Node.js "write after end" 错误

Question

从一个基本的节点应用程序开始，我不知道如何克服这个 "write after end" 错误，即使在几个网站上建议的回调也是如此。

index.js:

var server = require("./server");
var router = require("./router");
var requestHandlers = require("./requestHandlers");

var handle = {}
handle["/"] = requestHandlers.start;
handle["/start"] = requestHandlers.start;
handle["/upload"] = requestHandlers.upload;

server.start(router.route, handle);

server.js:

var http = require("http");
var url = require("url");

function start(route, handle) {
  function onRequest(request, response) {
    var postData ="";
    var pathname = url.parse(request.url).pathname;
    console.log("Request for " + pathname + " received.");

    route(handle, pathname, response);
   }

  http.createServer(onRequest).listen(8888);
  console.log("Server has started.");
}

exports.start = start;

router.js:

function route(handle, pathname, response) {
  console.log("About to route a request for " + pathname);
  if (typeof handle[pathname] === 'function') {
    handle[pathname](response);
  } 
  else {
    console.log("No request handler found for " + pathname);
    response.writeHead(404, {"Content-Type": "text/plain"});
    response.write("404 Not found");
    response.end();
  }
}

exports.route = route;

and now the culprit, requestHandlers.js:

function start(response) {
  console.log("Request handler 'start' was called.");

  var body = '<html>'+
    '<head>'+
    '<meta http-equiv="Content-Type" content="text/html; '+
    'charset=UTF-8" />'+
    '</head>'+
    '<body>'+
    '<div>Hello Start</div>' +
    '</body>'+
    '</html>';

    response.writeHead(200, {"Content-Type": "text/html"});
    response.write(body);
    response.end();
}

function upload(response) {
    console.log("Request handler 'upload' was called");
    response.writeHead(200, {"Content-Type": "text/plain"}); 
    response.write("Hello Upload");
    response.end();
}

exports.start = start;
exports.upload = upload;

这是堆栈跟踪：

C02RF8L7FVH5:HelloWorld francop$ node index.js Server has started. Request for / received. About to route a request for / Request handler 'start' was called. About to route a request for / Request handler 'start' was called. events.js:141 throw er; // Unhandled 'error' event ^

Error: write after end at ServerResponse.OutgoingMessage.write (_http_outgoing.js:430:15) at Object.start (/Users/francop/Documents/Apps/HelloWorld/requestHandlers.js:18:14) at route (/Users/francop/Documents/Apps/HelloWorld/router.js:5:21) at IncomingMessage. (/Users/francop/Documents/Apps/HelloWorld/server.js:19:6) at emitNone (events.js:67:13) at IncomingMessage.emit (events.js:166:7) at endReadableNT (_stream_readable.js:921:12) at nextTickCallbackWith2Args (node.js:442:9) at process._tickCallback (node.js:356:17)

我在任何地方找到的唯一答案是 "It's async so use a callback" 像这样：

response.write(body, function(err) {
    response.end();
});

...引发完全相同的错误。

任何对此的帮助都会很棒。我在网上找到的一些稀疏答案根本没有帮助。

谢谢！

Answer 1

Return response.end() 中的 body 而不是 response.write()

function start (response) {
    console.log("Request handler 'start' was called.");
    var body = '<html>'+
    '<head>'+
    '<meta http-equiv="Content-Type" content="text/html; '+
    'charset=UTF-8" />'+
    '</head>'+
    '<body>'+
    '<div>Hello Start</div>' +
    '</body>'+
    '</html>';

    response.writeHead(200, {"Content-Type": "text/html"});
    response.end(body);
}

编辑 1：

第一次调用response.write()，会将缓冲的header信息和第一个body发送给客户端。第二次调用 response.write() 时，Node.js 假定您要流式传输数据，并单独发送。也就是说，响应被缓冲到 body.

的第一个块

所以，如果你只想发送一个块，你必须使用response.end(body)，如果你想发送多个块，你必须在多个[=14]之后用response.end()结束调用=].

单块示例：

function (chunk){
    response.end(chunk);
}

示例多个块：

function (chunkArray){
    // loop on chunks 
    for(var i=0; i < chunkArray.length; i++){
        response.write(chunkArray[i]);                
    }

    // end the response with empty params
    response.end();
}

Answer 2

这是来自 "The Node Beginner"

的示例

我已经重新post编辑了下面的文件，因为截至目前post，"router.js" 和[=32] 之间的post 没有分隔=].

当我运行当前在节点 v8 中运行时没有事件节点 v9.5.0，我遇到了同样的问题。我并不是将此作为问题的解决方案，只是说它对我有用。也许这是更新版本中解决的问题我不能肯定。

您的错误流也显示 "requestHandlers.js:18:14" 如果您确认代码中的第 18 行（将来），您可能会得到更好的结果。没有空格的第 18 行是上传功能声明之前的行。实际上这个错误是由 "response.end();"

触发的

index.js

var server = require("./server");
var router = require("./router");
var requestHandlers = require("./requestHandlers");

var handle = {}
handle["/"] = requestHandlers.start;
handle["/start"] = requestHandlers.start;
handle["/upload"] = requestHandlers.upload;

server.start(router.route, handle);

router.js

function route(handle, pathname, response) {
  console.log("About to route a request for " + pathname);
  if (typeof handle[pathname] === 'function') {
    handle[pathname](response);
  } 
  else {
    console.log("No request handler found for " + pathname);
    response.writeHead(404, {"Content-Type": "text/plain"});
    response.write("404 Not found");
    response.end();
  }
}

exports.route = route;

server.js

var http = require("http");
var url = require("url");

function start(route, handle) {
  function onRequest(request, response) {
    var postData ="";
    var pathname = url.parse(request.url).pathname;
    console.log("Request for " + pathname + " received.");

    route(handle, pathname, response);
   }

  http.createServer(onRequest).listen(8888);
  console.log("Server has started.");
}

exports.start = start;

requestHandlers.js

function start(response) {
  console.log("Request handler 'start' was called.");

  var body = '<html>'+
    '<head>'+
    '<meta http-equiv="Content-Type" content="text/html; '+
    'charset=UTF-8" />'+
    '</head>'+
    '<body>'+
    '<div>Hello Start</div>' +
    '</body>'+
    '</html>';

    response.writeHead(200, {"Content-Type": "text/html"});
    response.write(body);
    response.end();
}

function upload(response) {
    console.log("Request handler 'upload' was called");
    response.writeHead(200, {"Content-Type": "text/plain"}); 
    response.write("Hello Upload");
    response.end();
}

exports.start = start;
exports.upload = upload;

Node.js "write after end" 错误

Node.js "write after end" error

javascript

node.js

node.js-stream

编辑 1：

单块示例：

示例多个块：