WSO2 API Manager is a complete solution for publishing APIs, creating and managing a developer community and for routing API traffic in a scalable manner. It leverages the integration, security and governance components from the WSO2 Enterprise Service Bus, WSO2 Identity Server, and WSO2 Governance Registry. In addition, as it is powered by the WSO2 Business Activity Monitor (BAM), the WSO2 API Manager is ready for massively scalable deployment immediately.
This guide walks you thorough the main usecases of the API Manager:
Introduction to basic concepts
Let's take a look at the basic concepts that you need to know before using the API Manager.
The API manager comprises the following components:
- API Gateway : Secures, protects, manages, and scales API calls. It is a simple API proxy that intercepts API requests and applies policies such as throttling and security checks. It is also instrumental in gathering API usage statistics. The Web interface can be accessed via
- API Key Manager : Handles all security and key-related operations. API gateway connects with the key manager to check the validity of OAuth tokens when APIs are invoked . Key Manager also provides a token API to generate Oauth tokens that can be accessed via the Gateway.
- API Publisher : Enables API providers to publish APIs, share documentation, provision API keys, and gather feedback on API features, quality and usage. The Web interface can be accessed via
- API Store : Enables API consumers to self register, discover API functionality, subscribe to APIs, evaluate them and interact with API publishers. The Web interface can be accessed via
- Additionally, statistics are provided by the monitoring component, which integrates with WSO2 BAM.
Users and roles
The API manager offers three distinct community roles that are applicable to most enterprises:
- Creator : a creator is a person in a technical role who understands the technical aspects of the API (interfaces, documentation, versions, how it is exposed by API Gateway) and uses the API publisher to provision APIs into the API store. The creator uses the API Store to consult ratings and feedback provided by API users. Creator can add APIs to the store but cannot manage their lifecycle (i.e., make them visible to the outside world).
- Publisher : a publisher manages a set of APIs across the enterprise or business unit and controls the API lifecycle and monetization aspects. The publisher is also interested in usage patterns for APIs and as such has access to all API statistics.
- Consumer : a consumer uses the API store to discover APIs, see the documentation and forums and rate/comment on the APIs. S/he subscribes to APIs to obtain API keys.
An API is the published interface, while the service is the implementation running in the backend. APIs have their own lifecycles that are independent to the backend services they rely on. This lifecycle is exposed in the API publisher Web interface and is managed by the API publisher role.
The following stages are available in the default API life cycle:
- CREATED : API metadata is added to the API Store, but it is not visible to subscribers yet, nor deployed to the API gateway
- PUBLISHED : API is visible in the API Store
- DEPRECATED : API is still deployed into the API Gateway (i.e., available at runtime to existing users) but not visible to subscribers. An API can automatically be deprecated when a new version is published.
- RETIRED : API is unpublished from the API gateway and deleted from the store
- BLOCKED : Access is temporarily blocked. Runtime calls are blocked and the API is not shown in the API Store anymore.
You can manage the API and service lifecycles in the same governance registry/repository and automatically link them. This feature is available in WSO2 Governance Registry (version 4.5 onwards).
An application is primarily used to decouple the consumer from the APIs. It allows you to :
- Generate and use a single key for multiple APIs
- Subscribe multiple times to a single API with different SLA levels
You create an application to subscribe to an API. The API Manager comes with a default application and you can also create as many applications as you like.
Throttling tiers are associated to an API at subscription time. They define the throttling limits enforced by the API gateway. E.g., 10 TPS (transactions per second). You define the list of tiers that are available for a given API at the publisher level. The API Manager comes with three predefined tiers (
Gold/Silver/Bronze) and a special tier called
Unlimited, which can be disabled by editing the <TierManagement>element of <PRODUCT_HOME>/repository/conf/api-manager.xml file. To edit existing tiers or create your own tiers, see Adding New Throttling Tiers.
The API Manager supports two scenarios for authentication:
- An access token is used to identify and authenticate a whole application
- An access token is used to identify the final user of an application (for example, the final user of a mobile application deployed on many different devices)
Application access token
Application access tokens are generated by the API consumer and must be passed in the incoming API requests. The API Manager uses OAuth2 standard to provide key management. The API key is a simple string that you pass to an HTTP header (e.g., "
Authorization: Bearer NtBQkXoKElu0H1a1fQ0DWfo6IX4a") and it works equally well for SOAP and REST calls.
Application access tokens are generated at the application level and valid for all APIs that are associated to the application. These tokens have a fixed expiration time, which is set to 60 minutes by default. You can change this to a longer time, even for several weeks. Consumers can re-generate the access token directly from the API Store Web interface. To change the default expiration time, you open
<APIM_HOME>/repository/conf/identity.xml file and change the value for element
<ApplicationAccessTokenDefaultValidityPeriod>. You set a negative value to
<ApplicationAccessTokenDefaultValidityPeriod> element to never expire the application access token.
Application user access token
You can generate access tokens on demand using the token API. In case a token expires, you use the token API to refresh it.
