javascript - CORS 的问题。 flask <-> AngularJS

Question

使用 angularjs 客户端应用程序和提供 api 的 flask 应用程序开始一个新项目。我使用 mongodb 作为数据库。我必须立即排除 jsonp，因为我需要能够跨不同端口进行 POST。所以我们有 localhost:9000 用于 Angular 应用程序和 localhost:9001 用于 flask 应用程序。

我在我的 API 以及我的 Angular 文件中完成了 CORS 所需的更改。请参阅下面的来源。我遇到的第一个问题是 CORS 允许 header 无法识别 Chrome 中的 localhost 的错误。我更新了我的主机文件，以便我可以使用 moneybooks.dev，这适用于我的 GET 请求，而无需使用 JSONP。

现在，谈谈我面临的问题。提交 POST 请求时，其声明 Origin http://moneybooks.dev:9000 is not allowed by Access-Control-Allow-Origin 什么？ GET 可以通过，但 POST 被拒绝。我看到请求通过 flask ，但它返回 HTTP 400。我需要帮助使 POST 请求正常工作。

另一个可能相关的问题是，在我的 GET 请求中，有时 GET 请求根本不会触发。就像 BudgetCtrl 中的 loadBudget 函数一样。在 #/budgets/budgetID 上，有时根本不会加载预算名称。我检查了 flask 日志，没有看到通过的请求。然后我单击刷新，我看到了请求，预算名称出现在页面上但是在 flask 日志中我看到了一个错误。 [Errno 10053] 已建立的连接被主机中的软件中止。 这是一个连接错误，仅在 GET 请求成功时才会出现在 flask 日志中。

这些问题是否相关？谁能看到我做错了什么？

app.js

'use strict';

angular.module('MoneybooksApp', ['ui.bootstrap', 'ngResource'])
  .config(['$routeProvider', '$httpProvider', function ($routeProvider, $httpProvider) {
    $httpProvider.defaults.useXDomain = true;
    delete $httpProvider.defaults.headers.common['X-Requested-With'];
    $routeProvider
      .when('/', {
        templateUrl: 'views/main.html',
        controller: 'MainCtrl'
      })
      .otherwise({
        redirectTo: '/'
      });
  }]);

budgets.js

'use strict';

angular.module('MoneybooksApp')
  .config(['$routeProvider', function ($routeProvider) {
    $routeProvider
      .when('/budgets', {
        templateUrl: 'views/budgets-list.html',
        controller: 'BudgetListCtrl'
      })
      .when('/budgets/:budgetID', {
        templateUrl: 'views/budget.html',
        controller: 'BudgetCtrl'
      });
  }])
  .controller('BudgetListCtrl', function ($scope, $http, $resource) {
    $scope.budgets = [];

    var init = function () {
      $scope.loadBudgets();
    }

    $scope.loadBudgets = function() {
      $http.get('http://moneybooks.dev:9001/api/budgets')
        .success(function (data) {
          $scope.budgets = data;
        })
        .error(function (data) {
          console.error(data);
        });
    };

    init();
  })
  .controller('BudgetCtrl', function ($scope, $http, $routeParams, $resource) {
    $scope.budget = {};

    var init = function () {
      $scope.loadBudget();
    };

    $scope.loadBudget = function() {
      $http.get('http://moneybooks.dev:9001/api/budgets/'+$routeParams['budgetID'])
        .success(function (data) {
          $scope.budget = data;
        })
        .error(function (data) {
          console.error(data);
        });
    };

    init();
  })
  .controller('TransactionCtrl', function ($scope, $http, $routeParams, $resource) {
    $scope.transactions = [];
    $scope.editing = false;
    $scope.editingID;

    var init = function () {};


    $scope.syncUp = function () {
      $http.post('http://moneybooks.dev:9001/api/budgets/'+$routeParams['budgetID']+'/transactions', {transactions: $scope.transactions});
    };

    $scope.syncDown = function () {
      $http.get('http://moneybooks.dev:9001/api/budgets/'+$$routeParams['budgetID']+'/transactions')
        .success(function (transactions) {
          $scope.transactions = transactions;
        });
    };

    $scope.add = function() {
      $scope.transactions.push({
        amount: $scope.amount,
        description: $scope.description,
        datetime: $scope.datetime
      });

      reset();
      $scope.defaultSort();
    };

