Restore PDF OCR capability from shell version of rclpdf script
This commit is contained in:
Jean-Francois Dockes
parent
7af11764c1
commit
82a5469d23
1 changed files with 151 additions and 33 deletions
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@ -16,6 +16,20 @@
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# 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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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@ -27,6 +41,8 @@ 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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tmpdir = None
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@ -40,22 +56,15 @@ def signal_handler(signal, frame):
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atexit.register(finalcleanup)
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try:
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signal.signal(signal.SIGHUP, signal_handler)
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except:
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pass
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try:
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signal.signal(signal.SIGINT, signal_handler)
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except:
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pass
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try:
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signal.signal(signal.SIGQUIT, signal_handler)
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except:
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pass
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try:
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signal.signal(signal.SIGTERM, signal_handler)
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except:
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pass
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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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@ -68,11 +77,30 @@ def vacuumdir(dir):
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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 = ""
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self.pdftk = ""
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self.pdftotext = None
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self.em = em
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self.confdir = rclconfig.RclConfig().getConfDir()
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# See if we'll try to perform OCR. Need the commands and the
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# presence of a file in the config dir (could be replaced by a
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# config variable now that we actually use rclconfig)
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self.ocrpossible = False
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if 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
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self.attextractdone = False
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self.attachlist = []
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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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# Extract all attachments if any into temporary directory
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def extractAttach(self):
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@ -112,9 +140,93 @@ class PDFExtractor:
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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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pdflangfile = os.path.join(os.path.dirname(self.filename), ".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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tesseractlang = os.environ.get("RECOLL_TESSERACT_LANG", "");
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if tesseractlang:
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return tesseractlang
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tesseractlang = \
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open(os.path.join(self.confdir, "ocrpdf"), "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 ""
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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 ""
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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('\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 = ""
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for f in files:
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data += open(f, "r").read()
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if not data:
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return ""
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return '''<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"></head><body><pre>''' + \
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self.em.htmlescape(data) + \
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'''</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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@ -122,6 +234,7 @@ class PDFExtractor:
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didcs = False
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output = b''
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cont = b''
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isempty = True
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for line in input.split(b'\n'):
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line = cont + line
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cont = b''
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@ -148,6 +261,10 @@ class PDFExtractor:
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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 != "\x0c" and s != "<":
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isempty = False
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# Remove end-of-line hyphenation. It's not clear that
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# we should do this as pdftotext without the -layout
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# option does it ?
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@ -165,7 +282,7 @@ class PDFExtractor:
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output += line + b'\n'
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return output
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return output, isempty
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def _selfdoc(self):
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self.em.setmimetype('text/html')
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@ -178,10 +295,22 @@ class PDFExtractor:
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data = 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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data = self._fixhtml(data)
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#self.em.rclog("%s" % data)
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data, isempty = self._fixhtml(data)
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#self.em.rclog("ISEMPTY: %d : data: \n%s" % (isempty, data))
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if isempty and self.ocrpossible:
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data = self.ocrpdf()
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return (True, data, "", 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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self.filename = params["filename:"]
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@ -197,18 +326,7 @@ class PDFExtractor:
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print("RECFILTERROR HELPERNOTFOUND pdftotext")
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sys.exit(1);
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if not self.pdftk:
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self.pdftk = rclexecm.which("pdftk")
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if self.pdftk:
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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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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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