Proxy.php 频谱分析支撑功能介绍
一、核心定位
Proxy.php 是专为 Web Audio 频谱分析 设计的音频资源代理网关，解决浏览器加载音频文件时的跨域拦截、DNS 污染、MIME 不匹配、大文件分块、文本元数据乱码等问题，让前端 AnalyzerNode 能稳定获取 AudioBuffer 并执行 FFT（快速傅里叶变换）生成可视化频谱/波形。
二、频谱分析场景下的请求流程
-
前端频谱模块发起
fetch(url)或AudioContext.decodeAudioData()调用 -
浏览器因 CORS 无法直连跨域/受限音频，转而请求
proxy.php?url=目标音频地址 - proxy.php 判定音频位置（本地/远程），绕过 DNS 污染拉取资源
- 返回符合 Web Audio 要求的 CORS 头、正确 MIME、支持 Range 的音频流
-
前端拿到 AudioBuffer → 喂给 AnalyzerNode → 执行
getByteFrequencyData/getByteTimeDomainData→ 渲染频谱
<?php
/**
* Proxy.php —— Web Audio 频谱分析资源代理网关
*
* 功能：本地/远程音频代理转发、CORS 跨域、Range 分块、DNS 污染绕过、
* 自动编码转换（GBK→UTF-8）、多 IP 自动 fallback、Debug 调试面板
*
* @author LMP34
* @date 2026-10-24
* @link https://www.cnlog.cc/
* @require PHP 5.4+ / curl / mbstring / allow_url_fopen=On
*/
error_reporting(E_ALL);
ini_set('display_errors', 0);
ini_set('log_errors', 0);
//ini_set('error_log', __DIR__ . '/proxy_error.log');
$url = isset($_GET['url']) ? $_GET['url'] : '';
if ($url === '') {
header('HTTP/1.1 400 Bad Request');
exit('no url');
}
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, HEAD, OPTIONS');
header('Access-Control-Allow-Headers: Range, Content-Type');
if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
header('HTTP/1.1 204 No Content');
exit;
}
$hasRange = isset($_SERVER['HTTP_RANGE']) && $_SERVER['HTTP_RANGE'] !== '';
$debug = isset($_GET['debug']) ? true : false;
$debugLog = array();
function proxyLog($msg) {
global $debugLog;
$debugLog[] = $msg;
// @file_put_contents(__DIR__ . '/proxy_error.log', date('Y-m-d H:i:s') . ' ' . $msg . "\n", FILE_APPEND);
}
$urlParts = parse_url($url);
$isRemoteProxy = isset($urlParts['scheme']) && ($urlParts['scheme'] === 'http' || $urlParts['scheme'] === 'https')
&& isset($urlParts['host']) && $urlParts['host'] !== $_SERVER['HTTP_HOST'];
if (!$isRemoteProxy && isset($urlParts['path'])) {
$localFile = __DIR__ . '/' . ltrim($urlParts['path'], '/');
if (file_exists($localFile) && is_file($localFile)) {
proxyLog("LOCAL FILE: " . $localFile);
$ext = strtolower(pathinfo($localFile, PATHINFO_EXTENSION));
$audioExts = array('mp3'=>'audio/mpeg','wav'=>'audio/wav','ogg'=>'audio/ogg','m4a'=>'audio/mp4','aac'=>'audio/aac','flac'=>'audio/flac','wma'=>'audio/x-ms-wma');
$videoExts = array('mp4'=>'video/mp4','webm'=>'video/webm','ogv'=>'video/ogg','mov'=>'video/quicktime','m4v'=>'video/x-m4v');
$textExts = array('lrc'=>'text/plain','txt'=>'text/plain','srt'=>'text/plain','ass'=>'text/plain','vtt'=>'text/plain','xml'=>'application/xml','json'=>'application/json','css'=>'text/css','js'=>'application/javascript','html'=>'text/html','htm'=>'text/html','ini'=>'text/plain','csv'=>'text/plain','log'=>'text/plain','md'=>'text/plain','smi'=>'text/plain','krc'=>'text/plain');
$ct = 'application/octet-stream';
if (isset($audioExts[$ext])) $ct = $audioExts[$ext];
elseif (isset($videoExts[$ext])) $ct = $videoExts[$ext];
elseif (isset($textExts[$ext])) $ct = $textExts[$ext] . '; charset=utf-8';
$size = filesize($localFile);
if ($hasRange) {
if (preg_match('/bytes=(\d*)-(\d*)/', $_SERVER['HTTP_RANGE'], $m)) {
$start = ($m[1] !== '') ? intval($m[1]) : 0;
$end = ($m[2] !== '') ? intval($m[2]) : $size - 1;
