[IMP] mass_mailing: add 'view in browser' link in mailings

PURPOSE

Add a block that allows recipients to check the email in a browser in case
their mail service provider does not render it well or to see it full screen.

SPECIFICATIONS

A thumbnail has been added in the snippet thumbnails list of the mail editor.
It allows to add an header snippet. This snippet contains a link allowing the
recipient to see the mail in its browser instead of its mail client.

Add a route to display a mailing content. This route should be recipient
dependent as mailings could contain jinja markers. Using the same access token
and check as unsubscribe route this public route allows to display a mailing
content directly rendered for a given customer.

_get_unsubscribe_url method is moved from mail_mail to mailing as it does
not really belong to the mail model. Indeed it is mailing dependent.

A view URL leading to the view in browser route is added. It is managed like
the unsubscribe url: magically avoid shortening, magically rewrite when
sending email.

Task ID-2239327
PR #49886

7 files changed, 93 insertions, 21 deletions

diff --git a/addons/mass_mailing/controllers/main.py b/addons/mass_mailing/controllers/main.py
index 30653260425..bae258f9bf1 100644
--- a/addons/mass_mailing/controllers/main.py
+++ b/addons/mass_mailing/controllers/main.py
@@ -105,6 +105,35 @@ class MassMailController(http.Controller):
 
         return response
 
+    @http.route(['/mailing/<int:mailing_id>/view'], type='http', website=True, auth='public')
+    def view(self, mailing_id, email=None, res_id=None, token=""):
+        mailing = request.env['mailing.mailing'].sudo().browse(mailing_id)
+        if mailing.exists():
+            res_id = int(res_id) if res_id else False
+            if not self._valid_unsubscribe_token(mailing_id, res_id, email, str(token)) and not request.env.user.has_group('mass_mailing.group_mass_mailing_user'):
+                raise exceptions.AccessDenied()
+
+            res = mailing.convert_links()
+            base_url = request.env['ir.config_parameter'].sudo().get_param('web.base.url').rstrip('/')
+            urls_to_replace = [
+               (base_url + '/unsubscribe_from_list', mailing._get_unsubscribe_url(email, res_id)),
+               (base_url + '/view', mailing._get_view_url(email, res_id))
+            ]
+            for url_to_replace, new_url in urls_to_replace:
+                if url_to_replace in res[mailing_id]:
+                    res[mailing_id] = res[mailing_id].replace(url_to_replace, new_url if new_url else '#')
+
+            res[mailing_id] = res[mailing_id].replace(
+                'class="o_snippet_view_in_browser"',
+                'class="o_snippet_view_in_browser" style="display: none;"'
+            )
+
+            return request.render('mass_mailing.view', {
+                    'body': res[mailing_id],
+                })
+
+        return request.redirect('/web')
+
     @http.route('/r/<string:code>/m/<int:mailing_trace_id>', type='http', auth="public")
     def full_url_redirect(self, code, mailing_trace_id, **post):
         # don't assume geoip is set, it is part of the website module
diff --git a/addons/mass_mailing/models/mail_mail.py b/addons/mass_mailing/models/mail_mail.py
index 4c627234c27..4339dfdf6bc 100644
--- a/addons/mass_mailing/models/mail_mail.py
+++ b/addons/mass_mailing/models/mail_mail.py
@@ -29,21 +29,6 @@ class MailMail(models.Model):
         token = tools.hmac(self.env(su=True), 'mass_mailing-mail_mail-open', self.id)
         return werkzeug.urls.url_join(base_url, 'mail/track/%s/%s/blank.gif' % (self.id, token))
 
-    def _get_unsubscribe_url(self, email_to):
-        base_url = self.env['ir.config_parameter'].sudo().get_param('web.base.url')
-        url = werkzeug.urls.url_join(
-            base_url, 'mail/mailing/%(mailing_id)s/unsubscribe?%(params)s' % {
-                'mailing_id': self.mailing_id.id,
-                'params': werkzeug.urls.url_encode({
-                    'res_id': self.res_id,
-                    'email': email_to,
-                    'token': self.mailing_id._unsubscribe_token(
-                        self.res_id, email_to),
-                }),
-            }
-        )
-        return url
-
     def _send_prepare_body(self):
         """ Override to add the tracking URL to the body and to add
         trace ID in shortened urls """
@@ -81,10 +66,15 @@ class MailMail(models.Model):
         if self.mailing_id and res.get('body') and res.get('email_to'):
             emails = tools.email_split(res.get('email_to')[0])
             email_to = emails and emails[0] or False
-            unsubscribe_url = self._get_unsubscribe_url(email_to)
-            link_to_replace = base_url + '/unsubscribe_from_list'
-            if link_to_replace in res['body']:
-                res['body'] = res['body'].replace(link_to_replace, unsubscribe_url if unsubscribe_url else '#')
+
+            urls_to_replace = [
+               (base_url + '/unsubscribe_from_list', self.mailing_id._get_unsubscribe_url(email_to, self.res_id)),
+               (base_url + '/view', self.mailing_id._get_view_url(email_to, self.res_id))
+            ]
+
+            for url_to_replace, new_url in urls_to_replace:
+                if url_to_replace in res['body']:
+                    res['body'] = res['body'].replace(url_to_replace, new_url if new_url else '#')
         return res
 
