Express：根据Cookie提供静态文件

Question

I want to serve static files dependant on a specific cookie.

Let say the cookie language has the value 'en', i would like to serve dist/browser/en.

Something like this:

app.use(express.static(path.join(__dirname, '../../client/dist/browser/',req.cookies.language), { maxAge: '2d'}));

I know this doesnt work bc i dont have access to the req in here, but hints how to achieve this are highly appreciated.

Answer 1

You can't use express.static() in a "dynamic" fashion that determines what it does based on information in the request. It's called express.static() for a reason, the routes are static and do the same thing for everyone.

To serve data dynamically, you will have to write your own route that examines the cookie and then finds the appropriate file and streams that file back as the response. express-static is based on the serve-static module and you can examine the source code here . It's not very complicated.

Answer 2

Thanks to the help of jfriend00´s Answer i could write a code that does what i want:

app.use("*",function(req,res,next){
    const parts = req.originalUrl.split( ".");                     //sepaprate the url to finmd out if file is requested
    if(parts.length >= 2 &&                                                 //if there is a file ending
        req.originalUrl.length - req.originalUrl.lastIndexOf(".") <= 4){     //check if its really a file
        let language = req.cookies?req.cookies.language:null;
        if(!language){    // set standard language
            language = "de";
        }
        res.sendFile(path.join(__dirname, '../../client/dist/locales/',language,req.originalUrl), { maxAge: '2d'}); // send file
    }else{
        //otherwise let someone else handle the request
        next();
    }
});