[ADD] tools: utility to merge pdf files

odoo/tools/__init__.py

@@ -4,6 +4,7 @@
 import copy
 from . import win32
 from . import appdirs
+from . import pdf
 from .config import config
 from .misc import *
 from .convert import *

odoo/tools/pdf.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+from cStringIO import StringIO
+from PyPDF2 import PdfFileWriter, PdfFileReader
+
+
+def merge_pdf(pdf_data):
+    ''' Merge a collection of PDF documents in one
+    :param list pdf_data: a list of PDF datastrings
+    :return: a unique merged PDF datastring
+    '''
+    writer = PdfFileWriter()
+    for document in pdf_data:
+        reader = PdfFileReader(StringIO(document), strict=False)
+        for page in range(0, reader.getNumPages()):
+            writer.addPage(reader.getPage(page))
+    _buffer = StringIO()
+    writer.write(_buffer)
+    merged_pdf = _buffer.getvalue()
+    _buffer.close()
+    return merged_pdf