Build REST API's using Swagger and IBM Integration Bus IIB v10
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The document outlines the process for building REST APIs using Swagger and IBM Integration Bus (IIB) v10, including installation steps and a simple API definition for a payments service. It provides a detailed Swagger definition in YAML format that describes GET and POST operations for managing scheduled payments. Additionally, it explains implementation steps in IIB, testing the API with Postman, and notes on returning valid JSON responses.
Build REST API's using Swagger and IBM Integration Bus IIB v10
- 1. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] Build REST APIs using Swagger and IBM Integration Bus – IIB v10 Installing Swagger locally 1. Install NodeJS a. Choose the appropriate installer from https://nodejs.org/download/ 2. git clone https://github.com/swagger-api/swagger-editor.git 3. cd swagger-editor 4. npm start Note for 3. You will find the Swagger-editor in thebelow location in Windows C:Users{UserName}DocumentsGitHubswagger-editor Once Swagger Editor starts locally it will open the Editor in the below location http://localhost:8080/#/ The browserbased swagger editor is available in the internet at http://editor.swagger.io/#/ Swagger API Specification can be found here https://github.com/swagger-api/swagger-spec/blob/master/versions/2.0.md Create a Simple Rest API Definition in Swagger Below is a simple REST API named Payment API. The Payment API will enable customers to view all scheduled payments for a Customer and post payments to different accounts setup for bill pay. The goal here is to just show how to define a REST API using Swagger as use it for development in IIB v10. I will cover how to model REST APIs using RAML in a different post. Below is the Payment API Swagger definition. Swagger definitions are in YAML format. swagger: '2.0' info: version: '1.0.0' title: Payment API
- 2. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] description: The Payment API enables customers to retrieve about all scheduled payments & post payments termsOfService: http://wwww.ibmdeveloper.com/terms/ contact: name: API Management Team email: [email protected] url: http://www.ibmdeveloper.com license: name: MIT url: http://opensource.org/licenses/MIT host: ibmdeveloper.com basePath: /billpay schemes: - http consumes: - application/json produces: - application/json paths: /payments/{customerId}: get: description: Returns all Payments that are scheduled for a customer operationId: findPayments produces: - application/json - application/xml - text/xml - text/html parameters: - name: customerId in: path type: string description: ID of the Customer required: true responses: '200': description: scheduled payments response schema: type: array items: $ref: '#/definitions/payments' default: description: unexpected error schema: $ref: '#/definitions/errorModel' post: description: Schedule/Post a new payment operationId: postPayment produces: - application/json parameters: - name: customerId in: path type: string description: ID of the Customer required: true
- 3. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] - in: formData name: paymentAmount description: Payment Amount to be posted required: true type: number format: float - in: formData name: paymentDate description: Payment Date required: true type: string - in: formData name: paymentAccount description: Account where payment is to be posted required: true type: string responses: '200': description: payment response schema: $ref: '#/definitions/paymentId' default: description: unexpected error schema: $ref: '#/definitions/errorModel' definitions: payments: required: - paymentId - paymentAccount - paymentDate properties: paymentId: $ref: '#/definitions/paymentId' paymentAccount: type: string paymentDate: type: string tag: type: string paymentId: type: integer format: int64 errorModel: required: - code - message properties: code: type: integer format: int32 message: type: string
- 4. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] IIB v10 expects the definitionto be in JSON format. The Swagger editor provides theoption to save the file in JSON format. The Payment API has 2 methods, GET and POST
- 5. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] The GET method will retrieve all the payments that are scheduled for a Customer. The Customer Id is the key that identifies a specific customer. The POST method enables a customer to post/schedule payments to a specific bill pay account.
- 6. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] Below are the message models / response message formats. The errorModel defines a generic error message format for any errors. The response to the POST is a paymentId. The response to the GET is the payments structure, which returns the paymentAccount, paymentDate & paymentId
- 7. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] REST API Implementation using Integration Bus - IIBv10 Choose New -> Start by creating a REST API Specify the nameof the REST API
- 8. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] Select the PaymentAPI.json file we downloaded earlier from the Swagger Editor Review the API definition
- 9. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] Once the import is successful, the API description and sample message flows arecreated like below. Below is the IIB generated Payment_API.msgflow. The default message domain as you cansee below is JSON.
- 10. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] Below is the REST API description inside the toolkit. Choose ‘Implement theoperation’ next to both This will create a sub-flow for each operation i.e. one for GET and one for POST. Below is the sub-flow for the GET operation. The name of the sub-flow reflects the operationId in the API definition.
- 11. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] Before we complete the entire implementation, I would like to deploy theAPI to make sure we can invoke theAPI. To test the API, I usePostman which is great for REST API testing. There are many other tools available and you can use the tool of your choice. Postman is available in the Chrome App Store. Right Click on the Payment API and deploy it to an integration server. Once it is deployed, you should be able to see the properties like below. It shows you the URL you need to invoke. Let’s try to invoke the above URL using Postman
- 12. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] This returns a 404 as the API does not support base URL invocation. The right URL should bebaseURL + /billpay/{customerId} Let’s change the URL to http://localhost:7800/billpay/payments/1212 This returns a 501 as we haven’t completed the sub-flow implementations yet. Now that wecan invoke the API, let’s moveon to complete the message flows. Let’s add a Compute Node to both the sub-flows and leave the ESQL code like below, deploy and test
- 13. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] When you try to test GET operation now, you a 200 Status code. But the responseis empty as we haven’t implemented any code to return as valid JSON response. Let’s make some changes to the above ESQL to return a valid response.
- 14. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] I have just hardcoded the values as our goal is to just build a basic API. I haven’t shown how to integrate with a backend etc. for a comprehensive implementation as it is beyond the scope of what I am trying to demonstrate here. Now let’s try to invokethe URL again for GET
- 15. Build REST APIs using Swagger and IBM Integration Bus – IIB v10 | Julian Smiles [email protected] Now you get a valid JSON response. You can try your POST operation similarly Here is the representation of the JSON message tree in the debugger for the POST I hope this information was useful to you.