Automatic Code Generation: OAuth2.0 Authentication

This SDK has been generated through APIMatic's automatic code generation engine. I've worked extensively on this code generation engine during my time as a software engineer at APIMatic (I've worked on JavaScript SDK Generation). This SDK has been generated for Dropbox's API v2. It is just a sample SDK, generated for demo purposes. Therefore, it allows consumption of 1 endpoint only.

Dropbox API uses OAuth2.0 for authentication purposes. And this generated SDK has built-in support for handling the OAuth2 authentication flow. For this demo, Implicit Grant is being used. But there's support for the following grant types as well:

• Authentication Code Grant
• Resource Owner Password Grant
• Client Credentials Grant

For this demo, the item of interest is the OAuthManager.js file. It is an OAuth2.0 client which exposes methods to obtain & refresh access tokens. It takes care of all the technical details internally. You just have to call the retrieveAndSetAccessToken method to obtain an access token. And after authentication, API calls can be made. I wrote the implementation for this client from scratch.

I have already written the code to obtain an access token and make an API call (to show a demo). You can simply open up the index.html file, open up the console in the browser. And watch the magic happen! :D

Please take a look at app.js as well if you want to understand how this is working. Be sure to change the configuration (to add in the clientId and redirectURI) according to your Dropbox app.

Note: All the automatically generated code is in the ./scripts/DropboxLib/ folder.

Note: This code is not confidential. You can generate an SDK for any API too, you will require an API description file to do so.

The documentation below is also automatically generated with the SDK.

Getting started

Sample App for testing OAuth2.0 flow with Dropbox API v2

How to Build

The generated SDK requires AngularJS framework to work. If you do not already have angular downloaded, please go ahead and do it from here. You will also need to download and link angular-moment and moment.js with your project because the SDK internally uses moment.js.

How to Use

The following section describes how to use the generated SDK in an existing/new project.

1. Configure Angular and Generated SDK

Perform the following steps to configure angular and the SDK:

• Make a scripts folder inside the root folder of the project. If you already have a scripts folder, skip to the next step.
• Move the angular.min.js file inside the scripts folder.
• Move the DropboxLib folder inside the scripts folder.
• If any of the Custom Types in your API have Date/Datetime type fields or any endpoint has Date/Datetime response, you will need to download angular-moment and moment.js. Move these 2 files into the scripts folder as well.

2. Open Project Folder

Open an IDE/Text Editor for JavaScript like Sublime Text. The basic workflow presented here is also applicable if you prefer using a different editor or IDE.
Click on File and select Open Folder

Select the folder of your SDK and click on Select Folder to open it up in Sublime Text. The folder will become visible in the bar on the left.

3. Create an Angular Application

Since Angular JS is used for client-side web development, in order to use the generated library, you will have to develop an application first. If you already have an angular application, skip to Step 6. Otherwise, follow these steps to create one:

• In the IDE, click on File and choose New File to create a new file.
• Add the following starting code in the file:

var app = angular.module('myApp', []);
app.controller('testController', function($scope) 
{

});

• Save it with the name app.js in the scripts folder.

4. Create HTML File

Skip to the next step if you are working with an existing project and already have an html file. Otherwise follow the steps to create one:

• Inside the IDE, right click on the project folder name and select the New File option to create a new test file.
• Save it with an appropriate name such as index.html in the root of your project folder. index.html should look like this:

<!DOCTYPE html>
<html>
<head>
	<title>Angular Project</title>
	<script></script>
</head>

<body>
</body>

</html>

5. Including links to Angular in HTML file

Your HTML file needs to have a link to angular.min.js file to use Angular-JS. Add the link using script tags inside the head section of index.html like:

<script src="scripts/angular.min.js" ></script>

If any of the Custom Types that you have defined have Date/Datetime type fields or any endpoint has Date/Datetime response, you will also need to link to angular-moment and moment.js like:

<script src="scripts/angular.min.js" ></script>
<script src="scripts/moment.min.js" ></script>
<script src="scripts/angular-moment.min.js" ></script>

6. Include SDK references in HTML file

Import the reference to the generated SDK files inside your html file like:

