Factory - A factory is a simple function which allows you to add some logic before creating the object. It returns the created object.

When to use: It is just a collection of functions like a class. Hence, it can be instantiated in different controllers when you are using it with constructor function.

Service - A service is a constructor function which creates the object using new keyword. You can add properties and functions to a service object by using this keyword. Unlike factory, it doesn’t return anything.

When to use: It is a singleton object. Use it when you need to share a single object across the application.
For example, authenticated user details.

Provider - A provider is used to create a configurable service object. It returns value by using $get() function.

When to use: When you need to provide module-wise configuration for your service object before making it available.

$http service is a core Angular service which allows you to make AJAX requests by using GET, HEAD, POST, PUT, DELETE, JSONP and PATCH methods. It is very much like the $.ajax() method in jQuery. It can be used with RESTful and Non-RESTful server-side data sources.

$http is good for quick retrieval of server-side data that doesn’t really need any specific structure or complex behaviors.

$resource warps $http and allows you to interact with RESTful server-side data sources. It requires the ngResource module to be installed which exist in angular-resource.js

$http is good for retrieval of RESTful server-side data sources that might need any specific structure or complex behaviors.

The $http service supports the following methods:
1. $http.get()
2. $http.head()
3. $http.post()
4. $http.put()
5. $http.delete()
6. $http.jsonp()
7. $http.patch()

You can enable caching in $http service by setting configuration property cache to true. When cache is enabled, $http service stores the response from the server in local cache. In this way, next time the response will be served from the cache without sending request to server.
$http.get("http://server/myserviceapi",{ cache:true }).sucess(function(){ 

//TO DO: 

});

The $resource service object supports the following methods:
1. get()
2. query()
3. save()
4. remove()
5. delete()