加入排队angulars $ http服务 [英] Add queueing to angulars $http service

问题描述

我有一个非常古怪的API，它只能同时处理一个请求。
因此，我需要确保每一次请求时，它进入一个队列，该队列执行一次一个请求，直到它是空的。

I have a very quirky api that can only handle a single request at a time. Therefore, I need to ensure that every time a request is made, it goes into a queue, and that queue is executed one request at a time, until it is empty.

通常情况下，我只使用jQuery内置的队列，因为该网站已经在使用jQuery。但是，我不知道如果我能以某种方式装饰$ http服务，或者在一次返回一行诺言另一服务，还是其他什么东西包裹。

Normally, I just use jQuery's built in queue, since the site is already using jQuery. However, I was not sure if I could somehow decorate the $http service, or wrap it in another service that returns one promise at a time, or something else.

推荐答案

下面是我的解决办法： http://plnkr.co/编辑/ Tmjw0MCfSbBSgWRhFvcg

Here is my solution for that: http://plnkr.co/edit/Tmjw0MCfSbBSgWRhFvcg

的理念是：服务的每个运行添加请求排队并返回承诺。当请求的$ HTTP完成决心/拒绝归还承诺，从队列执行下一个任务（如有）。

The idea is: each run of service add request to queue and return promise. When request to $http is finished resolve/refuse returned promise and execute next task from queue if any.

app.factory('srv', function($q,$http) {

  var queue=[];
  var execNext = function() {
    var task = queue[0];
    $http(task.c).then(function(data) {
      queue.shift();
      task.d.resolve(data);
      if (queue.length>0) execNext();
    }, function(err) {
      queue.shift();
      task.d.reject(err);
      if (queue.length>0) execNext();
    })
    ;
  }; 
  return function(config) {
    var d = $q.defer();
    queue.push({c:config,d:d});
    if (queue.length===1) execNext();            
    return d.promise;
  };
});

看起来相当简单：）

Looks quite simple :)

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