how to process php REST url resources - php

Question

I have read many about REST api in php articles. but I still get quite confusing.
they basically rewrite the url to a index.php, which process the url and depends on the method, then send response
but which is the properly way to process the url? this looks doen't look correct...
get the uri and split it
I should know what to do with each portion, eg. for GET /usr/1 I should do something like:
if($myUri[0]=="usr")
getUser($myUri[1]);
if the request url is like GET www.domain.com/user/1
it would call getUser($id);
but what happen if you can also retrieve the user by name, or maybe e-mail? so the url can also be www.domain.com/user/john or www.domain.com/user/john#gmail.com
and each url should call different methods like getUsrByName($name) or getUsrByEmail($mail)

Answer 1

The proper way of handling this would be to have URLs like this:
domain.com/user/id/1 -> user::getById
domain.com/user/email/foo#bar.com -> user::getByEmail
domain.com/user/username/foo -> user::getByUsername
However, specifying multiple "parameters" is more like a search, I'd go against using resources for that, because a path should be absolute. Which means:
domain.com/user/name/Kossel/likes/StackOverflow
And:
domain.com/user/likes/StackOverflow/name/Kossel
Are not the same resource. Instead I'd do:
domain.com/user/?name=Kossel&likes=StackOverflow
This is what Stack Overflow uses:
stackoverflow.com/questions/tagged/php
stackoverflow.com/tags/php/new
stackoverflow.com/questions/tagged/mysql?sort=featured

Answer 2

To avoid long if/else statement, use variable function names. this allows you to use the url string to call the correct function.
http://php.net/manual/en/functions.variable-functions.php
Also, you may want to use classes/class methods instead of functions. this way you can set up an __autoload function, which will allow you to only load code that you are going to use each time the index.php is called.
MVC architecture usually breaks their urls into /class_name/class_method_name/arguments...