[IMP] http_routing, website: allow to customize the lang in URL

With this commit it is now possible to change the lang displayed in the URL.
Eg, you could use `/fr` instead of `/fr_BE`, or even a fancier `/french`.

Task-32838

Courtesy of pla@odoo.com

closes odoo/odoo#35135

Signed-off-by: Romain Derie (rde) <rde@odoo.com>

30 files changed, 238 insertions, 152 deletions

diff --git a/addons/auth_signup/controllers/main.py b/addons/auth_signup/controllers/main.py
index 0618cd367f3..6f21118e369 100644
--- a/addons/auth_signup/controllers/main.py
+++ b/addons/auth_signup/controllers/main.py
@@ -123,9 +123,9 @@ class AuthSignupHome(Home):
             raise UserError(_("The form was not properly filled in."))
         if values.get('password') != qcontext.get('confirm_password'):
             raise UserError(_("Passwords do not match; please retype them."))
-        supported_langs = [code for code, _ in request.env['res.lang'].get_installed()]
-        if request.lang in supported_langs:
-            values['lang'] = request.lang
+        supported_lang_codes = [code for code, _ in request.env['res.lang'].get_installed()]
+        if request.lang.code in supported_lang_codes:
+            values['lang'] = request.lang.code
         self._signup_with_values(qcontext.get('token'), values)
         request.env.cr.commit()
 
diff --git a/addons/http_routing/__manifest__.py b/addons/http_routing/__manifest__.py
index 6305f25310a..f4636332f45 100644
--- a/addons/http_routing/__manifest__.py
+++ b/addons/http_routing/__manifest__.py
@@ -11,6 +11,7 @@ Proposes advanced routing options not available in web or base to keep
 base modules simple.
 """,
     'data': [
+        'views/res_lang_views.xml',
     ],
     'depends': ['web'],
 }
diff --git a/addons/http_routing/models/ir_http.py b/addons/http_routing/models/ir_http.py
index d6a4524eb31..c9d08f3c754 100644
--- a/addons/http_routing/models/ir_http.py
+++ b/addons/http_routing/models/ir_http.py
@@ -128,41 +128,58 @@ def unslug_url(s):
 # Language tools
 # ------------------------------------------------------------
 
-def url_for(path_or_uri, lang=None):
-    current_path = request.httprequest.path     # should already be text
+def url_for(path_or_uri, lang_code=None):
+    ''' Given a relative URL, make it absolute and add the required lang or
+        remove useless lang.
+        Nothing will be done for absolute URL.
+        If there is only one language installed, the lang will not be handled
+        unless forced with `lang` parameter.
+
+        :param lang_code: Must be the lang `code`. It could also be something
+                          else, such as `'[lang]'` (used for url_return).
+    '''
+    Lang = request.env['res.lang']
     location = pycompat.to_text(path_or_uri).strip()
-    force_lang = lang is not None
+    force_lang = lang_code is not None
     url = werkzeug.urls.url_parse(location)
-
+    # relative URL with either a path or a force_lang
     if not url.netloc and not url.scheme and (url.path or force_lang):
-        location = werkzeug.urls.url_join(current_path, location)
-
-        lang = pycompat.to_text(lang or request.context.get('lang') or 'en_US')
-        langs = [lg[0] for lg in request.env['ir.http']._get_language_codes()]
+        location = werkzeug.urls.url_join(request.httprequest.path, location)
+        lang_url_codes = [url_code for _, url_code, _ in Lang.get_available()]
+        lang_code = pycompat.to_text(lang_code or request.context['lang'])
+        lang_url_code = Lang._lang_get(lang_code).url_code
+        lang_url_code = lang_url_code if lang_url_code in lang_url_codes else lang_code
 
-        if (len(langs) > 1 or force_lang) and is_multilang_url(location, langs):
+        if (len(lang_url_codes) > 1 or force_lang) and is_multilang_url(location, lang_url_codes):
             ps = location.split(u'/')
-            if ps[1] in langs:
+            default_lg = request.env['ir.http']._get_default_lang()
+            if ps[1] in lang_url_codes:
                 # Replace the language only if we explicitly provide a language to url_for
                 if force_lang:
-                    ps[1] = lang
+                    ps[1] = lang_url_code
                 # Remove the default language unless it's explicitly provided
-                elif ps[1] == request.env['ir.http']._get_default_lang().code:
+                elif ps[1] == default_lg.url_code:
                     ps.pop(1)
             # Insert the context language or the provided language
-            elif lang != request.env['ir.http']._get_default_lang().code or force_lang:
-                ps.insert(1, lang)
+            elif lang_url_code != default_lg.url_code or force_lang:
+                ps.insert(1, lang_url_code)
             location = u'/'.join(ps)
 
     return location
 
 
-def is_multilang_url(local_url, langs=None):
-    if not langs:
-        langs = [lg[0] for lg in request.env['ir.http']._get_language_codes()]
+def is_multilang_url(local_url, lang_url_codes=None):
+    ''' Check if the given URL content is supposed to be translated.
+        To be considered as translatable, the URL should either:
+        1. Match a POST (non-GET actually) controller that is `website=True` and
+           either `multilang` specified to True or if not specified, with `type='http'`.
+        2. If not matching 1., everything not under /static/ will be translatable
+    '''
+    if not lang_url_codes:
+        lang_url_codes = [url_code for _, url_code, _ in request.env['res.lang'].get_available()]
     spath = local_url.split('/')
     # if a language is already in the path, remove it
-    if spath[1] in langs:
+    if spath[1] in lang_url_codes:
         spath.pop(1)
         local_url = '/'.join(spath)
     try:
@@ -223,10 +240,6 @@ class IrHttp(models.AbstractModel):
         )
 
     @classmethod
-    def _get_language_codes(cls):
-        return request.env['res.lang'].get_installed()
-
-    @classmethod
     def _get_default_lang(cls):
         lang_code = request.env['ir.default'].sudo().get('res.partner', 'lang')
         if lang_code:
@@ -285,13 +298,17 @@ class IrHttp(models.AbstractModel):
             return any(bot in user_agent.encode('ascii', 'ignore') for bot in cls.bots)
 
