Get a Single Header with cURL

By  on  

Debugging third party apps can be difficult for a variety of reasons.  You take for granted that the third party has not only properly coded their app but that their server is also serving files properly.  As more a developer than a sysadmin I tend to spend a long time on the code before I ensure the server stuff is correct.  One mistake often made on the server side is not sending correct Content-Type headers with content, especially audio and video files, and that can cause a real problem for the app or codec trying to do something with the content.  These days I check response headers before I do anything else.

Getting complete response headers with cURL is easy:

#  Get response headers
curl -I https://davidwalsh.name

#  Result:
#  HTTP/1.1 301 Moved Permanently
#  Date: Wed, 03 Feb 2016 17:29:51 GMT
#  Content-Type: text/html; charset=iso-8859-1
#  Connection: keep-alive
#  Set-Cookie: __cfduid=dab1e532a38b35ce7d764344217ddd8dc1454520590; expires=Thu, 02-Feb-17 17:29:50 GMT; path=/; domain=.davidwalsh.name; HttpOnly
#  Location: https://davidwalsh.name/
#  Cache-Control: max-age=1
#  Expires: Wed, 03 Feb 2016 17:29:52 GMT
#  Vary: Accept-Encoding
#  Server: cloudflare-nginx
#  CF-RAY: 26efdc3d2aa841ef-MSP

But that's a lot of info to sift through if you only want the one header.  Here's how you can retrieve just one header:

#  Get single header only
#  curl {url} -I | grep -Fi {header_name}
curl https://davidwalsh.name -I | grep -Fi Content-Type

#  Result:
#  Content-Type: text/html; charset=iso-8859-1

With the extra grep above you'll only get the one header back.  Simple!

Recent Features

  • By
    Write Simple, Elegant and Maintainable Media Queries with Sass

    I spent a few months experimenting with different approaches for writing simple, elegant and maintainable media queries with Sass. Each solution had something that I really liked, but I couldn't find one that covered everything I needed to do, so I ventured into creating my...

  • By
    CSS Filters

    CSS filter support recently landed within WebKit nightlies. CSS filters provide a method for modifying the rendering of a basic DOM element, image, or video. CSS filters allow for blurring, warping, and modifying the color intensity of elements. Let's have...

Incredible Demos

  • By
    jQuery Comment Preview

    I released a MooTools comment preview script yesterday and got numerous requests for a jQuery version. Ask and you shall receive! I'll use the exact same CSS and HTML as yesterday. The XHTML The CSS The jQuery JavaScript On the keypress and blur events, we validate and...

  • By
    HTML5 Input Types Alternative

    As you may know, HTML5 has introduced several new input types: number, date, color, range, etc. The question is: should you start using these controls or not? As much as I want to say "Yes", I think they are not yet ready for any real life...

Discussion

  1. Lev Nar

    this is the best answer that I found with my problem, but the only question i have is how to do this is curl php

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