how to do pagination in RESTFUL API in a effective way? - api

Question

I want to support pagination in my RESTful API.
My API method should return a JSON list of product via http://localhost/products/v1/getproductsbycategory, there are potentially thousands of products, and I want to page through them, so my request should look something like this:
public function getProductsByCategory($product_id,$page){
$perPage=5;
$start=($page-1)*$perPage;
$stmt=$this->conn->prepare("SELECT id,product,description,destination_url,expiry_type,savings,expiry,title,last_updated_on FROM products WHERE product_id=? ORDER BY last_updted_on DESC LIMIT $start ,$perPage");
$stmt->bind_param('i',$category_id);
$stmt->execute();
$productbycategory=$stmt->get_result();
$stmt->close();
return $productbycategory;
}
}

Answer 1

Firstly, in a RESTful call, the URL should ideally be noun-based and not verbs. We are using HTTP verbs (GET, PUT, POST, etc) to do an action on a noun - product in your case.
So, the URL should be http://localhost/products/v1/category
This effectively means you are GETting product of type v1 based on category. To get a given page number, simply add it as a query parameter -
http://localhost/products/v1/category?page=1
and handle it accordingly in your GET implementation corresponding to localhost/products/v1/category
Hope this helps.

Answer 2

Pagination has nothing to do with the JSON format per se - it's all about the query string in the URL and how the server interprets that.
Expanding on #Sampada's answer, you can have a URL like
http://localhost/products/v1/category?pageSize=5&pageNumber=2
and then you'll simply pick the corresponding elements on the server side (consider whether you'll want 0 or 1-based index for the pageNumber), and return them.
Additionally you can wrap this collection in an object that also provides links as to navigate to the previous/next/specific page - see HATEOAS & Richardson's Maturity Model level 3.