#!/usr/bin/env python3
# Copyright (C) 2014-2020 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.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 the configuration allows it, we may try to
# perform OCR.
import os
import sys
import re
import urllib.request
import subprocess
import tempfile
import glob
import traceback
import atexit
import signal
import rclexecm
import rclconfig
_mswindows = (sys.platform == "win32")
# Test access to the poppler-glib python3 bindings ? This allows
# extracting text from annotations.
# - On Ubuntu, this comes with package gir1.2-poppler-0.18
# - On opensuse the package is named typelib-1_0-Poppler-0_18
# (actual versions may differ of course).
#
# NOTE: we are using the glib introspection bindings for the Poppler C
# API, which is not the same as the Python bindings of the Poppler C++
# API (poppler-cpp). The interface is quite different
# (e.g. attachments are named "embeddedfiles" in the C++ interface.
havepopplerglib = False
try:
import gi
gi.require_version('Poppler', '0.18')
from gi.repository import Poppler
havepopplerglib = True
except:
pass
tmpdir = None
_htmlprefix =b'''
'''
_htmlsuffix = b'''
'''
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.pdfinfo = None
self.pdftk = None
self.em = em
self.tesseract = None
# Avoid picking up a default version on Windows, we want ours
if not _mswindows:
self.pdftotext = rclexecm.which("pdftotext")
if not self.pdftotext:
self.pdftotext = rclexecm.which("poppler/pdftotext")
if not self.pdftotext:
# No need for anything else. openfile() will return an
# error at once
return
self.config = rclconfig.RclConfig()
self.confdir = self.config.getConfDir()
# The user can set a list of meta tags to be extracted from
# the XMP metadata packet. These are specified as
# (xmltag,rcltag) pairs
self.extrameta = self.config.getConfParam("pdfextrameta")
if self.extrameta:
self.extrametafix = self.config.getConfParam("pdfextrametafix")
self._initextrameta()
# 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
# Pdftk is optionally used to extract attachments. This takes
# a hit on performance even in the absence of any attachments,
# so it can be disabled in the configuration.
self.attextractdone = False
self.attachlist = []
cf_attach = self.config.getConfParam("pdfattach")
cf_attach = rclexecm.configparamtrue(cf_attach)
if cf_attach:
self.pdftk = rclexecm.which("pdftk")
if self.pdftk:
self.maybemaketmpdir()
def _initextrameta(self):
if not _mswindows:
self.pdfinfo = rclexecm.which("pdfinfo")
if not self.pdfinfo:
self.pdfinfo = rclexecm.which("poppler/pdfinfo")
if not self.pdfinfo:
self.extrameta = None
return
# extrameta is like "metanm|rclnm ...", where |rclnm maybe absent (keep
# original name). Parse into a list of pairs.
l = self.extrameta.split()
self.extrameta = []
for e in l:
l1 = e.split('|')
if len(l1) == 1:
l1.append(l1[0])
self.extrameta.append(l1)
# Using lxml because it is better with
# namespaces. With xml, we'd have to walk the XML tree
# first, extracting all xmlns attributes and
# constructing a tree (I tried and did not succeed in
# doing this actually). lxml does it partially for
# us. See http://stackoverflow.com/questions/14853243/
# parsing-xml-with-namespace-in-python-via-elementtree
global ET
#import xml.etree.ElementTree as ET
try:
import lxml.etree as ET
except Exception as err:
self.em.rclog("Can't import lxml etree: %s" % err)
self.extrameta = None
self.pdfinfo = None
return
self.re_head = re.compile(br'', re.IGNORECASE)
self.re_xmlpacket = re.compile(br'<\?xpacket[ ]+begin.*\?>' +
br'(.*)' + br'<\?xpacket[ ]+end',
flags = re.DOTALL)
global EMF
EMF = None
if self.extrametafix:
try:
import importlib.util
spec = importlib.util.spec_from_file_location(
'pdfextrametafix', self.extrametafix)
EMF = importlib.util.module_from_spec(spec)
spec.loader.exec_module(EMF)
except Exception as err:
self.em.rclog("Import extrametafix failed: %s" % err)