if ($start > $end || $start >= $size) {
header('HTTP/1.1 416 Requested Range Not Satisfiable');
header('Content-Range: bytes */' . $size);
exit;
}
header('Content-Type: ' . $ct);
header('HTTP/1.1 206 Partial Content');
header('Content-Length: ' . ($end - $start + 1));
header('Content-Range: bytes ' . $start . '-' . $end . '/' . $size);
$fp = fopen($localFile, 'rb');
fseek($fp, $start);
echo fread($fp, $end - $start + 1);
fclose($fp);
exit;
}
}
if (isset($textExts[$ext])) {
$content = file_get_contents($localFile);
if ($content !== false && function_exists('mb_detect_encoding')) {
$detected = mb_detect_encoding($content, array('UTF-8', 'GBK', 'GB2312', 'GB18030', 'BIG5', 'UTF-7', 'ASCII'), true);
if ($detected && strtoupper($detected) !== 'UTF-8' && function_exists('mb_convert_encoding')) {
proxyLog("LOCAL ENCODING: detect=$detected converting to UTF-8");
$content = mb_convert_encoding($content, 'UTF-8', $detected);
} elseif (!$detected && function_exists('mb_convert_encoding')) {
$content2 = @mb_convert_encoding($content, 'UTF-8', 'GBK');
if ($content2 !== false && $content2 !== $content) {
proxyLog("LOCAL ENCODING: fallback GBK->UTF-8");
$content = $content2;
}
}
}
header('Content-Type: ' . $ct);
header('Content-Length: ' . strlen($content));
echo $content;
exit;
}
header('Content-Type: ' . $ct);
header('Accept-Ranges: bytes');
header('Content-Length: ' . $size);
readfile($localFile);
exit;
}
}
function debugDump($content, $httpCode, $errMsg) {
global $debugLog, $url;
header('Content-Type: text/html; charset=utf-8');
echo '<pre style="font-family:Consolas,monospace;font-size:13px;color:#eee;background:#1a1a2e;padding:20px;white-space:pre-wrap;word-break:break-all;">';
echo '<b style="color:#ffcc66;">=== LMP34 Proxy Debug ===</b>' . "\n\n";
echo '<b>INPUT URL:</b> ' . htmlspecialchars($url) . "\n\n";
echo '<b>LOG:</b>' . "\n";
foreach ($debugLog as $line) echo ' ' . htmlspecialchars($line) . "\n";
echo "\n" . '<b>HTTP CODE:</b> ' . $httpCode . "\n";
echo '<b>CURL ERROR:</b> ' . ($errMsg ? htmlspecialchars($errMsg) : '(none)') . "\n";
echo '<b>CONTENT LEN:</b> ' . strlen($content) . "\n";
if (strlen($content) > 0) {
echo "\n<b>CONTENT PREVIEW (first 2000 bytes):</b>\n";
echo htmlspecialchars(substr($content, 0, 2000));
if (strlen($content) > 2000) echo "\n\n... (truncated, total " . strlen($content) . " bytes)";
}
echo '</pre>';
exit;
}
/**
* 绕过服务器 DNS 污染：hosts 硬编码优先 + 公共 DNS 兜底
* 多个 IP 自动降级尝试
*/
function resolveWithPublicDns($host) {
if (filter_var($host, FILTER_VALIDATE_IP)) return false;
$hostsMap = array(
'www.panurl.cn' => array('104.16.36.185', '104.20.61.142'),
);
if (isset($hostsMap[$host])) {
$list = $hostsMap[$host];
proxyLog("DNS-resolve via hosts-map: {$host} => " . implode(', ', $list));
return $list;
}
$dnsServers = array('8.8.8.8', '223.5.5.5', '119.29.29.29');
if (function_exists('shell_exec')) {
foreach ($dnsServers as $dns) {
$out = @shell_exec("dig +short @{$dns} {$host} A 2>/dev/null");
if ($out) {
$ips = array_filter(array_map('trim', explode("\n", $out)), function($ip) {
return filter_var($ip, FILTER_VALIDATE_IP);
});
if (!empty($ips)) {
proxyLog("DNS-resolve via dig @{$dns}: {$host} => " . implode(', ', $ips));
