Downloads the latest version of Minecraft jars.

download_latest_minecraft.php

<?php

    echo "Downloading manifest.\n";
    $manifest = json_decode(file_get_contents('https://launchermeta.mojang.com/mc/game/version_manifest.json'), true);
    $error = json_last_error();
    if ($error != JSON_ERROR_NONE)
    {
        echo "ERROR: Could not parse manifest json, $error\n";
        exit;
    }
    $latest = $manifest['latest']['release'];

    $download_dir = 'Versions';
    $client_filename = 'minecraft_client.'.$latest.'.jar';
    $server_filename = 'minecraft_server.'.$latest.'.jar';
    $client_out_file = $download_dir.'/'.$client_filename;
    $server_out_file = $download_dir.'/'.$server_filename;

    
    if (file_exists($download_dir) == false)
    {
        mkdir($download_dir);   
    }

    $latest_version = null;
    foreach ($manifest['versions'] as $version)
    {
        if ($version['id'] == $latest)
        {
            $latest_version = $version;
            break;
        }
    }

    if ($latest_version == null)
    {
        echo "ERROR: Unable to find latest version.\n";
        exit;
    }

    echo "Downloading version manifest.\n";
    $version_manifest = json_decode(file_get_contents($latest_version['url']), true);
    if ($error != JSON_ERROR_NONE)
    {
        echo "ERROR: Could not parse version manifest json, $error\n";
        exit;
    }

    $client_sha1 = $version_manifest['downloads']['client']['sha1'];
    $server_sha1 = $version_manifest['downloads']['server']['sha1'];

    $download_client = true;
    $download_server = true;
    
    if (file_exists($client_out_file))
    {
        if (sha1_file($client_out_file) == $client_sha1)
        {
            $download_client = false;
            echo "Client exists, skipping download.\n";
        }
        else
        {
            echo "Client exists but it doesn't match SHA1 hash, redownloading.\n";
            unlink($client_out_file);
        }
    }

    if (file_exists($server_out_file))
    {
        if (sha1_file($server_out_file) == $server_sha1)
        {
            $download_server = false;
            echo "Server exists, skipping download.\n";
        }
        else
        {
            echo "Server exists but it doesn't match SHA1 hash, redownloading.\n";
            unlink($server_out_file);
        }
    }

    if ($download_client == false && $download_server == false)
    {
        echo "Nothing else to do.\n";
        exit;
    }

    $client_url = $version_manifest['downloads']['client']['url'];
    $server_url = $version_manifest['downloads']['server']['url'];
        
    if ($download_client)
    {
        downloadFile($client_url, $client_out_file);
    }

    if ($download_server)
    {
        downloadFile($server_url, $server_out_file);
    }

    function downloadFile($url, $save_as)
    {        
        echo "Downloading: $url\n";
        echo "To: $save_as\n";

        $fp = fopen($save_as, 'w+');
        if ($fp === false)
        {
            echo "ERROR: Could not open $save_as\n";
            return;
        }
        
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_FILE, $fp);
        curl_setopt($ch, CURLOPT_TIMEOUT, 300);
        curl_exec($ch);
        
        if (curl_errno($ch))
        {
            fclose($fp);
            echo "ERROR: ".curl_error($ch)."\n";
            curl_close($ch);
            return;
        }
        
        $status_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);
        fclose($fp);
        
        if ($status_code == 200)
        {
            echo  "Success\n";
        }
        else
        {
            echo "ERROR: Status code: $status_code\n";
            return;
        }
    }