[jira] [Created] (TIKA-1085) PDF header and mime detection

["Marco Quaranta (JIRA)" <ji...@apache.org>]

Marco Quaranta created TIKA-1085:
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             Summary: PDF header and mime detection
                 Key: TIKA-1085
                 URL: https://issues.apache.org/jira/browse/TIKA-1085
             Project: Tika
          Issue Type: Bug
          Components: mime
    Affects Versions: 1.3
            Reporter: Marco Quaranta
            Priority: Minor


I've found some PDF files Tika recognizes as application/octet-stream.
These files differs from regularly identified PDF having a different header: the %PDF-N.n string isn't at the beginning (zero offset) of the file but in the first 1024 bytes.

PDF reference states that "The first line of a PDF file shall be a header consisting of the 5 characters  %PDF–  followed by a version 
number of the form 1.N, where N is a digit between 0 and 7" (http://tinyurl.com/8vnzm3c "p. 7.5.2 File Header"). 

Looking further at implementation notes by Adobe (http://tinyurl.com/cbqpb24 p. 3.4.1 File Header) I've discover that: "Acrobat viewers require only that the header appear somewhere within the first 1024 bytes of the file"
What do you think about a PDF magic match with an offset 0:1024?

<match value="%PDF-" type="string" offset="0:1024"/>

Thank you,
Marco

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