Validating Input Values in a Data Request

Validators are added to individual input mappings in a query. Input validation allows data services to validate the input parameters in a request and stop the execution of the request if the input doesn’t meet the required criteria. The ESB profile of WSO2 Enterprise Integrator (WSO2 EI) provides a set of built-in validators for some of the most common use cases. It also provides an extension mechanism to write custom validators.

Let's get started!

Define a data service

Let's create a data service using the Create Data Service wizard:

1. Start the WSO2 ESB profile.
2. Open the ESB profile's Management Console using https://localhost:9443/carbon, and log in using admin as the username and the password.
3. Click Create under Data Service.

4. Add a name for the data service.

5. Click Next and then click Add New Datasource.

6. Connect the datasource to the Company database that you defined above.

   Datasource ID	Datasource
   Datasource Type	RDBMS
   Datasource Type (Default/External)	Leave Default selected.
   Database Engine	MySQL
   Driver Class	com.mysql.jdbc.Driver
   URL	jdbc:mysql://localhost:3306/EmployeeDatabase
   User Name	Enter your MySQL server's username. Example: root
   Password	Enter your MySQL server's password. If you have not assigned a password, keep this field empty.

7. Click Save and then click Next to go to the Queries screen.

Define a query with an input validator

Let's add a validator for the first name. If the user enters a name that is less than 3 characters for the first name an error needs to be thrown due to the validation.

Follow the steps given below.

1. Click Add New Query to specify the query details:

1. Enter addEmployeeQuery as the query ID.

2. Enter the following SQL dialect:

   insert into Employees (EmployeeNumber, FirstName, LastName, Email,Salary) values(:EmployeeNumber,:FirstName,:LastName,:Email,:Salary)

3. Click Generate Input Mapping and input mappings will be generated automatically.

4. Click Edit that is next to FirstName.

5. Update the input mapping:

   SQL Type	Select String.
   IN/OUT Type	Select IN.
   Validator	Select Length Validator. Maximum Value: Enter 30 as the maximum number of characters that can be entered for the first name. Minimum Value: Enter 3 as the minimum number of characters that need to be there for the first name. Click Add Validator.

6. Click Save and click Main Configurations to move to the query configurations.

7. Click Save.

2. Click Next and then click Add New Operation.

   1. Enter the following details to create the addEmployeeOp operation that adds new employees to the database.

      Operation Name	addEmployeeOp
      Query ID	addEmployeeQuery

   2. Save the operation.

3. Click Finish.

Try it out

The Deployed Services window allows you to manage data services. You can try the data service you created by using the TryIt tool in this screen, which is in your product by default.  

1. Click Try this service to open the TryIt tool.
2. Click the addEmployeeOp operation and enter the following parameter values to the request:
   • EmployeeNumber: 6001
   • FirstName: AB
   • LastName: Nick 
   • Email: test@test.com
   • Salary: 1500
3. Click Send to execute the operation. 
   A validation error is thrown as the response because the addEmployeeOp operation has failed. This is because the FirstName only has 2 characters.
4. Now, change the lastName and the email address in the request as shown below and execute the operation again.
   • EmployeeNumber: 6001
   • FirstName: ABC
   • lastName: Nick 
   • Email: test@test.com
   • Salary: 1500
   The employee details are added to the database table.