Get Redirect URL with cURL

By  on  

URL redirects can be glorious or annoying depending on which side of them you are on and which side you want to be on.  Redirects are helpful for vanity URLs (useful in advertising) but sometimes they're annoying in that they could potentially break your code if you encounter a redirect you weren't anticipating.

The useful and amazing cURL command line utility allows you to fetch an address and return its final destination URL:

# "/css" doesn't exist but WordPress tries to find the closest match
# and then redirects to it ("/css-animation-callback")

curl -Ls -w %{url_effective} -o /dev/null https://davidwalsh.name/css

# Outputs: https://davidwalsh.name/css-animation-callback

The url_effective variable is what we're after.  The L directive tells cURL to follow redirects, the s directive tells cURL to be silent (i.e. not output the page contents).  You provide the URL, cURL follows it to its endpoint -- easy!

Recent Features

  • By
    JavaScript Promise API

    While synchronous code is easier to follow and debug, async is generally better for performance and flexibility. Why "hold up the show" when you can trigger numerous requests at once and then handle them when each is ready?  Promises are becoming a big part of the JavaScript world...

  • By
    Create a CSS Cube

    CSS cubes really showcase what CSS has become over the years, evolving from simple color and dimension directives to a language capable of creating deep, creative visuals.  Add animation and you've got something really neat.  Unfortunately each CSS cube tutorial I've read is a bit...

Incredible Demos

  • By
    Simple Image Lazy Load and Fade

    One of the quickest and easiest website performance optimizations is decreasing image loading.  That means a variety of things, including minifying images with tools like ImageOptim and TinyPNG, using data URIs and sprites, and lazy loading images.  It's a bit jarring when you're lazy loading images and they just...

  • By
    MooTools Typewriter Effect Plugin

    Last week, I read an article in which the author created a typewriter effect using the jQuery JavaScript framework. I was impressed with the idea and execution of the code so I decided to port the effect to MooTools. After about an hour of coding...

Discussion

  1. J-K. Solbakken

    Follow a URL using JavaScript: https://www.npmjs.com/package/linkfollower

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!