    $scope.edit = function(index) {
      var transaction = $scope.transactions[index];

      $scope.amount = transaction.amount;
      $scope.description = transaction.description;
      $scope.datetime = transaction.datetime;

      $scope.inserting = false;
      $scope.editing = true;
      $scope.editingID = index;
    };

    $scope.save = function() {
      $scope.transactions[$scope.editingID].amount = $scope.amount;
      $scope.transactions[$scope.editingID].description = $scope.description;
      $scope.transactions[$scope.editingID].datetime = $scope.datetime;

      reset();
      $scope.defaultSort();
    };

    var reset = function() {
      $scope.editing = false;
      $scope.editingID = undefined;

      $scope.amount = '';
      $scope.description = '';
      $scope.datetime = '';
    };

    $scope.cancel = function() {
      reset();
    };


    $scope.remove = function(index) {
      $scope.transactions.splice(index, 1);
      if ($scope.editing) {
        reset();
      }
    };

    $scope.defaultSort = function() {
      var sortFunction = function(a, b) {
        var a_date = new Date(a['datetime']);
        var b_date = new Date(b['datetime']);

        if (a['datetime'] === b['datetime']) {
          var x = a['amount'], y = b['amount'];
          return x > y ? -1 : x < y ? 1 : 0;
        } else {
          return a_date - b_date
        }
      };

      $scope.transactions.sort(sortFunction);
    };

    $scope.descriptionSuggestions = function() {
      var suggestions = [];

      return $.map($scope.transactions, function(transaction) {
        if ($.inArray(transaction.description, suggestions) === -1){
          suggestions.push(transaction.description);
          return transaction.description;
        }
      });
    };

    $scope.dateSuggestions = function () {
      var suggestions = [];

      return $.map($scope.transactions, function(transaction) {
        if ($.inArray(transaction.datetime, suggestions) === -1){
          suggestions.push(transaction.datetime);
          return transaction.datetime;
        }
      });
    }

    $scope.getRunningTotal = function(index) {
      var runningTotal = 0;
      var selectedTransactions = $scope.transactions.slice(0, index+1);
      angular.forEach(selectedTransactions, function(transaction, index){
        runningTotal += transaction.amount;
      });
      return runningTotal;
    };

    init();

    $(function(){
      (function($){
        var header = $('#budget-header');
        var budget = $('#budget');
        var pos = header.offset();

        $(window).scroll(function(){
          if ($(this).scrollTop() > pos.top && header.css('position') == 'static') {
            header.css({
              position: 'fixed',
              width: header.width(),
              top: 0
            }).addClass('pinned');
            budget.css({
              'margin-top': '+='+header.height()
            });
          } else if ($(this).scrollTop() < pos.top && header.css('position') == 'fixed') {
            header.css({
              position: 'static'
            }).removeClass('pinned');
            budget.css({
              'margin-top': '-='+header.height()
            });
          }
        });
      })(jQuery);
    });
  });

API.py

from flask import Flask, Response, Blueprint, request
from pymongo import MongoClient
from bson.json_util import dumps
from decorators import crossdomain
from bson.objectid import ObjectId

try:
    import json
except ImportError:
    import simplejson as json

class APIEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, objectid.ObjectID):
            return str(obj)

app = Flask(__name__)

client = MongoClient()
db = client['moneybooks']

api = Blueprint('api', __name__, url_prefix="/api")

@api.route('/budgets', methods=['GET', 'POST', 'OPTIONS'])
@crossdomain(origin='*', methods=['GET', 'POST', 'OPTIONS'], headers=['X-Requested-With', 'Content-Type', 'Origin'])
def budgets():
    if request.method == "POST":
        budget_id = db.budgets.insert({
            'name': request.form['name']
        })
        budget_json = dumps(db.budgets.find_one({'_id': budget_id}), cls=APIEncoder)

    if request.method == "GET":
        budget_json = dumps(db.budgets.find(), cls=APIEncoder)

    return Response(budget_json, mimetype='application/json')