     @classmethod
-    def get_nearest_lang(cls, lang):
-        # Try to find a similar lang. Eg: fr_BE and fr_FR
-        short = lang.partition('_')[0]
+    def get_nearest_lang(cls, lang_code):
+        """ Try to find a similar lang. Eg: fr_BE and fr_FR
+            :param lang_code: the lang `code` (en_US)
+        """
         short_match = False
-        for code, dummy in cls._get_language_codes():
-            if code == lang:
-                return lang
+        if not lang_code:
+            return short_match
+        short = lang_code.partition('_')[0]
+        for code in [code for code, _, _ in request.env['res.lang'].get_available()]:
+            if code == lang_code:
+                return code
             if not short_match and code.startswith(short):
                 short_match = code
         return short_match
@@ -317,19 +334,28 @@ class IrHttp(models.AbstractModel):
 
     @classmethod
     def _add_dispatch_parameters(cls, func):
+        Lang = request.env['res.lang']
         # only called for is_frontend request
         if request.routing_iteration == 1:
             context = dict(request.context)
             path = request.httprequest.path.split('/')
-            langs = [code for code, _ in request.env['res.lang'].get_installed()]
             is_a_bot = cls.is_a_bot()
+
+            available_langs = Lang.get_available()
+            lang_codes = [code for code, _, _ in available_langs]
+            nearest_lang = not func and cls.get_nearest_lang(Lang._lang_get_code(path[1]))
             cook_lang = request.httprequest.cookies.get('frontend_lang')
-            nearest_lang = not func and cls.get_nearest_lang(path[1])
-            preferred_lang = ((cook_lang if cook_lang in langs else False)
-                              or (not is_a_bot and cls.get_nearest_lang(request.lang))
-                              or cls._get_default_lang().code)
+            cook_lang = cook_lang in lang_codes and cook_lang
+
+            if nearest_lang:
+                lang = Lang._lang_get(nearest_lang)
+            else:
+                nearest_ctx_lg = not is_a_bot and cls.get_nearest_lang(request.env.context['lang'])
+                preferred_lang = Lang._lang_get(cook_lang or nearest_ctx_lg) or cls._get_default_lang()
+                lang = preferred_lang
 
-            request.lang = context['lang'] = nearest_lang or preferred_lang
+            request.lang = lang
+            context['lang'] = lang.code
 
             # bind modified context
             request.context = context
@@ -380,34 +406,34 @@ class IrHttp(models.AbstractModel):
             return cls._handle_exception(e)
 
         # For website routes (only), add website params on `request`
-        cook_lang = request.httprequest.cookies.get('frontend_lang')
         if request.is_frontend:
             request.redirect = lambda url, code=302: werkzeug.utils.redirect(url_for(url), code)
 
             cls._add_dispatch_parameters(func)
 
             path = request.httprequest.path.split('/')
+            default_lg_id = cls._get_default_lang()
             if request.routing_iteration == 1:
                 is_a_bot = cls.is_a_bot()
-                nearest_lang = not func and cls.get_nearest_lang(path[1])
+                nearest_lang = not func and cls.get_nearest_lang(request.env['res.lang']._lang_get_code(path[1]))
                 url_lang = nearest_lang and path[1]
 
                 # if lang in url but not the displayed or default language --> change or remove
                 # or no lang in url, and lang to dispay not the default language --> add lang
                 # and not a POST request
                 # and not a bot or bot but default lang in url
-                if ((url_lang and (url_lang != request.lang or url_lang == cls._get_default_lang().code))
-                        or (not url_lang and request.is_frontend_multilang and request.lang != cls._get_default_lang().code)
+                if ((url_lang and (url_lang != request.lang.url_code or url_lang == default_lg_id.url_code))
+                        or (not url_lang and request.is_frontend_multilang and request.lang != default_lg_id)
                         and request.httprequest.method != 'POST') \
-                        and (not is_a_bot or (url_lang and url_lang == cls._get_default_lang().code)):
+                        and (not is_a_bot or (url_lang and url_lang == default_lg_id.url_code)):
                     if url_lang:
                         path.pop(1)
-                    if request.lang != cls._get_default_lang().code:
-                        path.insert(1, request.lang)
+                    if request.lang != default_lg_id:
+                        path.insert(1, request.lang.url_code)
                     path = '/'.join(path) or '/'
                     routing_error = None
                     redirect = request.redirect(path + '?' + request.httprequest.query_string.decode('utf-8'))
-                    redirect.set_cookie('frontend_lang', request.lang)
+                    redirect.set_cookie('frontend_lang', request.lang.code)
                     return redirect
                 elif url_lang:
                     request.uid = None
@@ -415,7 +441,7 @@ class IrHttp(models.AbstractModel):
                     routing_error = None
                     return cls.reroute('/'.join(path) or '/')
 
-            if request.lang == cls._get_default_lang().code:
+            if request.lang == default_lg_id:
                 context = dict(request.context)
                 context['edit_translations'] = False
                 request.context = context
@@ -426,8 +452,9 @@ class IrHttp(models.AbstractModel):
         # removed cache for auth public
         result = super(IrHttp, cls)._dispatch()
 
