[IMP] attachment_indexation: improved PDF text extraction

PyPDF performs badly on many types of PDF documents.
We add a text extraction with pdfminer, which is designed for this task.
Because pdf content extraction was so flaky, it was completely
deactivated by 1b753b0d53744a6e. We revert that :-)

closes odoo/odoo#38508

Task: 2152494
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

5 files changed, 33 insertions, 9 deletions

diff --git a/addons/attachment_indexation/models/ir_attachment.py b/addons/attachment_indexation/models/ir_attachment.py
index dcc662a3c5d..11152b6c2ea 100644
--- a/addons/attachment_indexation/models/ir_attachment.py
+++ b/addons/attachment_indexation/models/ir_attachment.py
@@ -2,14 +2,16 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 import io
 import logging
-import PyPDF2
 import xml.dom.minidom
 import zipfile
+from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
+from pdfminer.converter import TextConverter
+from pdfminer.pdfpage import PDFPage
 
 from odoo import api, models
 
 _logger = logging.getLogger(__name__)
-FTYPES = ['docx', 'pptx', 'xlsx', 'opendoc']
+FTYPES = ['docx', 'pptx', 'xlsx', 'opendoc', 'pdf']
 
 def textToString(element):
     buff = u""
@@ -91,17 +93,19 @@ class IrAttachment(models.Model):
 
     def _index_pdf(self, bin_data):
         '''Index PDF documents'''
-
-        # extractText gives very bad results for indexing, hence we don't index PDF anymore. A
-        # better alternative is probably PDFMiner.six, but not for stable.
-        # See POC at https://github.com/odoo/odoo/pull/27568.
         buf = u""
         if bin_data.startswith(b'%PDF-'):
             f = io.BytesIO(bin_data)
             try:
-                pdf = PyPDF2.PdfFileReader(f, overwriteWarnings=False)
-                for page in pdf.pages:
-                    buf += page.extractText()
+                resource_manager = PDFResourceManager()
+                with io.StringIO() as content, TextConverter(resource_manager, content) as device:
+                    logging.getLogger("pdfminer").setLevel(logging.CRITICAL)
+                    interpreter = PDFPageInterpreter(resource_manager, device)
+
+                    for page in PDFPage.get_pages(f):
+                        interpreter.process_page(page)
+
+                    buf = content.getvalue()
             except Exception:
                 pass
         return buf
diff --git a/addons/attachment_indexation/tests/__init__.py b/addons/attachment_indexation/tests/__init__.py
new file mode 100644
index 00000000000..d76ba91978d
--- /dev/null
+++ b/addons/attachment_indexation/tests/__init__.py
@@ -0,0 +1,3 @@
+# -*- coding: utf-8 -*-
+
+from . import test_indexation
diff --git a/addons/attachment_indexation/tests/files/test_content.pdf b/addons/attachment_indexation/tests/files/test_content.pdf
new file mode 100644
index 00000000000..062e1e6e2f6
--- /dev/null
+++ b/addons/attachment_indexation/tests/files/test_content.pdf
diff --git a/addons/attachment_indexation/tests/test_indexation.py b/addons/attachment_indexation/tests/test_indexation.py
new file mode 100644
index 00000000000..9f5fa0eca15
--- /dev/null
+++ b/addons/attachment_indexation/tests/test_indexation.py
@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+
+from odoo.tests.common import TransactionCase, tagged
+import os
+
+directory = os.path.dirname(__file__)
+
+
+@tagged('post_install', '-at_install')
+class TestCaseIndexation(TransactionCase):
+
+    def test_attachment_pdf_indexation(self):
+        with open(os.path.join(directory, 'files', 'test_content.pdf'), 'rb') as file:
+            pdf = file.read()
+            text = self.env['ir.attachment']._index(pdf, 'application/pdf')
+            self.assertEqual(text, 'TestContent!!\x0c', 'the index content should be correct')
diff --git a/requirements.txt b/requirements.txt
index f6057683875..2507a3d10fa 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -21,6 +21,7 @@ mock==2.0.0
 num2words==0.5.6
 ofxparse==0.19
 passlib==1.7.1
+pdfminer.six==20181108
 Pillow==5.4.1 ; python_version < '3.7' or sys_platform != 'win32'
 Pillow==6.1.0 ; sys_platform == 'win32' and python_version >= '3.7'
 polib==1.1.0