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Posted to dev@tika.apache.org by "Nick Burch (JIRA)" <ji...@apache.org> on 2015/09/29 15:47:04 UTC

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

     [ https://issues.apache.org/jira/browse/TIKA-1085?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Nick Burch resolved TIKA-1085.
------------------------------
       Resolution: Fixed
    Fix Version/s: 1.9
                   1.10

> PDF header and mime detection
> -----------------------------
>
>                 Key: TIKA-1085
>                 URL: https://issues.apache.org/jira/browse/TIKA-1085
>             Project: Tika
>          Issue Type: Improvement
>          Components: mime
>    Affects Versions: 1.3
>            Reporter: Marco Quaranta
>            Priority: Minor
>              Labels: detection, header, mime, pdf
>             Fix For: 1.10, 1.9
>
>         Attachments: hello-world-bom.pdf, hello-world.pdf, test.pdf
>
>
> 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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