549 lines
20 KiB
Python
Executable File
549 lines
20 KiB
Python
Executable File
#!/usr/bin/env python3
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# Copyright (C) 2014 J.F.Dockes
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the
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# Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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# Recoll PDF extractor, with support for attachments
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#
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# pdftotext sometimes outputs unescaped text inside HTML text sections.
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# We try to correct.
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#
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# If pdftotext produces no text and tesseract is available, we try to
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# perform OCR. As this can be very slow and the result not always
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# good, we only do this if a file named $RECOLL_CONFDIR/ocrpdf exists
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#
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# We guess the OCR language in order of preference:
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# - From the content of a ".ocrpdflang" file if it exists in the same
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# directory as the PDF
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# - From an RECOLL_TESSERACT_LANG environment variable
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# - From the content of $RECOLL_CONFDIR/ocrpdf
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# - Default to "eng"
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from __future__ import print_function
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import os
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import sys
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import re
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import rclexecm
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import subprocess
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import tempfile
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import atexit
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import signal
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import rclconfig
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import glob
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import traceback
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tmpdir = None
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def finalcleanup():
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if tmpdir:
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vacuumdir(tmpdir)
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os.rmdir(tmpdir)
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def signal_handler(signal, frame):
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sys.exit(1)
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atexit.register(finalcleanup)
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# Not all signals necessary exist on all systems, use catch
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try: signal.signal(signal.SIGHUP, signal_handler)
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except: pass
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try: signal.signal(signal.SIGINT, signal_handler)
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except: pass
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try: signal.signal(signal.SIGQUIT, signal_handler)
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except: pass
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try: signal.signal(signal.SIGTERM, signal_handler)
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except: pass
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def vacuumdir(dir):
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if dir:
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for fn in os.listdir(dir):
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path = os.path.join(dir, fn)
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if os.path.isfile(path):
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os.unlink(path)
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return True
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class PDFExtractor:
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def __init__(self, em):
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self.currentindex = 0
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self.pdftotext = None
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self.pdfinfo = None
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self.pdftk = None
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self.em = em
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self.tesseract = None
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self.pdftotext = rclexecm.which("pdftotext")
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if not self.pdftotext:
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self.pdftotext = rclexecm.which("poppler/pdftotext")
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if not self.pdftotext:
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# No need for anything else. openfile() will return an
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# error at once
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return
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self.config = rclconfig.RclConfig()
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self.confdir = self.config.getConfDir()
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# The user can set a list of meta tags to be extracted from
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# the XMP metadata packet. These are specified as
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# (xmltag,rcltag) pairs
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self.extrameta = self.config.getConfParam("pdfextrameta")
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if self.extrameta:
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self._initextrameta()
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# Check if we need to escape portions of text where old
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# versions of pdftotext output raw HTML special characters.
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self.needescape = True
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try:
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version = subprocess.check_output([self.pdftotext, "-v"],
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stderr=subprocess.STDOUT)
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major,minor,rev = version.split()[2].split('.')
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# Don't know exactly when this changed but it's fixed in
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# jessie 0.26.5
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if int(major) > 0 or int(minor) >= 26:
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self.needescape = False
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except:
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pass
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# See if we'll try to perform OCR. Need the commands and the
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# either the presence of a file in the config dir (historical)
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# or a set config variable.
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self.ocrpossible = False
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cf_doocr = self.config.getConfParam("pdfocr")
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if cf_doocr or os.path.isfile(os.path.join(self.confdir, "ocrpdf")):
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self.tesseract = rclexecm.which("tesseract")
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if self.tesseract:
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self.pdftoppm = rclexecm.which("pdftoppm")
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if self.pdftoppm:
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self.ocrpossible = True
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self.maybemaketmpdir()
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# self.em.rclog("OCRPOSSIBLE: %d" % self.ocrpossible)
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# Pdftk is optionally used to extract attachments. This takes
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# a hit on performance even in the absence of any attachments,
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# so it can be disabled in the configuration.
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self.attextractdone = False
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self.attachlist = []
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cf_attach = self.config.getConfParam("pdfattach")
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if cf_attach:
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self.pdftk = rclexecm.which("pdftk")
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if self.pdftk:
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self.maybemaketmpdir()
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def _initextrameta(self):
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self.pdfinfo = rclexecm.which("pdfinfo")
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if not self.pdfinfo:
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self.pdfinfo = rclexecm.which("poppler/pdfinfo")
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if not self.pdfinfo:
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self.extrameta = None
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return
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# extrameta is like "samename metanm|rclnm ..."
