Question

Below is a simple example of code to fetch results from a REST XML API.

This is just a small portion I have extracted from my real PHP class for this question.

in the API URL which returns an XML document, I am curious about how I could fetch all the results from 1 page and then move on to fetch from the next page.

$this->api_page sets the page that the API returns data from.

Looking at the basic code below using SimpleXMLElement how could I for example return the data from 10 pages or all pages in the API starting at a page number, loading the results for that page and then fetching the next page an moving on.

Right now I am doing it with JavaScript and PHP by passing a Page number in the URL to my script using $_GET['page'] the problem with this is it requires a user to load the page and it’s kind of sloppy.

My real API script will be ran from a Cron job on the server, so with that in mind, how could I fetch all pages?

I ask this question based on this example code below but also because it is a task that I often have to do on other projects and I don’t know a good way of doing this?

<?php

$this->api_url = 'http://api.rescuegroups.org/rest/?key=' .$this->api_key.
'&type=animals&limit=' .$this->api_limit.
'&startPage='. $this->api_page;

$xmlObj = new SimpleXMLElement($this->api_url, NULL, TRUE); 

foreach($xmlObj->pet as $pet){

    echo $pet->animalID;
    echo $pet->orgID;
    echo $pet->status;

    // more fields from the  Pet object that is returned from the API call

    // Save results to my own Database

}
?>

Answer 1

Based on the assumption that you run on a pretty stable environment you could loop through the pages like this:

<?php
$this->base_url = 'http://api.rescuegroups.org/rest/?key=' .$this->api_key.
'&type=animals&limit=' .$this->api_limit.
'&startPage=';
$start_page = $this->api_page;
$end_page = 10; //If you have a value for max pages.
// sometimes you might get the number of pages from the first returned XML and then you could update the $end_page inside the loop.

for ($counter = $start_page; $counter <= $end_page; $counter++) {
    try {
        $xmlObj = new SimpleXMLElement($this->base_url . $counter, NULL, TRUE); 

        foreach($xmlObj->pet as $pet){

            echo $pet->animalID;
            echo $pet->orgID;
            echo $pet->status;

            // more fields from the  Pet object that is returned from the API call

            // Save results to my own Database

        }


    } catch (Exception $e) {
        // Something went wrong, possibly no more pages?
        // Please Note! You wil also get an Exception if there is an error in the XML
        // If so you should do some extra error handling
        break;
    }
}

?>