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AngularJS - Correctly formatting asynchronous calls - javascript

newbie here.
I am trying to understand how I need to structure asynchronous calls within my controller to fit my specific use case:
Consider the following code snippet from an Angular Module in "service.js" within my project:
function getSearchObjects(projectName, title) {
var payload = JSON.stringify({
"title": title
});
var request = $http({
method: 'post',
url: URL + '/search/' + projectName,
data: payload
});
return request.then(handleSuccess, handleError);
};
function runQuery(projectName, fromDate, toDate, sort, direction, columns) {
var from = Date.parse(fromDate);
var to = Date.parse(toDate);
var payload = JSON.stringify({
"fromDate": from,
"toDate": to,
"sort": sort,
"direction": direction,
"columns": columns
});
console.log(payload);
var request = $http({
method: 'post',
url: URL + '/query/' + projectName,
data: payload
});
return request.then(handleSuccess, handleError);
}
function handleSuccess(response) {
return response.data;
};
function handleError(response) {
if (!angular.isObject( response.data ) || !response.data.error) {
return( $q.reject( "An unknown error occurred." ) );
}
return $q.reject( response.data.error );
};
});
Within my controller, I am trying to troubleshoot the following function:
$scope.submit = function() {
var objectProperties = exportsStorageService.getSearchObjects($scope.selected.project.name, $scope.selected.search)
.then(function(result) {
exportsStorageService.runQuery($scope.selected.project.name, $scope.selected.start_date, $scope.selected.end_date, objectProperties.sort, objectProperties.direction, objectProperties.columns)
},
function(error) {
console.log(error);
});
};
getSearchObjects matches a title ($scope.selected.search) selected in my UI and grabs the following more detailed object from an API call:
{ title: 'Duplication Example',
sort: '#_traac-timestamp',
direction: 'desc',
columns: [ '#_traac-remote_ip', 'c-platform-m-distinct-id_s', '_type' ] }
I am trying to grab the properties returned from getSearchObjects and pass them along with a few user selected values from my UI to runQuery, which then returns data from a database to the user, but when I check the values passed to runQuery using the above logic in my controller, I get the following values. All of the objectProperties values I am attempting to pass to runQuery are undefined:
project_name: "Example Project"
start_date: 1499770800000
end_date: 1499943600000
sort: undefined
direction: undefined
columns: undefined
I have been trying to debug this, but I am too new to using Angular and asynchronous calls to really understand what I am doing wrong. My best guess currently is that I am calling runQuery before the values retrieved from getSearchObjects are attached to objectProperties. Either that or I am incorrectly referencing the properties within the objectProperties variable.
Could someone help me troubleshoot this issue, and better understand what I am doing wrong?
Thank you in advance for your help!

When you do this:
var objectProperties = some async function...
You are assigning the promise of the async function to the variable, not the result of it.
The result is coming in the .then, like you declared:
.then(function(result) { ... }
So, instead of objectProperties.sort, objectProperties.direction, objectProperties.columns, try using result.sort, result.direction, result.columns :)
If you are new to Promises, take a look at this simple, but great tutorial.
EDIT
Based on your comment, you are receiving, inside the response.data, the following object:
{"objectMatch": {
"title": "doc-event",
"sort": "#_traac-timestam‌​p",
"direction": "desc‌​",
"columns": [
"m-doc-‌​name_s",
"m-user_s",
"‌​m-full-action-type_s‌​",
"m-event-action-de‌​scriptor_s"
]}
}
So you have: response > data > objectMatch > properties you want.
The response.data you are extracting on your handleSuccess function:
function handleSuccess(response) {
return response.data;
};
So here, your result is response.data, containing the property objectMatch.
$scope.submit = function() {
var objectProperties = exportsStorageService.getSearchObjects($scope.selected.project.name, $scope.selected.search)
.then(function(result) {
...
},
...
If all of that is correct, you should be able to access the values you want using result.objectMatch.<sort, direction or columns>, like:
exportsStorageService.runQuery($scope.selected.project.name, $scope.selected.start_date, $scope.selected.end_date,
result.objectMatch.sort, result.objectMatch.direction, result.objectMatch.columns)

