Node.js v21.7.1 返回静态文件时出现ERR_INVALID_ARG_TYPE错误求助

使用Node.js v21.7.1开发Web服务器，返回如jquery/jquery-2.2.1.min.js这类静态文件时，控制台抛出如下错误：

L392 [strFilename] typeof:string value:[/scripts/jquery/jquery-2.2.1.min.js]
2024-03-22 10:21:42.566 HTTP request for: /scripts/jquery/jquery-2.2.1.min.js from: localhost:8000
2024-03-22 10:21:42.566 Full path: C:\www\scripts\jquery\jquery-2.2.1.min.js
L438 C:/www/scripts/jquery/jqwidgets/styles/jqx.base.css
L441 File: C:/www/scripts/jquery/jqwidgets/styles/jqx.base.css text/css
node:_http_outgoing:949
    throw new ERR_INVALID_ARG_TYPE(
    ^

TypeError [ERR_INVALID_ARG_TYPE]: The "chunk" argument must be of type string or an instance of Buffer or Uint8Array. Received type number (200)
    at write_ (node:_http_outgoing:949:11)
    at ServerResponse.write (node:_http_outgoing:908:15)
    at C:\www\server.js:442:38
    at FSReqCallback.readFileAfterClose [as oncomplete] (node:internal/fs/read/context:68:3) {
  code: 'ERR_INVALID_ARG_TYPE'
}

Node.js v21.7.1

对应的处理代码：

fs.exists(strFullPath, function(exists) {
    if ( !exists ) {
        response.writeHead(404, {"Content-Type":"text/plain"});
        response.write("404 Not Found\n");
        response.end();
        return;
    }
    fs.readFile(strFullPath, "binary", function(err, file) {
        if ( err ) { console.log(consts.RED + "L434 " + consts.RESET + strFullPath);//HACK
            response.writeHead(500, {"Content-Type":"text/plain"});
            response.write(err + "\n");
            response.end();
            return;
        } console.log(consts.RED + "L438 " + consts.RESET + strFullPath);//HACK    
        const cstrExt = path.extname(strFullPath)
                ,cstrType = cstrContentTypes[cstrExt];
        if ( typeof cstrType == "string" ) {
console.log(consts.RED + "L441 File: " + consts.RESET + strFullPath + " " + cstrType);
            response.write(200, {"Content-Type":cstrType});
            response.write(file, "binary");
            response.end();
        } 
    });
});

错误原因 #

代码第442行误用了response.write方法：response.write(200, {"Content-Type":cstrType})。response.write的第一个参数是要发送给客户端的内容（chunk），要求是字符串、Buffer或Uint8Array类型，传入数字200直接触发了类型错误。设置HTTP状态码和响应头应该用response.writeHead方法。

修正后的代码 #

把错误的response.write替换为response.writeHead即可：

fs.exists(strFullPath, function(exists) {
    if ( !exists ) {
        response.writeHead(404, {"Content-Type":"text/plain"});
        response.write("404 Not Found\n");
        response.end();
        return;
    }
    fs.readFile(strFullPath, "binary", function(err, file) {
        if ( err ) { 
            console.log(consts.RED + "L434 " + consts.RESET + strFullPath);//HACK
            response.writeHead(500, {"Content-Type":"text/plain"});
            response.write(err + "\n");
            response.end();
            return;
        } 
        console.log(consts.RED + "L438 " + consts.RESET + strFullPath);//HACK    
        const cstrExt = path.extname(strFullPath)
                ,cstrType = cstrContentTypes[cstrExt];
        if ( typeof cstrType == "string" ) {
            console.log(consts.RED + "L441 File: " + consts.RESET + strFullPath + " " + cstrType);
            // 修正：使用writeHead设置状态码和响应头
            response.writeHead(200, {"Content-Type":cstrType});
            response.write(file, "binary");
            response.end();
        } 
    });
});

额外优化建议：fs.exists已被废弃，推荐使用fs.access或直接在fs.readFile中捕获文件不存在的错误，避免额外的文件系统调用。

内容的提问来源于stack exchange，提问作者SPlatten