Using PHP to Decode Base64 Image Data From Multidimensional Array-CodePudding

Overview: I'm integrating the Lighthouse Page Speed Insights API into a custom project I'm playing with. The goal is to simply bring page speed insights in-house. I have everything set up & working fine, but I would like to display the screenshots gathered of the page being tested. The initial request to the API is returned as JSON. Here is an example of the section of the response that I'm concerned with.

"screenshot-thumbnails": {
    "id": "screenshot-thumbnails",
    "title": "Screenshot Thumbnails",
    "description": "This is what the load of your site looked like.",
    "score": null,
    "scoreDisplayMode": "informative",
    "details": {
      "items": [
        {
          "data": "data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/2wCEAAMCAgMCAgMDAwMEAwMEBQgFBQQEBQoHBwYIDAoMDAsKCwsNDhIQDQ4RDgsLEBYQERMUFRUVDA8XGBYUGBIUFRQBAwQEBQQFCQUFCRQNCw0UFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFP/AABEIAFMAeAMBEQACEQEDEQH/xAGiAAABBQEBAQEBAQAAAAAAAAAAAQIDBAUGBwgJCgsQAAIBAwMCBAMFBQQEAAABfQECAwAEEQUSITFBBhNRYQcicRQygZGhCCNCscEVUtHwJDNicoIJChYXGBkaJSYnKCkqNDU2Nzg5OkNERUZHSElKU1RVVldYWVpjZGVmZ2hpanN0dXZ3eHl6g4SFhoeIiYqSk5SVlpeYmZqio6Slpqeoqaqys7S1tre4ubrCw8TFxsfIycrS09TV1tfY2drh4uPk5ebn6Onq8fLz9PX29/j5 gEAAwEBAQEBAQEBAQAAAAAAAAECAwQFBgcICQoLEQACAQIEBAMEBwUEBAABAncAAQIDEQQFITEGEkFRB2FxEyIygQgUQpGhscEJIzNS8BVictEKFiQ04SXxFxgZGiYnKCkqNTY3ODk6Q0RFRkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqCg4SFhoeIiYqSk5SVlpeYmZqio6Slpqeoqaqys7S1tre4ubrCw8TFxsfIycrS09TV1tfY2dri4 Tl5ufo6ery8/T19vf4 fr/2gAMAwEAAhEDEQA/AP1ToAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgD//Z",
          "timing": 300,
          "timestamp": 2102707475296
        },

I dynamically save that json response inside a directory on my web server, then using file_get_contents to decode that to a PHP array.

$ret = file_get_contents("logs/pagespeed/$selected.json");
$result = json_decode($ret, true);

Next, I am assigning a variable to the array that contains each item (or in this case item = screenshot. The values inside those arrays are base64 encoded image data, timestamp, and the timing in ms of the screenshot)

// Screenshot Thumbnails
$ss_data = $result['lighthouseResult']['audits']['screenshot-thumbnails']['details']['items'];

Then finally, I am using two foreach loops to echo out the appropriate data for each screenshot.

foreach($ss_data as $key => $value) {
    foreach ($value as $comp => $values) {
        echo "<b>".$comp."</b>" . ":" . $values . "<br>";
    }
}

An example of one of the results outputted is this:

timestamp:3218752607871
timing:300
data:data:image/jpeg;base64,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 gEAAwEBAQEBAQEBAQAAAAAAAAECAwQFBgcICQoLEQACAQIEBAMEBwUEBAABAncAAQIDEQQFITEGEkFRB2FxEyIygQgUQpGhscEJIzNS8BVictEKFiQ04SXxFxgZGiYnKCkqNTY3ODk6Q0RFRkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqCg4SFhoeIiYqSk5SVlpeYmZqio6Slpqeoqaqys7S1tre4ubrCw8TFxsfIycrS09TV1tfY2dri4 Tl5ufo6ery8/T19vf4 fr/2gAMAwEAAhEDEQA/AP1ToAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgAoAKACgD//Z

The Question: How can I either assign a variable to the $value of the $key "$data" in order to run a base64 decode on it, or is there an easy way to run a base64 decoding inside the foreach?

Image Example of What I'm Looking to Do: image from lighthouse page speed insights tests

-- If something here did not make sense, please let me know so that I can clarify. Thanks for taking the time to read this. Maybe this can help somebody in the future.

CodePudding user response：

If your objective is to display the data as an image, do exactly that. You can use a data URL as the src for an image element, so...

foreach($ss_data as $key => $value) {
    foreach ($value as $comp => $values) {
        if ($key === "data") {
            echo "<img src='$value'><br>";
        } else {
            echo "<b>".$comp."</b>" . ":" . $values . "<br>";
        }
    }
}