[英]Handling Errors In Angular Promises
I am still learning promises in angular and have this bit of code where I am making a "GET" request two times. 我仍在学习有角度的promise,并在两次发出“ GET”请求的地方有这段代码。 I want to run one get request before calling the other.
我想在调用另一个之前运行一个get请求。 This is working fine, but how would I handle errors here?
一切正常,但是如何处理错误? If I get an error for my first GET request how do I find out what that error is and prevent my code from calling the second GET request?
如果在第一个GET请求中遇到错误,如何找出错误并阻止代码调用第二个GET请求? Examples with my code would be most helpful.
我的代码示例将最有帮助。
apiServices.login = function(user,password,callback) {
$http.get("http://magainteractive.com/prototypes/cisco-ima-dashboard/cms/web/api/login/login/?username="+user+"&password="+password+"")
.then(function(contentResponse){
resultsObject.content = contentResponse;
return $http.get("http://magainteractive.com/prototypes/cisco-ima-dashboard/cms/web/api/data/list/");
})
.then(function(dataResponse){
resultsObject.reports = dataResponse;
resultsObject.success = 1;
console.log(resultsObject);
callback(resultsObject);
apiServices.useData(resultsObject);
});
}
dummyData.login(username, password, function (dataStatus) {
if (dataStatus.success = 1) {
$rootScope.loggedIn = true;
$rootScope.selectedDashboard = 1;
} else {
console.log("Error");
}
});
I would do things slightly different from Lucas, I prefer chaining a catch block( basically it would act like the synchrounous try...catch
block we use) rather than adding an error callback function so code would be like: 我会做一些与Lucas稍有不同的事情,我更喜欢链接一个catch块(基本上它的行为就像我们使用的同步
try...catch
块一样),而不是添加一个错误回调函数,因此代码如下:
return $http.get(url1)
.then(function(result){
resultsObject.url1 = result;
return $http.get(url2);
}).then(function(result){
resultsObject.url2 = result;
return resultsObject;
}).catch(function(error){
// handle error.
});
PS: most of your code is fine, but I am not really sure why you have that callback(resultsObject);
PS:您的大多数代码都可以,但是我不确定为什么要使用该
callback(resultsObject);
, when you are using promises, callbacks are redundant, you could just return the promise chain $http.get...
,当您使用诺言时,回调是多余的,您可以只返回诺言链
$http.get...
You can pass a second parameter in the first callback handling. 您可以在第一个回调处理中传递第二个参数。 This will trigger if there's an error in the request, then you can handle it however you want:
如果请求中有错误,这将触发,然后您可以根据需要进行处理:
$http({
method: 'GET',
url: '/someUrl'
}).then(function successCallback(response) {
// this callback will be called asynchronously
// when the response is available
}, function errorCallback(response) {
// called asynchronously if an error occurs
// or server returns response with an error status.
});
Or in your coding: 或在您的编码中:
$http.get('/someUrl').then(successCallback, errorCallback);
Your code would look like: 您的代码如下所示:
$http.get("http://magainteractive.com/prototypes/cisco-ima-dashboard/cms/web/api/login/login/?username="+user+"&password="+password+"")
.then(function(contentResponse){
resultsObject.content = contentResponse;
return $http.get("http://magainteractive.com/prototypes/cisco-ima-dashboard/cms/web/api/data/list/");
}, function(error){
//HANDLE ERROR HERE
})
.then(function(dataResponse){
resultsObject.reports = dataResponse;
resultsObject.success = 1;
console.log(resultsObject);
callback(resultsObject);
apiServices.useData(resultsObject);
});
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