Redirect all trailing slashes globally in express

Question

I am using Node.js and Express and I have the following routing :

app.get(\'/\', function(req,res){
    locals.date = new Date().toLocaleDateString();

    r         


        

Answer 1

The answers above will work in a lot of cases but GET vars can encounter issues and if you were to put that inside another express middleware its reliance on req.path will cause a problem and its reliance on req.url can also have unwanted side effects. If you're looking for a tighter solution this will do the trick:

// Redirect non trailing slash to trailing slash
app.use(function(req, res, next){
    // Find the query string
    var qsi = req.originalUrl.indexOf('?');
    // Get the path
    var path = req.originalUrl;
    if(qsi > -1) path = path.substr(0, qsi);
    // Continue if the path is good or it's a static resource
    if(path.substr(-1) === '/' || ~path.indexOf('.')) return next();
    // Save just the query string
    var qs = '';
    if(qsi > -1) qs = req.originalUrl.substr(qsi);
    // Save redirect path
    var redirect = path + '/' + qs;
    // Redirect client
    res.redirect(301, redirect);

    console.log('301 redirected ' + req.originalUrl + ' to ' + redirect);
});

It's always happy with GET variables and won't break if you were to put it inside middleware.

Answer 2

Try adding a middleware for that;

app.use((req, res, next) => {
  const test = /\?[^]*\//.test(req.url);
  if (req.url.substr(-1) === '/' && req.url.length > 1 && !test)
    res.redirect(301, req.url.slice(0, -1));
  else
    next();
});

Answer 3

The answer by Tolga Akyüz is inspiring but doesn't work if there is any characters after the slash. For example http://example.com/api/?q=a is redirected to http://example.com/api instead of http://example.com/api?q=a.

Here is an improved version of the proposed middleware that fix the problem by adding the original query to the end of the redirect destination url:

app.use(function(req, res, next) {
    if (req.path.substr(-1) == '/' && req.path.length > 1) {
        var query = req.url.slice(req.path.length);
        res.redirect(301, req.path.slice(0, -1) + query);
    } else {
        next();
    }
});

Note: As noted by jamesk and stated in RFC 1738, the trailing slash can only be omitted when there is nothing after the domain. Therefore, http://example.com?q=a is an invalid url where http://example.com/?q=a is a valid one. In such case, no redirection should be done. Fortunately, the expression req.path.length > 1 takes care of that. For example, given the url http://example.com/?q=a, the path req.path equals to / and thus the redirection is avoided.

Answer 4

The connect-slashes middleware was designed specifically for this need: https://npmjs.org/package/connect-slashes

Install it with:

$ npm install connect-slashes

Read the full documentation: https://github.com/avinoamr/connect-slashes

Answer 5

/**
 * @param {express.Request} req
 * @param {express.Response} res
 * @param {express.NextFunction} next
 * @return {void}
 */
function checkTrailingSlash(req, res, next) {
    if (req.path.slice(req.path.length-1) !== '/') {
        res.redirect(301, req.path + '/' + req.url.slice(req.path.length));
    } else {
        next();
    }
}
  
app.use(checkTrailingSlash);

Example results:

/         ==> /
/a        ==> /a/
/a/       ==> /a/
/a/b      ==> /a/b/
/a/b/     ==> /a/b/
/a/b?c=d  ==> /a/b/?c=d
/a/b/?c=d ==> /a/b/?c=d

Answer 6

One liner:

router.get('\\S+\/$', function (req, res) {
  return res.redirect(301, req.path.slice(0, -1) + req.url.slice(req.path.length));
});

This will only catch the url's that need to be redirected, and ignore the others.

Example results:

/         ==> /
/a        ==> /a
/a/       ==> /a
/a/b      ==> /a/b
/a/b/     ==> /a/b
/a/b/?c=d ==> /a/b?c=d