<head>
    ...
    <!-- Helper files -->
    <script src="scripts/DropboxLib/Module.js"></script>
    <script src="scripts/DropboxLib/Configuration.js"></script>
    <script src="scripts/DropboxLib/ModelFactory.js"></script>
    <script src="scripts/DropboxLib/ObjectMapper.js"></script>
    <script src="scripts/DropboxLib/APIHelper.js"></script>
    <script src="scripts/DropboxLib/OAuthManager.js"></script>
    <script src="scripts/DropboxLib/Http/Client/HttpContext.js"></script>
    <script src="scripts/DropboxLib/Http/Client/HttpClient.js"></script>
    <script src="scripts/DropboxLib/Http/Request/HttpRequest.js"></script>
    <script src="scripts/DropboxLib/Http/Response/HttpResponse.js"></script>

    <!-- API Controllers -->
    <script src="scripts/DropboxLib/Controllers/BaseController.js"></script>
    <script src="scripts/DropboxLib/Controllers/AccountController.js"></script>


    <!-- Models -->
    <script src="scripts/DropboxLib/Models/BaseModel.js"></script>
    <script src="scripts/DropboxLib/Models/Account.js"></script>
    <script src="scripts/DropboxLib/Models/OAuthToken.js"></script>
    <script src="scripts/DropboxLib/Models/OAuthProviderErrorEnum.js"></script>
    <script src="scripts/DropboxLib/Models/OAuthToken.js"></script>
    <script src="scripts/DropboxLib/Models/OAuthProviderErrorEnum.js"></script>

    ...
</head>

The Module.js file should be imported before the other files. After Module.js, Configuration.js should be imported. The ModelFactory.js file is needed by ObjectMapper.js file. The ObjectMapper in turn, is needed by BaseController.js.

7. Including link to app.js in HTML file

Link your app.js file to your index.html file like:

<head>
	...
	<script src="scripts/app.js"></script>
</head>

The link to app.js needs to be included at the very end of the head tag, after the SDK references have been added

8. Initializing the Angular App

You need to initialize your app and the controller associated with your view inside your index.html file. Do so like:

• Add ng-app directive to initialize your app inside the body tag.

<body ng-app="myApp">

• Add ng-controller directive to initialize your controller and bind it with your view (index.html file).

...
<body ng-app="myApp">
	<div ng-controller="testController">
		...
	</div>
	...
</body>
...

9. Consuming the SDK

In order to use the generated SDK's modules, controllers and factories, the project needs to be added as a dependency in your angular app's module. This will be done inside the app.js file. Add the dependency like this:

var app = angular.module('myApp', ['DropboxLib']);

At this point, the SDK has been successfully included in your project. Further steps include using a service/factory from the generated SDK. To see working example of this, please head on over here and choose any class to see its functions and example usage.

10. Running The App

To run the app, simply open up the index.html file in a browser.

Initialization

The Angular Application can be initialized as following:

var app = angular.module('myApp', [DropboxLib]);
// now controllers/services can be created which import
// the factories provided by the sdk

Authentication

In order to setup authentication and initialization of the Angular App, you need the following information.

var app = angular.module('myApp', [DropboxLib]);

app.run(function(Configuration) {
    // Configuration parameters and credentials
    Configuration.oAuthClientId = 'oAuthClientId'; // OAuth 2 Client ID
    Configuration.oAuthRedirectUri = 'oAuthRedirectUri'; // OAuth 2 Redirection endpoint or Callback Uri
    
});

You must now authorize the client.

Authorizing your client

Your application must obtain user authorization before it can execute an endpoint call. The SDK uses OAuth 2.0 Implicit Grant to obtain a user's consent to perform an API request on user's behalf. The entire flow of building the authorization URL, obtaining consent from the user and storing the access token is handled by the SDK itself.

retrieveAndSetAccessToken() method will be called in order to obtain and set the access token in the Configuration.

Calling this method will open up the consent screen.

Consent screen and access token retrieval

Once the user responds to the consent request, the OAuth 2.0 server responds to your application's access request by redirecting the user to the redirect URI specified in Configuration.