-        if request.is_frontend and cook_lang != request.lang and hasattr(result, 'set_cookie'):
-            result.set_cookie('frontend_lang', request.lang)
+        cook_lang = request.httprequest.cookies.get('frontend_lang')
+        if request.is_frontend and cook_lang != request.lang.code and hasattr(result, 'set_cookie'):
+            result.set_cookie('frontend_lang', request.lang.code)
 
         return result
 
@@ -463,8 +490,8 @@ class IrHttp(models.AbstractModel):
             generated_path = werkzeug.url_unquote_plus(path)
             current_path = werkzeug.url_unquote_plus(request.httprequest.path)
             if generated_path != current_path:
-                if request.lang != cls._get_default_lang().code:
-                    path = '/' + request.lang + path
+                if request.lang != cls._get_default_lang():
+                    path = '/' + request.lang.url_code + path
                 if request.httprequest.query_string:
                     path += '?' + request.httprequest.query_string.decode('utf-8')
                 return werkzeug.utils.redirect(path, code=301)
diff --git a/addons/http_routing/models/res_lang.py b/addons/http_routing/models/res_lang.py
new file mode 100644
index 00000000000..e69de29bb2d
--- /dev/null
+++ b/addons/http_routing/models/res_lang.py
diff --git a/addons/http_routing/views/res_lang_views.xml b/addons/http_routing/views/res_lang_views.xml
new file mode 100644
index 00000000000..96d03217f69
--- /dev/null
+++ b/addons/http_routing/views/res_lang_views.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0"?>
+<odoo>
+    <record id="res_lang_form_inherit_model" model="ir.ui.view">
+        <field name="name">res.lang.form.http_routing.inherit</field>
+        <field name="model">res.lang</field>
+        <field name="inherit_id" ref="base.res_lang_form"/>
+        <field name="arch" type="xml">
+            <field name="url_code" position="attributes">
+                <attribute name="invisible">0</attribute>
+            </field>
+        </field>
+    </record>
+
+    <record id="res_lang_tree_inherit_model" model="ir.ui.view">
+        <field name="name">res.lang.tree.model.inherit</field>
+        <field name="model">res.lang</field>
+        <field name="inherit_id" ref="base.res_lang_tree"/>
+        <field name="arch" type="xml">
+            <field name="url_code" position="attributes">
+                <attribute name="invisible">0</attribute>
+            </field>
+        </field>
+    </record>
+</odoo>
diff --git a/addons/web/controllers/main.py b/addons/web/controllers/main.py
index 591849a8bc0..dfe575b8f6f 100644
--- a/addons/web/controllers/main.py
+++ b/addons/web/controllers/main.py
@@ -762,7 +762,9 @@ class WebClient(http.Controller):
         # For performance reasons we only load a single translation, so for
         # sub-languages (that should only be partially translated) we load the
         # main language PO instead - that should be enough for the login screen.
-        lang = request.lang.split('_')[0]
+        context = dict(request.context)
+        request.session._fix_lang(context)
+        lang = context['lang'].split('_')[0]
 
         translations_per_module = {}
         for addon_name in mods:
diff --git a/addons/website/controllers/main.py b/addons/website/controllers/main.py
index a1cca57919f..f91870adfaf 100644
--- a/addons/website/controllers/main.py
+++ b/addons/website/controllers/main.py
@@ -107,10 +107,14 @@ class Website(Home):
     # Business
     # ------------------------------------------------------
 
+    @http.route('/website/get_languages', type='json', auth="user", website=True)
+    def website_languages(self, **kwargs):
+        return [(lg.code, lg.url_code, lg.name) for lg in request.website.language_ids]
+
     @http.route('/website/lang/<lang>', type='http', auth="public", website=True, multilang=False)
     def change_lang(self, lang, r='/', **kwargs):
         if lang == 'default':
-            lang = request.website.default_lang_code
+            lang = request.website.default_lang_id.url_code
             r = '/%s%s' % (lang, r or '/')
         redirect = werkzeug.utils.redirect(r or ('/%s' % lang), 303)
         redirect.set_cookie('frontend_lang', lang)
diff --git a/addons/website/models/ir_http.py b/addons/website/models/ir_http.py
index 58c15a8128c..ecacdc62bac 100644
--- a/addons/website/models/ir_http.py
+++ b/addons/website/models/ir_http.py
@@ -15,7 +15,7 @@ import odoo
 from odoo import api, models, registry
 from odoo import SUPERUSER_ID
 from odoo.http import request
-from odoo.tools import config
+from odoo.tools import config, ormcache
 from odoo.tools.safe_eval import safe_eval
 from odoo.osv.expression import FALSE_DOMAIN, OR
 
@@ -133,18 +133,6 @@ class Http(models.AbstractModel):
             request.website = request.website.with_context(request.context)
 
     @classmethod
-    def _get_languages(cls):
-        if getattr(request, 'website', False):
-            return request.website.language_ids
-        return super(Http, cls)._get_languages()
-
-    @classmethod
-    def _get_language_codes(cls):
-        if getattr(request, 'website', False):
-            return request.website._get_languages()
-        return super(Http, cls)._get_language_codes()
-
-    @classmethod
     def _get_default_lang(cls):
         if getattr(request, 'website', False):
             return request.website.default_lang_id
@@ -205,7 +193,7 @@ class Http(models.AbstractModel):
     @classmethod
     def _handle_exception(cls, exception):
         code = 500  # default code
-        is_website_request = bool(getattr(request, 'is_frontend', False) and getattr(request, 'website', False))
+        is_website_request = bool(getattr(request, 'is_frontend', False) and get_request_website())
         if not is_website_request:
             # Don't touch non website requests exception handling
             return super(Http, cls)._handle_exception(exception)
diff --git a/addons/website/models/ir_qweb.py b/addons/website/models/ir_qweb.py
index 0e93876be45..d3483fcb1b4 100644
--- a/addons/website/models/ir_qweb.py
+++ b/addons/website/models/ir_qweb.py
@@ -4,9 +4,10 @@ import re
 from collections import OrderedDict
 
 from odoo import models
-from odoo.addons.http_routing.models.ir_http import url_for
 from odoo.http import request
 from odoo.addons.base.models.assetsbundle import AssetsBundle
+from odoo.addons.http_routing.models.ir_http import url_for
+from odoo.addons.website.models import ir_http
 from odoo.tools import html_escape as escape
 
 re_background_image = re.compile(r"(background-image\s*:\s*url\(\s*['\"]?\s*)([^)'\"]+)")
@@ -47,7 +48,7 @@ class QWeb(models.AbstractModel):
            options.get('edit_translations') or options.get('debug') or (request and request.session.debug):
             return atts
 