Application user access tokens have a fixed expiration time, which is 60 minutes by default. You can update it to a longer time, such as several weeks, by editing the
<AccessTokenDefaultValidityPeriod> element in
The token API takes the following parameters to generate the access token:
- Grant Type
To generate a new access token, you issue a token API call with the above parameters where grant_type=password. The Token API then returns two tokens: an access token and a refresh token. The access token can then be stored in a session on the client side (the application itself does not need to manage users and passwords). On the API Gateway side, the access token is validated for each API call. When the token expires, you refresh the token by issuing a token API call with the above parameters where grant_type=refresh_token and passing the refresh token as a parameter.
Starting the API Manager
- Download WSO2 API Manager from http://wso2.com/products/api-manager/.
- Install Oracle Java SE Development Kit (JDK) version 1.6.24 or later or 1.7.*.
- Set the JAVA_HOME environment variable.
- Using the command line, go to <Installation directory>/bin and execute wso2server.bat (for Windows) or wso2server.sh (for Linux).
- Wait until you see the message "WSO2 Carbon started in 'n' seconds."
It indicates that the server started successfully. To stop the API Manager, simply hit Ctrl-C in the command window.
Creating users and roles
In section , we introduced you to a set of users that are commonly found in many enterprises. To create these users in the API Manager, you log in to the management console as an administration user (credentials: admin/admin). The admin use can play the creator, publisher and subscriber roles described earlier. In this section, we explain how to set up these users or custom users and roles.
Log in to the management console user interface (
https://<hostname>:9443/carbon) of the API Manager using admin/admin credentials.
- Select the Users and Roles menu under the Configure menu.
- Click Add New Role and provide
creatoras the role name.
- Click Next.
- Select the following permissions from the list that opens and click Finish.
- Manage > API > Create
- Manage > Resources > Govern and all underlying permissions
Similarly, create the
publisherrole with the following permissions.
- Manage > API > Publish
- You can now create users for each of those roles. To do so, click the Users and Roles menu under the Configure menu.
- Click Users.
- Click Add New User, provide the username/password and click Next.
Select the role you want to assign to the user (e.g.,
subscriber) and click Finish. Given below is a list of usernames and the roles we assign to them in this guide.
Username Role apicreator creator apipublisher publisher
Repeat the steps to create at least one user for all roles.
Creating an API
An API creator uses the API provider Web application to create and publish APIs into the API Store. In this section, we explain how to create an API and attach documentation to it.
In this guide, we work with a service exposed by the Cdyne services provider (www.wdyne.com). We use their phone validation service, which has SOAP and REST interfaces and is documented using a WSDL file. This service is documented at : http://wiki.cdyne.com/index.php/Phone_Verification.
Let's create this API and add it to the API Store.
- Open the API Publisher (
https://<hostname>:9443/publisher) and log in as
Click the Add link and provide the mandatory information, as described in the table below, to your API.
Field Value Description NamePhoneVerificationName of API as you want it to appear in the APIstoreContext/phoneverifyURI context path that is used by to API consumers Version 1.0.0 API version (in the form of version.major.minor) Tier Availability Bronze/Gold/Silver/Unlimited The API can be available at different level of service; you can select multiple entries from the list. At subscription time, the consumer chooses which tier they are interested in. Transports Select HTTP/HTTPSEndpoint Security SchemeNon-Secured/SecuredIf the back-end service is a secured service, select 'Secured' and enter the credentials for secured service in appearing text boxes. Else keep as Non-Secured. Endpoint Type SelectEndpoint Type. E.g., High available and load balanced endpoints Production Endpoint URLEndpoint of the back-end service URL, here: Sandbox Endpoint URLEndpoint of sandbox (testing) back end service. A sandbox URL is meant to be used for online testing of an API with easy access to an API key. WSDL URLURL of WSDL file (describing API interface) http://ws.cdyne.com/phoneverify/phoneverify.asmx?wsdl WADL URL URL to WADL file (describing API interface)
Adding API resources
An API is made up of one or more resources. Each resource handles a particular type of requests. A resource is analogous to a method (function) in a larger API.
API resources accept following attributes:
- Verbs: HTTP verbs a particular resource accepts. Allowed values are GET, POST, PUT, DELETE. Multiple values can be specified.
- URL pattern: URI template as defined in http://tools.ietf.org/html/rfc6570. E.g.,
- Auth type: Resource level authentication along HTTP verbs. Can be one of the following:
- None : Can access the API resource without any access tokens
- Application: Application access token is required to access the API resource
- Application User: User access token is required to access the API resource
Once a request is accepted by a resource, it is mediated through an in-sequence. Any response from the backend is handled through the out-sequence. Fault sequences are used to mediate errors that might occur in either in or our sequences. Default in-sequence, out-sequence and fault sequence are generated when the API is published.
Adding API documentation
After creating the API, click on its icon to open its details. Select the Docs tab.