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# we turn it into a list of pairs
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l = self.extrameta.split()
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self.extrameta = []
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for e in l:
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l1 = e.split('|')
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if len(l1) == 1:
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l1.append(l1[0])
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self.extrameta.append(l1)
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# Using lxml because it is better with
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# namespaces. With xml, we'd have to walk the XML tree
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# first, extracting all xmlns attributes and
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# constructing a tree (I tried and did not succeed in
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# doing this actually). lxml does it partially for
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# us. See http://stackoverflow.com/questions/14853243/
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# parsing-xml-with-namespace-in-python-via-elementtree
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global ET
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#import xml.etree.ElementTree as ET
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try:
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import lxml.etree as ET
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except Exception as err:
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self.em.rclog("Can't import lxml etree: %s" % err)
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self.extrameta = None
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self.pdfinfo = None
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return
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self.re_head = re.compile(br'<head>', re.IGNORECASE)
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self.re_xmlpacket = re.compile(br'<\?xpacket[ ]+begin.*\?>' +
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br'(.*)' + br'<\?xpacket[ ]+end',
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flags = re.DOTALL)
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# Extract all attachments if any into temporary directory
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def extractAttach(self):
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if self.attextractdone:
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return True
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self.attextractdone = True
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global tmpdir
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if not tmpdir or not self.pdftk:
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# no big deal
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return True
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try:
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vacuumdir(tmpdir)
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subprocess.check_call([self.pdftk, self.filename, "unpack_files",
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"output", tmpdir])
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self.attachlist = sorted(os.listdir(tmpdir))
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return True
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except Exception as e:
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self.em.rclog("extractAttach: failed: %s" % e)
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# Return true anyway, pdf attachments are no big deal
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return True
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def extractone(self, ipath):
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#self.em.rclog("extractone: [%s]" % ipath)
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if not self.attextractdone:
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if not self.extractAttach():
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return (False, "", "", rclexecm.RclExecM.eofnow)
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path = os.path.join(tmpdir, ipath)
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if os.path.isfile(path):
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f = open(path)
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docdata = f.read();
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f.close()
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if self.currentindex == len(self.attachlist) - 1:
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eof = rclexecm.RclExecM.eofnext
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else:
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eof = rclexecm.RclExecM.noteof
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return (True, docdata, ipath, eof)
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# Try to guess tesseract language. This should depend on the input
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# file, but we have no general way to determine it. So use the
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# environment and hope for the best.
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def guesstesseractlang(self):
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tesseractlang = ""
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# First look for a language def file in the file's directory
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pdflangfile = os.path.join(os.path.dirname(self.filename),
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b".ocrpdflang")
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if os.path.isfile(pdflangfile):
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tesseractlang = open(pdflangfile, "r").read().strip()
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if tesseractlang:
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return tesseractlang
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# Then look for a global option. The normal way now that we
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# have config reading capability in the handlers is to use the
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# config. Then, for backwards compat, environment variable and
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# file inside the configuration directory
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tesseractlang = self.config.getConfParam("pdfocrlang")
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if tesseractlang:
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return tesseractlang
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tesseractlang = os.environ.get("RECOLL_TESSERACT_LANG", "");
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if tesseractlang:
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return tesseractlang
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pdflangfile = os.path.join(self.confdir, b"ocrpdf")
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if os.path.isfile(pdflangfile):
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tesseractlang = open(pdflangfile, "r").read().strip()
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if tesseractlang:
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return tesseractlang
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# Half-assed trial to guess from LANG then default to english
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localelang = os.environ.get("LANG", "").split("_")[0]
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if localelang == "en":
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tesseractlang = "eng"
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elif localelang == "de":
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tesseractlang = "deu"
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elif localelang == "fr":
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tesseractlang = "fra"
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if tesseractlang:
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return tesseractlang
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if not tesseractlang:
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tesseractlang = "eng"
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return tesseractlang
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# PDF has no text content and tesseract is available. Give OCR a try
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def ocrpdf(self):
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global tmpdir
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if not tmpdir:
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return b""
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tesseractlang = self.guesstesseractlang()
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# self.em.rclog("tesseractlang %s" % tesseractlang)
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tesserrorfile = os.path.join(tmpdir, "tesserrorfile")
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tmpfile = os.path.join(tmpdir, "ocrXXXXXX")
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# Split pdf pages
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try:
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vacuumdir(tmpdir)
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subprocess.check_call([self.pdftoppm, "-r", "300", self.filename,
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tmpfile])
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except Exception as e:
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self.em.rclog("pdftoppm failed: %s" % e)
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return b""
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files = glob.glob(tmpfile + "*")
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for f in files:
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try:
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out = subprocess.check_output([self.tesseract, f, f, "-l",
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tesseractlang],
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stderr = subprocess.STDOUT)
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except Exception as e:
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self.em.rclog("tesseract failed: %s" % e)
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errlines = out.split(b'\n')
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if len(errlines) > 2:
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self.em.rclog("Tesseract error: %s" % out)
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# Concatenate the result files
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files = glob.glob(tmpfile + "*" + ".txt")
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data = b""
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for f in files:
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data += open(f, "rb").read()
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if not data:
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return b""
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return b'''<html><head>
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<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\">
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</head><body><pre>''' + \
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self.em.htmlescape(data) + \
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b'''</pre></body></html>'''
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# pdftotext (used to?) badly escape text inside the header
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# fields. We do it here. This is not an html parser, and depends a
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# lot on the actual format output by pdftotext.
