AngularJS : factory to return data from a php service using $http

Question

I'm newbie to js and this is my first question in stackoverflow as well. So any comment or act of downgrading is understandable.

This is the angular-js-flowchart project on github. This is another stackoverflow topic that teachs how to use factory as a data getter involving $http.

My need is to generate data for the chart by using an Angular factory that returns a $http function. The $http talks to a php service that retrieve data from database. I have tested the service using jsonlint and its working fine. The directory of service is checked, relatively to the html file.

I copied the "factory" code from another stackoverflow question and applied to app.js in the angularjs-flowchart Github project.

The problem is that the Chrome console keeps throwing an error that I can not understand. Data is not retrieved. The error on console is "TypeError: Cannot read property 'getData' of undefined"

This is the modified-by-me app.js:

//
// Define the 'app' module.
//
angular.module('app', ['flowChart', ])

//
// Simple service to create a prompt.
//
.factory('prompt', function () {

    /* Uncomment the following to test that the prompt service is working as expected.
    return function () {
        return "Test!";
    }
    */

    // Return the browsers prompt function.
    return prompt;
})

//
// Application controller.
//
.controller('AppCtrl', ['$scope', 'prompt', function AppCtrl ($scope, prompt, dataFactory) {

    //
    // Code for the delete key.
    //
    var deleteKeyCode = 46;

    //
    // Code for control key.
    //
    var ctrlKeyCode = 65;

    //
    // Set to true when the ctrl key is down.
    //
    var ctrlDown = false;

    //
    // Code for A key.
    //
    var aKeyCode = 17;

    //
    // Code for esc key.
    //
    var escKeyCode = 27;

    //
    // Selects the next node id.
    //
    var nextNodeID = 10;


    //
    // Event handler for key-down on the flowchart.
    //
    $scope.keyDown = function (evt) {

        if (evt.keyCode === ctrlKeyCode) {

            ctrlDown = true;
            evt.stopPropagation();
            evt.preventDefault();
        }
    };

    //
    // Event handler for key-up on the flowchart.
    //
    $scope.keyUp = function (evt) {

        if (evt.keyCode === deleteKeyCode) {
            //
            // Delete key.
            //
            $scope.chartViewModel.deleteSelected();
        }

        if (evt.keyCode == aKeyCode && ctrlDown) {
            // 
            // Ctrl + A
            //
            $scope.chartViewModel.selectAll();
        }

        if (evt.keyCode == escKeyCode) {
            // Escape.
            $scope.chartViewModel.deselectAll();
        }

        if (evt.keyCode === ctrlKeyCode) {
            ctrlDown = false;

            evt.stopPropagation();
            evt.preventDefault();
        }
    };

    //
    // Add a new node to the chart.
    //
    $scope.addNewNode = function () {

        var nodeName = prompt("Enter a task name:", "New Task");
        if (!nodeName) {
            return;
        }

        //
        // Template for a new node.
        //
        var newNodeDataModel = {
            name: nodeName,
            id: nextNodeID++,
            x: 0,
            y: 0,
            inputConnectors: [ 
                {
                    name: "Pre"
                }           
            ],
            outputConnectors: [ 
                {
                    name: "Sub"
                }           
            ],
        };

        $scope.chartViewModel.addNode(newNodeDataModel);
    };

    //
    // Add an input connector to selected nodes.
    //
    $scope.addNewInputConnector = function () {
        var connectorName = prompt("Enter a connector name:", "New connector");
        if (!connectorName) {
            return;
        }

        var selectedNodes = $scope.chartViewModel.getSelectedNodes();
        for (var i = 0; i < selectedNodes.length; ++i) {
            var node = selectedNodes[i];
            node.addInputConnector({
                name: connectorName,
            });
        }
    };

    //
    // Add an output connector to selected nodes.
    //
    $scope.addNewOutputConnector = function () {
        var connectorName = prompt("Enter a connector name:", "New connector");
        if (!connectorName) {
            return;
        }

        var selectedNodes = $scope.chartViewModel.getSelectedNodes();
        for (var i = 0; i < selectedNodes.length; ++i) {
            var node = selectedNodes[i];
            node.addOutputConnector({
                name: connectorName,
            });
        }
    };

    //
    // Delete selected nodes and connections.
    //
    $scope.deleteSelected = function () {

        $scope.chartViewModel.deleteSelected();
    };


    //
    // Setup the data-model for the chart.
    //
    var chartDataModel = {};
    var handleSuccess = function(data, status){
        chartDataModel = data;
        console.log(chartDataModel);
    };

    dataFactory.getData().success(handleSuccess);

    //
    // Create the view-model for the chart and attach to the scope.
    //
    $scope.chartViewModel = new flowchart.ChartViewModel(chartDataModel);
}])
.factory('dataFactory', function($http){
    return {
        getData : function(){
            return $http.post("chart-data-retrieve.php");
        }
    };

});

Basically, what i added but doesn't work is

// Setup the data-model for the chart.
//
var chartDataModel = {};
var handleSuccess = function(data, status){
    chartDataModel = data;
    console.log(chartDataModel);
};

dataFactory.getData().success(handleSuccess);

and

.factory('dataFactory', function($http){
    return {
        getData : function(){
            return $http.post("chart-data-retrieve.php");
        }
    };

});

Please help, thanks.

locnguyen · Accepted Answer · 2014-06-26 03:52:34Z

2

I tried to set the chartViewModel of the $scope directly inside the service call, so the variable chartDataModel becomes redundant. And it works.

// Create the view-model for the chart and attach to the scope.
//
myService.then(function(data) {
    $scope.chartViewModel = new flowchart.ChartViewModel(data);
});

answered Jun 26, 2014 at 3:52

locnguyen

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locnguyen · Accepted Answer · 2014-06-26 01:15:57Z

I tried to return a promise, not a $http from the factory. It works now. The controller can now use the service to retrieve data. However I still could not set the controller's variable to the data retrieved. The following is the code:

.factory('myService', function($http, $q) {
  //this runs the first time the service is injected
  //this creates the service
  var deferred = $q.defer();

  $http.get('chart-data-retrieve.php').then(function(resp) {
    deferred.resolve(resp.data);
  });

  return deferred.promise;
})

And the code inside controller:

var chartDataModel = {};
//get data from myService factory
myService.then(function(data) {
    alert(data);
    chartDataModel = data;
});

Currently, the alert() show me the data already. However, the variable chartDataModel is still unset.

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