AngularJS $资源为$ save方法发出HTTP OPTIONS请求而不是HTTP POST

Question

我正在编写一个简单的库应用程序,以便为使用AngularJS的大型项目做好准备.在网上阅读了很多关于使用$resource与RESTful API交互的内容之后,我认为它可能会提供一些节省时间和扩展的好处来实现它而不是$http用于每个请求.问题是,由于某种原因(我不是CORS的专家,并且请求是跨域发送的),在使用$save我的Node.js控制台显示的方法时:

OPTIONS /books 200 1ms - 161b 

使用该query()方法工作正常 - 节点控制台显示:

GET /books 200 1ms - 228b

此时我已经被困了几个小时,尝试下面的变化,但它总是最终成为OPTIONS请求而不是POST(这应该是根据Angular文档应该是该$save方法).

AngularJS Web App

app.js

var libraryApp = angular.module('libraryApp', ['ngResource', 'ngRoute', 'libraryControllers']);

libraryApp.factory('$book', ['$resource', function ($resource) {

    return $resource('http://mywebserver\\:1337/books/:bookId', { bookId: '@bookId' });
}]);

controllers.js

var libraryControllers = angular.module('libraryControllers', []);

libraryControllers.controller('BookCtrl', ['$scope', '$book', function($scope, $book) {

    ...

    $scope.addBook = function () {
        var b = new $book;
        b.isbn = "TEST";
        b.description = "TEST";
        b.price = 9.99;
        b.$save();
    };
}]);

带有Express REST API的Node.js

app.js

var express = require('express'),
    books = require('./routes/books'),
    http = require('http'),
    path = require('path');

var app = express();

...

// enable cross-domain scripting
app.all('*', function(req, res, next) {
    res.header("Access-Control-Allow-Origin", req.headers.origin);
    res.header("Access-Control-Allow-Headers", "X-Requested-With");
    next();
});

// routing
app.get('/books', books.getAll);
app.get('/books/:isbn', books.get);
// This is what I want to fire with the $save method
app.post('/books', books.add);

http.createServer(app).listen(app.get('port'), function(){
    console.log('Express server listening on port ' + app.get('port'));
});

./routes/books.js

...

exports.add = function(req, res) {

    console.log("POST request received...");
    console.log(req.body.isbn);
};

尝试将此行放入我的配置功能delete $httpProvider.defaults.headers.common["X-Requested-With"];但没有变化.

我不是Angular/Node pro,但现在我认为它与跨域有关,就像我说的那样,我不是CORS的专家.

提前致谢.

Answer 1

我知道回答我自己的问题可能不太好,但是在发布这个问题几天后我就发现了问题.

这一切都归结为浏览器如何管理CORS.当在JavaScript中进行非"简单"的跨域请求时(即GET请求 - 这解释了query()函数的工作原理),浏览器将自动向指定的URL/URI发出HTTP OPTIONS请求,称为"预先航班"请求或"承诺".只要远程源返回HTTP状态代码200以及它将在响应头中接受的内容的相关详细信息,浏览器就会继续执行原始JavaScript调用.

这是一个简短的jQuery示例:

function makeRequest() {
    // browser makes HTTP OPTIONS request to www.myotherwebsite.com/api/test
    // and if it receives a HTTP status code of 200 and relevant details about
    // what it will accept in HTTP headers, then it will make this POST request...
    $.post( "www.myotherwebsite.com/api/test", function(data) {
        alert(data);
    });
    // ...if not then it won't - it's that simple.
}

我所要做的就是在响应头中添加服务器将接受的详细信息:

// apply this rule to all requests accessing any URL/URI
app.all('*', function(req, res, next) {
    // add details of what is allowed in HTTP request headers to the response headers
    res.header('Access-Control-Allow-Origin', req.headers.origin);
    res.header('Access-Control-Allow-Methods', 'POST, GET, PUT, DELETE, OPTIONS');
    res.header('Access-Control-Allow-Credentials', false);
    res.header('Access-Control-Max-Age', '86400');
    res.header('Access-Control-Allow-Headers', 'X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept');
    // the next() function continues execution and will move onto the requested URL/URI
    next();
});

然后在Express路由之前插入这几行,只需为每个OPTIONS请求返回一个HTTP 200状态代码:

// fulfils pre-flight/promise request
app.options('*', function(req, res) {
    res.send(200);
});

希望这将有助于任何偶然发现此页面的人遭遇同样的问题.