-        website = request and getattr(request, 'website', None)
+        website = ir_http.get_request_website()
         if not website and options.get('website_id'):
             website = self.env['website'].browse(options['website_id'])
 
diff --git a/addons/website/models/ir_ui_view.py b/addons/website/models/ir_ui_view.py
index 6949f173a46..6b1efe5a717 100644
--- a/addons/website/models/ir_ui_view.py
+++ b/addons/website/models/ir_ui_view.py
@@ -302,7 +302,7 @@ class View(models.Model):
         if request and getattr(request, 'is_frontend', False):
 
             editable = request.website.is_publisher()
-            translatable = editable and self._context.get('lang') != request.website.default_lang_code
+            translatable = editable and self._context.get('lang') != request.website.default_lang_id.code
             editable = not translatable and editable
 
             # in edit mode ir.ui.view will tag nodes
@@ -355,7 +355,7 @@ class View(models.Model):
                 url_for=url_for,
                 res_company=request.website.company_id.sudo(),
                 default_lang_code=request.env['ir.http']._get_default_lang().code,
-                languages=request.env['ir.http']._get_language_codes(),
+                languages=request.env['res.lang'].get_available(),
                 translatable=translatable,
                 editable=editable,
                 menu_data=self.env['ir.ui.menu'].load_menus_root() if request.website.is_user() else None,
@@ -367,7 +367,7 @@ class View(models.Model):
     def get_default_lang_code(self):
         website_id = self.env.context.get('website_id')
         if website_id:
-            lang_code = self.env['website'].browse(website_id).default_lang_code
+            lang_code = self.env['website'].browse(website_id).default_lang_id.code
             return lang_code
         else:
             return super(View, self).get_default_lang_code()
diff --git a/addons/website/models/res_config_settings.py b/addons/website/models/res_config_settings.py
index 6bcae68b61f..0fff2f6eb3b 100644
--- a/addons/website/models/res_config_settings.py
+++ b/addons/website/models/res_config_settings.py
@@ -19,15 +19,11 @@ class ResConfigSettings(models.TransientModel):
     website_country_group_ids = fields.Many2many(related='website_id.country_group_ids', readonly=False)
     website_company_id = fields.Many2one(related='website_id.company_id', string='Website Company', readonly=False)
     website_logo = fields.Binary(related='website_id.logo', readonly=False)
-    language_ids = fields.Many2many(related='website_id.language_ids', relation='res.lang',
-        readonly=False)
+    language_ids = fields.Many2many(related='website_id.language_ids', relation='res.lang', readonly=False)
     website_language_count = fields.Integer(string='Number of languages', compute='_compute_website_language_count', readonly=True)
-    website_default_lang_id = fields.Many2one(
-        string='Default language', related='website_id.default_lang_id', readonly=False,
-        relation='res.lang')
-    website_default_lang_code = fields.Char(
-        'Default language code', related='website_id.default_lang_code', readonly=False,
-        )
+    website_default_lang_id = fields.Many2one(string='Default language', related='website_id.default_lang_id',
+                                              readonly=False, relation='res.lang')
+    website_default_lang_code = fields.Char('Default language code', related='website_id.default_lang_id.code', readonly=False)
     specific_user_account = fields.Boolean(related='website_id.specific_user_account', readonly=False,
                                            help='Are newly created user accounts website specific')
 
diff --git a/addons/website/models/res_lang.py b/addons/website/models/res_lang.py
index c84a212ed5a..9fc3f69e998 100644
--- a/addons/website/models/res_lang.py
+++ b/addons/website/models/res_lang.py
@@ -1,8 +1,10 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
-from odoo import api, models, _
+from odoo import api, models, tools, _
+from odoo.addons.website.models import ir_http
 from odoo.exceptions import UserError
+from odoo.http import request
 
 
 class Lang(models.Model):
@@ -13,3 +15,12 @@ class Lang(models.Model):
             if self.env['website'].search([('language_ids', 'in', self._ids)]):
                 raise UserError(_("Cannot deactivate a language that is currently used on a website."))
         return super(Lang, self).write(vals)
+
+    @api.model
+    @tools.ormcache_context(keys=("website_id",))
+    def get_available(self):
+        """ Return the available languages as a list of (code, name) sorted by name. """
+        website = ir_http.get_request_website()
+        if website:
+            return sorted([(lang.code, lang.url_code, lang.name) for lang in request.website.language_ids])
+        return super(Lang, self).get_available()
diff --git a/addons/website/models/website.py b/addons/website/models/website.py
index 8ce3d46568a..29398c35872 100644
--- a/addons/website/models/website.py
+++ b/addons/website/models/website.py
@@ -56,7 +56,6 @@ class Website(models.Model):
     company_id = fields.Many2one('res.company', string="Company", default=lambda self: self.env.company, required=True)
     language_ids = fields.Many2many('res.lang', 'website_lang_rel', 'website_id', 'lang_id', 'Languages', default=_active_languages)
     default_lang_id = fields.Many2one('res.lang', string="Default Language", default=_default_language, required=True)
-    default_lang_code = fields.Char("Default language code", related='default_lang_id.code', store=True, readonly=False)
     auto_redirect_lang = fields.Boolean('Autoredirect Language', default=True, help="Should users be redirected to their browser's language")
 
     def _default_social_facebook(self):
@@ -156,7 +155,8 @@ class Website(models.Model):
         public_user_to_change_websites = self.env['website']
         self._handle_favicon(values)
 
-        self._get_languages.clear_cache(self)
+        self.clear_caches()
+
         if 'company_id' in values and 'user_id' not in values:
             public_user_to_change_websites = self.filtered(lambda w: w.sudo().user_id.company_id.id != values['company_id'])
             if public_user_to_change_websites:
@@ -437,19 +437,11 @@ class Website(models.Model):
     # Languages
     # ----------------------------------------------------------
 
