我对Node.js相当陌生,我有一些问题。

我使用的是Node.js 4.10和Express 2.4.3。

当我尝试访问http://127.0.0.1:8888/auth/facebook时,我将被重定向到http://127.0.0.1:8888/auth/facebook_callback。

然后我收到以下错误:

Error: Can't render headers after they are sent to the client.
    at ServerResponse.<anonymous> (http.js:573:11)
    at ServerResponse._renderHeaders (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:64:25)
    at ServerResponse.writeHead (http.js:813:20)
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/auth.strategies/facebook.js:28:15
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/index.js:113:13
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/strategyExecutor.js:45:39)
    at [object Object].pass (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/authExecutionScope.js:32:3)
    at [object Object].halt (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/authExecutionScope.js:29:8)
    at [object Object].redirect (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/authExecutionScope.js:16:8)
    at [object Object].<anonymous> (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/auth.strategies/facebook.js:77:15)
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:195:11)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:150:23)
    at param (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:189:13)
    at pass (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:191:10)
    at Object.router [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:197:6)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
    at Object.auth [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/index.js:153:7)
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:207:9)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:150:23)
    at param (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:189:13)
    at pass (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:191:10)
    at Object.router [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:197:6)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
    at Object.auth [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/index.js:153:7)
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:150:23)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:207:9)
    at Object.auth [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/index.js:153:7)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
    at HTTPServer.handle (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:211:3)
    at Object.handle (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:105:14)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:150:23)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:207:9)
    at HTTPServer.handle (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:211:3)
    at Object.handle (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:105:14)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session.js:323:9
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session.js:338:9

node.js:134
        throw e; // process.nextTick error, or 'error' event on first tick
        ^
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:207:9)
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session.js:323:9
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session.js:338:9
    at Array.<anonymous> (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session/memory.js:57:7)
    at EventEmitter._tickCallback (node.js:126:26)

以下是我的代码:

var fbId= "XXX";
var fbSecret= "XXXXXX";
var fbCallbackAddress= "http://127.0.0.1:8888/auth/facebook_callback"

var cookieSecret = "node";     // enter a random hash for security

var express= require('express');
var auth = require('connect-auth')
var app = express.createServer();


app.configure(function(){
    app.use(express.bodyParser());
    app.use(express.methodOverride());
    app.use(express.cookieParser());
    app.use(express.session({secret: cookieSecret}));
    app.use(auth([
        auth.Facebook({
            appId : fbId,
            appSecret: fbSecret,
            callback: fbCallbackAddress,
            scope: 'offline_access,email,user_about_me,user_activities,manage_pages,publish_stream',
            failedUri: '/noauth'
        })
    ]));
    app.use(app.router);
});


app.get('/auth/facebook', function(req, res) {
  req.authenticate("facebook", function(error, authenticated) {
    if (authenticated) {
      res.redirect("/great");
      console.log("ok cool.");
      console.log(res['req']['session']);
    }
  });
});

app.get('/noauth', function(req, res) {
  console.log('Authentication Failed');
  res.send('Authentication Failed');
});

app.get('/great', function( req, res) {
  res.send('Supercoolstuff');
});

app.listen(8888);

我可以知道我的代码有什么问题吗?


当前回答

有时,当你试图在res.end或res.send之后调用next()函数时,你可能会得到这个错误,如果你在函数中res.send或res.end之后调用next(),请尝试删除。 注意:这里的next()表示在响应客户端后(i。E res.send或res.end)你仍然试图执行一些代码来再次响应,所以这是不合法的。

例子:

router.get('/',function (req,res,next){
     res.send("request received");
     next(); // this will give you the above exception 
});

从上面的函数中删除next(),它将工作。

其他回答

在Typescript中,我的问题是我没有在收到消息后关闭websocket连接。

WebSocket.on("message", (data) => {
    receivedMessage = true;
    doSomething(data);
    localSocket.close(); //This close the connection, allowing 
});

很多人都犯过这个错误。这与异步处理很容易混淆。最有可能的是,你的一些代码在第一个tick设置头,然后你在未来的tick运行一个异步回调。在此期间,响应头被发送,但随后进一步的头(如30X重定向)尝试添加额外的头,但为时已晚,因为响应头已经被传输。

我不确定究竟是什么原因导致了您的错误,但请将所有回调作为潜在的调查领域。

简化代码的一个简单技巧。去掉app.configure(),直接在顶层作用域调用app.use。

请参见everyauth模块,该模块用于Facebook和十几个其他第三方身份验证提供商。

有时,当你试图在res.end或res.send之后调用next()函数时,你可能会得到这个错误,如果你在函数中res.send或res.end之后调用next(),请尝试删除。 注意:这里的next()表示在响应客户端后(i。E res.send或res.end)你仍然试图执行一些代码来再次响应,所以这是不合法的。

例子:

router.get('/',function (req,res,next){
     res.send("request received");
     next(); // this will give you the above exception 
});

从上面的函数中删除next(),它将工作。

Express中的res对象是Node.js的http的子类。ServerResponse(读取http.js源代码)。你可以调用res.setHeader(name, value),直到你调用res.writeHead(statusCode)。在writeHead之后,头被烘焙进去,你只能调用res.write(data),最后调用res.end(data)。

错误“错误:发送后无法设置报头”意味着您已经处于Body或Finished状态,但某些函数试图设置报头或statusCode。当您看到此错误时,请尝试查找在已经写入部分正文之后试图发送头的任何内容。例如,查找意外调用两次的回调,或者在正文发送之后发生的任何错误。

在您的示例中,您调用了res.redirect(),这导致响应变为Finished。然后你的代码抛出一个错误(res.req是null)。并且由于错误发生在您的实际函数(req, res, next)(而不是回调函数)中,Connect能够捕获它,然后尝试发送一个500错误页面。但是由于头已经发送,Node.js的setHeader抛出了你所看到的错误。

Node.js/Express响应方法的综合列表,以及何时必须调用它们:

响应必须在头部,并保持在头部:

res.writeContinue () res.statusCode = 404 res.setHeader(名称、值) res.getHeader(名字) res.removeHeader(名字) res.header(key[, val]) res.charset = 'utf-8'(仅限Express;只影响特定于express的方法) res.contentType(类型)(仅适用于Express)

Response必须在Head中并成为Body:

作家(雕像,[原因],[标题])

Response可以在Head/Body中任意一个,并保留在Body中:

res.write (chunk, encoding =‘utf8)

Response可以在Head/Body中任意一个,变成Finished:

res.end((数据),(编码))

响应可以在Head/Body中任意一个,并保持当前状态:

res.addTrailers(头)

响应必须在头部,成为完成:

return next([err]) (Connect/Express only) Any exceptions within middleware function(req, res, next) (Connect/Express only) res.send(body|status[, headers|status[, status]]) (Express only) res.attachment(filename) (Express only) res.sendfile(path[, options[, callback]]) (Express only) res.json(obj[, headers|status[, status]]) (Express only) res.redirect(url[, status]) (Express only) res.cookie(name, val[, options]) (Express only) res.clearCookie(name[, options]) (Express only) res.render(view[, options[, fn]]) (Express only) res.partial(view[, options]) (Express only)

我遇到了问题 这就是我在做的

const user  = await User.findOne({_id: req.params.id})

所以我不得不改变findOne到findById,它为我做的伎俩

const user = await User.findById(req.params.id)