Interrogate API until no results left - php

Question

I am working with an API at the moment that will only return 200 results at a time, so I am trying to run some code that works out if there is more data to fetch based on whether or not the results have a offsetCursor param in them as this tells me that that there are more results to get, this offsetCursor is then sent a param in the next request, the next set of results come back and if there is an offsetCursor param then we make another request.
What I am wanting to do is push the results of each request into a an array, here is my attempt,
function get_cars($url, $token)
{
$cars = [];
$curl = curl_init();
curl_setopt_array($curl, array(
CURLOPT_URL => $url,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "GET",
CURLOPT_HTTPHEADER => array(
"Content-Type: application/x-www-form-urlencoded",
"Authorization: Bearer " . $token
)
));
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if($err) {
return false;
} else {
$results = json_decode($response, TRUE);
//die(print_r($results));
$cars[] = $results['_embedded']['results'];
if(isset($results['cursorOffset']))
{
//die($url.'&cursor_offset='.$results['cursorOffset']);
get_cars('https://abcdefg.co.uk/service/search1/advert?size=5&cursor_offset='.$results['cursorOffset'], $token);
//array_push($cars, $results['_embedded']['results']);
}
}
die(print_r($cars));
}
I assume I am doing the polling of the api correct in so mush as that if there is a cursor offet then I just call the function from within itself? But I am struggling to create an array from the results that isnt just an array within and array like this,
[
[result from call],
[resul from call 2]
]
what I really want is result from call1 right through to call n be all within the same sequential array.

Answer 1

using a do+while loop, you'll have only 1 instance of cars variable, that would work.
Since you're using recursion, when you call get_cars inside get_cars, you have 2 instances of cars variable, one per get_cars call.
IMHO, using a loop is better in your case.
But if you still want to use recursion, you should use the result of get_cars call, something like this:
if(isset($results['cursorOffset']))
{
//die($url.'&cursor_offset='.$results['cursorOffset']);
$newcars = get_cars('https://abcdefg.co.uk/service/search1/advert?size=5&cursor_offset='.$results['cursorOffset'], $token);
$cars = array_merge($cars, $newcars);
//array_push($cars, $results['_embedded']['results']);
}
(and get_cars should return $cars, instead of printing it with print_r)
Edit: here is an example of, untested, code with a while loop (no need for do+while here)
<?php
function get_cars($baseUrl, $token)
{
$cars = [];
// set default url to call (1st call)
$url = $baseUrl;
while (!empty($url))
$curl = curl_init();
curl_setopt_array($curl, array(
CURLOPT_URL => $url,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "GET",
CURLOPT_HTTPHEADER => array(
"Content-Type: application/x-www-form-urlencoded",
"Authorization: Bearer " . $token
)
));
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if($err)
{
// it was "return false" in your code
// what if it's the 3rd call that fails ?
// - "return $cars" will return cars from call 1 and 2 (which are OK)
// - "return false" will return no car (but call 1 and 2 were OK !!)
return $cars;
}
$results = json_decode($response, TRUE);
$cars[] = $results['_embedded']['results'];
if(isset($results['cursorOffset']))
{
// next call will be using this url
$url = $baseUrl . '&cursor_offset='.$results['cursorOffset'];
// DONT DO THE FOLLOWING (concatenating with $url, $url = $url . 'xxx')
// you will end up with url like 'http://example.com/path/to/service?cursor_offset=xxx&cursor_offset==yyy&cursor_offset==zzz'
// $url = $url . '&cursor_offset='.$results['cursorOffset'];
}
else
{
$url = null;
}
}
return $cars;
}