Related

I have a problem with angular-ui typeahead component. It does not show values populated by angular resources, however using $http works well. I suppose I missing some trick here with asycn call and correct population of returned values.
Working code
$scope.searchForContact = function(val) {
return $http.get('/api/contacts/search', {
params: {
q: val
}
}).then(function(response){
return response.data.map(function(item){
return item.name;
});
});
};
Not working code
$scope.searchForContact = function(val) {
return Contact.search({q: val}, function(response){
return response.map(function(item){
return item.name;
});
});
});
...
'use strict';
app.factory("Contact", function($resource, $http) {
var resource = $resource("/api/contacts/:id", { id: "#_id" },
{
'create': { method: 'POST' },
'index': { method: 'GET', isArray: true },
'search': { method: 'GET', isArray: true, url: '/api/contacts/search', params: true },
'show': { method: 'GET', isArray: false },
'update': { method: 'PUT' },
'destroy': { method: 'DELETE' }
}
);
return resource;
});
Pug template code
input.form-control(
type='text'
ng-model='asyncSelected'
uib-typeahead='contact for contact in searchForContact($viewValue)'
typeahead-loading='loadingLocations'
typeahead-no-results='noResults'
)
i.glyphicon.glyphicon-refresh(ng-show='loadingLocations')
div(ng-show='noResults')
i.glyphicon.glyphicon-remove
|
|No Results Found
Angular resources are working fine, including search endpoint - I just output on page result returned by the search endpoint. In both results should be just an array with string values. What am I doing wrong?

The difference between $http.get and your Contact.search is that the first one returns a promise and the latter doesn't. Any $resource method will usually be resolved to the actual response. I'll show that with an example.
Getting data with $http
var httpResult = $http.get('http://some.url/someResource').then(function(response) {
return response.map(function(item) { return item.name });
});
The httpResult object contains a promise, so we need to use then method to get the actual data. Moreover, the promise will be resolved to the mapped array, which is the expected result.
Getting data with $resource
var someResource = $resource('http://some.url/someResource');
var resourceResult = someResource.query(function(response) {
return response.map(function(item) { return item.name });
});
The resourceResult isn't a promise here. It's a $resource object which will contain the actual data after the response comes from the server (in short, resourceResult will be the array of contacts - the original, not mapped, even though there is a map function). However, the $resource object contains a $promise property which is a promise similar to one returned by $http.get. It might be useful in this case.
Solution
I read in documentation that in order to make uib-typehead work properly, the $scope.searchForContact needs to return a promise. Instead of passing the callback function to search, I would simply chain it with the $promise from $resource object to make it work.
$scope.searchForContact = function(val) {
return Contact.search({q: val}).$promise.then(function(response){
return response.map(function(item){
return item.name;
});
});
});
Let me know if it works for you.

I need to retrieve a value from an async service to add as a parameter to every rest call. The casService.getProxyTicket() is an $http call...
I have the following code :-
myFactories.factory('myFactory', [
'Restangular'
, 'casService'
, function (Restangular
, casService) {
return Restangular.withConfig(function (config) {
config.setBaseUrl('https://host:port/somecontext/rest');
config.addFullRequestInterceptor(function (element
, operation
, route
, url
, headers
, params
, httpConfig) {
... What do I need to do here?
casService.getProxyTicket(url).then(function(st){
console.log('proxyTicket = ' + st.data.ticket);
});
params.ticket = ?????? <= st.data.ticket
...
return {
element: element
, headers: headers
, params: params
, httpConfig: httpConfig
}
});
}).service('myCollection');
}]
);
...thanks in advance!!!!

Ok, my lack of understanding coming from a backend developer's background...
This can/should NOT be done this way! I was trying to make the call to get a proxy ticket synchronous.... DON'T DO IT!
What I did was to rearrange my code thus ...
function readItem(id) {
var endpoint = myFactory.one(id);
return casService.getProxyTicket(endpoint.getRestangularUrl())
.then(function (response) {
return endpoint.get({ticket: response.data.proxyTicket});
}).then(function (response) {
return response.plain();
});
}
...works like a charm!

I've been trying to make a request to a NodeJS API. For the client, I am using the Mithril framework. I used their first example to make the request and obtain data:
var Model = {
getAll: function() {
return m.request({method: "GET", url: "http://localhost:3000/store/all"});
}
};
var Component = {
controller: function() {
var stores = Model.getAll();
alert(stores); // The alert box shows exactly this: function (){return arguments.length&&(a=arguments[0]),a}
alert(stores()); // Alert box: undefined
},
view: function(controller) {
...
}
};
After running this I noticed through Chrome Developer Tools that the API is responding correctly with the following:
[{"name":"Mike"},{"name":"Zeza"}]
I can't find a way to obtain this data into the controller. They mentioned that using this method, the var may hold undefined until the request is completed, so I followed the next example by adding:
var stores = m.prop([]);
Before the model and changing the request to:
return m.request({method: "GET", url: "http://localhost:3000/store/all"}).then(stores);
I might be doing something wrong because I get the same result.
The objective is to get the data from the response and send it to the view to iterate.

