How to debug Javascript + PHP + Web services

Disclaimer: May be a insane question but I have suffered a lot so came here.

I am working on a legacy application which uses JS + PHP + Web services (Written in spring).

Flow of the application :

Whenever any web service is called from JS it is redirected to one php file. The php file authenticates the user(using one web service) and then forwards the request to actual web service.

How can I debug this application ? I have debugged JS using Firebug and servr side code using Eclips开发者_如何学编程e but never debugged such a application.

~Ajinkya.

I think there are a variety of things that need to be done, and I must say this question is sufficiently general as to not have a straight answer so I will do my best. As xdazz mentioned, var_dump (and die) are necessary from the PHP standpoint.

Whenever anything is returned to JS console.log it. In addition, ensure XHTTP requests are turned on for Firebug or alternatively view the output of each request in the Chrome Network tab.

With a combination of console.log, var_dump, and die, you can trace non-functioning parts of the application repeatedly step by step until you come across the bug.

Alternatively, and in the long run you ought to be doing this anyway, build error handling code into all the PHP code that is only activated when a debug flag is set to true. This way you can get detailed error messages and then when you deploy, you can turn them off to avoid compromising security.

If you are needing to inspect the entire lifecycle of a Web service request in your scenario you will need to combine a several techniques. Considering the fact that the scope of your scenario spans from client to server you will need to decide with what you will persist the information you need to inspect.

Personally, I would choose the path of least resistance which in my case would probably be cookies. With that being said you should be able chronologically log the necessary information via JavaScript and PHP, both before, during and after the request and even redirect has occurred.

This strategy would then allow for the information logged with cookies to then be dumped or analyzed via JavaScript, WebKit inspector or Firebug. Again, this is probably how I would handle such a scenario. Lastly, you can apply different storage strategies to this technique such as using a session or database for persistence.

Note: You can use something like WebKit Inspector, and possibly Firebug, to analyze data transmitted and received for GET, POST and even WebSocket requests.