-    def get_languages(self):
-        self.ensure_one()
-        return self._get_languages()
-
-    @tools.cache('self.id')
-    def _get_languages(self):
-        return [(lg.code, lg.name) for lg in self.language_ids]
-
     def get_alternate_languages(self, req=None):
         langs = []
         if req is None:
             req = request.httprequest
-        default = self.get_current_website().default_lang_code
+        default = self.get_current_website().default_lang_id.url_code
         shorts = []
 
         def get_url_localized(router, lang):
@@ -460,11 +452,11 @@ class Website(models.Model):
             return router.build(request.endpoint, arguments)
 
         router = request.httprequest.app.get_db_router(request.db).bind('')
-        for code, dummy in self.get_languages():
-            lg_path = ('/' + code) if code != default else ''
-            lg_codes = code.split('_')
+        for lg in self.language_ids:
+            lg_path = ('/' + lg.url_code) if lg.url_code != default else ''
+            lg_codes = lg.code.split('_')
             shorts.append(lg_codes[0])
-            uri = get_url_localized(router, code) if request.endpoint else request.httprequest.path
+            uri = get_url_localized(router, lg.url_code) if request.endpoint else request.httprequest.path
             if req.query_string:
                 uri += u'?' + req.query_string.decode('utf-8')
             lang = {
diff --git a/addons/website/models/website_visitor.py b/addons/website/models/website_visitor.py
index 9b262c26031..307ba256214 100644
--- a/addons/website/models/website_visitor.py
+++ b/addons/website/models/website_visitor.py
@@ -122,10 +122,9 @@ class WebsiteVisitor(models.Model):
     def _create_visitor(self, website_page_id=False):
         country_code = request.session.get('geoip', {}).get('country_code', False)
         country_id = request.env['res.country'].sudo().search([('code', '=', country_code)], limit=1).id if country_code else False
-        lang_id = request.env['res.lang'].sudo().search([('code', '=', request.lang)], limit=1).id
         vals = {
             'last_connection_datetime': datetime.now(),
-            'lang_id': lang_id,
+            'lang_id': request.lang.id,
             'country_id': country_id,
             'website_id': request.website.id
         }
diff --git a/addons/website/static/src/js/content/website_root.js b/addons/website/static/src/js/content/website_root.js
index 4b61a33d779..a8e208f1408 100644
--- a/addons/website/static/src/js/content/website_root.js
+++ b/addons/website/static/src/js/content/website_root.js
@@ -105,7 +105,7 @@ var WebsiteRoot = publicRootData.PublicRoot.extend({
         var $target = $(ev.target);
         // retrieve the hash before the redirect
         var redirect = {
-            lang: $target.data('lang'),
+            lang: $target.data('url_code'),
             url: encodeURIComponent($target.attr('href').replace(/[&?]edit_translations[^&?]+/, '')),
             hash: encodeURIComponent(window.location.hash)
         };
diff --git a/addons/website/static/src/js/menu/seo.js b/addons/website/static/src/js/menu/seo.js
index 3844a1d4731..2ac6d7fcded 100644
--- a/addons/website/static/src/js/menu/seo.js
+++ b/addons/website/static/src/js/menu/seo.js
@@ -497,9 +497,7 @@ var MetaKeywords = Widget.extend({
             },
         });
         this._rpc({
-            model: 'website',
-            method: 'get_languages',
-            args: [[context.website_id]],
+            route: '/website/get_languages',
         }).then(function (data) {
             self.$('#language-box').html(core.qweb.render('Configurator.language_promote', {
                 'language': data,
diff --git a/addons/website/static/src/js/menu/translate.js b/addons/website/static/src/js/menu/translate.js
index 043a900fff6..cab37bf3473 100644
--- a/addons/website/static/src/js/menu/translate.js
+++ b/addons/website/static/src/js/menu/translate.js
@@ -46,14 +46,11 @@ var TranslatePageMenu = websiteNavbarData.WebsiteNavbarActionWidget.extend({
      * @returns {Promise}
      */
     _goToMasterPage: function () {
-        var lang = '/' + utils.get_cookie('frontend_lang');
-
         var current = document.createElement('a');
         current.href = window.location.toString();
         current.search += (current.search ? '&' : '?') + 'enable_editor=1';
-        if (current.pathname.indexOf(lang) === 0) {
-            current.pathname = current.pathname.replace(lang, '');
-        }
+        // we are in translate mode, the pathname starts with '/<url_code/'
+        current.pathname = current.pathname.substr(current.pathname.indexOf('/', 1));
 
         var link = document.createElement('a');
         link.href = '/website/lang/default';
diff --git a/addons/website/static/src/xml/website.seo.xml b/addons/website/static/src/xml/website.seo.xml
index e3c442d8f32..6bafe769f16 100644
--- a/addons/website/static/src/xml/website.seo.xml
+++ b/addons/website/static/src/xml/website.seo.xml
@@ -2,7 +2,7 @@
 <templates id="template" xml:space="preserve">
     <t t-name="Configurator.language_promote">
         <t t-foreach="language" t-as="lang">
-            <option t-att-value="lang[0]" t-att-selected="lang[0] == def_lang ? 'selected' : null"><t t-esc="lang[1]" /></option>
+            <option t-att-value="lang[0]" t-att-selected="lang[0] == def_lang ? 'selected' : null"><t t-esc="lang[2]" /></option>
         </t>
     </t>
 
