NAME

ExtractText - extracts text from documenmts.

SYNOPSIS

loadplugin Mail::SpamAssassin::Plugin::ExtractText

ifplugin Mail::SpamAssassin::Plugin::ExtractText

  extracttext_external  pdftotext  /usr/bin/pdftotext -nopgbrk -layout -enc UTF-8 {} -
  extracttext_use       pdftotext  .pdf application/pdf

  # http://docx2txt.sourceforge.net
  extracttext_external  docx2txt   /usr/bin/docx2txt {} -
  extracttext_use       docx2txt   .docx application/docx

  extracttext_external  antiword   /usr/bin/antiword -t -w 0 -m UTF-8.txt {}
  extracttext_use       antiword   .doc application/(?:vnd\.?)?ms-?word.*

  extracttext_external  unrtf      /usr/bin/unrtf --nopict {}
  extracttext_use       unrtf      .doc .rtf application/rtf text/rtf

  extracttext_external  odt2txt    /usr/bin/odt2txt --encoding=UTF-8 {}
  extracttext_use       odt2txt    .odt .ott application/.*?opendocument.*text
  extracttext_use       odt2txt    .sdw .stw application/(?:x-)?soffice application/(?:x-)?starwriter

  extracttext_external  tesseract  {OMP_THREAD_LIMIT=1} /usr/bin/tesseract -c page_separator= {} -
  extracttext_use       tesseract  .jpg .png .bmp .tif .tiff image/(?:jpeg|png|x-ms-bmp|tiff)

  add_header   all          ExtractText-Flags _EXTRACTTEXTFLAGS_
  header       PDF_NO_TEXT  X-ExtractText-Flags =~ /\bpdftotext_NoText\b/
  describe     PDF_NO_TEXT  PDF without text
  score        PDF_NO_TEXT  0.001

  header       DOC_NO_TEXT  X-ExtractText-Flags =~ /\b(?:antiword|openxml|unrtf|odt2txt)_NoText\b/
  describe     DOC_NO_TEXT  Document without text
  score        DOC_NO_TEXT  0.001

  header       EXTRACTTEXT  exists:X-ExtractText-Flags
  describe     EXTRACTTEXT  Email processed by extracttext plugin
  score        EXTRACTTEXT  0.001

endif

DESCRIPTION

This module uses external tools to extract text from message parts, and then sets the text as the rendered part. External tool must output plain text, not HTML or other non-textual result.

How to extract text is completely configurable, and based on MIME part type and file name.

CONFIGURATION

All configuration lines in user_prefs files will be ignored.

extracttext_maxparts (default: 10): Configure the maximum mime parts number to analyze, a value of 0 means all mime parts will be analyzed
extracttext_timeout (default: 5 10): Configure the timeout in seconds of external tool checks, per attachment.
Second argument speficies maximum total time for all checks.

Tools

extracttext_use

Specifies what tool to use for what message parts.

The general syntax is

extracttext_use "name" "specifiers"

name

the internal name of a tool.

specifiers

File extension and regular expressions for file names and MIME types. The regular expressions are anchored to beginning and end.

Examples

        extracttext_use  antiword  .doc application/(?:vnd\.?)?ms-?word.*
        extracttext_use  openxml   .docx .dotx .dotm application/(?:vnd\.?)openxml.*?word.*
        extracttext_use  openxml   .doc .dot application/(?:vnd\.?)?ms-?word.*
        extracttext_use  unrtf     .doc .rtf application/rtf text/rtf

extracttext_external

Defines an external tool. The tool must read a document on standard input or from a file and write text to standard output.

The special keyword "{}" will be substituted at runtime with the temporary filename to be scanned by the external tool.

Environment variables can be defined with "{KEY=VALUE}", these strings will be removed from commandline.

It is required that commandline used outputs result directly to STDOUT.

The general syntax is

extracttext_external "name" "command" "parameters"

name

The internal name of this tool.

command

The full path to the external command to run.

parameters

Parameters for the external command. The temporary file name containing the document will be automatically added as last parameter.

Examples

        extracttext_external  antiword  /usr/bin/antiword -t -w 0 -m UTF-8.txt {} -
        extracttext_external  unrtf     /usr/bin/unrtf --nopict {}
        extracttext_external  odt2txt   /usr/bin/odt2txt --encoding=UTF-8 {}

Metadata

The plugin adds some pseudo headers to the message. These headers are seen by the bayes system, and can be used in normal SpamAssassin rules.

The headers are also available as template tags as noted below.

Example

The fictional example headers below are based on a message containing this:

1 A perfectly normal PDF.
2 An OpenXML document with a word document inside. Neither Office document contains text.

Headers

X-ExtractText-Chars

Tag: _EXTRACTTEXTCHARS_

Contains a count of characters that were extracted.

X-ExtractText-Chars: 10970

X-ExtractText-Words

Tag: _EXTRACTTEXTWORDS_

Contains a count of "words" that were extracted.

X-ExtractText-Chars: 1599

X-ExtractText-Tools

Tag: _EXTRACTTEXTTOOLS_

Contains chains of tools used for extraction.

X-ExtractText-Tools: pdftotext openxml_antiword

X-ExtractText-Types

Tag: _EXTRACTTEXTTYPES_

Contains chains of MIME types for parts found during extraction.

X-ExtractText-Types: application/pdf; application/vnd.openxmlformats-officedocument.wordprocessingml.document, application/ms-word

X-ExtractText-Extensions

Tag: _EXTRACTTEXTEXTENSIONS_

Contains chains of canonicalized file extensions for parts found during extraction.

X-ExtractText-Extensions: pdf docx

X-ExtractText-Flags

Tag: _EXTRACTTEXTFLAGS_

Contains notes from the plugin.

X-ExtractText-Flags: openxml_NoText

Rules

Example:

        header    PDF_NO_TEXT  X-ExtractText-Flags =~ /\bpdftotext_Notext\b/
        describe  PDF_NO_TEXT  PDF without text