Debugging HTTP Lorna Mitchell, SmashingConf 2015 

Why Debugging HTTP? 

6 Stages of Debugging 

Denial That can't happen. 

Frustration That doesn't happen on my machine. 

Disbelief That shouldn't happen. 

Testing Why does that happen? 

Gotcha Oh, I see. 

Relief How did that ever work? 

Fault-Finding HTTP ... is just like fault-finding elsewhere in a web project Seeing the problem is usually harder than fixing it 

Developer Tools Get to know the tools in your browser. 

Developer Tools 

Curl Curl (or cURL) is command-line multitool for HTTP http://curl.haxx.se/ 

Lornajane's Curl Cheat Sheet -X [verb] The verb to use for this request -H "[Header :value]" A header to send. Use as many times as needed -d [value] Body data as a string, a filename, or a key/value pair -s The "silent" switch, to hide curl's progress meter when piping the output to something else -c [filename] Where to store any incoming cookies for future use -b [filename] Cookies to send with the request -v to show headers for both request and response 

Postman 

RESTClient 

Paw 

Ngrok Expose local websites to the wider web https://ngrok.com/ 

Charles Proxy Multi-platform Web Debugging Proxy http://www.charlesproxy.com/ 

Debugging SSL Charles can perform a man-in-the-middle attack 

Debugging SSL You need to authorise the "attack" 

Make Debugging Your Super Power 

Other Excellent Tools • Postman (Chrome) http://getpostman.com/ • RESTClient http://restclient.net/ • Paw http://luckymarmot.com/paw • Fiddler http://www.telerik.com/fiddler 

Questions? From http://www.oreilly.com Contact: http://lornajane.net - @lornajane