@api.route('/budgets/<budget_id>', methods=['GET', 'OPTIONS'])
@crossdomain(origin='*', methods=['GET', 'OPTIONS'], headers=['X-Requested-With', 'Content-Type', 'Origin'])
def budget(budget_id):
  budget_json = dumps(db.budgets.find_one({'_id': ObjectId(budget_id)}), cls=APIEncoder)
  return Response(budget_json, mimetype='application/json')

@api.route('/budgets/<budget_id>/transactions', methods=['GET', 'POST', 'OPTIONS'])
@crossdomain(origin='*', methods=['GET', 'POST', 'OPTIONS'], headers=['X-Requested-With', 'Content-Type', 'Origin'])
def transactions(budget_id):
    if request.method == "POST":
        db.budgets.update({
            '_id': ObjectId(budget_id)
        }, {
            '$set': {
                'transactions': request.form['transactions']
            }
        });
        budget_json = dumps(db.budgets.find_one({'_id': ObjectId(budget_id)}), cls=APIEncoder)

    if request.method == "GET":
        budget_json = dumps(db.budgets.find_one({'_id': ObjectId(budget_id)}).transactions, cls=APIEncoder)

    return Response(budget_json, mimetype='application/json')

app.register_blueprint(api)

if __name__ == '__main__':
    app.config['debug'] = True
    app.config['PROPAGATE_EXCEPTIONS'] = True
    app.run()

decorators.py

from datetime import timedelta
from flask import make_response, request, current_app
from functools import update_wrapper

def crossdomain(origin=None, methods=None, headers=None, max_age=21600, attach_to_all=True, automatic_options=True):
    if methods is not None:
        methods = ', '.join(sorted(x.upper() for x in methods))
    if headers is not None and not isinstance(headers, basestring):
        headers = ', '.join(x.upper() for x in headers)
    if isinstance(max_age, timedelta):
        max_age = max_age.total_seconds()

    def get_methods():
        if methods is not None:
            return methods

        options_resp = current_app.make_default_options_response()
        return options_resp.headers['allow']

    def decorator(f):
        def wrapped_function(*args, **kwargs):
            if automatic_options and request.method == 'OPTIONS':
                resp = current_app.make_default_options_response()
            else:
                resp = make_response(f(*args, **kwargs))
            if not attach_to_all and request.method != 'OPTIONS':
                return resp

            h = resp.headers
            h['Access-Control-Allow-Origin'] = origin
            h['Access-Control-Allow-Methods'] = get_methods()
            h['Access-Control-Max-Age'] = str(max_age)

            if headers is not None:
                h['Access-Control-Allow-Headers'] = headers
            return resp

        f.provide_automatic_options = False
        f.required_methods = ['OPTIONS']
        return update_wrapper(wrapped_function, f)
    return decorator

编辑

来自 chrome 开发控制台的输出。

控制台:

XMLHttpRequest 无法加载 http://moneybooks.dev:9001/api/budgets/5223e780f58e4d20509b4b8b/transactions。 Access-Control-Allow-Origin 不允许来源 http://moneybooks.dev:9000。

网络

Name: transactions /api/budgets/5223e780f58e4d20509b4b8b
Method: POST
Status: (canceled)
Type: Pending
Initiator: angular.js:9499
Size: 13 B / 0 B
Latency: 21 ms

Answer 1

正如@TheSharpieOne 所指出的，CORS 错误很可能是由 Chrome 开发工具错误引起的红鲱鱼。如果这是一个实际的 CORS 问题，则飞行前 OPTIONS 调用应该返回相同的错误。

我相信您的 400 错误可能来自 POST 请求处理程序中的 request.form['transactions']。 request.form 是一个 MultiDict 数据结构，根据 http://werkzeug.pocoo.org/docs/datastructures/#werkzeug.datastructures.MultiDict 上的文档:

From Werkzeug 0.3 onwards, the KeyError raised by this class is also a subclass of the BadRequest HTTP exception and will render a page for a 400 BAD REQUEST if caught in a catch-all for HTTP exceptions.

我相信如果你检查 request.forms.keys() 中的 'transactions' 键，你会发现它不存在。请注意，POST 的内容类型是 application/json 而不是 x-www-form-urlencoded。根据 http://flask.pocoo.org/docs/api/#flask.Request.get_json 上的文档，当请求 mimetype 为 application/json 时，您需要使用 request.get_json() 函数获取请求数据。