From a984947846c7b83d3151fc4987ca615edcb168ef Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Sun, 11 Oct 2020 15:05:16 +0200
Subject: i18n for survey

---
 talermerchantdemos/survey/survey.py | 60 ++++++++++++++++++++++++++++++-------
 1 file changed, 49 insertions(+), 11 deletions(-)

(limited to 'talermerchantdemos/survey/survey.py')

diff --git a/talermerchantdemos/survey/survey.py b/talermerchantdemos/survey/survey.py
index b6a5ceb..140088d 100644
--- a/talermerchantdemos/survey/survey.py
+++ b/talermerchantdemos/survey/survey.py
@@ -1,6 +1,6 @@
 ##
 # This file is part of GNU TALER.
-# Copyright (C) 2017 Taler Systems SA
+# Copyright (C) 2017, 2020 Taler Systems SA
 #
 # TALER is free software; you can redistribute it and/or modify it under the
 # terms of the GNU Lesser General Public License as published by the Free Software
@@ -23,9 +23,14 @@ import base64
 import logging
 from urllib.parse import urljoin
 import flask
+from flask import request
+from flask_babel import Babel
+from flask_babel import refresh
+from flask_babel import force_locale
+from flask_babel import gettext
 import traceback
 from taler.util.talerconfig import TalerConfig, ConfigurationError
-from ..httpcommon import backend_get, backend_post, fallback_404
+from ..httpcommon import backend_get, backend_post, self_localized
 import sys
 
 if not sys.version_info.major == 3 and sys.version_info.minor >= 6:
@@ -37,6 +42,8 @@ BASE_DIR = os.path.dirname(os.path.abspath(__file__))
 app = flask.Flask(__name__, template_folder=BASE_DIR)
 app.debug = True
 app.secret_key = base64.b64encode(os.urandom(64)).decode('utf-8')
+
+LOGGER = logging.getLogger(__name__)
 TC = TalerConfig.from_env()
 try:
     BACKEND_URL = TC["frontends"]["backend"].value_string(required=True)
@@ -47,9 +54,30 @@ except ConfigurationError as ce:
     exit(1)
 
 app.config.from_object(__name__)
-LOGGER = logging.getLogger(__name__)
+babel = Babel(app)
 INSTANCED_URL = urljoin(BACKEND_URL, f"instances/survey/")
 
+print("Using translations from:")
+print(list(babel.translation_directories))
+translations = [str(translation) for translation in babel.list_translations()]
+if not 'en' in translations:
+    translations.append('en')
+print("Operating with the following translations available:")
+print(translations)
+
+app.jinja_env.globals.update(self_localized=self_localized)
+
+@babel.localeselector
+def get_locale():
+    parts = request.path.split('/', 2)
+    if (2 >= len(parts)):
+        # Totally unexpected path format, do not localize
+        return "en"
+    lang = parts[1]
+    if lang in translations:
+        return lang
+    return "en"
+
 ##
 # Make the environment available into templates.
 #
@@ -80,8 +108,8 @@ def utility_processor():
 @app.errorhandler(Exception)
 def internal_error(e):
     return flask.render_template(
-        "templates/error.html",
-        message="Internal error",
+        "templates/error.html.j2",
+        message=gettext("Internal error"),
         stack=traceback.format_exc()
     )
 
@@ -92,7 +120,7 @@ def internal_error(e):
 # @return the favicon.ico file.
 @app.route("/favicon.ico")
 def favicon():
-    print("will look into: " + os.path.join(app.root_path, 'static'))
+    LOGGER.info("will look into: " + os.path.join(app.root_path, 'static'))
     return flask.send_from_directory(
         os.path.join(app.root_path, 'static'),
         "favicon.ico",
@@ -105,7 +133,7 @@ def favicon():
 # @param abort_status_code status code to return along the response.
 # @param params _kw_ arguments to passed verbatim to the templating engine.
 def err_abort(abort_status_code, **params):
-    t = flask.render_template("templates/error.html", **params)
+    t = flask.render_template("templates/error.html.j2", **params)
     flask.abort(flask.make_response(t, abort_status_code))
 
 ##
@@ -127,16 +155,26 @@ def submit_survey():
     return flask.redirect(backend_resp["tip_status_url"])
 
 ##
-# Serve the main index page.
+# Serve the main index page, redirecting to /<lang>/
 #
 # @return response object of the index page.
-@app.route("/", methods=["GET"])
+@app.route("/")
 def index():
+    default = 'en'
+    target = flask.request.accept_languages.best_match(translations, default)
+    return flask.redirect("/" + target + "/", code=302)
+
+##
+# Serve the internationalized main index page.
+#
+# @return response object of the index page.
+@app.route("/<lang>/", methods=["GET"])
+def start(lang):
     return flask.render_template(
-        "templates/index.html", merchant_currency=CURRENCY
+        "templates/index.html.j2", merchant_currency=CURRENCY, lang=lang
     )
 
 @app.errorhandler(404)
 def handler(e):
     return flask.render_template(
-        "templates/error.html", message="Page not found")
+        "templates/error.html.j2", message=gettext("Page not found"))
-- 
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