AngularJS：HTTP链接承诺$ Q在服务 [英] AngularJS : chaining http promises $q in a service

问题描述

我有问题，当谈到在angularjs $ HTTP承诺。我这样做在我的服务：（该getSomething函数应链中的两个承诺）

i have problems when it comes to $http promises in angularjs. i am doing this in my service: (the getSomething function should chain two promises)

第二个函数使用外部回调函数！

the second function uses a external callback function!

app.service('blubb', function($http, $q) {

  var self = this;

  this.getSomething = function(uri, data) {
    return self.getData(uri).then(function(data2) {
      return self.compactData(uri, data2);
    });
  };

  this.getData = function(uri) {
    var deferred = $q.defer();
    $http.get(uri).success(function(data) {
      deferred.resolve(data);
    }).error(function() {
      deferred.reject();
    });

    return deferred.promise;
  };

  this.compactData = function(uri, data) {
    var deferred = $q.defer();
    /* callback function */
      if(!err) {
        console.log(compacted);
        deferred.resolve(compacted);
      } else {
        console.log(err);
        deferred.reject(err);
      }
    /* end of function */

    return deferred.promise;
  };
});

当我使用这项服务在我的控制器它不输出的console.log：

when i use the service in my controller it doesn't output the console.log:

blubb.getSomething(uri, input).then(function(data) {
  console.log(data)
});

编辑：
如果我自己在compactData它的工作原理定义回调函数，但我使用jsonld.compact从<一个href=\"https://raw.github.com/digitalbazaar/jsonld.js/master/js/jsonld.js\">https://raw.github.com/digitalbazaar/jsonld.js/master/js/jsonld.js这不行！

    jsonld.compact(input, context, function(err, compacted) {
      if(!err) {
        console.log(compacted);
        deferred.resolve(compacted);
      } else {
        deferred.reject('JSON-LD compacting');
      }
    });

我得到在jsonld.compact中的console.log输出，但决心不工作，我不知道为什么。

i am getting the console.log output in jsonld.compact but the resolve doesn't work and i don't know why..

它仅适用于$ rootScope $申请（deferred.resolve（压缩的））;

it only works with $rootScope.$apply(deferred.resolve(compacted));

推荐答案

我使用链接的承诺是这样的：

I'm using chaining promises like this:

            $http.get('urlToGo')
                .then(function(result1) {
                    console.log(result1.data);
                    return $http.get('urlToGo');
                }).then(function(result2) {
                    console.log(result2.data);
                    return $http.get('urlToGo');
                }).then(function(result3) {
                    console.log(result3.data);
                });

这篇关于AngularJS：HTTP链接承诺$ Q在服务的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！