نمایش تدریجی پاسخ هوش مصنوعی (Streaming) در سایت

<?php
// stream-test.php — delete after testing
header('Content-Type: text/event-stream');
header('Cache-Control: no-cache');
header('X-Accel-Buffering: no');

while (ob_get_level() > 0) {
    ob_end_flush();
}

for ($i = 1; $i <= 5; $i++) {
    echo "data: {$i}\n\n";
    flush();
    sleep(1);
}

curl -N https://example.com/stream-test.php

SetEnvIf Request_URI "ai-stream\.php$" no-gzip=1

<?php
// ai-stream.php
declare(strict_types=1);

require dirname(__DIR__) . '/private/config.php'; // defines AI_API_KEY, outside web root

session_start();
$token = $_SESSION['csrf'] ?? '';

if (! is_string($token) || $token === '' || ! hash_equals($token, (string) ($_POST['csrf'] ?? ''))) {
    http_response_code(403);
    exit;
}
// Also check login and the per-user quota here
session_write_close(); // release the session lock before the long request

$question = trim((string) ($_POST['q'] ?? ''));
if ($question === '' || mb_strlen($question) > 2000) {
    http_response_code(422);
    exit;
}

ini_set('zlib.output_compression', '0');
while (ob_get_level() > 0) {
    ob_end_flush();
}
if (function_exists('set_time_limit')) {
    set_time_limit(150);
}

header('Content-Type: text/event-stream; charset=utf-8');
header('Cache-Control: no-cache');
header('X-Accel-Buffering: no');

function sse(string $event, array $data): void
{
    echo "event: {$event}\n";
    echo 'data: ' . json_encode($data, JSON_UNESCAPED_UNICODE) . "\n\n";
    flush();
}

$payload = [
    'model' => 'MODEL_NAME',
    'messages' => [['role' => 'user', 'content' => $question]],
    'max_tokens' => 800,
    'stream' => true,
    'stream_options' => ['include_usage' => true], // remove if your provider rejects it
];

$buffer = '';
$errorBody = '';
$usage = null;

$ch = curl_init('https://api.openai.com/v1/chat/completions');

curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_CONNECTTIMEOUT => 10,
    CURLOPT_TIMEOUT => 120,
    CURLOPT_HTTPHEADER => ['Content-Type: application/json', 'Authorization: Bearer ' . AI_API_KEY],
    CURLOPT_POSTFIELDS => json_encode($payload, JSON_UNESCAPED_UNICODE),
    CURLOPT_WRITEFUNCTION => function (CurlHandle $ch, string $chunk) use (&$buffer, &$errorBody, &$usage): int {
        if (connection_aborted()) {
            return 0; // visitor left: stop the transfer
        }
        if (curl_getinfo($ch, CURLINFO_HTTP_CODE) !== 200) {
            $errorBody .= $chunk;
            return strlen($chunk);
        }

        $buffer .= $chunk;

        while (($pos = strpos($buffer, "\n")) !== false) {
            $line = trim(substr($buffer, 0, $pos));
            $buffer = substr($buffer, $pos + 1);

            if (! str_starts_with($line, 'data:') || $line === 'data: [DONE]') {
                continue;
            }

            $event = json_decode(substr($line, 5), true);
            $text = $event['choices'][0]['delta']['content'] ?? '';

            if ($text !== '') {
                sse('token', ['t' => $text]);
            }
            if (isset($event['usage'])) {
                $usage = $event['usage'];
            }
        }

        return strlen($chunk);
    },
]);

$ok = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);

if ($ok === false || $status !== 200) {
    error_log("AI stream failed: {$status} {$errorBody}");
    sse('error', ['message' => 'پاسخ کامل نشد. دوباره تلاش کنید.']);
} else {
    sse('done', ['usage' => $usage]);
}

async function askStream(question, csrf, output) {
  const body = new FormData();
  body.append('q', question);
  body.append('csrf', csrf);

  const res = await fetch('/ai-stream.php', { method: 'POST', body });
  if (!res.ok || !res.body) {
    output.textContent = 'اتصال برقرار نشد.';
    return;
  }

  const reader = res.body.getReader();
  const decoder = new TextDecoder();
  let buffer = '';

  while (true) {
    const { value, done } = await reader.read();
    if (done) break;
    buffer += decoder.decode(value, { stream: true });

    let end;
    while ((end = buffer.indexOf('\n\n')) !== -1) {
      const block = buffer.slice(0, end);
      buffer = buffer.slice(end + 2);

      let event = 'message';
      let data = '';
      for (const line of block.split('\n')) {
        if (line.startsWith('event:')) event = line.slice(6).trim();
        if (line.startsWith('data:')) data += line.slice(5).trim();
      }
      if (!data) continue;

      const msg = JSON.parse(data);
      if (event === 'token') output.textContent += msg.t;
      if (event === 'error') output.textContent += '\n' + msg.message;
    }
  }
}