MediaRecorder实时音频分块录制与服务器端保存：解决文件损坏问题

var mediaRecorder = null;
let chunks = [];

if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
   console.log('getUserMedia supported.');
   navigator.mediaDevices.getUserMedia(
      {
         audio: true
      })
      .then(function(stream) {
        // 关键：在MediaRecorder构造函数中指定mimeType
        const mrOptions = { mimeType: 'audio/ogg; codecs=opus' };
        mediaRecorder = new MediaRecorder(stream, mrOptions);

        // 每2秒触发一次ondataavailable事件，收集数据块
        mediaRecorder.start(2000); 

        mediaRecorder.ondataavailable = function(e) {
            // 确保e.data中有数据
            if (e.data.size > 0) {
                chunks.push(e.data);
                // 使用MediaRecorder实例的mimeType来创建Blob
                const blob = new Blob(chunks, { type : mediaRecorder.mimeType });
                chunks = []; // 清空chunks，准备接收下一个数据块

                var reader = new FileReader();
                reader.readAsDataURL(blob); 
                reader.onloadend = function() {
                    // 提取Base64编码的数据
                    var data = reader.result.split(";base64,")[1]; 
                    // 发送数据到服务器
                    requestp2("a.php", "data=" + encodeURIComponent(data));
                }
            }
        };

        mediaRecorder.onstop = function() {
            console.log("录制停止");
            // 可以在这里处理最后剩余的chunks，如果需要
        };

      })
      .catch(function(err) {
         console.log('获取麦克风权限失败: ' + err);
      }
   );
} else {
   console.log('当前浏览器不支持getUserMedia！');
}

/**
 * 封装的POST请求函数
 * @param {string} path 请求路径
 * @param {string} data 要发送的数据
 */
function requestp2(path, data) {
    var http = new XMLHttpRequest();
    http.open('POST', path, true);
    http.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
    http.onreadystatechange = function() {
        if (http.readyState === 4 && http.status === 200) {
            console.log("数据发送成功", http.responseText);
        } else if (http.readyState === 4 && http.status !== 200) {
            console.error("数据发送失败", http.status);
        }
    };
    http.send(data);
}

<?php
// 定义保存音频文件的路径和文件名
$audioFilePath = "r.ogg";

if (isset($_POST["data"])) {
    $base64Data = $_POST["data"];

    // 解码Base64数据
    $decodedData = base64_decode($base64Data);

    if ($decodedData === false) {
        error_log("Base64解码失败！");
        http_response_code(400); // Bad Request
        echo "Error: Base64 decoding failed.";
        exit;
    }

    // 关键：使用FILE_APPEND标志将数据追加到文件末尾
    // 如果文件不存在，file_put_contents 会尝试创建它
    if (file_put_contents($audioFilePath, $decodedData, FILE_APPEND | LOCK_EX) === false) {
        error_log("文件写入失败：" . $audioFilePath);
        http_response_code(500); // Internal Server Error
        echo "Error: Failed to write to file.";
        exit;
    }

    echo "Success: Audio chunk saved.";
    exit;   
} else {
    http_response_code(400); // Bad Request
    echo "Error: No data received.";
    exit;
}
?>