return array_values($ips);
}
}
}
foreach ($dnsServers as $dns) {
$out = @shell_exec("nslookup {$host} {$dns} 2>/dev/null");
if ($out && preg_match_all('/Address:\s*(\d+\.\d+\.\d+\.\d+)/', $out, $m)) {
$ips = array_unique($m[1]);
proxyLog("DNS-resolve via nslookup @{$dns}: {$host} => " . implode(', ', $ips));
return array_values($ips);
}
}
}
$ip = @gethostbyname($host);
if ($ip && $ip !== $host && filter_var($ip, FILTER_VALIDATE_IP)) {
proxyLog("DNS-resolve via gethostbyname: {$host} -> {$ip}");
return array($ip);
}
proxyLog("DNS-resolve FAILED for {$host}");
return false;
}
proxyLog("REQUEST: " . $url . " range=" . ($hasRange ? $_SERVER['HTTP_RANGE'] : 'none'));
$urlParts = parse_url($url);
$targetHost = isset($urlParts['host']) ? $urlParts['host'] : '';
$targetPort = isset($urlParts['scheme']) && $urlParts['scheme'] === 'https' ? 443 : 80;
$resolvedIps = false;
if ($targetHost) {
$resolvedIps = resolveWithPublicDns($targetHost);
}
// 构造 curl 的 CURLOPT_RESOLVE 映射（多 IP 供 curl 自动 fallback）
$resolveMap = array();
if (is_array($resolvedIps)) {
foreach ($resolvedIps as $ip) {
$resolveMap[] = "{$targetHost}:{$targetPort}:{$ip}";
}
}
$ext = strtolower(pathinfo(parse_url($url, PHP_URL_PATH), PATHINFO_EXTENSION));
$audioExts = array('mp3'=>'audio/mpeg','wav'=>'audio/wav','ogg'=>'audio/ogg','m4a'=>'audio/mp4','aac'=>'audio/aac','flac'=>'audio/flac','wma'=>'audio/x-ms-wma');
$videoExts = array('mp4'=>'video/mp4','webm'=>'video/webm','ogv'=>'video/ogg','mov'=>'video/quicktime','m4v'=>'video/x-m4v');
$textExts = array('lrc'=>'text/plain','txt'=>'text/plain','srt'=>'text/plain','ass'=>'text/plain','vtt'=>'text/plain','xml'=>'application/xml','json'=>'application/json','css'=>'text/css','js'=>'application/javascript','html'=>'text/html','htm'=>'text/html','ini'=>'text/plain','csv'=>'text/plain','log'=>'text/plain','md'=>'text/plain','smi'=>'text/plain','krc'=>'text/plain');
$defaultCt = 'application/octet-stream';
if (isset($audioExts[$ext])) $defaultCt = $audioExts[$ext];
elseif (isset($videoExts[$ext])) $defaultCt = $videoExts[$ext];
elseif (isset($textExts[$ext])) $defaultCt = $textExts[$ext] . '; charset=utf-8';
$content = false;
$respHeaders = array();
$httpCode = 0;
$errMsg = '';
if (function_exists('curl_init')) {
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_MAXREDIRS, 10);
curl_setopt($ch, CURLOPT_ENCODING, 'gzip, deflate');
curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36');
curl_setopt($ch, CURLOPT_REFERER, dirname($url) . '/');
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_TIMEOUT, 60);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 15);
$extraHeaders = array(
'Accept: */*',
'Accept-Language: zh-CN,zh;q=0.9,en;q=0.8'
);
if ($hasRange) {
$extraHeaders[] = 'Range: ' . $_SERVER['HTTP_RANGE'];
}
curl_setopt($ch, CURLOPT_HTTPHEADER, $extraHeaders);
curl_setopt($ch, CURLOPT_HEADERFUNCTION, function($ch, $header) use (&$respHeaders) {
$trimmed = trim($header);
if ($trimmed !== '' && strpos($trimmed, ':') !== false) {
list($k, $v) = explode(':', $trimmed, 2);
$respHeaders[strtolower(trim($k))] = trim($v);
}
return strlen($header);
});