diff --git a/addons/website/static/tests/tours/rte.js b/addons/website/static/tests/tours/rte.js
index a57b282bd09..a5cd53eaf61 100644
--- a/addons/website/static/tests/tours/rte.js
+++ b/addons/website/static/tests/tours/rte.js
@@ -32,7 +32,7 @@ tour.register('rte_translator', {
     timeout: 60000,
 }, {
     content: "go to english version",
-    trigger: '.js_language_selector a[data-lang="en_US"]',
+    trigger: '.js_language_selector a[data-url_code="en"]',
     extra_trigger: 'html[lang*="fr"]',
 }, {
     content: "Open new page menu",
@@ -73,7 +73,7 @@ tour.register('rte_translator', {
     extra_trigger: 'body:not(.o_wait_reload):not(:has(.note-editor))',
 }, {
     content: "click on french version",
-    trigger: '.js_language_selector a[data-lang="fr_BE"]',
+    trigger: '.js_language_selector a[data-url_code="fr_BE"]',
     extra_trigger: 'html[lang*="en"]:not(:has(button[data-action=save]))',
 }, {
     content: "translate",
@@ -137,7 +137,7 @@ tour.register('rte_translator', {
     extra_trigger: 'html[lang*="fr"]:not(:has(#wrap p span))',
 }, {
     content: "return to english version",
-    trigger: '.js_language_selector a[data-lang="en_US"]',
+    trigger: '.js_language_selector a[data-url_code="en"]',
 }, {
     content: "edit english version",
     trigger: 'a[data-action=edit]',
@@ -170,7 +170,7 @@ tour.register('rte_translator', {
     trigger : '.js_language_selector .dropdown-toggle',
 }, {
     content: "return in french",
-    trigger : 'html[lang="en-US"] .js_language_selector .js_change_lang[data-lang="fr_BE"]',
+    trigger : 'html[lang="en-US"] .js_language_selector .js_change_lang[data-url_code="fr_BE"]',
 }, {
     content: "check bis: content is translated",
     trigger: '#wrap p font:first:contains(translated french text)',
diff --git a/addons/website/tests/__init__.py b/addons/website/tests/__init__.py
index dc24bd6e22a..9bb3efd60de 100644
--- a/addons/website/tests/__init__.py
+++ b/addons/website/tests/__init__.py
@@ -1,15 +1,16 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
-from . import test_converter
 from . import test_base_url
+from . import test_converter
+from . import test_crawl
 from . import test_get_current_website
+from . import test_lang_url
+from . import test_menu
+from . import test_page
 from . import test_qweb
-from . import test_crawl
 from . import test_ui
 from . import test_views
-from . import test_menu
-from . import test_page
 from . import test_website_favicon
 from . import test_website_reset_password
 from . import test_website_visitor
diff --git a/addons/website/tests/test_lang_url.py b/addons/website/tests/test_lang_url.py
new file mode 100644
index 00000000000..f4998168074
--- /dev/null
+++ b/addons/website/tests/test_lang_url.py
@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo.addons.http_routing.models.ir_http import url_for
+from odoo.addons.website.tools import MockRequest
+from odoo.tests import HttpCase, tagged
+
+
+@tagged('-at_install', 'post_install')
+class TestLangUrl(HttpCase):
+    def setUp(self):
+        super(TestLangUrl, self).setUp()
+
+        # Simulate multi lang without loading translations
+        self.website = self.env['website'].browse(1)
+        lang_fr = self.env.ref('base.lang_fr')
+        lang_fr.write({'active': True, 'url_code': 'fr'})
+        self.website.language_ids = self.env.ref('base.lang_en') + lang_fr
+        self.website.default_lang_id = self.env.ref('base.lang_en')
+
+    def test_01_url_for(self):
+        with MockRequest(self.env, website=self.website):
+            self.assertEqual(url_for('', '[lang]'), '/[lang]/hello/', "`[lang]` is used to be replaced in the url_return after installing a language, it should not be replaced or removed.")
+
+    def test_02_url_redirect(self):
+        url = '/fr_WHATEVER/contactus'
+        r = self.url_open(url)
+        self.assertEqual(r.status_code, 200)
+        self.assertTrue(r.url.endswith('/fr/contactus'), "fr_WHATEVER should be forwarded to 'fr_FR' lang as closest match")
+
+        url = '/fr_FR/contactus'
+        r = self.url_open(url)
+        self.assertEqual(r.status_code, 200)
+        self.assertTrue(r.url.endswith('/fr/contactus'), "lang in url should use url_code ('fr' in this case)")
diff --git a/addons/website/tests/test_qweb.py b/addons/website/tests/test_qweb.py
index 9386c9f81e3..9cc199291a9 100644
--- a/addons/website/tests/test_qweb.py
+++ b/addons/website/tests/test_qweb.py
@@ -77,7 +77,7 @@ class TestQwebProcessAtt(TransactionCase):
         self.website.default_lang_id = self.env.ref('base.lang_en')
         self.website.cdn_activated = True
         self.website.cdn_url = "http://test.cdn"
-        self.website.cdn_filters = "\n".join(["^(/[a-z]{2}_[A-Z]{2})?/a$", "^/b$"])
+        self.website.cdn_filters = "\n".join(["^(/[a-z]{2}_[A-Z]{2})?/a$", "^(/[a-z]{2})?/a$", "^/b$"])
 
     def _test_att(self, url, expect, tag='a', attribute='href'):
         self.assertEqual(
@@ -88,8 +88,8 @@ class TestQwebProcessAtt(TransactionCase):
     def test_process_att_no_request(self):
         # no request so no URL rewriting
         self._test_att('/', {'href': '/'})
-        self._test_att('/en_US/', {'href': '/en_US/'})
-        self._test_att('/fr_FR/', {'href': '/fr_FR/'})
+        self._test_att('/en/', {'href': '/en/'})
+        self._test_att('/fr/', {'href': '/fr/'})
         # no URL rewritting for CDN
         self._test_att('/a', {'href': '/a'})
 
@@ -97,8 +97,8 @@ class TestQwebProcessAtt(TransactionCase):
         with MockRequest(self.env):
             # no website so URL rewriting
             self._test_att('/', {'href': '/'})
-            self._test_att('/en_US/', {'href': '/en_US/'})
-            self._test_att('/fr_FR/', {'href': '/fr_FR/'})
+            self._test_att('/en/', {'href': '/en/'})
+            self._test_att('/fr/', {'href': '/fr/'})
             # no URL rewritting for CDN
             self._test_att('/a', {'href': '/a'})
 
