Inject service in app.config

问题:

I want to inject a service into app.config, so that data can be retrieved before the controller is called. I tried it like this:

Service:

app.service(\'dbService\', function() {
    return {
        getData: function($q, $http) {
            var defer = $q.defer();
            $http.get(\'db.php/score/getData\').success(function(data) {
                defer.resolve(data);            
            });
            return defer.promise;
        }
    };
});

Config:

app.config(function ($routeProvider, dbService) {
    $routeProvider
        .when(\'/\',
        {
            templateUrl: \"partials/editor.html\",
            controller: \"AppCtrl\",
            resolve: {
                data: dbService.getData(),
            }
        })
});

But I get this error:

Error: Unknown provider: dbService from EditorApp

How to correct setup and inject this service?

回答1:

Alex provided the correct reason for not being able to do what you\'re trying to do, so +1. But you are encountering this issue because you\'re not quite using resolves how they\'re designed.

resolve takes either the string of a service or a function returning a value to be injected. Since you\'re doing the latter, you need to pass in an actual function:

resolve: {
  data: function (dbService) {
    return dbService.getData();
  }
}

When the framework goes to resolve data, it will inject the dbService into the function so you can freely use it. You don\'t need to inject into the config block at all to accomplish this.

Bon appetit!

回答2:

Set up your service as a custom AngularJS Provider

Despite what the Accepted answer says, you actually CAN do what you were intending to do, but you need to set it up as a configurable provider, so that it\'s available as a service during the configuration phase.. First, change your Service to a provider as shown below. The key difference here is that after setting the value of defer, you set the defer.promise property to the promise object returned by $http.get:

Provider Service: (provider: service recipe)

app.provider(\'dbService\', function dbServiceProvider() {

  //the provider recipe for services require you specify a $get function
  this.$get= [\'dbhost\',function dbServiceFactory(dbhost){
     // return the factory as a provider
     // that is available during the configuration phase
     return new DbService(dbhost);  
  }]

});

function DbService(dbhost){
    var status;

    this.setUrl = function(url){
        dbhost = url;
    }

    this.getData = function($http) {
        return $http.get(dbhost+\'db.php/score/getData\')
            .success(function(data){
                 // handle any special stuff here, I would suggest the following:
                 status = \'ok\';
                 status.data = data;
             })
             .error(function(message){
                 status = \'error\';
                 status.message = message;
             })
             .then(function(){
                 // now we return an object with data or information about error 
                 // for special handling inside your application configuration
                 return status;
             })
    }    
}

Now, you have a configurable custom Provider, you just need to inject it. Key difference here being the missing \"Provider on your injectable\".

config:

app.config(function ($routeProvider) { 
    $routeProvider
        .when(\'/\', {
            templateUrl: \"partials/editor.html\",
            controller: \"AppCtrl\",
            resolve: {
                dbData: function(DbService, $http) {
                     /*
                     *dbServiceProvider returns a dbService instance to your app whenever
                     * needed, and this instance is setup internally with a promise, 
                     * so you don\'t need to worry about $q and all that
                     */
                    return DbService(\'http://dbhost.com\').getData();
                }
            }
        })
});

use resolved data in your appCtrl

app.controller(\'appCtrl\',function(dbData, DbService){
     $scope.dbData = dbData;

     // You can also create and use another instance of the dbService here...
     // to do whatever you programmed it to do, by adding functions inside the 
     // constructor DbService(), the following assumes you added 
     // a rmUser(userObj) function in the factory
     $scope.removeDbUser = function(user){
         DbService.rmUser(user);
     }

})

Possible Alternatives

The following alternative is a similar approach, but allows definition to occur within the .config, encapsulating the service to within the specific module in the context of your app. Choose the method that right for you. Also see below for notes on a 3rd alternative and helpful links to help you get the hang of all these things

app.config(function($routeProvider, $provide) {
    $provide.service(\'dbService\',function(){})
    //set up your service inside the module\'s config.

    $routeProvider
        .when(\'/\', {
            templateUrl: \"partials/editor.html\",
            controller: \"AppCtrl\",
            resolve: {
                data: 
            }
        })
});

A few helpful Resources

• John Lindquist has an excellent 5 minute explanation and demonstration of this at egghead.io, and it\'s one of the free lessons! I basically modified his demonstration by making it $http specific in the context of this request
• View the AngularJS Developer guide on Providers
• There is also an excellent explanation about factory/service/provider at clevertech.biz.

The provider gives you a bit more configuration over the .service method, which makes it better as an application level provider, but you could also encapsulate this within the config object itself by injecting $provide into config like so:

回答3:

Short answer: you can\'t. AngularJS won\'t allow you to inject services into the config because it can\'t be sure they have been loaded correctly.

See this question and answer: AngularJS dependency injection of value inside of module.config

A module is a collection of configuration and run blocks which get applied to the application during the bootstrap process. In its simplest form the module consist of collection of two kinds of blocks:

Configuration blocks - get executed during the provider registrations and configuration phase. Only providers and constants can be injected into configuration blocks. This is to prevent accidental instantiation of services before they have been fully configured.

