[ADD] Module to provide file types for attachments

attachment_file_type/__init__.py

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+from . import models

attachment_file_type/__openerp__.py

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+# -*- coding: utf-8 -*-
+##############################################################################
+#
+#    OpenERP, Open Source Management Solution
+#    This module copyright (C) 2015 Therp BV (<http://therp.nl>).
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
+{
+    "name": "File types for attachments",
+    "version": "1.0",
+    "author": "Therp BV",
+    "license": "AGPL-3",
+    "description": """
+File types for attachments
+==========================
+Adds a content type to attachments. This is useful for instance in combination
+with http://bazaar.launchpad.net/~ocb/ocb-web/6.1/revision/2524, which makes
+Odoo offer downloads with the correct file type based on this field.
+
+The document module makes this field available as well. This module does not
+interfere with its functionality when both are installed.
+
+Installation
+============
+To install this module, you need to install python-magic in your environment
+first.
+
+Configuration
+=============
+This module comes with a daily scheduled task to provide content types for
+attachments without one in small batches (instead of trying to do this for all
+attachments at installation time). Depending on the number of attachments in
+your system you may deactivate this task after some time. You can follow the
+progress in the logs at the time that the cron job is fired.
+
+Credits
+=======
+Contributors
+------------
+
+* Stefan Rijnhart <stefan@therp.nl>
+* Holger Brunn <hbrunn@therp.nl>
+
+Maintainer
+----------
+
+.. image:: http://odoo-community.org/logo.png
+   :alt: Odoo Community Association
+   :target: http://odoo-community.org
+
+This module is maintained by the OCA.
+
+OCA, or the Odoo Community Association, is a nonprofit organization whose
+mission is to support the collaborative development of Odoo features and
+promote its widespread use.
+
+To contribute to this module, please visit http://odoo-community.org.
+    """,
+    "category": "Knowledge Management",
+    "depends": ['base'],
+    "data": ['data/ir_cron.xml'],
+    "license": 'AGPL-3',
+    "external_dependencies": {
+        'python': ['magic'],
+    },
+}

attachment_file_type/data/ir_cron.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<openerp>
+    <data noupdate="1">
+
+        <record id="cron_update_file_type" model="ir.cron">
+            <field name="name">Provide file types for attachments without one</field>
+            <field name="interval_number">24</field>
+            <field name="interval_type">hours</field>
+            <field name="numbercall">-1</field>
+            <field name="active">True</field>
+            <field name="doall" eval="False" />
+            <field name="model">ir.attachment</field>
+            <field name="function">update_file_type_from_cron</field>
+            <field name="args">(1000,)</field>
+        </record>
+
+    </data>
+</openerp>

attachment_file_type/models/__init__.py

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+from . import ir_attachment

attachment_file_type/models/ir_attachment.py

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+# -*- coding: utf-8 -*-
+##############################################################################
+#
+#    OpenERP, Open Source Management Solution
+#    This module copyright (C) 2015 Therp BV (<http://therp.nl>).
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
+import logging
+from openerp.osv import orm, fields
+from base64 import b64decode
+
+
+class Attachment(orm.Model):
+    _inherit = 'ir.attachment'
+
+    def update_file_type_from_cron(self, cr, uid, count=1000, context=None):
+        ids = self.search(
+            cr, uid, [('file_type', '=', False)], context=context)
+        logging.getLogger('openerp.addons.attachment_file_type').info(
+            'Found %s attachments without file type in the database.', len(ids))
+        self.update_file_type(cr, uid, ids, force=True, context=None)
+
+    def update_file_type(self, cr, uid, ids, force=False, context=None):
+        """ Write the file types for these attachments. If the document module
+        is installed, don't do anything unless in force mode. """
+        if not ids:
+            return True
+        if not force:
+            cr.execute(
+                "SELECT id from ir_module_module WHERE name = 'document' "
+                "AND state = 'installed'")
+            if cr.fetchone():
+                return True
+        if isinstance(ids, (int, long)):
+            ids = [ids]
+
+        logger = logging.getLogger('openerp.addons.attachment_file_type')
+        import magic
+        ms = magic.open(
+            # MAGIC_MIME gives additional encoding, but old versions of the
+            # 'file' package come with py_magic.c that lack MAGIC_MIME_TYPE
+            magic.MAGIC_MIME_TYPE if hasattr(magic, 'MAGIC_MIME_TYPE')
+            else magic.MAGIC_MIME)
+        ms.load()
+        for attachment in self.browse(cr, uid, ids, context=context):
+            file_type = ms.buffer(
+                b64decode(attachment.datas)).split(';')[0]
+            logger.debug(
+                'Found file type %s for attachment with id %s',
+                file_type, attachment.id)
+            attachment.write({'file_type': file_type})
+        return True
+
+    def write(self, cr, uid, ids, vals, context=None):
+        """ Update the mime type when the contents are overwritten """
+        res = super(Attachment, self).write(
+            cr, uid, ids, vals, context=context)
+        if vals.get('datas'):
+            self.update_file_type(cr, uid, ids, context=context)
+        return res
+
+    def create(self, cr, uid, vals, context=None):
+        """ Determine the mime type when the attachment is created """
+        res_id = super(Attachment, self).create(
+            cr, uid, vals, context=context)
+        if vals.get('datas'):
+            self.update_file_type(cr, uid, [res_id], context=context)
+        return res_id
+
+    _columns = {
+        'file_type': fields.char('Content Type', size=128),
+        }