let user choose interface language #51

app/__init__.py

@@ -4,7 +4,7 @@
 import logging
 from logging.handlers import SMTPHandler, RotatingFileHandler
 import os
-from flask import Flask, request, current_app
+from flask import Flask, request, current_app, session
 from flask_sqlalchemy import SQLAlchemy
 from flask_migrate import Migrate
 from flask_login import LoginManager
@@ -20,10 +20,13 @@ from config import Config
 
 
 def get_locale():
-    try:
+    if session.get('ui_language', None):
-        return request.accept_languages.best_match(current_app.config['LANGUAGES'])
+        return session['ui_language']
-    except:
+    else:
-        return 'en'
+        try:
+            return request.accept_languages.best_match(current_app.config['LANGUAGES'])
+        except:
+            return 'en'
 
 
 db = SQLAlchemy()  # engine_options={'pool_size': 5, 'max_overflow': 10} # session_options={"autoflush": False}

app/auth/routes.py

@@ -56,6 +56,7 @@ def login():
         if user.waiting_for_approval():
             return redirect(url_for('auth.please_wait'))
         login_user(user, remember=True)
+        session['ui_language'] = user.interface_language
         current_user.last_seen = utcnow()
         current_user.ip_address = ip_address()
         db.session.commit()

app/models.py

@@ -606,6 +606,8 @@ class User(UserMixin, db.Model):
     theme = db.Column(db.String(20), default='')
     referrer = db.Column(db.String(256))
     markdown_editor = db.Column(db.Boolean, default=False)
+    interface_language = db.Column(db.String(10))           # a locale that the translation system understands e.g. 'en' or 'en-us'. If empty, use browser default
+    language_id = db.Column(db.Integer, db.ForeignKey('language.id'))   # the default choice in the language dropdown when composing posts & comments
 
     avatar = db.relationship('File', lazy='joined', foreign_keys=[avatar_id], single_parent=True, cascade="all, delete-orphan")
     cover = db.relationship('File', lazy='joined', foreign_keys=[cover_id], single_parent=True, cascade="all, delete-orphan")

app/templates/user/edit_settings.html

@@ -31,6 +31,7 @@
             {{ render_field(form.searchable) }}
             {{ render_field(form.indexable) }}
             <h5> Preferences </h5>
+            {{ render_field(form.interface_language) }}
             {{ render_field(form.markdown_editor) }}
             {{ render_field(form.default_sort) }}
             {{ render_field(form.theme) }}

app/user/forms.py

@@ -3,6 +3,7 @@ from flask_login import current_user
 from flask_wtf import FlaskForm
 from wtforms import StringField, SubmitField, PasswordField, BooleanField, EmailField, TextAreaField, FileField, \
     RadioField, DateField, SelectField
+from wtforms.fields.choices import SelectMultipleField
 from wtforms.validators import ValidationError, DataRequired, Email, EqualTo, Length, Optional
 from flask_babel import _, lazy_gettext as _l
 
@@ -31,6 +32,7 @@ class ProfileForm(FlaskForm):
 
 
 class SettingsForm(FlaskForm):
+    interface_language = SelectField(_l('Interface language'), coerce=str, validators=[Optional()], render_kw={'class': 'form-select'})
     newsletter = BooleanField(_l('Subscribe to email newsletter'))
     email_unread = BooleanField(_l('Receive email about missed notifications'))
     ignore_bots = BooleanField(_l('Hide posts by bots'))

app/user/routes.py

@@ -3,7 +3,7 @@ from time import sleep
 
 from flask import redirect, url_for, flash, request, make_response, session, Markup, current_app, abort, json
 from flask_login import login_user, logout_user, current_user, login_required
-from flask_babel import _
+from flask_babel import _, lazy_gettext as _l
 
 from app import db, cache, celery
 from app.activitypub.signature import post_request, default_context
@@ -164,6 +164,13 @@ def change_settings():
         abort(404)
     form = SettingsForm()
     form.theme.choices = theme_list()
+    form.interface_language.choices = [
+        ('', _l('Auto-detect')),
+        ('ca', _l('Catalan')),
+        ('en', _l('English')),
+        ('fr', _l('French')),
+        ('de', _l('German')),
+    ]
     if form.validate_on_submit():
         propagate_indexable = form.indexable.data != current_user.indexable
         current_user.newsletter = form.newsletter.data
@@ -176,6 +183,8 @@ def change_settings():
         current_user.theme = form.theme.data
         current_user.email_unread = form.email_unread.data
         current_user.markdown_editor = form.markdown_editor.data
+        current_user.interface_language = form.interface_language.data
+        session['ui_language'] = form.interface_language.data
         import_file = request.files['import_file']
         if propagate_indexable:
             db.session.execute(text('UPDATE "post" set indexable = :indexable WHERE user_id = :user_id'),
@@ -213,6 +222,7 @@ def change_settings():
         form.default_sort.data = current_user.default_sort
         form.theme.data = current_user.theme
         form.markdown_editor.data = current_user.markdown_editor
+        form.interface_language.data = current_user.interface_language
 
     return render_template('user/edit_settings.html', title=_('Edit profile'), form=form, user=current_user,
                            moderating_communities=moderating_communities(current_user.get_id()),

config.py

@@ -22,7 +22,7 @@ class Config(object):
     RECAPTCHA_PUBLIC_KEY = os.environ.get("RECAPTCHA_PUBLIC_KEY") or None
     RECAPTCHA_PRIVATE_KEY = os.environ.get("RECAPTCHA_PRIVATE_KEY") or None
     MODE = os.environ.get('MODE') or 'development'
-    LANGUAGES = ['de', 'en']
+    LANGUAGES = ['de', 'en', 'fr']
     FULL_AP_CONTEXT = bool(int(os.environ.get('FULL_AP_CONTEXT', 0)))
     CACHE_TYPE = os.environ.get('CACHE_TYPE') or 'FileSystemCache'
     CACHE_REDIS_URL = os.environ.get('CACHE_REDIS_URL') or 'redis://localhost:6379/1'

migrations/versions/e73996747d7e_user_language.py

@@ -0,0 +1,36 @@
+"""user language
+
+Revision ID: e73996747d7e
+Revises: 94828ddc7c63
+Create Date: 2024-05-09 13:37:17.010724
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'e73996747d7e'
+down_revision = '94828ddc7c63'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('user', schema=None) as batch_op:
+        batch_op.add_column(sa.Column('interface_language', sa.String(length=10), nullable=True))
+        batch_op.add_column(sa.Column('language_id', sa.Integer(), nullable=True))
+        batch_op.create_foreign_key(None, 'language', ['language_id'], ['id'])
+
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('user', schema=None) as batch_op:
+        batch_op.drop_constraint(None, type_='foreignkey')
+        batch_op.drop_column('language_id')
+        batch_op.drop_column('interface_language')
+
+    # ### end Alembic commands ###