[英]Angular $q returning promise multiple $http calls
I'm working on an $http call that loops over each of multiple api's and returns all of the data in one object. 我正在进行$ http调用,它遍历多个api中的每一个并返回一个对象中的所有数据。 I usually have the promise ready to resolve when the $http call has been made. 我通常已经准备好在$ http调用时解决。 Similar to this: 与此类似:
function getAllData(api) {
return $http({
method: 'GET',
url: '/api/' + api
})
.then(sendResponseData)
.catch (sendGetVolunteerError);
}
The current function I have loops over each api and pushes each object in the api into an array and then pushes it into an overall array. 当前函数我遍历每个api并将api中的每个对象推送到一个数组中,然后将其推送到整个数组中。 I had this functioning, returning an multi-dimensional array, which needed to be flattened out. 我有这个功能,返回一个多维数组,需要被展平。
I'd like to return this in a promise, but am returning undefined
. 我想在一个承诺中返回这个,但是返回undefined
。 Here is what I have so far? 这是我到目前为止的情况? Is there a better way to approach this? 有没有更好的方法来解决这个问题?
dataService: DataService的:
function getSearchData() {
return {
loadDataFromUrls: function () {
var apiList = ["abo", "ser", "vol", "con", "giv", "blo", "par"];
var deferred = $q.defer();
var log = [];
angular.forEach(apiList, function (item, key) {
var logNew = [];
$http({
method: 'GET',
url: '/api/' + item
}).then(function (response) {
angular.forEach(response.data, function (item, key) {
this.push(item);
}, logNew);
return logNew;
});
this.push(logNew);
}, log);
$q.all(log).then(
function (results) {
deferred.resolve(
JSON.stringify(results))
},
function (errors) {
deferred.reject(errors);
},
function (updates) {
deferred.update(updates);
});
return deferred.promise;
}
};
};
Controller: 控制器:
function getSearchData(){
return dataService.getSearchData.loadDataFromUrls;
}
$scope.searchData = getSearchData();
$q.all
and a map
function are what you need here: 您需要$q.all
和map
功能:
function getSearchData() {
return {
// returns a promise for an object like:
// { abo: resultFromAbo, ser: resultFromSer, ... }
loadDataFromUrls: function () {
var apiList = ["abo", "ser", "vol", "con", "giv", "blo", "par"];
return $q.all(apiList.map(function (item) {
return $http({
method: 'GET',
url: '/api/' + item
});
}))
.then(function (results) {
var resultObj = {};
results.forEach(function (val, i) {
resultObj[apiList[i]] = val.data;
});
return resultObj;
});
}
};
}
If you have an arbitrary set of api calls I would do something like this: 如果你有一组任意api调用,我会做这样的事情:
function getSearchData(){
var deferred = $q.defer();
var noOfCalls = apiList.length;
var results = [];
var called = 0;
angular.forEach(apiList, function(item, key) {
$http.get(url).then(function(result){
results.push(result);
called++;
if(called == noOfCalls){
deferred.resolve(results);
}
})
});
return deferred.promise;
}
However if you know what each api call represents its better to use $.all in this way 但是,如果您知道每个api调用代表什么,那么以这种方式使用$ .all会更好
function search1(){
return $http.get(search1Url).then(function(result){
// do something to it
return result;
});
}
function search2(){
return $http.get(search2Url).then(function(result){
// do something to it
return result;
});
}
function search3(){
return $http.get(search3Url).then(function(result){
// do something to it
return result;
});
}
function search4(){
return $http.get(search4Url).then(function(result){
// do something to it
return result;
});
}
function getSearchResult(){
return $q.all([search1(), search2(), search3(), search4()]).then(function(results){
// OPTIONAL aggregate results before resolving
return results;
});
}
You should add a list of promises in $q
( not resolved promises like in your code ) , which is a $promise service
你应该在$q
添加一个promises列表(在代码中没有解析的promises),这是一个$promise service
Example: 例:
var firstPromise = service1.getMethod1().$promise;
var secondPromise = service2.getMethod2().$promise;
$q.all([firstPromise, secondPromise]).then(function(dataList){
// dataList[0] will be result of `firstPromise`
// dataList[1] will be result of `secondPromise`
});
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