Commit 9e375b8e authored by Jérome Perrin's avatar Jérome Perrin

Lighter processing for OCR activities

When running OCR, we sometimes have issues because processing is "too heavy":
 - [x] use 2 or 3 Go of disk space for a one page PDF created by erp5_document_scanner, because we convert pdf -> png -> tiff before sending to tesseract. Modern Ghostscript supports running tesseract directly, so we use it if it's available.
 - [x] use 300% of CPU. Fixed by setting `OMP_THREAD_LIMIT` when running tesseract. This will only apply when OCR from Images. OCR embedded in Ghostscript does not seem to need this.
 - [x] ... and often crash, so is restarted. This is fixed by updated tesseract.

Updates of ghostscript and tesseract are part of slapos!985

See merge request !1420
parents f084c646 f775724e
......@@ -165,21 +165,66 @@ class PDFDocument(Image):
security.declarePrivate('_convertToText')
def _convertToText(self, format='txt'): # pylint: disable=redefined-builtin
"""
Convert the PDF text content to text with pdftotext
"""Convert the PDF to text
If the PDF have text, return the text, otherwise try to do OCR using
tesseract.
"""
if not self.hasData():
return ''
data = str(self.getData())
try:
from PyPDF2 import PdfFileReader
from PyPDF2.utils import PdfReadError
except ImportError:
pass
else:
try:
if PdfFileReader(StringIO(data)).isEncrypted:
return ''
except PdfReadError:
return ''
mime_type = 'text/plain'
portal_transforms = self.getPortalObject().portal_transforms
filename = self.getFilename()
result = portal_transforms.convertToData(mime_type, str(self.getData()),
result = portal_transforms.convertToData(mime_type, data,
context=self, filename=filename,
mimetype=self.getContentType())
if result:
return result
else:
# Try to use OCR
# Try to use OCR from ghostscript, but tolerate that the command might
# not be available.
process = None
command = [
'gs', '-q', '-dQUIET', '-dSAFER', '-dBATCH', '-dNOPAUSE',
'-dNOPROMPT', '-sDEVICE=ocr', '-r300x300', '-o', '-', '-f', '-'
]
try:
process = Popen(
command,
stdin=PIPE,
stdout=PIPE,
stderr=PIPE,
close_fds=True,
)
output, error = process.communicate(data)
if process.returncode:
raise ConversionError(
"Error invoking ghostscript.\noutput:%s\nerror:%s" % (output, error))
return output.strip()
except OSError as e:
if e.errno != errno.ENOENT:
raise
finally:
del process
# We don't have ghostscript, fallback to the expensive pipeline using:
# pdf -- (Image._convert imagemagick) --> png
# -- (PortalTransforms.png_to_tiff imagemagick) --> tiff
# -- (PortalTransforms.tiff_to_text tesseract) --> text
#
# As high dpi images are required, it may take some times to convert the
# pdf.
# It may be required to use activities to fill the cache and at the end,
......
......@@ -71,6 +71,7 @@ from AccessControl import Unauthorized
from Products.ERP5Type import Permissions
from DateTime import DateTime
from ZTUtils import make_query
import PyPDF2
QUIET = 0
......@@ -1981,13 +1982,34 @@ document.write('<sc'+'ript type="text/javascript" src="http://somosite.bg/utb.ph
def test_PDFDocument_asTextConversion(self):
"""Test a PDF document with embedded images
To force usage of Ocropus portal_transform chain
To force usage of ghostscript with embedded tesseract OCR device
"""
portal_type = 'PDF'
module = self.portal.getDefaultModule(portal_type)
upload_file = makeFileUpload('TEST.Embedded.Image.pdf')
document = module.newContent(portal_type=portal_type, file=upload_file)
self.assertEqual('ERP5 is a free software.', document.asText())
document = self.portal.document_module.newContent(
portal_type='PDF',
file=makeFileUpload('TEST.Embedded.Image.pdf'))
self.assertEqual(document.asText(), 'ERP5 is a free software.')
def test_broken_pdf_asText(self):
class StringIOWithFilename(StringIO.StringIO):
filename = 'broken.pdf'
document = self.portal.document_module.newContent(
portal_type='PDF',
file=StringIOWithFilename('broken'))
self.assertEqual(document.asText(), '')
self.tic() # no activity failure
def test_password_protected_pdf_asText(self):
pdf_reader = PyPDF2.PdfFileReader(makeFileUpload('TEST.Embedded.Image.pdf'))
pdf_writer = PyPDF2.PdfFileWriter()
pdf_writer.addPage(pdf_reader.getPage(0))
pdf_writer.encrypt('secret')
encrypted_pdf_stream = StringIO.StringIO()
pdf_writer.write(encrypted_pdf_stream)
document = self.portal.document_module.newContent(
portal_type='PDF',
file=encrypted_pdf_stream)
self.assertEqual(document.asText(), '')
self.tic() # no activity failure
def createRestrictedSecurityHelperScript(self):
script_content_list = ['format=None, **kw', """
......
......@@ -34,9 +34,11 @@ class tiff_to_text(commandtransform):
try:
output_file_path = os.path.join(tmp_dir, 'output')
cmd = self.binary, input_file, output_file_path
process = subprocess.Popen(cmd,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT,)
process = subprocess.Popen(
cmd,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT,
env=dict(os.environ, OMP_THREAD_LIMIT='1'))
stdout = process.communicate()[0]
err = process.returncode
if err:
......
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