EMF = None
pass
# 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)
# Note: the java version of pdftk sometimes/often fails
# here with writing to stdout:
# Error occurred during initialization of VM
# Could not allocate metaspace: 1073741824 bytes
# Maybe unsufficient resources when started from Python ?
# In any case, the important thing is to discard the
# output, until we fix the error or preferably find a way
# to do it with poppler...
subprocess.check_call(
[self.pdftk, self.filename, "unpack_files", "output",
tmpdir], stdout=sys.stderr)
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
# 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 = []
isempty = True
for line in input.split(b'\n'):
if re.search(b'', line):
inheader = False
if re.search(b'', line):
inbody = False
if inheader:
if not didcs:
output.append(b'\n')
didcs = True
if self.needescape:
m = re.search(b'''(.*)(.*)(<\/title>.*)''', line)
if not m:
m = re.search(b'''(.*content=")(.*)(".*/>.*)''', line)
if m:
line = m.group(1) + rclexecm.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 != b"\x0c" and s != b"<":
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 = rclexecm.htmlescape(line)
if re.search(b'<head>', line):
inheader = True
if re.search(b'<pre>', line):
inbody = True
output.append(line)
return b'\n'.join(output), isempty
def _metatag(self, nm, val):
return b"<meta name=\"" + rclexecm.makebytes(nm) + b"\" content=\"" + \
rclexecm.htmlescape(rclexecm.makebytes(val)) + b"\">"
# metaheaders is a list of (nm, value) pairs
def _injectmeta(self, html, metaheaders):
metatxt = b''
for nm, val in metaheaders:
metatxt += self._metatag(nm, val) + b'\n'
if not metatxt:
return html
res = self.re_head.sub(b'<head>\n' + metatxt, html)
#self.em.rclog("Substituted html: [%s]"%res)
if res:
return res
else:
return html
def _xmltreetext(self, elt):
'''Extract all text content from subtree'''
text = ''
for e in elt.iter():
if e.text:
text += e.text + " "
return text.strip()
# or: return reduce((lambda t,p : t+p+' '),
# [e.text for e in elt.iter() if e.text]).strip()
def _setextrameta(self, html):
if not self.pdfinfo:
return html
emf = EMF.MetaFixer() if EMF else None
# Execute pdfinfo and extract the XML packet
all = subprocess.check_output([self.pdfinfo, "-meta", self.filename])
res = self.re_xmlpacket.search(all)
xml = res.group(1) if res else ''
# self.em.rclog("extrameta: XML: [%s]" % xml)
if not xml:
return html
metaheaders = []
# The namespace thing is a drag. Can't do it from the top. See
# the stackoverflow ref above. Maybe we'd be better off just
# walking the full tree and building the namespaces dict.
root = ET.fromstring(xml)
#self.em.rclog("NSMAP: %s"% root.nsmap)
namespaces = {'rdf' : "http://www.w3.org/1999/02/22-rdf-syntax-ns#"}
rdf = root.find("rdf:RDF", namespaces)
#self.em.rclog("RDF NSMAP: %s"% rdf.nsmap)
if rdf is None:
return html
rdfdesclist = rdf.findall("rdf:Description", rdf.nsmap)
for metanm,rclnm in self.extrameta:
for rdfdesc in rdfdesclist:
try:
elts = rdfdesc.findall(metanm, rdfdesc.nsmap)
except:
# We get an exception when this rdf:Description does not
# define the required namespace.
continue
if elts:
for elt in elts:
text = None
try:
# First try to get text from a custom element handler
text = emf.metafixelt(metanm, elt)
except:
pass
if text is None:
# still nothing here, read the element text
text = self._xmltreetext(elt)
try:
# try to run metafix
text = emf.metafix(metanm, text)
except:
pass
if text:
# Can't use setfield as it only works for
# text/plain output at the moment.
#self.em.rclog("Appending: (%s,%s)"%(rclnm,text))
metaheaders.append((rclnm, text))
else:
