[jira] [Commented] (TIKA-2771) enableInputFilter() wrecks charset detection for some short html documents

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[jira] [Commented] (TIKA-2771) enableInputFilter() wrecks charset detection for some short html documents

JIRA jira@apache.org

    [ https://issues.apache.org/jira/browse/TIKA-2771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16677340#comment-16677340 ]

Hans Brende commented on TIKA-2771:
-----------------------------------

[~[hidden email]] I've implemented my ideas for charset detection improvement in [this pull request|https://github.com/apache/any23/pull/131] over in Any23. If you have time to look it over, I'd appreciate any feedback you can give. Some of it might be useful for Tika as well (as I've taken into account a few open issues here).

> enableInputFilter() wrecks charset detection for some short html documents
> --------------------------------------------------------------------------
>
>                 Key: TIKA-2771
>                 URL: https://issues.apache.org/jira/browse/TIKA-2771
>             Project: Tika
>          Issue Type: Bug
>          Components: detector
>    Affects Versions: 1.19.1
>            Reporter: Hans Brende
>            Priority: Critical
>
> When I try to run the CharsetDetector on http://w3c.github.io/microdata-rdf/tests/0065.html I get the very strange most confident result of "IBM500" with a confidence of 60 when I enable the input filter, *even if I set the declared encoding to UTF-8*.
> This can be replicated with the following code:
> {code:java}
> CharsetDetector detect = new CharsetDetector();
> detect.enableInputFilter(true);
> detect.setDeclaredEncoding("UTF-8");
> detect.setText(("<!DOCTYPE html>\n" +
>         "<div>\n" +
>         "  <div itemscope itemtype=\"http://schema.org/Person\" id=\"amanda\" itemref=\"a b\"></div>\n" +
>         "  <p id=\"a\">Name: <span itemprop=\"name\">Amanda</span></p>\n" +
>         "  <p id=\"b\" itemprop=\"band\">Jazz Band</p>\n" +
>         "</div>").getBytes(StandardCharsets.UTF_8));
> Arrays.stream(detect.detectAll()).forEach(System.out::println);
> {code}
> which prints:
> {noformat}
> Match of IBM500 in fr with confidence 60
> Match of UTF-8 with confidence 57
> Match of ISO-8859-9 in tr with confidence 50
> Match of ISO-8859-1 in en with confidence 50
> Match of ISO-8859-2 in cs with confidence 12
> Match of Big5 in zh with confidence 10
> Match of EUC-KR in ko with confidence 10
> Match of EUC-JP in ja with confidence 10
> Match of GB18030 in zh with confidence 10
> Match of Shift_JIS in ja with confidence 10
> Match of UTF-16LE with confidence 10
> Match of UTF-16BE with confidence 10
> {noformat}
> Note that if I do not set the declared encoding to UTF-8, the result is even worse, with UTF-8 falling from a confidence of 57 to 15.
> This is screwing up 1 out of 84 of my online microdata extraction tests over in Any23 (as that particular page is being rendered into complete gibberish), so I had to implement some hacky workarounds which I'd like to remove if possible.
> EDIT: This issue may be related to TIKA-2737 and [this comment|https://issues.apache.org/jira/browse/TIKA-539?focusedCommentId=13213524&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13213524].



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