if (!empty($resolveMap)) {
curl_setopt($ch, CURLOPT_RESOLVE, $resolveMap);
proxyLog("CURLOPT_RESOLVE: " . count($resolveMap) . " IP(s) set");
}
$content = curl_exec($ch);
$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
$errMsg = curl_error($ch);
$effectiveUrl = curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
curl_close($ch);
proxyLog("CURL: code=$httpCode effective=$effectiveUrl err=$errMsg len=" . ($content === false ? 'false' : strlen($content)));
}
if ($content === false) {
$opts = array(
'http' => array(
'method' => 'GET',
'header' => "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36\r\nReferer: " . dirname($url) . "/\r\n",
'timeout' => 60
),
'ssl' => array('verify_peer' => false, 'verify_peer_name' => false)
);
if ($hasRange) {
$opts['http']['header'] .= 'Range: ' . $_SERVER['HTTP_RANGE'] . "\r\n";
}
$headerHost = ($resolvedIps && $targetHost) ? "Host: {$targetHost}\r\n" : '';
$ctx = stream_context_create($opts);
if ($resolvedIps && $targetHost) {
foreach ($resolvedIps as $ip) {
$fgcUrl = preg_replace('/^(' . preg_quote($urlParts['scheme'], '/') . ':\/\/)' . preg_quote($targetHost, '/') . '/', '$1' . $ip, $url, 1);
proxyLog("FGC try: {$fgcUrl}");
$tryCtx = stream_context_create(array(
'http' => array(
'method' => 'GET',
'header' => $headerHost . $opts['http']['header'],
'timeout' => 60
),
'ssl' => $opts['ssl']
));
$content = @file_get_contents($fgcUrl, false, $tryCtx);
if ($content !== false) {
$httpCode = 200;
$errMsg = '';
proxyLog("FGC success via {$ip} len=" . strlen($content));
break;
}
proxyLog("FGC failed via {$ip}");
}
} else {
$content = @file_get_contents($url, false, $ctx);
if ($content !== false) {
$httpCode = 200;
proxyLog("FGC: success len=" . strlen($content));
} else {
proxyLog("FGC: failed");
}
}
}
if ($content === false) {
proxyLog("FINAL: 502 error");
if ($debug) debugDump('', 0, $errMsg ? $errMsg : 'fetch failed');
header('HTTP/1.1 502 Bad Gateway');
header('Content-Type: text/plain');
echo 'proxy error: ' . ($errMsg ? $errMsg : 'fetch failed');
exit;
}
if (strlen($content) === 0) {
proxyLog("FINAL: empty response");
if ($debug) debugDump('', $httpCode, 'empty response from remote');
header('HTTP/1.1 502 Bad Gateway');
header('Content-Type: text/plain');
echo 'proxy error: empty response from remote';
exit;
}
$contentInfo = isset($respHeaders['content-type']) ? $respHeaders['content-type'] : 'unknown';
proxyLog("CONTENT: type=$contentInfo len=" . strlen($content) . " firstbytes=" . bin2hex(substr($content, 0, 16)));
if ($httpCode >= 400) {
proxyLog("FINAL: remote error $httpCode");
if ($debug) debugDump($content, $httpCode, 'remote returned ' . $httpCode);
header('HTTP/1.1 ' . $httpCode);
header('Content-Type: text/plain');
echo 'remote error ' . $httpCode;
exit;
}
$ct = isset($respHeaders['content-type']) ? $respHeaders['content-type'] : $defaultCt;
if (isset($textExts[$ext]) && strpos($ct, 'charset') === false) {
$ct = rtrim($ct, '; ') . '; charset=utf-8';
}
if (isset($textExts[$ext]) && !$hasRange) {
$detected = false;
if (function_exists('mb_detect_encoding')) {
$detected = mb_detect_encoding($content, array('UTF-8', 'GBK', 'GB2312', 'GB18030', 'BIG5', 'UTF-7', 'ASCII'), true);
