Node - Redirect with Parameters in Express

  • Estimated read time: 3 min read
  • Written by Chad Campbell on Jul 16th 2016

Recently, I wanted to move some URLs around on this site. Specifically, I had my training courses listed at a URL like this: /about/publications/courses. Beyond that, each course was listed at something like /about/publications/courses/[course-name]. Well, I wanted to redirect from those URLs to /courses and /courses/[course-name] respectively.

In this post, I'll show you what I learned. First, I'm going to show you how to do a basic redirect in Express. Then, I'll show you how to do a redirect if you're requested URL has parameters.

Redirecting with a URL

Meeting my first requirement was pretty easy. I wanted to permanently redirect from /about/publications/courses to /courses. So, I just needed to use the Response.redirect function. This function is baked into Express. This gave me something like this.

app.use('/about/publications/courses', function(req, res) {
    res.redirect(301, '/courses');

In this function call, I used two parameters. The first parameter I passed in was 301. This value is the HTTP status code for a permanent redirect. Well, my goal was to permanently move towards this URL structure. So, this status code made sense in my case. However, that value doesn't always make sense. I encourage you to understand what you're trying to accomplish before setting the status code. It's really important. Still, had I not included the 301, a status code of 302 (Found) would've been used.

The second parameter is the URL that I wanted to redirect to. This value can be a relative URL like I used. Or, it can be a fully qualified URL. The choice is yours. Still, I assumed that redirecting with parameters was going to be just as easy.

Redirecting with Parameters

Next, I wanted to redirect to each individual training course page. Those pages provide each course's details. At first, I assumed I could just do this:

app.use('/about/publications/courses/:slug', function(req, res) {        
    res.redirect(301, '/courses/:slug');

However, that is incorrect. My brain was turned off when I tried that. But, it is the thing that made me decide to write this blog post.

This lead me to the point where I needed to build the path to my URL. So, I ended up writing the following:

app.use('/about/publications/courses/:slug', function(req, res) {        
    let redirectUrl = '/courses/' + req.params.slug;
    res.redirect(301, redirectUrl);

This block of code appends two strings together: "/courses/" and the value of req.params.slug. I then redirect to that URL. If I was using ES6, I could've used a template string. I chose not to do that in this blog post. The reason why is because I wanted to focus on the problem at hand and hopefully make this valuable for you.

Still, I hope you found this post helpful. If you're interested in any of my training courses, they are now located at the /courses endpoint. If you don't believe me, you can try to use the old URL I mentioned in this post . Beyond that, thanks for reading.


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Chad Campbell
Chad Campbell

Chad is an independent software professional. He has been named a Microsoft MVP five times. His books have been translated into multiple languages and distributed worldwide. He holds a computer science degree from Purdue University, where he also studied psychology.

Chad has built sites, apps, frameworks, libraries, and platforms using Java, .NET, and Node. He's ran his own startups and has created software for Fortune 100 companies. In short, Chad knows how to create software. From ideation to delivery. From start-to-finish.

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