# Some docs define the values as attributes. don't
# know if this is valid but anyway...
try:
prefix,nm = metanm.split(":")
fullnm = "{%s}%s" % (rdfdesc.nsmap[prefix], nm)
except:
fullnm = metanm
text = rdfdesc.get(fullnm)
if text:
try:
# try to run metafix
text = emf.metafix(metanm, text)
except:
pass
metaheaders.append((rclnm, text))
if metaheaders:
if emf:
try:
emf.wrapup(metaheaders)
except:
pass
return self._injectmeta(html, metaheaders)
else:
return html
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')
if self.pdftk and re.match("/snap/", self.pdftk):
# We know this is Unix (Ubuntu actually). Check that tmpdir
# belongs to the user as snap commands can't use /tmp to share
# files. Don't generate an error as this only affects
# attachment extraction
ok = False
if "TMPDIR" in os.environ:
st = os.stat(os.environ["TMPDIR"])
if st.st_uid == os.getuid():
ok = True
if not ok:
self.em.rclog(
"pdftk is a snap command and needs TMPDIR to be "
"a directory you own")
def _process_annotations(self, html):
doc = Poppler.Document.new_from_file(
'file://%s' %
urllib.request.pathname2url(os.path.abspath(self.filename)), None)
n_pages = doc.get_n_pages()
all_annots = 0
# output format
f = 'P.: {0}, {1:10}, {2:10}: {3}'
# Array of annotations indexed by page number. The page number
# here is the physical one (evince -i), not a page label (evince
# -p). This may be different for some documents.
abypage = {}
for i in range(n_pages):
page = doc.get_page(i)
pnum = i+1
annot_mappings = page.get_annot_mapping ()
num_annots = len(annot_mappings)
for annot_mapping in annot_mappings:
atype = annot_mapping.annot.get_annot_type().value_name
if atype != 'POPPLER_ANNOT_LINK':
# Catch because we sometimes get None values
try:
atext = f.format(
pnum,
annot_mapping.annot.get_modified(),
annot_mapping.annot.get_annot_type().value_nick,
annot_mapping.annot.get_contents()) + "\n"
if pnum in abypage:
abypage[pnum] += atext
else:
abypage[pnum] = atext
except:
pass
#self.em.rclog("Annotations: %s" % abypage)
pagevec = html.split(b"\f")
html = b""
annotsfield = b""
pagenum = 1
for page in pagevec:
html += page
if pagenum in abypage:
html += abypage[pagenum].encode('utf-8')
annotsfield += abypage[pagenum].encode('utf-8') + b" - "
html += b"\f"
pagenum += 1
if annotsfield:
self.em.setfield("pdfannot", annotsfield)
return html
def _selfdoc(self):
'''Extract the text from the pdf doc (as opposed to attachment)'''
self.em.setmimetype('text/html')
if self.attextractdone and len(self.attachlist) == 0:
eof = rclexecm.RclExecM.eofnext
else:
eof = rclexecm.RclExecM.noteof
html = subprocess.check_output([self.pdftotext, "-htmlmeta", "-enc",
"UTF-8", "-eol", "unix", "-q",
self.filename, "-"])
html, isempty = self._fixhtml(html)
#self.em.rclog("ISEMPTY: %d : data: \n%s" % (isempty, html))
if isempty:
self.config.setKeyDir(os.path.dirname(self.filename))
s = self.config.getConfParam("pdfocr")
if rclexecm.configparamtrue(s):
try:
cmd = [sys.executable, os.path.join(_execdir, "rclocr.py"),
self.filename]
data = subprocess.check_output(cmd)
html = _htmlprefix + rclexecm.htmlescape(data) + _htmlsuffix
except Exception as e:
self.em.rclog("%s failed: %s" % (cmd, e))
pass
if self.extrameta:
try:
html = self._setextrameta(html)
except Exception as err:
self.em.rclog("Metadata extraction failed: %s %s" %
(err, traceback.format_exc()))
if havepopplerglib:
try:
html = self._process_annotations(html)
except Exception as err:
self.em.rclog("Annotation extraction failed: %s %s" %
(err, traceback.format_exc()))
return (True, html, "", eof)
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, "rb")
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)
###### File type handler api, used by rclexecm ---------->
def openfile(self, params):
if not self.pdftotext:
print("RECFILTERROR HELPERNOTFOUND pdftotext")
sys.exit(1);
self.filename = rclexecm.subprocfile(params["filename"])
#self.em.rclog("openfile: [%s]" % self.filename)
self.currentindex = -1
self.attextractdone = False
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 Exception as ex:
self.em.rclog("getnext: extractone failed for index %d: %s" %
(self.currentindex, ex))
return (False, "", "", rclexecm.RclExecM.eofnow)
# Main program: create protocol handler and extractor and run them
_execdir = os.path.dirname(sys.argv[0])
proto = rclexecm.RclExecM()
extract = PDFExtractor(proto)
rclexecm.main(proto, extract)