Monthly Archives: March 2016

 

Let’s say you are debugging some simple web requests and trying to discern where things are slowing down.  Curl is perfect for that.  Well, sort of perfect. I don’t know about you but I forget all the switches for curl to make it work like I want.  Especially in a situation where you need to do something quickly.

Let me introduce you to curl-trace.

It’s not a new thing to install, its just an opinionated way to run curl.  To give you a feel for what it does, lets start with the output from curl-trace.

As you can see, this breaks up the request details like response code, redirects and IP in the Request Details section and then breaks down the timing of the request in the Timing Analysis section.  This uses curl’s --write-out option and was inspired by this post, this post, and my co-worker Marcus Barczak.

The goal of curl-trace is to quickly expose details for troubleshooting web performance.

How to setup curl-trace

Step 1

Download .curl-format from github (or copy from below)

\n
 Request Details:\n
 url: %{url_effective}\n
 num_redirects: %{num_redirects}\n
 content_type: %{content_type}\n
 response_code: %{response_code}\n
 remote_ip: %{remote_ip}\n
 \n
 Timing Analysis:\n
 time_namelookup: %{time_namelookup}\n
 time_connect: %{time_connect}\n
 time_appconnect: %{time_appconnect}\n
 time_pretransfer: %{time_pretransfer}\n
 time_redirect: %{time_redirect}\n
 time_starttransfer: %{time_starttransfer}\n
 ----------\n
 time_total: %{time_total}\n
 \n

And put that in your home directory as .curl-format or wherever you find convenient.

Step 2

Add an alias to your .bash_profile (and source .bash_profile) for curl-trace like this:


alias curl-trace='curl -w "@/path/to/.curl-format" -o /dev/null -s'


Be sure to change the /path/to/.curl-format to the location you saved .curl-format. Once you do that and source your .bash_profile you are ready to go.

Usage

Now you can run this:

$ curl-trace https://google.com

Or follow redirects with -L

$ curl-trace -L https://google.com

Thats it…

Now you are ready to use curl-trace. If you have anything to add to it, just send me an issue on github or a PR or ping me on twitter: https://twitter.com/wickett.

Enjoy!

UPDATE: 3/17/2016

There was a lot of good feedback on curl-trace so it has now been moved to its own repo: https://github.com/wickett/curl-trace