More work

max/translations.py

@@ -0,0 +1,77 @@
+import json
+import os
+import re
+
+
+ACCEPT_LANGUAGE_HEADER_REGEX = re.compile(r"([a-zA-Z]{2,3})(-[a-zA-Z\-]+)?")
+
+
+def t(*args, **kwargs):
+    return TranslationHandler.translate(*args, **kwargs)
+
+
+class TranslationHandler:
+    translations = {}
+    language = "en"
+    language_available = {"en": True}
+    always_reload_translations = False
+
+    @classmethod
+    def init(cls, app):
+        cls.app = app
+        cls.always_reload_translations = app.debug
+        app.context_processor(lambda: dict(t=t))
+
+    @classmethod
+    def is_language_available(cls, language):
+        if language not in cls.language_available:
+            cls.language_available[language] = os.path.exists(
+                cls.get_language_filepath(language)
+            )
+        return cls.language_available[language]
+
+    @classmethod
+    def set_language(cls, language):
+        if not cls.is_language_available(language):
+            cls.app.logger.info(f"Cannot find language {language}. Default to en.")
+            language = "en"
+
+        cls.language = language
+        if language != "en" and (
+            cls.always_reload_translations or language not in cls.translations
+        ):
+            cls.translations[language] = json.load(
+                open(cls.get_language_filepath(language), "r")
+            )
+
+    @classmethod
+    def translate(cls, string, **interpolation):
+        if cls.language == "en":
+            return string.format(**interpolation)
+
+        if string not in cls.translations[cls.language]:
+            cls.app.logger.warning(
+                f'Unknown translation to {cls.language} for "{string}"'
+            )
+            return string.format(**interpolation)
+
+        return cls.translations[cls.language][string].format(**interpolation)
+
+    @classmethod
+    def parse_language_header(cls, header):
+        if not header:
+            return None
+
+        if "*" in header:
+            return None
+
+        languages = [match[0] for match in ACCEPT_LANGUAGE_HEADER_REGEX.findall(header)]
+        # take the first matching one
+        for language in languages:
+            if cls.is_language_available(language):
+                return language
+        return None
+
+    @classmethod
+    def get_language_filepath(cls, language):
+        return os.path.join(cls.app.root_path, f"private_static/i18n/{language}.json")