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# We also determine if the doc has actual content, for triggering OCR
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def _fixhtml(self, input):
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#print input
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inheader = False
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inbody = False
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didcs = False
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output = []
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isempty = True
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for line in input.split(b'\n'):
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if re.search(b'</head>', line):
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inheader = False
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if re.search(b'</pre>', line):
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inbody = False
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if inheader:
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if not didcs:
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output.append(b'<meta http-equiv="Content-Type"' + \
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b'content="text/html; charset=UTF-8">\n')
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didcs = True
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if self.needescape:
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m = re.search(b'''(.*<title>)(.*)(<\/title>.*)''', line)
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if not m:
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m = re.search(b'''(.*content=")(.*)(".*/>.*)''', line)
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if m:
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line = m.group(1) + self.em.htmlescape(m.group(2)) + \
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m.group(3)
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# Recoll treats "Subject" as a "title" element
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# (based on emails). The PDF "Subject" metadata
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# field is more like an HTML "description"
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line = re.sub(b'name="Subject"', b'name="Description"', line, 1)
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elif inbody:
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s = line[0:1]
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if s != b"\x0c" and s != b"<":
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isempty = False
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# We used to remove end-of-line hyphenation (and join
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# lines), but but it's not clear that we should do
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# this as pdftotext without the -layout option does it ?
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line = self.em.htmlescape(line)
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if re.search(b'<head>', line):
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inheader = True
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if re.search(b'<pre>', line):
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inbody = True
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output.append(line)
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return b'\n'.join(output), isempty
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def _metatag(self, nm, val):
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return b"<meta name=\"" + rclexecm.makebytes(nm) + b"\" content=\"" + \
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self.em.htmlescape(rclexecm.makebytes(val)) + b"\">"
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# metaheaders is a list of (nm, value) pairs
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def _injectmeta(self, html, metaheaders):
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metatxt = b''
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for nm, val in metaheaders:
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metatxt += self._metatag(nm, val) + b'\n'
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if not metatxt:
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return html
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res = self.re_head.sub(b'<head>\n' + metatxt, html)
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#self.em.rclog("Substituted html: [%s]"%res)
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if res:
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return res
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else:
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return html
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def _xmltreetext(self, elt):
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'''Extract all text content from subtree'''
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text = ''
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for e in elt.iter():
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if e.text:
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text += e.text + " "
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return text.strip()
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# or: return reduce((lambda t,p : t+p+' '),
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# [e.text for e in elt.iter() if e.text]).strip()
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def _setextrameta(self, html):
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if not self.pdfinfo:
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return html
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all = subprocess.check_output([self.pdfinfo, "-meta", self.filename])
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# Extract the XML packet
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res = self.re_xmlpacket.search(all)
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xml = ''
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if res:
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xml = res.group(1)
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# self.em.rclog("extrameta: XML: [%s]" % xml)
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if not xml:
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return html
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metaheaders = []
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# The namespace thing is a drag. Can't do it from the top. See
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# the stackoverflow ref above. Maybe we'd be better off just
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# walking the full tree and building the namespaces dict.
