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2023-04-10 08:00:04

错误:发送到客户端后无法设置标头

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

我也有同样的问题，是猫鼬引起的。

为了解决这个问题，你必须启用承诺，所以你可以添加:猫鼬。承诺=全球。承诺你的代码，这使得使用原生js承诺。

这个解决方案的其他替代方案是:

var mongoose = require('mongoose');
// set Promise provider to bluebird
mongoose.Promise = require('bluebird');

and

// q
mongoose.Promise = require('q').Promise;

但是您需要先安装这些包。

2020-02-11 16:28:12

其他回答

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)

2011-08-17 00:11:24

Node的新版本支持res.headersSent布尔表达式。你可以用它来验证你是否已经发送了一个响应:

if (!res.headersSent) // if doesn't sent yet
    res.status(200).send({ "message": "This is a message" })

注意!虽然这可以工作并回答问题，但这不是解决问题的正确方法，不推荐!

多次发送响应表明代码中存在问题，需要修复(这与在函数中一个接一个地使用两个return语句是一样的。这是一个bug)。

2021-09-29 11:15:10

我也有同样的问题。对我来说，我有2 res.json(事件)给我这个错误。

res.json(savedEvent);
res.json({ event });

我们应该通过只有单一的反应才会起作用。

res.json(event);
2022-11-14 13:39:16

我在使用邮递员时也犯了同样的错误。我注意到请求体(数据)的格式不正确。错误指向我在路由中传递的中间件。当我删除一个中间件时，它就意味着删除下一个中间件。

2022-10-20 16:13:37

还有其他原因导致了这个错误，它是当你没有在res.send, res.json等前面添加return关键字时……

2020-07-16 23:00:54

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