@@ -106,37 +106,37 @@ class TestQwebProcessAtt(TransactionCase):
         with MockRequest(self.env, website=self.website, multilang=False):
             # lang not changed in URL but CDN enabled
             self._test_att('/a', {'href': 'http://test.cdn/a'})
-            self._test_att('/en_US/a', {'href': 'http://test.cdn/en_US/a'})
+            self._test_att('/en/a', {'href': 'http://test.cdn/en/a'})
             self._test_att('/b', {'href': 'http://test.cdn/b'})
-            self._test_att('/en_US/b', {'href': '/en_US/b'})
+            self._test_att('/en/b', {'href': '/en/b'})
 
     def test_process_att_no_request_lang(self):
         with MockRequest(self.env, website=self.website):
             self._test_att('/', {'href': '/'})
-            self._test_att('/en_US/', {'href': '/'})
-            self._test_att('/fr_FR/', {'href': '/fr_FR/'})
+            self._test_att('/en/', {'href': '/'})
+            self._test_att('/fr/', {'href': '/fr/'})
 
     def test_process_att_with_request_lang(self):
         with MockRequest(self.env, website=self.website, context={'lang': 'fr_FR'}):
-            self._test_att('/', {'href': '/fr_FR/'})
-            self._test_att('/en_US/', {'href': '/'})
-            self._test_att('/fr_FR/', {'href': '/fr_FR/'})
+            self._test_att('/', {'href': '/fr/'})
+            self._test_att('/en/', {'href': '/'})
+            self._test_att('/fr/', {'href': '/fr/'})
 
     def test_process_att_matching_cdn_and_lang(self):
         with MockRequest(self.env, website=self.website):
             # lang prefix is added before CDN
             self._test_att('/a', {'href': 'http://test.cdn/a'})
-            self._test_att('/en_US/a', {'href': 'http://test.cdn/a'})
-            self._test_att('/fr_FR/a', {'href': 'http://test.cdn/fr_FR/a'})
+            self._test_att('/en/a', {'href': 'http://test.cdn/a'})
+            self._test_att('/fr/a', {'href': 'http://test.cdn/fr/a'})
             self._test_att('/b', {'href': 'http://test.cdn/b'})
-            self._test_att('/en_US/b', {'href': 'http://test.cdn/b'})
-            self._test_att('/fr_FR/b', {'href': '/fr_FR/b'})
+            self._test_att('/en/b', {'href': 'http://test.cdn/b'})
+            self._test_att('/fr/b', {'href': '/fr/b'})
 
     def test_process_att_no_route(self):
         with MockRequest(self.env, website=self.website, context={'lang': 'fr_FR'}, routing=False):
             # default on multilang=True if route is not /{module}/static/
             self._test_att('/web/static/hi', {'href': '/web/static/hi'})
-            self._test_att('/my-page', {'href': '/fr_FR/my-page'})
+            self._test_att('/my-page', {'href': '/fr/my-page'})
 
     def test_process_att_url_crap(self):
         with MockRequest(self.env, website=self.website) as request:
diff --git a/addons/website/tools.py b/addons/website/tools.py
index e3bb897ec52..e7058d65541 100644
--- a/addons/website/tools.py
+++ b/addons/website/tools.py
@@ -84,14 +84,24 @@ class MockRequest(object):
         app.get_db_router = app.bind = app.match = app
         if not kw.get('routing', True):
             app.match = werkzeugRaiseNotFound
+
+        lang = kw.get('lang')
+        if not lang:
+            lang_code = kw.get('context', {}).get('lang', env.context.get('lang', 'en_US'))
+            lang = env['res.lang']._lang_get(lang_code)
+
+        context = kw.get('context', {})
+        context.setdefault('lang', lang_code)
+
         self.request = DotDict({
-            'context': kw.get('context', {}),
+            'context': context,
             'db': None,
             'env': env,
             'httprequest': {
                 'path': '/hello/',
                 'app': app,
             },
+            'lang': lang,
             'redirect': werkzeug.utils.redirect,
             'session': {
                 'geoip': {
diff --git a/addons/website/views/website_templates.xml b/addons/website/views/website_templates.xml
index 312d1ce701c..b89cb0721b4 100644
--- a/addons/website/views/website_templates.xml
+++ b/addons/website/views/website_templates.xml
@@ -227,7 +227,6 @@
             </t>
         </t>
 
-        <t t-set="languages" t-value="website.get_languages() if website else None"/>
         <t t-if="request and request.is_frontend_multilang and website">
             <t t-foreach="website.get_alternate_languages(request.httprequest)" t-as="lg">
                 <link rel="alternate" t-att-hreflang="lg['hreflang']" t-att-href="lg['href']"/>
@@ -395,16 +394,15 @@
         <li class="list-inline-item">
             <div class="dropup">
                 <button class="btn btn-sm btn-secondary dropdown-toggle" type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="true">
-                    <span t-esc="list(filter(lambda lg : lg[0] == lang, languages))[0][1].split('/').pop()"/>
+                    <span t-esc="list(filter(lambda lg : lg[0] == lang, languages))[0][2].split('/').pop()"/>
                     <span class="caret ml4"/>
                 </button>
                 <div class="dropdown-menu" role="menu">
                     <t t-foreach="languages" t-as="lg">
-                        <a t-att-href="url_for(request.httprequest.path + '?' + keep_query(), lang=lg[0])"
+                        <a t-att-href="url_for(request.httprequest.path + '?' + keep_query(), lang_code=lg[0])"
                            class="dropdown-item js_change_lang"
-                           t-att-data-default-lang="(editable or translatable) and 'true' if website and lg[0] == website.default_lang_code else None"
-                           t-att-data-lang="lg[0]">
-                            <t t-esc="lg[1].split('/').pop()"/>
+                           t-att-data-url_code="lg[1]">
+                            <t t-esc="lg[2].split('/').pop()"/>
                         </a>
                     </t>
                 </div>
diff --git a/addons/website_sale/controllers/main.py b/addons/website_sale/controllers/main.py
index 97a9e11169e..9412ddce2be 100644
--- a/addons/website_sale/controllers/main.py
+++ b/addons/website_sale/controllers/main.py
@@ -649,7 +649,7 @@ class WebsiteSale(http.Controller):
         if mode[0] == 'new':
             new_values['company_id'] = request.website.company_id.id
 
