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错误:发送到客户端后无法设置标头

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问题描述

我对 Node.js 还很陌生，但遇到了一些问题.

I'm fairly new to Node.js and I am having some issues.

我使用的是 Node.js 4.10 和 Express 2.4.3.

I am using Node.js 4.10 and Express 2.4.3.

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

When I try to access http://127.0.0.1:8888/auth/facebook, i'll be redirected to 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?

May I know what is wrong with my code?

推荐答案

Express 中的 res 对象是 Node.js 的 http.ServerResponse (阅读 http.js 源代码).您可以随意调用 res.setHeader(name, value)，直到调用 res.writeHead(statusCode).在writeHead 之后，headers 被烘焙，你只能调用res.write(data)，最后调用res.end(data).

The res object in Express is a subclass of Node.js's http.ServerResponse (read the http.js source). You are allowed to call res.setHeader(name, value) as often as you want until you call res.writeHead(statusCode). After writeHead, the headers are baked in and you can only call res.write(data), and finally res.end(data).

错误错误:发送标头后无法设置标头".意味着您已经处于 Body 或 Finished 状态，但某些函数试图设置标题或 statusCode.当您看到此错误时，请尝试查找在某些正文已写入后尝试发送标头的任何内容.例如，查找意外调用两次的回调，或发送正文后发生的任何错误.

The error "Error: Can't set headers after they are sent." means that you're already in the Body or Finished state, but some function tried to set a header or statusCode. When you see this error, try to look for anything that tries to send a header after some of the body has already been written. For example, look for callbacks that are accidentally called twice, or any error that happens after the body is sent.

在您的情况下，您调用了 res.redirect()，这导致响应变为 Finished.然后你的代码抛出了一个错误(res.req 是 null).并且由于错误发生在您实际的 function(req, res, next) 中(不在回调中)，Connect 能够捕获它，然后尝试发送 500 错误页面.但是由于标头已经发送，Node.js 的 setHeader 抛出了你看到的错误.

In your case, you called res.redirect(), which caused the response to become Finished. Then your code threw an error (res.req is null). and since the error happened within your actual function(req, res, next) (not within a callback), Connect was able to catch it and then tried to send a 500 error page. But since the headers were already sent, Node.js's setHeader threw the error that you saw.

响应必须在 Head 中并保留在 Head 中:

Response must be in Head and remains in Head:

  1. res.writeContinue()
  2. res.statusCode = 404
  3. res.setHeader(name, value)
  4. res.getHeader(name)
  5. res.removeHeader(name)
  6. res.header(key[, val])(仅限快递)
  7. res.charset = 'utf-8'(仅限 Express；仅影响 Express 特定的方法)
  8. res.contentType(type) (仅限快递)
  1. res.writeContinue()
  2. res.statusCode = 404
  3. res.setHeader(name, value)
  4. res.getHeader(name)
  5. res.removeHeader(name)
  6. res.header(key[, val]) (Express only)
  7. res.charset = 'utf-8' (Express only; only affects Express-specific methods)
  8. res.contentType(type) (Express only)

响应必须在 Head 并变成 Body:

Response must be in Head and becomes Body:

  1. res.writeHead(statusCode, [reasonPhrase], [headers])

响应可以在 Head/Body 中，也可以在 Body 中保留:

Response can be in either Head/Body and remains in Body:

  1. res.write(chunk, encoding='utf8')

响应可以在头部/正文中，并变为完成:

Response can be in either Head/Body and becomes Finished:

  1. res.end([data], [encoding])

响应可以在头部/身体中，并保持当前状态:

Response can be in either Head/Body and remains in its current state:

  1. res.addTrailers(headers)

响应必须在标题中并成为完成:

  1. return next([err])(仅限连接/快递)
  2. 中间件中的任何异常function(req, res, next)(仅限Connect/Express)
  3. res.send(body|status[, headers|status[, status]])(仅限快递)
  4. res.attachment(filename) (仅限快递)
  5. res.sendfile(path[, options[, callback]])(仅限快递)
  6. res.json(obj[, headers|status[, status]])(仅限快递)
  7. res.redirect(url[, status])(仅限快递)
  8. res.cookie(name, val[, options])(仅限快递)
  9. res.clearCookie(name[, options])(仅限快递)
  10. res.render(view[, options[, fn]])(仅限快递)
  11. res.partial(view[, options])(仅限快递)
  1. return next([err]) (Connect/Express only)
  2. Any exceptions within middleware function(req, res, next) (Connect/Express only)
  3. res.send(body|status[, headers|status[, status]]) (Express only)
  4. res.attachment(filename) (Express only)
  5. res.sendfile(path[, options[, callback]]) (Express only)
  6. res.json(obj[, headers|status[, status]]) (Express only)
  7. res.redirect(url[, status]) (Express only)
  8. res.cookie(name, val[, options]) (Express only)
  9. res.clearCookie(name[, options]) (Express only)
  10. res.render(view[, options[, fn]]) (Express only)
  11. res.partial(view[, options]) (Express only)

这篇关于错误:发送到客户端后无法设置标头的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！

08-05 04:57
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