使用 AngularJS 进行服务器轮询 [英] Server polling with AngularJS

问题描述

我正在尝试学习 AngularJS.我第一次尝试每秒获取新数据成功了:

I'm trying to learn AngularJS. My first attempt to get new data every second worked:

'use strict';

function dataCtrl($scope, $http, $timeout) {
    $scope.data = [];

    (function tick() {
        $http.get('api/changingData').success(function (data) {
            $scope.data = data;
            $timeout(tick, 1000);
        });
    })();
};

当我通过让线程休眠 5 秒来模拟慢速服务器时，它会在更新 UI 并设置另一个超时之前等待响应.问题是当我重写上述内容以使用 Angular 模块和 DI 进行模块创建时:

When I simulate a slow server by sleeping the thread for 5 seconds it waits for the response before updating the UI and setting another timeout. The problem is when I rewrote the above to use Angular modules and DI for module creation:

'use strict';

angular.module('datacat', ['dataServices']);

angular.module('dataServices', ['ngResource']).
    factory('Data', function ($resource) {
        return $resource('api/changingData', {}, {
            query: { method: 'GET', params: {}, isArray: true }
        });
    });

function dataCtrl($scope, $timeout, Data) {
    $scope.data = [];

    (function tick() {
        $scope.data = Data.query();
        $timeout(tick, 1000);
    })();
};

这仅在服务器响应快速时才有效.如果有任何延迟，它会在不等待响应的情况下每秒发送 1 个请求，并且似乎清除了 UI.我想我需要使用回调函数.我试过了:

This only works if the server response is fast. If there's any delay it spams out 1 request a second without waiting for a response and seems to clear the UI. I think I need to use a callback function. I tried:

var x = Data.get({}, function () { });

但出现错误:错误:destination.push 不是函数"这是基于 $resource 但我并没有真正理解那里的例子.

but got an error: "Error: destination.push is not a function" This was based on the docs for $resource but I didn't really understand the examples there.

如何使第二种方法奏效?

How do I make the second approach work?

推荐答案

您应该在 query 的回调中调用 tick 函数.

You should be calling the tick function in the callback for query.

function dataCtrl($scope, $timeout, Data) {
    $scope.data = [];

    (function tick() {
        $scope.data = Data.query(function(){
            $timeout(tick, 1000);
        });
    })();
};

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