How to find page_info in Shopify PHP app and how to print all products on it?

Question

I tried this for the app but it is not working:

$products = shopify_call($token, $shop, "/admin/api/2022-04/products/count.json", 'GET');
$response = json_decode($products['response'], JSON_PRETTY_PRINT);
        
$totalproducts = $response['count'];

$limit = 250;
$totalpage = ceil($totalproducts/$limit);
echo $totalpage;
$k = 0;

Here i don't have the page_info. How can I find it? On some research I found that there is on response header have link parameter where rel have next or previous but I have link parameter but it like something this:

[link] => max-age=1234567

for($i=1; $i<=$totalpage; $i++) { 

    $products = shopify_call($token, $shop, '/admin/api/2022-04/products.json?page_info='.$i.'&limit=250', 'GET');
          
    $response = json_decode($products['response'], JSON_PRETTY_PRINT);  
            
    // print_r($response);
          
    foreach($response['products'] as $prod) {
        $k++;
        echo $k . ' => ' . $prod['title']. ' => ' . $prod['id'];
        echo "<br>";
    }
}

How to find page_info and how to use it? I'm using core PHP.

Answer 1

I don't know what exactly does you shopify_call(), but yes you're on the right track about the headers, there should be the info for your next page. Here is a var_dump of my "next page" header when loading products:

[18] =>
array(2) {
  'name' =>
  string(4) "Link"
  'line' =>
  string(191) "Link: <https://my-test-page.myshopify.com/admin/api/2021-10/products.json?limit=5&page_info=eyJsYXN0X2lkIjo0MzY3MzE3MzAzMzM5LCJsYXN0X3ZhbHVlIjoiVGVzdCAyIiwiZGlyZWN0aW9uIjoibmV4dCJ9>; rel="next""
}

In the response there are a bunch of headers but the one with the info for the next page is named "Link" as you can see from the dump. As I said IDK what you have inside your shopify_call method, it is up to you to find the right way to get response headers and if "Link" header to extract the line, which is this string:

"<https://my-test-page.myshopify.com/admin/api/2021-10/products.json?limit=5&page_info=eyJsYXN0X2lkIjo0MzY3MzE3MzAzMzM5LCJsYXN0X3ZhbHVlIjoiVGVzdCAyIiwiZGlyZWN0aW9uIjoibmV4dCJ9>; rel="next""

To extract just the link for your next request you can use preg_match() with this regex:

    // let's assume you've extracted and stored the string in your response
    // as $products['nextLink']
    
    $matches = [];
    if (! empty($products['nextLink'])) { 
        preg_match(
          "/<(.*)>; rel=\"next\"/",
          $products['nextLink'],
          $matches
       );
       
       // extracted url will be stored at 1-st key in $matches array
       $nextLink = $matches[1];
    }

    var_dump($matches);

    array(2) {
      [0]=>
      string(187) "<https://my-test-page.myshopify.com/admin/api/2021-10/products.json?limit=5&page_info=eyJsYXN0X2lkIjo0MzY3MzE3MzAzMzM5LCJsYXN0X3ZhbHVlIjoiVGVzdCAyIiwiZGlyZWN0aW9uIjoibmV4dCJ9>; rel="next""
      [1]=>
      string(173) "https://my-test-page.myshopify.com/admin/api/2021-10/products.json?limit=5&page_info=eyJsYXN0X2lkIjo0MzY3MzE3MzAzMzM5LCJsYXN0X3ZhbHVlIjoiVGVzdCAyIiwiZGlyZWN0aW9uIjoibmV4dCJ9"
    }

If there is no next page, this header won't be presented in the response headers, that's it.