以$路线的决心解决微风查询/ Q承诺停止页 [英] Resolving breeze query/Q promise with $route resolve stops page

问题描述

我在执行与棱角分明的决心轻而易举查询视图显示以前的问题。我试图从服务器获取一些数据前视图与渲染的微风。我使用

I'm having problems executing a breeze query with angular resolve before the view is rendered. I'm trying to get some data from the server before the view is rendered with breeze. I'm using

$routeProvider.when('/countries', { templateUrl: 'App/partials/countries.html', controller: Ctrl, resolve: Ctrl.resolve }).

控制器和服务片段：

controller and service snippets:

function Ctrl($scope, Q, datacontext, countries) {

//...

}

function getCountries(forceRefresh) {

            var query = entityQuery.
                from("countries").
                orderBy("name");

            return manager.executeQuery(query).
            then(getSucceeded);

        }

        function getSucceeded(data) {
            return data.results;
        }

这使得我的观点从来没有渲染：

this makes my view never render:

Ctrl.resolve = {
    countries: function (datacontext) {
        return datacontext.getCountries();
    }
}

而如果我创建了一个计时器，需要较长的时间，它的工作原理。我试着用$ Q包装，但我似乎无法得到它的工作。

whereas if I create a timer that takes longer time, it works. I've tried wrapping it with $q but I can't seem to get it to work.

这会使，因为超时的观点：

this will render the view because of the timeout:

Ctrl.resolve = {
    countries: function (datacontext) {
        return datacontext.getCountries();


    },
    delay: function ($q, $timeout) {
        var delay = $q.defer();
        $timeout(delay.resolve, 6000);
        return delay.promise;
    }
}

如果任何人都可以帮助我，这将是巨大的。我不知道如果我做错了什么，或者有与决心Q承诺或微风的限制。

If anyone can help me with this, it would be great. I'm not sure if I'm doing something wrong or if there are limitations with Q promises or breeze in resolve.

推荐答案

我觉得你的痛苦。一个在$ Q /路由解决执行中的错误是，决心不履行 Q.then 方法。违反支持互换的承诺实现（叹气）普遍接受的做法。

I feel your pain. One of the mistakes in the $q/route resolve implementation is that the resolve does not honor the Q.then method. That violates the generally accepted practice of supporting interchangeable promise implementations (sigh).

但是，这不是真正的问题。真正的问题是，当你的异步方法解析角不知道。你必须手动调用 $ rootScope。$适用在成功和失败的回调。角的$ http和$ Q为你做这个（或同等学历）。得到它的权利是自己皮塔。

But that's not the real problem. The real problem is that Angular doesn't know when your async method is resolved. You have to call $rootScope.$apply manually in both success and failure callbacks. Angular's $http and $q do this (or equivalent) for you. Getting it right yourself is a PITA.

正如我所说的，我们觉得你的痛苦。很快可以转换问答承诺$ Q承诺，应减轻痛苦，我们会发布一个小小的中的Q插件。至少它为我： - ）

As I said, we feel your pain. Very soon we will release a tiny Q plug-in that converts a Q promise to $q promise and should alleviate that pain. At least it does for me :-).

在简单地说，发现不远的地方你的应用程序开始的地方，并延长Q是这样的：

In a nutshell, find a place near where your app starts and extend Q something like this:

angular.module('app').factory('util', ['$q', '$rootScope', util]);

function util($q, $rootScope) {

   extendQ();

   ... other utilities here ...

   // Monkey patch to$q method into Q.js' promise prototype
   // ex usage: return manager.executeQuery(qry).to$q(succ, fail);
   function extendQ() {
       var promise = Q.defer().promise;
       var fn = Object.getPrototypeOf(promise);
       if (fn.to$q) return; // already extended
       fn.to$q = function (success, fail) {
           return to$q(this, success, fail);
       };
   }

   function to$q(qPromise, success, fail) {
       var d = $q.defer();
       qPromise
           .then(function (data) {
               if (data === undefined) {
                   logger.logError("Programming error: no data. " +
                   "Perhaps success callback didn't return a value or " +
                    "fail callback didn't re-throw error");
                   // If an error is caught and not re-thrown in an earlier promise chain
                   // you will arrive here with data === undefined. 
                   // Neglecting to re-throw is a common, accidental omission.
                   // To be safe, have every success callback return something
                   // and trap here if data is ever undefined
               }
               d.resolve(data);
               $rootScope.$apply();// see https://groups.google.com/forum/#!topic/angular/LQoBCQ-V_tM
           })
          .fail(function (error) {
              d.reject(error);
              $rootScope.$apply();// see https://groups.google.com/forum/#!topic/angular/LQoBCQ-V_tM
          });

       if (success || fail) {
           d.promise = d.promise.then(success, fail);
       }
       return d.promise;
   }

现在这样使用它（根据你的例子）：

Now use it like this (based on your example):

function getCountries() {

    var query = breeze.EntityQuery.from("countries").orderBy("name");

    return manager.executeQuery(query).to$q(getSucceeded);

    function getSucceeded(data) { return data.results; }
}

附录

我一直在问：

的为什么这么复杂？你为什么不使用 $ q.when（qPromse）转换Q承诺$ Q承诺？的

"Why so complicated? Why don't you use $q.when(qPromse) to convert Q promise to $q promise?"

我试过了...并不能使它发挥作用。具体来说，我尝试这样做：

I tried that ... and couldn't make it work. Specifically, I tried this:

function to$q(qPromise, success, fail) {
    var promise = $q.when(qPromise);
    if (success || fail) {
       promise = promise.then(success, fail);
    }
    return promise;
}

我相信是有什么毛病 $ q.when 。

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