Interactive documentation support helps users understand and experience the APIs. WSO2 API Manager provides this functionality by integrating Swagger. Swagger is a specification and a complete framework implementation for describing, producing, consuming, and visualizing RESTful Web services. In Swagger, when APIs are described in simple, static JSON representation, they can be loaded through the Swagger UI and made available as interactive documentation.
The idea of this interactive console is allowing users to test the APIs and get to know how they respond without subscribing to the APIs. When an API is created in the API Publisher, the JSON representation of that API is automatically generated and saved into the registry as an API definition. This API definition describes the API using the information provided at the time it is created. You can modify the API definition using the Doc tab in the management console. In API Store, Swagger UI discovers the API definition for each API and displays the interactive documentation under the API's Overview tab.
Explained below is how to get an interactive documentation for an API:
We use API named
FindFeeds, which is based on the online search functionality provided by Youtube (http://youtube.com/). We use http://gdata.youtube.com/feeds/api/standardfeeds as the Production Url/Endpoint.
Creating an API
- Log in to API Publisher Web interface (https://localhost:9443/publisher), and go to Add API page. Create a new API with following information.
- Name: PhoneVerification
- Context: /phoneverify
- Version: 1.0.0
- Choose to create a wildcard resource (/*)
- Endpoint type: HTTP
- Production Endpoint: http://ws.cdyne.com/phoneverify/phoneverify.asmx
- Tier availability: Bronze/Gold/Silver/Unlimited
- Transports: HTTP/HTTPS
- Define API resources for the operations you need to perform.
Specify None as the Auth Type of OPTIONS
For each of the resource that has HTTP verbs requiring Authentication (i.e., Auth Type is not NONE), enable OPTIONS with None Auth type. For example, as the following screen shot shows, resources with /* URL Pattern has HTTP verbs with Auth Type as
Application & Application User. Therefore, we must give None as the Auth Type of OPTIONS. This is to support CORS (Cross Origin Resource Sharing) between the API Store and Gateway. But, if no authentication is needed for any of the HTTP verbs, you don't have to specify None Auth type to OPTIONS.
Publish the API to the API Store.
When an API is created, the JSON representation of that API is automatically generated. To customize it, go to the Docs tab of the API in the API Publisher and click Edit Content.
Modify the paths, parameters, descriptions etc. by editing the JSON representation of API definition. For example, in the
PhoneVerificationAPI, we have changed the path for all the HTTP methods of API definition from
Invoking the interactive documentation
- Log in to the API Store Web interface (https://localhost:9443/store) and click the API published before.
- Subscribe to this API.
- The API opens. Go to the API Console tab to see the interactive documentation of the API.
Provide the necessary parameters and click Try it out to call the API. For example, the
PhoneVerificationAPI takes two parameters: the phone number and a license key, which is set to 0 for testing purposes.
Note the following in the above UI:
Base URL Appears at the bottom of the console. Using the base URL and the parameters, the system creates the API URL in the form
http://host:8280/<context>/<version>/<back end service requirements included as parameters>.For example,
Query Parameters Give the API payload as PhoneNumber=18006785432&LicenseKey=0 where /phoneverify is the context and 1.1.0 is the version. The rest of the URL is driven by the backend service requirements. Authorization In the authorization header, pass the application key that was generated at the time a user subscribes to an API. This is prefixed by the string "Bearer". For example, Bearer q6- JeSXxZDDzBnccK3ZZGf5_AZTk.
WSO2 API Manager enforces OAuth security on all the published APIs. Consumers who talk to the API Manager should send their credentials (application key) as per the OAuth bearer token profile. If you don't send an application key or send a wrong key, you will receive a 401 Unauthorized response in return.
- Note the response for the API invocation that appears as follows:
- Within a minute after the first API invocation, make another attempt to invoke the API and note that the second invocation results in a throttling error.
This is because you applied a Bronze tier at the time you subscribed to the API and the Bronze tier only allows one API call per minute.
Updating the API definition
The API creator can update/customize the automatically generated API definition for each API.
- In the API Publisher, go to the Doc tab of
FindFeedsAPI to see its API definition.
API definition contains the JSON representation of the API. You can easily modify existing content, add/remove elements, change paths and parameters etc. using the JSON editor.
- API Manager 1.5.0 onwards has integrated JSONMate as the editor for modifying the API Definition.
- For the Swagger specification of API declaration, see https://github.com/wordnik/swagger-core/wiki/API-Declaration.
By default, all the POST and PUT operations have the Payload parameter, which you can use to send any payload when invoking the API. The GET, DELETE operations have Query parameters, which you can use to send URL-appended parameters. You can also add named parameters.
For example, to modify the path of the API created above with a parameter, edit the path and add the relevant parameter.
To add new elements, click Add New Value and provide the value. To delete elements, delete the value of Key. For example, if you delete Key value description, that element will be deleted. The screenshot below shows path modified with a parameter.
The following screenshot shows parameter definition added for param and the default Payload parameter removed:
Also be sure to modify descriptions, notes, summary on each of the operations.
Once the modifications are done, save and Publish the API.
Log in to the API Store and click on GET operation to expand it. There you can enter the parameters and try it out.
Next, see API Versioning.