回答4:

I don\'t think you\'re supposed to be able to do this, but I have successfully injected a service into a config block. (AngularJS v1.0.7)

angular.module(\'dogmaService\', [])
    .factory(\'dogmaCacheBuster\', [
        function() {
            return function(path) {
                return path + \'?_=\' + Date.now();
            };
        }
    ]);

angular.module(\'touch\', [
        \'dogmaForm\',
        \'dogmaValidate\',
        \'dogmaPresentation\',
        \'dogmaController\',
        \'dogmaService\',
    ])
    .config([
        \'$routeProvider\',
        \'dogmaCacheBusterProvider\',
        function($routeProvider, cacheBuster) {
            var bust = cacheBuster.$get[0]();

            $routeProvider
                .when(\'/\', {
                    templateUrl: bust(\'touch/customer\'),
                    controller: \'CustomerCtrl\'
                })
                .when(\'/screen2\', {
                    templateUrl: bust(\'touch/screen2\'),
                    controller: \'Screen2Ctrl\'
                })
                .otherwise({
                    redirectTo: bust(\'/\')
                });
        }
    ]);

angular.module(\'dogmaController\', [])
    .controller(\'CustomerCtrl\', [
        \'$scope\',
        \'$http\',
        \'$location\',
        \'dogmaCacheBuster\',
        function($scope, $http, $location, cacheBuster) {

            $scope.submit = function() {
                $.ajax({
                    url: cacheBuster(\'/customers\'),  //server script to process data
                    type: \'POST\',
                    //Ajax events
                    // Form data
                    data: formData,
                    //Options to tell JQuery not to process data or worry about content-type
                    cache: false,
                    contentType: false,
                    processData: false,
                    success: function() {
                        $location
                            .path(\'/screen2\');

                        $scope.$$phase || $scope.$apply();
                    }
                });
            };
        }
    ]);

回答5:

** Explicitly request services from other modules using angular.injector **

Just to elaborate on kim3er\'s answer, you can provide services, factories, etc without changing them to providers, as long as they are included in other modules...

However, I\'m not sure if the *Provider (which is made internally by angular after it processes a service, or factory) will always be available (it may depend on what else loaded first), as angular lazily loads modules.

Note that if you want to re-inject the values that they should be treated as constants.

Here\'s a more explicit, and probably more reliable way to do it + a working plunker

var base = angular.module(\'myAppBaseModule\', [])
base.factory(\'Foo\', function() { 
  console.log(\"Foo\");
  var Foo = function(name) { this.name = name; };
  Foo.prototype.hello = function() {
    return \"Hello from factory instance \" + this.name;
  }
  return Foo;
})
base.service(\'serviceFoo\', function() {
  this.hello = function() {
    return \"Service says hello\";
  }
  return this;
});

var app = angular.module(\'appModule\', []);
app.config(function($provide) {
  var base = angular.injector([\'myAppBaseModule\']);
  $provide.constant(\'Foo\', base.get(\'Foo\'));
  $provide.constant(\'serviceFoo\', base.get(\'serviceFoo\'));
});
app.controller(\'appCtrl\', function($scope, Foo, serviceFoo) {
  $scope.appHello = (new Foo(\"app\")).hello();
  $scope.serviceHello = serviceFoo.hello();
});

回答6:

You can use $inject service to inject a service in you config

app.config(function($provide){

    $provide.decorator(\"$exceptionHandler\", function($delegate, $injector){
        return function(exception, cause){
            var $rootScope = $injector.get(\"$rootScope\");
            $rootScope.addError({message:\"Exception\", reason:exception});
            $delegate(exception, cause);
        };
    });

});

Source: http://odetocode.com/blogs/scott/archive/2014/04/21/better-error-handling-in-angularjs.aspx

回答7:

Using $injector to call service methods in config

I had a similar issue and resolved it by using the $injector service as shown above. I tried injecting the service directly but ended up with a circular dependency on $http. The service displays a modal with the error and I am using ui-bootstrap modal which also has a dependency on $https.

    $httpProvider.interceptors.push(function($injector) {
    return {
        \"responseError\": function(response) {

            console.log(\"Error Response status: \" + response.status);

            if (response.status === 0) {
                var myService= $injector.get(\"myService\");
                myService.showError(\"An unexpected error occurred. Please refresh the page.\")
            }
        }
    }

回答8:

A solution very easy to do it

Note : it\'s only for an asynchrone call, because service isn\'t initialized on config execution.

You can use run() method. Example :

1. Your service is called \"MyService\"
2. You want to use it for an asynchrone execution on a provider \"MyProvider\"

Your code :

(function () { //To isolate code TO NEVER HAVE A GLOBAL VARIABLE!

    //Store your service into an internal variable
    //It\'s an internal variable because you have wrapped this code with a (function () { --- })();
    var theServiceToInject = null;

    //Declare your application
    var myApp = angular.module(\"MyApplication\", []);

    //Set configuration
    myApp.config([\'MyProvider\', function (MyProvider) {
        MyProvider.callMyMethod(function () {
            theServiceToInject.methodOnService();
        });
    }]);

    //When application is initialized inject your service
    myApp.run([\'MyService\', function (MyService) {
        theServiceToInject = MyService;
    }]);
});

回答9:

Easiest way: $injector = angular.element(document.body).injector()

Then use that to run invoke() or get()

回答10:

Well, I struggled a little with this one, but I actually did it.

I don\'t know if the answers are outdated because of some change in angular, but you can do it this way:

This is your service:

.factory(\'beerRetrievalService\', function ($http, $q, $log) {
  return {
    getRandomBeer: function() {
      var deferred = $q.defer();
      var beer = {};

      $http.post(\'beer-detail\', {})
      .then(function(response) {
        beer.beerDetail = response.data;
      },
      function(err) {
        $log.error(\'Error getting random beer\', err);
        deferred.reject({});
      });

      return deferred.promise;
    }
  };
 });

And this is the config

.when(\'/beer-detail\', {
  templateUrl : \'/beer-detail\',
  controller  : \'productDetailController\',

  resolve: {
    beer: function(beerRetrievalService) {
      return beerRetrievalService.getRandomBeer();
    }
  }
})