How to design RESTful search/filtering?

Question

I'm currently designing and implementing a RESTful API in PHP. However, I have been unsuccessful implementing my initial design.

GET /users # list of users
GET /user/1 # get user with id 1
POST /user # create new user
PUT /user/1 # modify user with id 1
DELETE /user/1 # delete user with id 1

So far pretty standard, right?

My problem is with the first one GET /users. I was considering sending parameters in the request body to filter the list. This is because I want to be able to specify complex filters without getting a super long url, like:

GET /users?parameter1=value1&parameter2=value2&parameter3=value3&parameter4=value4

Instead I wanted to have something like:

GET /users
# Request body:
{
    "parameter1": "value1",
    "parameter2": "value2",
    "parameter3": "value3",
    "parameter4": "value4"
}

which is much more readable and gives you great possibilities to set complex filters.

Anyway, file_get_contents('php://input') didn't return the request body for GET requests. I also tried http_get_request_body(), but the shared hosting that I'm using doesn't have pecl_http. Not sure it would have helped anyway.

I found this question and realized that GET probably isn't supposed to have a request body. It was a bit inconclusive, but they advised against it.

So now I'm not sure what to do. How do you design a RESTful search/filtering function?

I suppose I could use POST, but that doesn't seem very RESTful.

Answer 1

The best way to implement a RESTful search is to consider the search itself to be a resource. Then you can use the POST verb because you are creating a search. You do not have to literally create something in a database in order to use a POST.

For example:

Accept: application/json
Content-Type: application/json
POST http://example.com/people/searches
{
  "terms": {
    "ssn": "123456789"
  },
  "order": { ... },
  ...
}

You are creating a search from the user's standpoint. The implementation details of this are irrelevant. Some RESTful APIs may not even need persistence. That is an implementation detail.