     def _postprocess_sent_message(self, success_pids, failure_reason=False, failure_type=None):
diff --git a/addons/mass_mailing/models/mail_render_mixin.py b/addons/mass_mailing/models/mail_render_mixin.py
index 4447f3931c8..133643f29ff 100644
--- a/addons/mass_mailing/models/mail_render_mixin.py
+++ b/addons/mass_mailing/models/mail_render_mixin.py
@@ -18,6 +18,6 @@ class MailRenderMixin(models.AbstractModel):
                 rendered[res_id] = self._shorten_links(
                     html,
                     self.env.context['post_convert_links'],
-                    blacklist=['/unsubscribe_from_list']
+                    blacklist=['/unsubscribe_from_list', '/view']
                 )
         return rendered
diff --git a/addons/mass_mailing/models/mailing.py b/addons/mass_mailing/models/mailing.py
index 7d6426b2ca1..78890b1a6d8 100644
--- a/addons/mass_mailing/models/mailing.py
+++ b/addons/mass_mailing/models/mailing.py
@@ -8,6 +8,7 @@ import lxml
 import random
 import re
 import threading
+import werkzeug.urls
 from ast import literal_eval
 from datetime import datetime
 from dateutil.relativedelta import relativedelta
@@ -528,6 +529,34 @@ class MassMailing(models.Model):
         done_res_ids = [record['res_id'] for record in already_mailed]
         return [rid for rid in res_ids if rid not in done_res_ids]
 
+    def _get_unsubscribe_url(self, email_to, res_id):
+        base_url = self.env['ir.config_parameter'].sudo().get_param('web.base.url')
+        url = werkzeug.urls.url_join(
+            base_url, 'mail/mailing/%(mailing_id)s/unsubscribe?%(params)s' % {
+                'mailing_id': self.id,
+                'params': werkzeug.urls.url_encode({
+                    'res_id': res_id,
+                    'email': email_to,
+                    'token': self._unsubscribe_token(res_id, email_to),
+                }),
+            }
+        )
+        return url
+
+    def _get_view_url(self, email_to, res_id):
+        base_url = self.env['ir.config_parameter'].sudo().get_param('web.base.url')
+        url = werkzeug.urls.url_join(
+            base_url, 'mailing/%(mailing_id)s/view?%(params)s' % {
+                'mailing_id': self.id,
+                'params': werkzeug.urls.url_encode({
+                    'res_id': res_id,
+                    'email': email_to,
+                    'token': self._unsubscribe_token(res_id, email_to),
+                }),
+            }
+        )
+        return url
+
     def action_send_mail(self, res_ids=None):
         author_id = self.env.user.partner_id.id
 
@@ -583,7 +612,7 @@ class MassMailing(models.Model):
             if mass_mailing.medium_id:
                 vals['medium_id'] = mass_mailing.medium_id.id
 
-            res[mass_mailing.id] = mass_mailing._shorten_links(html, vals, blacklist=['/unsubscribe_from_list'])
+            res[mass_mailing.id] = mass_mailing._shorten_links(html, vals, blacklist=['/unsubscribe_from_list', '/view'])
 
         return res
 
diff --git a/addons/mass_mailing/static/src/img/blocks/block_header_browser.png b/addons/mass_mailing/static/src/img/blocks/block_header_browser.png
new file mode 100755
index 00000000000..c05196e7e5e
--- /dev/null
+++ b/addons/mass_mailing/static/src/img/blocks/block_header_browser.png
diff --git a/addons/mass_mailing/views/mass_mailing_templates_portal.xml b/addons/mass_mailing/views/mass_mailing_templates_portal.xml
index a3cbdc4dc32..52da35d41e1 100644
--- a/addons/mass_mailing/views/mass_mailing_templates_portal.xml
+++ b/addons/mass_mailing/views/mass_mailing_templates_portal.xml
@@ -97,6 +97,11 @@
         </div>
     </template>
 
+    <template id="view" name="Browser View">
+        <!-- Raw body inserted here because it is a rendered mailing, therefore internal content -->
+        <t t-raw="body"/>
+    </template>
+
     <template id="page_unsubscribe" name="Unsubscribe">
         <t t-call="mass_mailing.layout">
             <t t-call="mass_mailing.unsubscribe"/>
diff --git a/addons/mass_mailing/views/snippets_themes.xml b/addons/mass_mailing/views/snippets_themes.xml
index dad05aa1e5c..5d88537b190 100644
--- a/addons/mass_mailing/views/snippets_themes.xml
+++ b/addons/mass_mailing/views/snippets_themes.xml
@@ -28,6 +28,7 @@
                     <t t-snippet="mass_mailing.s_mail_block_header_text_social" t-thumbnail="/mass_mailing/static/src/img/blocks/block_header_text_social.png"/>
                     <t t-snippet="mass_mailing.s_mail_block_header_logo" t-thumbnail="/mass_mailing/static/src/img/blocks/block_header_logo.png"/>
                     <t t-snippet="mass_mailing.s_mail_block_banner" t-thumbnail="/mass_mailing/static/src/img/blocks/block_banner.png"/>
+                    <t t-snippet="mass_mailing.s_mail_block_header_view" t-thumbnail="/mass_mailing/static/src/img/blocks/block_header_browser.png"/>
                 </div>
             </div>
             <div id="email_designer_default_body" class="o_panel">
@@ -154,6 +155,24 @@
     </div>
 </template>
 
+<template id="s_mail_block_header_view" name="View in browser">
+    <div class="o_snippet_view_in_browser">
+        <div class="o_mail_snippet_general">
+            <table align="center" cellspacing="0" cellpadding="0" border="0" class="o_mail_table_styles">
+                <tbody>
+                    <tr>
+                        <td width="100%" class="o_mail_h_padding o_mail_v_padding o_mail_no_colorpicker text-center">
+                            <a href="/view">
+                                View this email in your browser
+                            </a>
+                        </td>
+                    </tr>
+                </tbody>
+            </table>
+        </div>
+    </div>
+</template>
+
 <template id="s_mail_block_title_text" name="Title Content">
     <div class="o_mail_block_title_text">
         <div class="o_mail_snippet_general">