#!/usr/bin/env python2
# Copyright (C) 2014 J.F.Dockes
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the
# Free Software Foundation, Inc.,
# 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
# Recoll PDF extractor, with support for attachments
#
# pdftotext sometimes outputs unescaped text inside HTML text sections.
# We try to correct.
#
# If pdftotext produces no text and tesseract is available, we try to
# perform OCR. As this can be very slow and the result not always
# good, we only do this if a file named $RECOLL_CONFDIR/ocrpdf exists
#
# We guess the OCR language in order of preference:
# - From the content of a ".ocrpdflang" file if it exists in the same
# directory as the PDF
# - From an RECOLL_TESSERACT_LANG environment variable
# - From the content of $RECOLL_CONFDIR/ocrpdf
# - Default to "eng"
from __future__ import print_function
import os
import sys
import re
import rclexecm
import subprocess
import tempfile
import atexit
import signal
import rclconfig
import glob
tmpdir = None
def finalcleanup():
if tmpdir:
vacuumdir(tmpdir)
os.rmdir(tmpdir)
def signal_handler(signal, frame):
sys.exit(1)
atexit.register(finalcleanup)
# Not all signals necessary exist on all systems, use catch
try: signal.signal(signal.SIGHUP, signal_handler)
except: pass
try: signal.signal(signal.SIGINT, signal_handler)
except: pass
try: signal.signal(signal.SIGQUIT, signal_handler)
except: pass
try: signal.signal(signal.SIGTERM, signal_handler)
except: pass
def vacuumdir(dir):
if dir:
for fn in os.listdir(dir):
path = os.path.join(dir, fn)
if os.path.isfile(path):
os.unlink(path)
return True
class PDFExtractor:
def __init__(self, em):
self.currentindex = 0
self.pdftotext = None
self.em = em
self.confdir = rclconfig.RclConfig().getConfDir()
cf_doocr = rclconfig.RclConfig().getConfParam("pdfocr")
cf_attach = rclconfig.RclConfig().getConfParam("pdfattach")
self.pdftotext = rclexecm.which("pdftotext")
if not self.pdftotext:
self.pdftotext = rclexecm.which("poppler/pdftotext")
# Check if we need to escape portions of text where old
# versions of pdftotext output raw HTML special characters.
self.needescape = True
try:
version = subprocess.check_output([self.pdftotext, "-v"],
stderr=subprocess.STDOUT)
major,minor,rev = version.split()[2].split('.')
# Don't know exactly when this changed but it's fixed in
# jessie 0.26.5
if int(major) > 0 or int(minor) >= 26:
self.needescape = False
except:
pass
# See if we'll try to perform OCR. Need the commands and the
# either the presence of a file in the config dir (historical)
# or a set config variable.
self.ocrpossible = False
if cf_doocr or os.path.isfile(os.path.join(self.confdir, "ocrpdf")):
self.tesseract = rclexecm.which("tesseract")
if self.tesseract:
self.pdftoppm = rclexecm.which("pdftoppm")
if self.pdftoppm:
self.ocrpossible = True
self.maybemaketmpdir()
# self.em.rclog("OCRPOSSIBLE: %d" % self.ocrpossible)
# Pdftk is optionally used to extract attachments. This takes
# a hit on perfmance even in the absence of any attachments,
# so it can be disabled in the configuration.
self.attextractdone = False
self.attachlist = []
if cf_attach:
self.pdftk = rclexecm.which("pdftk")
else:
self.pdftk = None
if self.pdftk:
self.maybemaketmpdir()
# Extract all attachments if any into temporary directory
def extractAttach(self):
if self.attextractdone:
return True
self.attextractdone = True
global tmpdir
if not tmpdir or not self.pdftk:
# no big deal
return True
try:
vacuumdir(tmpdir)
subprocess.check_call([self.pdftk, self.filename, "unpack_files",
"output", tmpdir])
self.attachlist = sorted(os.listdir(tmpdir))
return True
except Exception as e:
self.em.rclog("extractAttach: failed: %s" % e)
# Return true anyway, pdf attachments are no big deal
return True
def extractone(self, ipath):
#self.em.rclog("extractone: [%s]" % ipath)
if not self.attextractdone:
if not self.extractAttach():
return (False, "", "", rclexecm.RclExecM.eofnow)
path = os.path.join(tmpdir, ipath)
if os.path.isfile(path):
f = open(path)
docdata = f.read();
f.close()
if self.currentindex == len(self.attachlist) - 1:
eof = rclexecm.RclExecM.eofnext
else:
eof = rclexecm.RclExecM.noteof
return (True, docdata, ipath, eof)
