Language code mismatch causes failure to load translations, because separator in language code is '-'

[ruiheng]

Event using the lastest commit '47018bc', My FastAPI app still does not work.

My browser sends the following Accept-Languages header:

zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2

After processing by the fastapi-babel middleware, the preferred languages list contains codes like "zh-CN". However, the language subdirectories under the lang directory use underscores instead of dashes, e.g. "zh_CN".

This causes a failure to locate the proper MO files for translations.

The lang directory structure is created by the fastapi-babel command line tool, which only accepts language codes with underscores like "zh_CN". Codes with dashes like "zh-CN" cause errors in the babel library, which uses underscores by default.

My suggested fix is to simply replace dashes with underscores in the language codes, as shown in this patch:

--- middleware.py	2023-12-21 09:32:34.000000000 +0800
+++ middleware.py	2023-12-21 09:33:07.000000000 +0800
@@ -38,6 +38,7 @@
             return self.babel.config.BABEL_DEFAULT_LOCALE
         languages = re.findall(r"([a-z]{2}-[A-Z]{2}|[a-z]{2})(;q=\d.\d{1,3})?", lang_code)
         languages = sorted(languages, key=lambda x: x[1], reverse=True) # sort the priority, no priority comes last
+        languages = map(lambda x: (x[0].replace('-', '_'), x[1]), languages)
         translation_directory = Path(self.babel.config.BABEL_TRANSLATION_DIRECTORY)
         translation_files = [i.name for i in translation_directory.iterdir()]
         explicit_priority = None

[Legopapurida]

Hello dude
we have tried this method, thanks for announcing us due this problem, we will be glad if
you can fix this code and contribute to the project.

[AnderUstarroz]

@ruiheng is right, this needs to be resolved or language detection will be kind of useless otherwise.

I have fixed it and sent a Pull request #26 with a performant solution.

Please @Legopapurida could you take few minutes to take a look and create the new release v0.0.9? The old v0.0.8 crashes whenever the requested language doesn't exist instead of using a default language. There is no point of having a broken release when we already have that fixed.

Thanks,

[AnderUstarroz]

Thanks for merging the PR @Legopapurida !

Any chance to update the pip package to v0.0.9?
Then you could close the following issues:

• Language code mismatch causes failure to load translations, because separator in language code is '-' #24
• Any chance to make a new release? #27
• Locale languages not evaluated correctly from Accept-Language header #19

[peterschwarzdev]

Before updating the pip package to v0.0.9 I think you should also merge this Pull request #29 @Legopapurida ! It adds a huge improvement, I am using his branch in production and works great, but would be better for everyone having it released as an official PIP version.

[Legopapurida]

Hello everybody
I apologize for the long gap in checking the issues and pull requests.
I was so busy in these days.

I will check the issues and pull requests as soon as possible and this will be released to new version (v1)

[Legopapurida]

the problem has been fixed by @AnderUstarroz and a million thanks to @AnderUstarroz

[Legopapurida]

Thanks all