Explanation:
m.request is a function, m.request.then() too, that is why "store" value is:
"function (){return arguments.length&&(a=arguments[0]),a}"
"stores()" is undefined, because you do an async ajax request, so you cannot get the result immediately, need to wait a bit. If you try to run "stores()" after some delay, your data will be there. That is why you basically need promises("then" feature). Function that is passed as a parameter of "then(param)" is executed when response is ready.
Working sample:
You can start playing with this sample, and implement what you need:
var Model = {
getAll: function() {
return m.request({method: "GET", url: "http://www.w3schools.com/angular/customers.php"});
}
};
var Component = {
controller: function() {
var records = Model.getAll();
return {
records: records
}
},
view: function(ctrl) {
return m("div", [
ctrl.records().records.map(function(record) {
return m("div", record.Name);
})
]);
}
};
m.mount(document.body, Component);
If you have more questions, feel free to ask here.

I've come across this issue before with nested directives, but I managed to find a workaround there. I have code that looks a bit like,
var token = API.callGeneric({}, {method: 'kds.getTokenExtended2', params: ['demo', 'demo', '', '', '', '', '', false, '', '']}); //kds.
token.$promise
.then(function (result) {
if (!angular.isUndefined(result.error)) { // API error
$scope.msg = {iconClass: 'glyphicon-exclamation-sign', txt: 'Looks like there was a problem.'}
if (!APIErr.handle(result.error)) { // handle also returns continueExec flags
return;
}
}
$scope.msg = {iconClass: 'glyphicon-cloud-download', txt: 'almost there…'};
$scope.token = result.result;
console.log('result', result.result);
}, function (error) { // server error
$scope.msg = {iconClass: 'glyphicon-exclamation-sign', txt: 'issues with server, summoning the gods'}
APIErr.handle(error);
})
.then(function (result) {
$scope.msg = {}; // clear the message
// another api call to get bills
return API.callGeneric({}, {method: 'kds.getKitchenDisplayReceipts', params: [$scope.token, new Date().getTime()]});
}, APIErr.handle)
.then(function (result) {
console.log(result); // can see result.result.openReceipts
var receiptIds = result.result.openReceipts; // undefined?
}, APIErr.handle);
And API is a service that calls the API, obviously.
The problem is the last few lines, where console.log(result) shows result.result.openReceipts, and obviously result is a Resource object.
I'm stumped about what might be going on here. Any clues? How can I avoid this in future?

If you want to nest promises you need to return a promise every time.
Your second then is unnecessary in my opinion and could be done inside the first one as the first one is not returning any promises.
So it could be something like:
Pseudo-code:
API.call('token').then(function(result) {
...
return API.call('displayreceipts');
})
.then(function(result){
var recieptIds = result.result.openReceipts;
})
Let me know if it works.

I'm using jquery.couchdb.js to query my CouchDB database. The view I want to query has both map and reduce functions within. When sending the basic query as shown below:
$(document).ready(function() {
view_name = db_name+'/jobs_by_mod_stat'
options = {'group': 'true' , 'reduce': 'true' };
mod_stat = {};
$db.view(view_name , {
success: function(data) {
console.log(data)
for (i in data.rows) {
console.log(data.rows[i].value);
}
},
error: function(e) {
alert('Error loading from database: ' + e);
}
});
});
I see a sensible log for the data, indicating the query has been successful. However, changing the line:
$db.view(view_name , {
To
$db.view(view_name , options, {
I don't get a success outcome from the Ajax query, but an error message is not shown either. Firebug shows the query being sent, and the JSON data returned looks sensible:
{"rows":[
{"key":["template","completed"],"value":2},
{"key":["template","running"],"value":2},
{"key":["template","waiting"],"value":6}
]}
But the success function is not entered. Any ideas why I'm seeing this behaviour, I did wonder if it's a bug in jquery.couch.js (I have couchdb 1.1.0).
Cheers.

I've had a bit of trouble myself with the list function, until I went and looked through the source code of jquery.couch.js (the online documentation I found at http://bradley-holt.com/2011/07/couchdb-jquery-plugin-reference/ seems to be outdated).
Basically, the parameters for view and list are different, the list having an extra parameter for the options, instead of having everything under the same parameter as with views.
View:
$.couch.db('yourdb').view('couchapp/' + viewName, {
keys: ['keys here'],
success: function (data) {
}
});
List:
$.couch.db('yourdb').list('couchapp/' + listName, viewName, {
keys: ['keys here']
}, {
success: function (data) {
}
});