Как выглядит zip-архив и что мы с этим можем сделать. Часть 3 — Практическое применение

<?php

$buffer = '';
while (!feof(STDIN)) {
    $buffer .= fread(STDIN, 4096);
}

$photos = json_decode($buffer, true, 512, JSON_THROW_ON_ERROR);

$skeleton = ['files' => []];
$written = 0;
    
[$written, $skeleton] = writeZip($written, $skeleton, $photos);

$CDFH_Offset = $written;

foreach ($skeleton['files'] as $index => $info) {
    $written += fwrite(STDOUT, $info['CDFH']);
    $skeleton['files'][$index]['CDFH'] = base64_encode($info['CDFH']);
}

$skeleton['EOCD'] = pack('LSSSSLLS', 0x06054b50, 0, 0, $records = count($skeleton['files']), $records, $written - $CDFH_Offset, $CDFH_Offset, 0); 
$written += fwrite(STDOUT, $skeleton['EOCD']);
$skeleton['EOCD'] = base64_encode($skeleton['EOCD']);

fwrite(STDERR, json_encode($skeleton));

function writeZip($written, $skeleton, $files)
{    
    $c = curl_init();
    
    curl_setopt_array($c, [
        CURLOPT_RETURNTRANSFER => 1,
        CURLOPT_TIMEOUT        => 50,
        CURLOPT_FOLLOWLOCATION => true,
    ]);

    foreach ($files as $index => $url) {
        $fileName = $index . '.jpg';
        
        for ($i = 0; $i < 1; $i++ ) {
            try {            
                curl_setopt($c, CURLOPT_URL, $url);
                
                [$content, $code, $contentLength] = [
                    curl_exec($c), 
                    (int) curl_getinfo($c, CURLINFO_HTTP_CODE), 
                    (int) curl_getinfo($c, CURLINFO_CONTENT_LENGTH_DOWNLOAD)
                ];
                
                if ($code !== 200) {
                    throw new \Exception("[{$index}] " . 'Photo download error (' . $code . '): ' . curl_error($c));
                }
                    
                if (strlen($content) !== $contentLength) {
                    var_dump(strlen($content), $contentLength);
                    throw new \Exception("[{$index}] " . 'Different content-length');
                }
                
                if ((false === $imageSize = @getimagesizefromstring($content)) || $imageSize[0] < 1 || $imageSize[1] < 1) {
                    throw new \Exception("[{$index}] " . 'Broken image');
                }            
                [$width, $height] = $imageSize;
                $t = null;
                break;
            } catch (\Throwable $t) {}
        }
        
        if ($t !== null) {
            throw new \Exception('Error: ' . $index . ' > ' . $url, 0, $t);
        }
        
        $fileInfo = [
            'versionToExtract'      => 10,
            'generalPurposeBitFlag' => 0,
            'compressionMethod'     => 0,
            'modificationTime'      => 28021,
            'modificationDate'      => 20072,
            'crc32'                 => hexdec(hash('crc32b', $content)),
            'compressedSize'        => $size = strlen($content),
            'uncompressedSize'      => $size,
            'filenameLength'        => strlen($fileName),
            'extraFieldLength'      => 0,
        ];
        
        $LFH_Offset = $written;
        
        $skeleton['files'][$index] = [
            'LFH'  => pack('LSSSSSLLLSSa*', 0x04034b50, ...array_values($fileInfo + ['filename' => $fileName])),
            'CDFH' => pack('LSSSSSSLLLSSSSSLLa*', 0x02014b50, 798, ...array_values($fileInfo + [
                'fileCommentLength' => 0,
                'diskNumber' => 0,
                'internalFileAttributes' => 0,
                'externalFileAttributes' => 2176057344,
                'localFileHeaderOffset' => $LFH_Offset,
                'filename' => $fileName,
            ])),
            'width' => $width,
            'height' => $height,
        ];
        
        $written += fwrite(STDOUT, $skeleton['files'][$index]['LFH']);
        $written += fwrite(STDOUT, $content);
        $skeleton['files'][$index]['LFH'] = base64_encode($skeleton['files'][$index]['LFH']);
    }
    
    curl_close($c);
    
    return [$written, $skeleton];
}

<?php

define('TOKEN', ''); // токен телеграм бота

use Amp\Artax\DefaultClient;
use Amp\Artax\Request as ArtaxRequest;
use Amp\Http\Server\RequestHandler\CallableRequestHandler;
use Amp\Http\Server\Server as HttpServer;
use Amp\Http\Server\Request;
use Amp\Http\Server\Response;
use Amp\Http\Status;
use Amp\Parallel\Sync\SharedMemoryParcel;
use Amp\Socket;
use Psr\Log\NullLogger;

require 'vendor/autoload.php';

Amp\Loop::run(function () {
    $structure = json_decode(file_get_contents('structure.json'), true, 512, JSON_THROW_ON_ERROR);
    $stored = json_decode(file_get_contents('stored.json'), true, 512, JSON_THROW_ON_ERROR);
    
    $parcel = SharedMemoryParcel::create($id = bin2hex(random_bytes(10)), []);
    $client = new DefaultClient();
    
    $handler = function (Request $request) use ($parcel, $client, $structure, $stored) {
        $cached = yield $parcel->synchronized(function (array $value) use ($client, $stored) {
            if (!isset($value['file_path']) || $value['expires'] <= time()) {
                $response = yield $client->request('https://api.telegram.org/bot' . TOKEN  . '/getFile?' . http_build_query([
                    'file_id' => $stored['result']['document']['file_id']
                ]));
                $json = json_decode(yield $response->getBody(), true, 512, JSON_THROW_ON_ERROR);
                
                $value = ['file_path' => $json['result']['file_path'], 'expires' => time() + 55 * 60];
            }
            
            return $value;
        });
        
        $selectedFile = $structure['files'][array_rand($structure['files'])];
        $LFH = base64_decode($selectedFile['LFH']);
        $CDFH = base64_decode($selectedFile['CDFH']);

        $fileLength = unpack('Llen', substr($CDFH, 24, 4))['len'];
        $fileStart = unpack('Lpos', substr($CDFH, 42, 4))['pos'] + strlen($LFH);
        $fileEnd = $fileStart + $fileLength;
        
        $request = (new ArtaxRequest('https://api.telegram.org/file/bot' . TOKEN . '/' . $cached['file_path']))
            ->withHeader('Range', "bytes={$fileStart}-{$fileEnd}");
        $response = yield $client->request($request);
        
        if (!in_array($response->getStatus(), [200, 206])) {
            return new Response(Status::SERVICE_UNAVAILABLE, ['content-type' => 'text/plain'], "Service Unavailable.");
        }
        
        return new Response(Status::OK, ['content-type' => 'image/jpeg'], $response->getBody());
    };
    
    $server = new HttpServer([Socket\listen("0.0.0.0:10051")], new CallableRequestHandler($handler), new NullLogger);
    yield $server->start();

    Amp\Loop::onSignal(SIGINT, function (string $watcherId) use ($server) {
        Amp\Loop::cancel($watcherId);
        yield $server->stop();
    });
});