer
<<
/Root 1 0 R
>>
%%EOF

The collaboration settings are properly set in template fdf file. Adobe should then use the MD5 hash algorithm to determine if any comments are available. For this example the following path would contain an fdf file.

http://adproofing.XXX.com/adproofing/FDFs/q-MQkI2GAKgImGTFjyFFzA/

For explanation see the below excerpt from the Adobe OnlineComments.pdf document.

2.3 Data Structure
When the user opens a PDF in the browser, Acrobat reads the URL from the network layer, and then
uses Domain Name Servers (DNS) to translate the name to an IP address. The DNS conversion
guarantees that the comments will be stored in the correct repository regardless of whether or not
the users use the same URL to access the collaboration document. Acrobat then takes the converted
URL and makes an MD5 hash. For example: http://www.adobe.com/docs/foo.pdf would be
converted to http://152.30.132.12/docs/foo.pdf, which would hash into
UAtOJErFgHsL2xbLvPPJgC. More information on MD5 hash can be found in RFC 1321 or in many
places on the web, such as http://www.ietf.org/rfc/rfc1321.txt.
Note: There is no way to reverse the MD5 hash to obtain the URL.
Do not change the location of the collaboration document until the period of collaboration is over.
The folder names are based on the URL of the original document. If the location of the collaboration
document is changed and more comments are added, the new comments will not be saved in
the same location as the initial comments.
When working with multiple versions of a document, name each version differently; otherwise the
comments will not align properly. In the example above, the MD5 hash for
http://152.30.132.12/docs/foo.pdf is UAtOJErFgHsL2xbLvPPJgC, while the MD5 hash for
http://152.30.132.12/docs/foo2.pdf is 1N2AwJKLt6BxpzjHp4_W7B. If one was to revise
foo.pdf and place the updated document in the same location without changing the file name to
reflect the version, the comments saved under that hash would not correlate to the new document.
Highlighting may exist where there are no longer any words, or there may be line drawings correcting
a diagram that is now on another page.

Despite there being a proper FDF file in this directory, (lroyal.fdf) Adobe does not load the fdf and comments are not displayed. The fdf file does not appear to be corrupt as when the fdf file is loaded it retrieves the pdf file and the proof displays as expected.

This problem does not occur predictably and does not generate any error messages when comments are not loaded. Is there a recomended maximum limit to the number of these collaboration folders? Is a collision possible in this MD5 algorithm and if so could it cause the problem we have experienced.

Any Ideas?

-Stephen Vick


PDF In-Depth Free Product Trials Ubiquitous PDF

Debenu Aerialist

The ultimate plug-in for Adobe Acrobat. Advanced splitting, merging, stamping, bookmarking, and link...

Download free demo

Debenu PDF Tools Pro

It's simple to use and will let you preview and edit PDF files, it's a Windows application that makes...

Download free demo

Back to the past, 15 years ago! Open Publish 2002

Looking back to 2002, it's amazing how much of the prediction became a reality. Take a read and see what you think!

September 14, 2017
Platinum Sponsor





Search Planet PDF
more searching options...
Planet PDF Newsletter
Most Popular Articles
Featured Product

Debenu PDF Aerialist

The ultimate plug-in for Adobe Acrobat. Advanced splitting, merging, stamping, bookmarking, and link control. Take Acrobat to the next level.

Features

Adding a PDF Stamp Comment

OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.