Etsy API Pagination with PHP - php

Question

So, I'm fairly new to working with APIs, and am just trying to play around with using the Etsy API to display a certain set of listings.
By default, the API returns a set of 25 results, and can do a max of 100 at a time. I'd like to show more than that, so I'm trying to add pagination to my call. Here's what I've got so far:
<?php
//setting API key
define("API_KEY", XXX);
//setting request url
$url = "https://openapi.etsy.com/v2/listings/active?keywords=unicorn,unicorns&includes=Images:1:0&api_key=" . API_KEY;
while (isset($url) && $url != '') {
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
$response_body=curl_exec($curl);
curl_close($curl);
$response = json_decode($response_body);
foreach ($response->results as $listing) {
echo "<li>" . $listing->title . " ~*~ " . $listing->price . " " . $listing->currency_code . " ~*~ " . 'View on Etsy!' . "</li>" . "<br>";
}
$url = $response->pagination->next_page;
}
?>
I thought this would loop through and return the next set of 25 results, but it didn't. Anyone have experience working with this? Is there somewhere I'm getting tripped up?
Thanks!

Answer 1

In your while block, you are assigning the value of the next_page property to $url.
But the actual value is an int, 2, not an url.
Instead append the next_page to the initial url, as a query string variable.
$url .= "&page=" . $response->pagination->next_page;
See below an example on how you can isolate each process to a function.
We move the curl operation into its own function where it returns an object from json_decode.
We move the whole processing of the listings into a separate function, where for now, it just prints out the listings.
This second function is recursive, meaning, that if the next page exists it will call the first function, get the response, then process it.
<?php
//setting API key
define("API_KEY", 'br4j52uzdtlcpp6qxb6we3ge');
function get_listings($page=1){
$url = "https://openapi.etsy.com/v2/listings/active?keywords=unicorn,unicorns&includes=Images:1:0&api_key=" . API_KEY;
$url .= "&page=$page";
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
$response_body=curl_exec($curl);
curl_close($curl);
$responseObject = json_decode($response_body);
return $responseObject;
}
function process_listings($responseObject){
foreach ($responseObject->results as $listing) {
echo "Title: " . $listing->title . PHP_EOL .
"Price " . $listing->price . PHP_EOL .
"Currency code " . $listing->currency_code . PHP_EOL .
'URL ' . $listing->url . PHP_EOL;
}
print PHP_EOL . "Pagination " . $responseObject->pagination->next_page . PHP_EOL;
$next_page = $responseObject->pagination->next_page;
if ($next_page) {
$nextPageResponse = get_listings($next_page);
process_listings($nextPageResponse);
}
}
$firstPage = get_listings(); // page 1 is default
process_listings($firstPage);