How to convert images to PDF asynchronously for image to PDF API in PHP using PDF.co Web API

How to convert images to PDF asynchronously for image to PDF API in PHP: Step By Step Tutorial

Today we will explain the steps and algorithm of how to convert images to PDF asynchronously and how to make it work in your application. PDF.co Web API was made to help with image to PDF API in PHP. PDF.co Web API is the Web API with a set of tools for documents manipulation, data conversion, data extraction, splitting and merging of documents. Includes image recognition, built-in OCR, barcode generation and barcode decoders to decode bar codes from scans, pictures and pdf.

PHP code samples for PHP developers help to speed up the application’s code writing when using PDF.co Web API. Follow the instruction and copy – paste code for PHP into your project’s code editor. Further enhancement of the code will make it more vigorous.

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image-to-pdf-async.php

      
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Cloud API asynchronous "Image To PDF" job example (allows to avoid timeout errors).</title>
</head>
<body>

<?php 

// Cloud API asynchronous "Image To PDF" job example.
// Allows to avoid timeout errors when processing huge or scanned PDF documents.


// The authentication key (API Key).
// Get your own by registering at https://app.pdf.co/documentation/api
$apiKey = "***********************************";

// Direct URLs of image files to convert to PDF document. Check another example if you need to upload local files to the cloud.
$sourceFiles = array(
    "https://bytescout-com.s3.amazonaws.com/files/demo-files/cloud-api/image-to-pdf/image1.png", 
    "https://bytescout-com.s3.amazonaws.com/files/demo-files/cloud-api/image-to-pdf/image2.jpg");


// Prepare URL for `Image To PDF` API call
$url = "https://api.pdf.co/v1/pdf/convert/from/image";

$parameters = array();
$parameters["url"] = join(",", $sourceFiles);
$parameters["async"] = true;  // (!) Make asynchronous job

// Create Json payload
$data = json_encode($parameters);

// Create request
$curl = curl_init();
curl_setopt($curl, CURLOPT_HTTPHEADER, array("x-api-key: " . $apiKey, "Content-type: application/json"));
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);

// Execute request
$result = curl_exec($curl);

if (curl_errno($curl) == 0)
{
    $status_code = curl_getinfo($curl, CURLINFO_HTTP_CODE);
    
    if ($status_code == 200)
    {
        $json = json_decode($result, true);
        
        if ($json["error"] == false)
        {
            // URL of generated PDF file that will available after the job completion
            $resultFileUrl = $json["url"];
            // Asynchronous job ID
            $jobId = $json["jobId"];
            
            // Check the job status in a loop
            do
            {
                $status = CheckJobStatus($jobId, $apiKey); // Possible statuses: "working", "failed", "aborted", "success".
                
                // Display timestamp and status (for demo purposes)
                echo "<p>" . date(DATE_RFC2822) . ": " . $status . "</p>";
                
                if ($status == "success")
                {
                    // Display link to the file with conversion results
                    echo "<div><h2>Conversion Result:</h2><a href='" . $resultFileUrl . "' target='_blank'>" . $resultFileUrl . "</a></div>";
                    break;
                }
                else if ($status == "working")
                {
                    // Pause for a few seconds
                    sleep(3);
                }
                else 
                {
                    echo $status . "<br/>";
                    break;
                }
            }
            while (true);
        }
        else
        {
            // Display service reported error
            echo "<p>Error: " . $json["message"] . "</p>"; 
        }
    }
    else
    {
        // Display request error
        echo "<p>Status code: " . $status_code . "</p>"; 
        echo "<p>" . $result . "</p>"; 
    }
}
else
{
    // Display CURL error
    echo "Error: " . curl_error($curl);
}

// Cleanup
curl_close($curl);


function CheckJobStatus($jobId, $apiKey)
{
    $status = null;
    
	// Create URL
    $url = "https://api.pdf.co/v1/job/check";
    
    // Prepare requests params
    $parameters = array();
    $parameters["jobid"] = $jobId;

    // Create Json payload
    $data = json_encode($parameters);

    // Create request
    $curl = curl_init();
    curl_setopt($curl, CURLOPT_HTTPHEADER, array("x-api-key: " . $apiKey, "Content-type: application/json"));
    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_POST, true);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
    
    // Execute request
    $result = curl_exec($curl);
    
    if (curl_errno($curl) == 0)
    {
        $status_code = curl_getinfo($curl, CURLINFO_HTTP_CODE);
        
        if ($status_code == 200)
        {
            $json = json_decode($result, true);
        
            if ($json["error"] == false)
            {
                $status = $json["status"];
            }
            else
            {
                // Display service reported error
                echo "<p>Error: " . $json["message"] . "</p>"; 
            }
        }
        else
        {
            // Display request error
            echo "<p>Status code: " . $status_code . "</p>"; 
            echo "<p>" . $result . "</p>"; 
        }
    }
    else
    {
        // Display CURL error
        echo "Error: " . curl_error($curl);
    }
    
    // Cleanup
    curl_close($curl);
    
    return $status;
}

?>

</body>
</html>

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