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root = ET.fromstring(xml)
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#self.em.rclog("NSMAP: %s"% root.nsmap)
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namespaces = {'rdf' : "http://www.w3.org/1999/02/22-rdf-syntax-ns#"}
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rdf = root.find("rdf:RDF", namespaces)
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#self.em.rclog("RDF NSMAP: %s"% rdf.nsmap)
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if rdf is None:
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return html
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rdfdesclist = rdf.findall("rdf:Description", rdf.nsmap)
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for metanm,rclnm in self.extrameta:
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for rdfdesc in rdfdesclist:
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try:
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elt = rdfdesc.find(metanm, rdfdesc.nsmap)
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except:
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# We get an exception when this rdf:Description does not
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# define the required namespace.
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continue
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text = None
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if elt is not None:
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text = self._xmltreetext(elt)
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else:
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# Some docs define the values as attributes. don't
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# know if this is valid but anyway...
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try:
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prefix,nm = metanm.split(":")
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fullnm = "{%s}%s" % (rdfdesc.nsmap[prefix], nm)
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except:
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fullnm = nm
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text = rdfdesc.get(fullnm)
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if text:
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# Should we set empty values ?
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# Can't use setfield as it only works for
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# text/plain output at the moment.
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#self.em.rclog("Appending: (%s,%s)"%(rclnm,text))
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metaheaders.append((rclnm, text))
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if metaheaders:
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return self._injectmeta(html, metaheaders)
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else:
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return html
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def _selfdoc(self):
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'''Extract the text from the pdf doc (as opposed to attachment)'''
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self.em.setmimetype('text/html')
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if self.attextractdone and len(self.attachlist) == 0:
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eof = rclexecm.RclExecM.eofnext
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else:
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eof = rclexecm.RclExecM.noteof
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html = subprocess.check_output([self.pdftotext, "-htmlmeta", "-enc",
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"UTF-8", "-eol", "unix", "-q",
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self.filename, "-"])
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html, isempty = self._fixhtml(html)
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#self.em.rclog("ISEMPTY: %d : data: \n%s" % (isempty, html))
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if isempty and self.ocrpossible:
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html = self.ocrpdf()
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if self.extrameta:
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try:
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html = self._setextrameta(html)
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except Exception as err:
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self.em.rclog("Metadata extraction failed: %s %s" % (err, traceback.format_exc()))
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return (True, html, "", eof)
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def maybemaketmpdir(self):
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global tmpdir
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if tmpdir:
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if not vacuumdir(tmpdir):
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self.em.rclog("openfile: vacuumdir %s failed" % tmpdir)
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return False
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else:
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tmpdir = tempfile.mkdtemp(prefix='rclmpdf')
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###### File type handler api, used by rclexecm ---------->
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def openfile(self, params):
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if not self.pdftotext:
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print("RECFILTERROR HELPERNOTFOUND pdftotext")
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sys.exit(1);
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self.filename = rclexecm.subprocfile(params["filename:"])
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#self.em.rclog("openfile: [%s]" % self.filename)
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self.currentindex = -1
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self.attextractdone = False
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|
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if self.pdftk:
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preview = os.environ.get("RECOLL_FILTER_FORPREVIEW", "no")
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if preview != "yes":
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# When indexing, extract attachments at once. This
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# will be needed anyway and it allows generating an
|
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# eofnext error instead of waiting for actual eof,
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# which avoids a bug in recollindex up to 1.20
|
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self.extractAttach()
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else:
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self.attextractdone = True
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return True
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|
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def getipath(self, params):
|
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ipath = params["ipath:"]
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ok, data, ipath, eof = self.extractone(ipath)
|
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return (ok, data, ipath, eof)
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|
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def getnext(self, params):
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# self.em.rclog("getnext: current %d" % self.currentindex)
|
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if self.currentindex == -1:
|
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self.currentindex = 0
|
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return self._selfdoc()
|
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else:
|
|
self.em.setmimetype('')
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|
|
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if not self.attextractdone:
|
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if not self.extractAttach():
|
|
return (False, "", "", rclexecm.RclExecM.eofnow)
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|
|
if self.currentindex >= len(self.attachlist):
|
|
return (False, "", "", rclexecm.RclExecM.eofnow)
|
|
try:
|
|
ok, data, ipath, eof = \
|
|
self.extractone(self.attachlist[self.currentindex])
|
|
self.currentindex += 1
|
|
|
|
#self.em.rclog("getnext: returning ok for [%s]" % ipath)
|
|
return (ok, data, ipath, eof)
|
|
except:
|
|
return (False, "", "", rclexecm.RclExecM.eofnow)
|
|
|
|
|
|
# Main program: create protocol handler and extractor and run them
|
|
proto = rclexecm.RclExecM()
|
|
extract = PDFExtractor(proto)
|
|
rclexecm.main(proto, extract)
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