Midjourney API in PHP

<?php
// PHP 7.4+ with the curl extension. Run: USERAPI_KEY=... php client.php

const API_BASE = 'https://api.userapi.ai/midjourney/v2';

function userapi(string $method, string $path, ?array $payload = null): array
{
    $ch = curl_init(API_BASE . $path);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT => 30,
        CURLOPT_CUSTOMREQUEST => $method,
        CURLOPT_HTTPHEADER => [
            'api-key: ' . getenv('USERAPI_KEY'),
            'Content-Type: application/json',
        ],
    ]);
    if ($payload !== null) {
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($payload));
    }
    $body = curl_exec($ch);
    $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    if ($body === false || $code >= 400) {
        throw new RuntimeException("$path: HTTP $code $body");
    }
    return json_decode($body, true);
}

// Start a task and return its hash.
function start(string $method, array $payload): string
{
    return userapi('POST', "/$method", $payload)['hash'];
}

// Poll the status endpoint until the task is done or failed.
function wait(string $hash, int $interval = 5, int $timeout = 600): array
{
    $deadline = time() + $timeout;
    while (time() < $deadline) {
        $task = userapi('GET', '/status?hash=' . urlencode($hash));
        if ($task['status'] === 'done') {
            return $task;
        }
        if ($task['status'] === 'error') {
            throw new RuntimeException('task failed: ' . $task['status_reason']);
        }
        echo $task['status'], ' ', $task['progress'] ?? 0, "%\n";
        sleep($interval);
    }
    throw new RuntimeException("timeout waiting for $hash");
}

// 1. Generate a grid of four images
$grid = wait(start('imagine', ['prompt' => 'a red fox in a snowy forest, cinematic light --ar 3:2']));
echo 'grid: ', $grid['result']['url'], "\n";

// 2. Upscale the second image of the grid
$upscaled = wait(start('upscale', ['hash' => $grid['hash'], 'choice' => 2]));

// 3. Save it: Discord CDN links are not permanent storage
file_put_contents('fox.png', file_get_contents($upscaled['result']['url']));
echo "saved fox.png\n";

$hash = start('imagine', [
    'prompt' => 'isometric cozy coffee shop, soft pastel colors',
    'webhook_url' => 'https://your-server.com/webhook.php',
    'webhook_type' => 'result', // or 'progress' for every progress update
]);

<?php
// webhook.php: set https://your-server.com/webhook.php as webhook_url

$task = json_decode(file_get_contents('php://input'), true);

if (($task['status'] ?? '') === 'done') {
    error_log("{$task['type']} {$task['hash']} {$task['result']['url']}");
} elseif (($task['status'] ?? '') === 'error') {
    error_log("failed: {$task['hash']} {$task['status_reason']}");
}

http_response_code(200);