The redirect URI will receive the access token as the token argument in the URL fragment. This is how it will look

https://example.com/oauth/callback#token=XXXXXXXXXXXXXXXXXXXXXXXXX

The access token must be extracted by client-side JavaScript code.

OAuthCallbackScript.js is the script which retrieves the access token and passes it as an event data to the window which actually opened up the consent screen. You can simply link this with a html file to handle access token retrieval.

<script src="OAuthCallbackScript.js"></script>

Complete Example

In order to set up the client side script which extracts the access token from the uri, perform the following steps:

• Link the OAuthCallbackScript.js to the html file which is served at the registered redirect_uri for the application.

For example, if the redirect_uri is http://localhost/callback.html, create callback.html in the root of the project folder. And add the following content:

callback.html

<!DOCTYPE html>
<html>

<head>
    <title>OAuthTest</title>

</head>


<body>
    <script src="scripts/OAuthCallbackScript.js"></script>
</body>

</html>

This will ensure that the access token which will be received at http://localhost/callback.html will be retrieved by the OAuthCallbackScript.js.

After setting up as above, here's how the Implicit Grant flow can be executed.

app.js

var app = angular.module('OAuthTest', ['DropboxLib']);

app.controller('oauthClientController', function($scope, OAuthManager) {
    var scopes = [];
    var promise = OAuthManager.retrieveAndSetAccessToken(scopes, '', true);
    promise.then(function(success) {
        // client successfully authorized
        // make API calls as required
    });
});

index.html

<!DOCTYPE html>
<html>

<head>
    <title>OAuthTest</title>
    <meta charset="UTF8">

    <script src="scripts/angular.min.js"></script>

    <script src="scripts/DropboxLib/Module.js"></script>
    <script src="scripts/DropboxLib/Configuration.js"></script>
    <script src="scripts/DropboxLib/ModelFactory.js"></script>
    <script src="scripts/DropboxLib/ObjectMapper.js"></script>
    <script src="scripts/DropboxLib/APIHelper.js"></script>
    <script src="scripts/DropboxLib/Servers.js"></script>
    <script src="scripts/DropboxLib/Environments.js"></script>
    <script src="scripts/DropboxLib/Http/Client/HttpContext.js"></script>
    <script src="scripts/DropboxLib/Http/Request/HttpRequest.js"></script>
    <script src="scripts/DropboxLib/Http/Response/HttpResponse.js"></script>
    <script src="scripts/DropboxLib/Http/Client/HttpClient.js"></script>

    <!-- API Controllers -->
    <script src="scripts/DropboxLib/Controllers/BaseController.js"></script>
    <script src="scripts/DropboxLib/Controllers/AccountController.js"></script>


    <!-- Models -->
    <script src="scripts/DropboxLib/Models/BaseModel.js"></script>
    <script src="scripts/DropboxLib/Models/Account.js"></script>
    <script src="scripts/DropboxLib/Models/OAuthToken.js"></script>
    <script src="scripts/DropboxLib/Models/OAuthProviderErrorEnum.js"></script>
    <script src="scripts/DropboxLib/Models/OAuthToken.js"></script>
    <script src="scripts/DropboxLib/Models/OAuthProviderErrorEnum.js"></script>


    <script src="scripts/DropboxLib/OAuthManager.js"></script>
    <script src="scripts/app.js"></script>

</head>


<body ng-app="OAuthTest">
    <div ng-controller="oauthClientController">

    </div>
</body>

</html>

Class Reference

List of Controllers

• AccountController

AccountController

Get singleton instance

The singleton instance of the AccountController class can be accessed via Dependency Injection.

	app.controller("testController", function($scope, AccountController, Account){
	});

getAccountInfo

TODO: Add a method description

function getAccountInfo()

Example Usage

	app.controller("testController", function($scope, AccountController, Account){


		var result = AccountController.getAccountInfo();
        //Function call returns a promise
        result.then(function(success){
			//success case
			//getting context of response
			console.log(success.getContext());
		},function(err){
			//failure case
		});

	});

Back to List of Controllers