}
if ($detected && strtoupper($detected) !== 'UTF-8' && function_exists('mb_convert_encoding')) {
proxyLog("ENCODING: detect=$detected converting to UTF-8");
$content = mb_convert_encoding($content, 'UTF-8', $detected);
$ct = preg_replace('/charset=[^;]+/i', 'charset=utf-8', $ct);
if (strpos($ct, 'charset') === false) $ct = rtrim($ct, '; ') . '; charset=utf-8';
} elseif (!$detected && function_exists('mb_convert_encoding')) {
$content2 = @mb_convert_encoding($content, 'UTF-8', 'GBK');
if ($content2 !== false && $content2 !== $content) {
proxyLog("ENCODING: fallback GBK->UTF-8 (changed)");
$content = $content2;
$ct = preg_replace('/charset=[^;]+/i', 'charset=utf-8', $ct);
if (strpos($ct, 'charset') === false) $ct = rtrim($ct, '; ') . '; charset=utf-8';
}
}
}
header('Content-Type: ' . $ct);
header('Accept-Ranges: bytes');
$contentLength = strlen($content);
header('Content-Length: ' . $contentLength);
if ($hasRange && $httpCode === 206) {
header('HTTP/1.1 206 Partial Content');
if (isset($respHeaders['content-range'])) {
header('Content-Range: ' . $respHeaders['content-range']);
}
}
proxyLog("FINAL: ct=$ct len=$contentLength code=$httpCode");
if ($debug) debugDump($content, $httpCode, 'success');
echo $content;
三、频谱场景核心支撑功能
1. 跨域 CORS 全链路支持（频谱前提）
全局设置 Access-Control-Allow-Origin: *、允许 Range/Content-Type 头、拦截 OPTIONS 预检返回 204，彻底解决 Web Audio 跨域加载音频被浏览器拦截的问题，前端可直接用 fetch() 拉取任意域音频并 decode 成 AudioBuffer。
2. 音频资源自动适配（频谱解码基础）
按音频扩展名（mp3/wav/ogg/m4a/aac/flac/wma）自动映射正确的 Content-Type，确保 AudioContext.decodeAudioData() 不会因 MIME 不匹配报错；远程音频优先使用响应头 MIME，缺失时按扩展名兜底。
3. Range 分块请求支持（大音频频谱场景）
完整支持 HTTP Range 协议，本地文件通过 fseek 精准切片、远程资源原样透传 Range 头，让前端对大尺寸音频文件可分块加载，避免一次性加载全量 AudioBuffer 导致的内存溢出，同时适配 AnalyzerNode 分段处理需求。
4. DNS 污染绕过（受限音频频谱拉取）
内置三级降级 DNS 解析策略对抗运营商/防火墙 DNS 污染：
- 硬编码 hosts 映射：针对已知污染域名直接绑定多个真实 IP
- 公共 DNS 兜底：依次尝试多个公共 DNS 服务器
- 系统 gethostbyname 最终兜底
解析到多个 IP 后，cURL 分支通过 CURLOPT_RESOLVE 注入实现连接级自动 fallback；file_get_contents 分支则遍历 IP 逐个替换 Host 重试，确保被污染的音频 CDN 资源能被成功拉取。
5. 本地/远程音频统一入口（频谱逻辑简化）
前端无需区分音频存储位置（同服务器本地 or 外部远程），统一使用 proxy.php?url=xxx 格式请求，频谱模块只需处理一种 URL 规则，减少前端分支逻辑。
6. LRC/字幕元数据自动转码（频谱时间轴同步）
对文本类元数据（lrc/srt/ass/krc/smi 等）自动检测编码（UTF-8/GBK/GB2312/GB18030/BIG5），非 UTF-8 自动转换为 UTF-8，确保频谱分析时的音频时间轴与歌词/字幕时间轴能正确对齐，避免乱码导致的同步失效。
7. 远程音频拉取多重降级（频谱稳定性保障）
- 优先使用 cURL，支持多 IP 自动 fallback、gzip/deflate 解压、最多 10 次重定向跟随
-
cURL 不可用/失败时，降级为
file_get_contents + stream_context_create - file_get_contents 直连失败时，遍历解析到的所有 IP 逐个替换 Host 重试
- 所有方案均失败时返回 502 错误并附带 debug 信息
8. UA 伪装与防爬虫拦截（受限 CDN 兼容）
伪装成主流浏览器 User-Agent、自动模拟真实 Referer、禁用 SSL 严格校验，绕过音频 CDN 的爬虫拦截策略，确保受限资源能被正常拉取用于频谱分析。
9. Debug 调试面板（频谱问题快速排查）
URL 追加 &debug 时输出完整调试信息：DNS 解析链路、cURL 错误、HTTP 状态码、Content-Type、音频大小、响应头、资源前 2000 字节预览，快速定位频谱分析失败原因（如 MIME 错误、DNS 劫持、跨域拦截）。
四、频谱场景调用示例
-
本地测试音频：
proxy.php?url=audio/test.mp3 -
远程受限音频：
proxy.php?url=https://xxxxx.com/song.flac -
歌词+频谱同步：
proxy.php?url=https://xxxxx.com/lyric.lrc -
频谱问题调试：
proxy.php?url=https://xxxxx.com/song.flac&debug
五、频谱场景环境要求
- PHP 5.4+
-
必装扩展：
curl、mbstring（文本编码转换）、allow_url_fopen=On -
可选系统命令：
dig/nslookup（增强 DNS 污染绕过能力）
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