Lazy gettext with FastAPI response_model

[phamvanvuhb1999]

Hi, I'm facing some errors related to lazy gettext with FastAPI response_model,
It seem like lazytext not be evaluated correctly.
`
error_message = _("Some error message")

@app.get("/multilingual/template", response_class=JSONResponse)
async def multilingual_template(request: Request):
raise HTTPException(status_code=400, detail=error_message)

@app.get("/multilingual/template", response_class=JSONResponse)
async def multilingual_template(request: Request):
return {"data": error_message}
`
then both 2 endpoints raises "Lazytext is not Jsonable".

As I know, lazytext be evaluated (translated to string) when it needed, But how to force to do the translation in the view itself.

[Legopapurida]

@phamvanvuhb1999

I will fix this issue by forcing the lazy gettext object to be evaluated as a string (using str()) before returning it in FastAPI responses or exceptions.