Click Add New Document link.Documentation can be provided inline, via a URL or as a file. For inline documentation, you can edit the content directly from the API publisher interface. You get several documents types:
- Swagger documents
- How To
- Samples and SDK
- Public forum / Support forum (external link only)
- API message formats
- Select the How To type, a name for the document and a short description, which will appear in the API Store. Select inline or provide a URL.
- Click Add Document.
Once the document is added, click Edit Content link, which opens an embedded editor to edit the document contents.
Adding interactive documentation using Swagger
The API Manager provides facility to add interactive documentation support through the integration of 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, which in turn provides the interactive documentation.
When an API is created, the JSON representation of that API is automatically generated and saved into the registry as API definition. This definition describes the API with the information provided at the API creation level. You can customize the automatically generated API definition by going to the Doc tab of the
PhoneVerification API in the API Publisher. You can modify the paths, parameters, descriptions etc. by editing the JSON representation of API definition. For more information, see Adding Documentation Using Swagger.
Versioning the API
Next, we will create a new version of this API.
- Log in to the API Publisher as
apicreatorif you are not logged in already.
- Click on the
PhoneVerificationAPI and then the Copy button that appears in its Overview tab.
- Specify a new version number (of the version.major.minor format) and click Done.
A new version of the API is created. It is a duplication of all the contents of the original API, including the documentation. The API is now ready to be published. This is done by a user in the publisher role.
Publishing the API
- Log in to the API Publisher Web application as apipublisher.
- Click on the
PhoneVerificationAPI. Note that you can now see a tab as API Lifecycle in the API Publisher UI.
- Go to the Lifecycle tab and select the state as
PUBLISHEDfrom the drop-down list.
Propagate Changes to API Gateway
Used to define an API proxy in the API Gateway runtime component, allowing the API to be exposed to the consumers via the API Gateway. If this option is left unselected, the API metadata will not change and you will have to manually configure the API Gateway according to the information published in the API Store.
Deprecate Old Versions
If selected, any prior versions of the API will be set to the DEPRECATED state automatically.
Invalidates current user subscriptions, forcing users to subscribe again.
Subscribing to the API
You subscribe to APIs using the API Store Web application.
- Open the API Store (
https://<hostname>:9443/store) using your browser.
The API you published earlier appears in the API Store. You can browse the API Store, search APIs, check documentation without logging in. However, to comment, rate and subscribe to APIs, you need to sign up and log in.
- Self sign up to the API Store using the Sign-up link in the stop, right-hand corner of the screen.
- Log in to the API Store and click the API.
- You now see subscription option to your API as follows:
You need an application to subscribe to and consume APIs. Requests made from this application are regulated by throttling tiers. You can use the Default application, which comes by default with the API Manager, or you can create your own application as described below.
- Click My Applications link on the top menu or alternatively, you can create a new application right from the drop-down choice.
- The Applications page opens. Enter an application name, throttling tier and click Add.
Note that the Callback URL is optional and it is used for Authorization Code grant type of OAuth 2.0 with the exposed /authorized endpoint from the API Manager.
- Go back to the API subscription and select the application you just created, and a throttling tier and click Subscribe.
- Once the subscription is successful, switch to My Subscriptions page.
- In the My Subscriptions page, click the Generate buttons to generate production and sandbox access tokens and consumer key/secret pairs for the API. For more information on access tokens, see Working with Access Tokens.
Calling the API
To test the API, you can use the integrated REST client or any other client application such as curl.
- Open the API Store (
//<YourHostName>:9443/store) in a Web browser.
- The REST Client menu appears under the Tools menu in the top, right-hand corner of the screen. Clicking it opens the REST client.
- Provide the necessary parameters to call the API. For example, shown below is how to invoke a Google API using the REST Client.
In the above request, the application key generated at the time a user subscribes to an API is passed with the authorization header, which is prefixed by the string "Bearer". This is because, WSO2 API Manager enforces OAuth security on all the published APIs. Any consumer that talks to the API Manager should send their credential (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.
The number of API calls you can make depends on the throttling tier applied to the API. For example, if a Bronze tier is applied, the number of API calls is limited to 1 per minute. Another attempt to call the API during that time results in a throttling error.
Monitoring APIs and viewing statistics
The API publisher provides several statistical dashboards:
- Number of subscriptions per API (across all versions of an API)
- Number of API calls being made per API (across all versions of an API)
- The subscribers who did the last 10 API invocations and the APIs/versions they invoked
Usage of an API and from which resource path (per API version)
- Number of times a user has accessed an API
- The number of API invocations that failed to reach the endpoint per API per user
You view these statistics through the Statistics menu in API Publisher as follows:
Initially, it shows sample graphs for your reference. To see real runtime statistics specific to your server, you configure WSO2 Business Activity Monitor and trigger some events to generate statistics. For more information, see Publishing API Runtime Statistics.
You are done setting up the API Manager and taking a look at its common usecases. In you are looking for more advanced usecases, please see the User Guide and the Admin Guide of the API Manager documentation.