# Try to guess tesseract language. This should depend on the input
# file, but we have no general way to determine it. So use the
# environment and hope for the best.
def guesstesseractlang(self):
tesseractlang = ""
pdflangfile = os.path.join(os.path.dirname(self.filename), ".ocrpdflang")
if os.path.isfile(pdflangfile):
tesseractlang = open(pdflangfile, "r").read().strip()
if tesseractlang:
return tesseractlang
tesseractlang = os.environ.get("RECOLL_TESSERACT_LANG", "");
if tesseractlang:
return tesseractlang
tesseractlang = \
open(os.path.join(self.confdir, "ocrpdf"), "r").read().strip()
if tesseractlang:
return tesseractlang
# Half-assed trial to guess from LANG then default to english
localelang = os.environ.get("LANG", "").split("_")[0]
if localelang == "en":
tesseractlang = "eng"
elif localelang == "de":
tesseractlang = "deu"
elif localelang == "fr":
tesseractlang = "fra"
if tesseractlang:
return tesseractlang
if not tesseractlang:
tesseractlang = "eng"
return tesseractlang
# PDF has no text content and tesseract is available. Give OCR a try
def ocrpdf(self):
global tmpdir
if not tmpdir:
return ""
tesseractlang = self.guesstesseractlang()
# self.em.rclog("tesseractlang %s" % tesseractlang)
tesserrorfile = os.path.join(tmpdir, "tesserrorfile")
tmpfile = os.path.join(tmpdir, "ocrXXXXXX")
# Split pdf pages
try:
vacuumdir(tmpdir)
subprocess.check_call([self.pdftoppm, "-r", "300", self.filename,
tmpfile])
except Exception as e:
self.em.rclog("pdftoppm failed: %s" % e)
return ""
files = glob.glob(tmpfile + "*")
for f in files:
try:
out = subprocess.check_output([self.tesseract, f, f, "-l",
tesseractlang],
stderr = subprocess.STDOUT)
except Exception as e:
self.em.rclog("tesseract failed: %s" % e)
errlines = out.split('\n')
if len(errlines) > 2:
self.em.rclog("Tesseract error: %s" % out)
# Concatenate the result files
files = glob.glob(tmpfile + "*" + ".txt")
data = ""
for f in files:
data += open(f, "r").read()
if not data:
return ""
return '''<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"></head><body><pre>''' + \
self.em.htmlescape(data) + \
'''</pre></body></html>'''
# pdftotext (used to?) badly escape text inside the header
# fields. We do it here. This is not an html parser, and depends a
# lot on the actual format output by pdftotext.
# We also determine if the doc has actual content, for triggering OCR
def _fixhtml(self, input):
#print input
inheader = False
inbody = False
didcs = False
output = b''
isempty = True
for line in input.split(b'\n'):
if re.search(b'</head>', line):
inheader = False
if re.search(b'</pre>', line):
inbody = False
if inheader:
if not didcs:
output += b'<meta http-equiv="Content-Type"' + \
b'content="text/html; charset=UTF-8">\n'
didcs = True
if self.needescape:
m = re.search(b'''(.*<title>)(.*)(<\/title>.*)''', line)
if not m:
m = re.search(b'''(.*content=")(.*)(".*/>.*)''', line)
if m:
line = m.group(1) + self.em.htmlescape(m.group(2)) + \
m.group(3)
# Recoll treats "Subject" as a "title" element
# (based on emails). The PDF "Subject" metadata
# field is more like an HTML "description"
line = re.sub(b'name="Subject"', b'name="Description"', line, 1)
elif inbody:
s = line[0:1]
if s != "\x0c" and s != "<":
isempty = False
# We used to remove end-of-line hyphenation (and join
# lines), but but it's not clear that we should do
# this as pdftotext without the -layout option does it ?
line = self.em.htmlescape(line)
if re.search(b'<head>', line):
inheader = True
if re.search(b'<pre>', line):
inbody = True
output += line + b'\n'
return output, isempty
def _selfdoc(self):
self.em.setmimetype('text/html')
if self.attextractdone and len(self.attachlist) == 0:
eof = rclexecm.RclExecM.eofnext
else:
eof = rclexecm.RclExecM.noteof
data = subprocess.check_output([self.pdftotext, "-htmlmeta", "-enc",
"UTF-8", "-eol", "unix", "-q",
self.filename, "-"])
data, isempty = self._fixhtml(data)
#self.em.rclog("ISEMPTY: %d : data: \n%s" % (isempty, data))
if isempty and self.ocrpossible:
data = self.ocrpdf()
return (True, data, "", eof)
def maybemaketmpdir(self):
global tmpdir
if tmpdir:
if not vacuumdir(tmpdir):
self.em.rclog("openfile: vacuumdir %s failed" % tmpdir)
return False
else:
tmpdir = tempfile.mkdtemp(prefix='rclmpdf')
###### File type handler api, used by rclexecm ---------->
def openfile(self, params):
self.filename = params["filename:"]
#self.em.rclog("openfile: [%s]" % self.filename)
self.currentindex = -1
self.attextractdone = False
if not self.pdftotext:
print("RECFILTERROR HELPERNOTFOUND pdftotext")
sys.exit(1);
if self.pdftk:
preview = os.environ.get("RECOLL_FILTER_FORPREVIEW", "no")
if preview != "yes":
# When indexing, extract attachments at once. This
# will be needed anyway and it allows generating an
# eofnext error instead of waiting for actual eof,
# which avoids a bug in recollindex up to 1.20
self.extractAttach()
else:
self.attextractdone = True
return True
def getipath(self, params):
ipath = params["ipath:"]
ok, data, ipath, eof = self.extractone(ipath)
return (ok, data, ipath, eof)
def getnext(self, params):
# self.em.rclog("getnext: current %d" % self.currentindex)
if self.currentindex == -1:
self.currentindex = 0
return self._selfdoc()
else:
self.em.setmimetype('')
if not self.attextractdone:
if not self.extractAttach():
return (False, "", "", rclexecm.RclExecM.eofnow)
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)