-        lang = request.lang if request.lang in request.website.mapped('language_ids.code') else None
+        lang = request.lang.code if request.lang.code in request.website.mapped('language_ids.code') else None
         if lang:
             new_values['lang'] = lang
         if mode == ('edit', 'billing') and order.partner_id.type == 'contact':
diff --git a/addons/website_sale_stock/models/product_product.py b/addons/website_sale_stock/models/product_product.py
index 07a873fa1a7..8c33b40d895 100644
--- a/addons/website_sale_stock/models/product_product.py
+++ b/addons/website_sale_stock/models/product_product.py
@@ -2,7 +2,7 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from odoo import fields, models
-from odoo.http import request
+from odoo.addons.website.models import ir_http
 
 
 class ProductProduct(models.Model):
@@ -11,7 +11,7 @@ class ProductProduct(models.Model):
     cart_qty = fields.Integer(compute='_compute_cart_qty')
 
     def _compute_cart_qty(self):
-        website = request and getattr(request, 'website', None)
+        website = ir_http.get_request_website()
         if not website:
             self.cart_qty = 0
             return
diff --git a/odoo/addons/base/models/res_lang.py b/odoo/addons/base/models/res_lang.py
index 22c6221b5c2..eccb6b09c93 100644
--- a/odoo/addons/base/models/res_lang.py
+++ b/odoo/addons/base/models/res_lang.py
@@ -28,6 +28,7 @@ class Lang(models.Model):
     name = fields.Char(required=True)
     code = fields.Char(string='Locale Code', required=True, help='This field is used to set/get locales for user')
     iso_code = fields.Char(string='ISO code', help='This ISO code is the name of po files to use for translations')
+    url_code = fields.Char('URL Code', required=True, help='The Lang Code displayed in the URL')
     active = fields.Boolean()
     direction = fields.Selection([('ltr', 'Left-to-Right'), ('rtl', 'Right-to-Left')], required=True, default='ltr')
     date_format = fields.Char(string='Date Format', required=True, default=DEFAULT_DATE_FORMAT)
@@ -50,6 +51,7 @@ class Lang(models.Model):
     _sql_constraints = [
         ('name_uniq', 'unique(name)', 'The name of the language must be unique !'),
         ('code_uniq', 'unique(code)', 'The code of the language must be unique !'),
+        ('url_code_uniq', 'unique(url_code)', 'The URL code of the language must be unique !'),
     ]
 
     @api.constrains('active')
@@ -181,6 +183,10 @@ class Lang(models.Model):
     def _lang_get_id(self, code):
         return self.with_context(active_test=True).search([('code', '=', code)]).id
 
+    @tools.ormcache('url_code')
+    def _lang_get_code(self, url_code):
+        return self.with_context(active_test=True).search([('url_code', '=', url_code)]).code or url_code
+
     def _lang_get(self, code):
         """ Return the language using this code if it is active """
         return self.browse(self._lang_get_id(code))
@@ -198,7 +204,7 @@ class Lang(models.Model):
     def get_available(self):
         """ Return the available languages as a list of (code, name) sorted by name. """
         langs = self.with_context(active_test=False).search([])
-        return sorted([(lang.code, lang.name) for lang in langs], key=itemgetter(1))
+        return sorted([(lang.code, lang.url_code, lang.name) for lang in langs], key=itemgetter(2))
 
     @api.model
     @tools.ormcache()
@@ -218,6 +224,9 @@ class Lang(models.Model):
     @api.model_create_multi
     def create(self, vals_list):
         self.clear_caches()
+        for vals in vals_list:
+            if not vals.get('url_code'):
+                vals['url_code'] = vals.get('iso_code') or vals['code']
         return super(Lang, self).create(vals_list)
 
     def write(self, vals):
diff --git a/odoo/addons/base/views/res_lang_views.xml b/odoo/addons/base/views/res_lang_views.xml
index 2f7b4990e90..483f2c1879f 100644
--- a/odoo/addons/base/views/res_lang_views.xml
+++ b/odoo/addons/base/views/res_lang_views.xml
@@ -9,6 +9,7 @@
                     <field name="name"/>
                     <field name="code" groups="base.group_no_one"/>
                     <field name="iso_code" groups="base.group_no_one"/>
+                    <field name="url_code" groups="base.group_no_one" invisible="1"/>
                     <field name="direction" groups="base.group_no_one"/>
                     <field name="active"/>
                     <button name="%(base.action_view_base_language_install)d"
@@ -40,6 +41,7 @@
                             <group>
                                 <field name="code"/>
                                 <field name="iso_code"/>
+                                <field name="url_code" invisible="1" required="0"/>
                                 <field name="active"/>
                             </group>
                             <group>
diff --git a/odoo/addons/base/wizard/base_language_install.py b/odoo/addons/base/wizard/base_language_install.py
index 3a41302b40d..3d5c804af34 100644
--- a/odoo/addons/base/wizard/base_language_install.py
+++ b/odoo/addons/base/wizard/base_language_install.py
@@ -20,7 +20,7 @@ class BaseLanguageInstall(models.TransientModel):
 
     @api.model
     def _get_languages(self):
-        return self.env['res.lang'].get_available()
+        return [[code, name] for code, _, name in self.env['res.lang'].get_available()]
 
     lang = fields.Selection(_get_languages, string='Language', required=True,
                             default=_default_language)
diff --git a/odoo/http.py b/odoo/http.py
index 25200ebcecf..146d79f6aa6 100644
--- a/odoo/http.py
+++ b/odoo/http.py
@@ -84,7 +84,6 @@ ALLOWED_DEBUG_MODES = ['', '1', 'assets', 'tests']
 #----------------------------------------------------------
 # Thread local global request object
 _request_stack = werkzeug.local.LocalStack()
-
 request = _request_stack()
 """
     A global proxy that always redirect to the current request object.
@@ -270,13 +269,6 @@ class WebRequest(object):
         return self._env
 
     @lazy_property
-    def lang(self):
-        context = dict(self.context)
-        self.session._fix_lang(context)
-        self.context = context
-        return context["lang"]
-
-    @lazy_property
     def session(self):
         """ :class:`OpenERPSession` holding the HTTP session data for the
         current http session