How to get msgstr and msgid at the same time?

[Lounarok]

I know babel cannot extract variables.

However I'd like to reduce the duplication of my code between logging and translation.
I'd like to have my logging with msgid but my response is msgstr. It's easier to lookup the log in a fixed language or it'd be hard for looking into the log in Klingon. (No offense to Klingon)

Eg: I want to have logging text with User request is completed while response is qaStaHvIS qemlI'.

Example:

from flask_babel import _

# ... do something

logging.info('User request is completed') # Duplicate msg for not getting translated.
return _('User request is completed')     # Is it possible to reduce the duplication?

My expected way to deal with it:

# ... do something
msg, msgid = gettext_and_id('User request is completed')
# `msg` is translated string 'qaStaHvIS qemlI'
# `msgid` is the id 'User request is completed'

logging.info(msgid)
return msg

However I did check the source code of flask-babel and there is no similar functions.
Any suggestion is welcome.

Indeed, I could make a helper function on my own, but I'd like to have a better solution.

def gettext_and_id(msgid):
    return gettext(msgid), msgid

However this solution doesn't fix everything.
If I want to use Some {file} as a string for substitution, then it's still tedious...

filename = 'neverland'
# ... file doesn't exist
msg, msgid = gettext_and_id('{file} is not found')
msg = msg.format(file=filename)
msgid = msgid.format(file=filename)

My question is posted at stackoverflow as well.

[StanFromIreland]

@akx Can this be closed, you already gave a nice answer on SO :-)

[akx]

^{Cross-posting the SO answer here, just in case...}

Babel won't be able to pick up the string t's contents into a catalog from the expression _(t), because that would involve either static analysis to try and figure out if t is statically assigned, or actually running the code and capturing all _() invocations, both of which are a bit tough to do.

You can configure a custom keyword, say, msgid, and define that function in your program to simply return the same string at runtime.

Then you can do

msg = msgid('User request is completed')
logging.info(msg) 
reply(_(msg))

and Babel would pick up the message, but it would only actually get translated by the _() call.

Alternately, if you don't want to pay the runtime price for that identity msgid function, you could write a custom Babel extractor and tag your messages with some special syntax, e.g. here a # msgid comment:

msg = 'User request is completed'  # msgid
logging.info(msg) 
reply(_(msg))

[jun66j5]

You can configure a custom keyword, say, msgid, and define that function in your program to simply return the same string at runtime.

Then you can do

msg = msgid('User request is completed')
logging.info(msg) 
reply(_(msg))

We could use N_ which is added as an extractor keyword by default rather than adding custom keyword. The N_ keyword has been added in Babel 0.8.1.

N_ method should be defined yourself:

N_ = lambda string: string