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How To Use Soap Api In Postman

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Introduction to SOAP API Testing with Postman

SOAP (Simple Object Access Protocol) is a messaging protocol used for exchanging structured information between applications. Postman, a popular API platform, provides a robust environment for testing SOAP APIs. This guide will walk you through the essential steps and provide practical examples to help you get started with SOAP API testing in Postman.

Setting Up Your Environment

Before testing a SOAP API, ensure you have the following:

  1. Postman: Download and install the latest version of Postman from https://www.postman.com/.
  2. SOAP API Endpoint: Obtain the URL of the SOAP API endpoint you want to test.
  3. SOAP WSDL File: The WSDL (Web Services Description Language) file defines the structure and functionality of the SOAP API. You can usually find it at the same location as the endpoint or a related location.

Using the SOAP Request Builder in Postman

Postman offers a dedicated SOAP Request Builder to simplify the process of constructing SOAP requests. Follow these steps:

  1. Create a New Request: Click on the “New” button in Postman and select “Request.”
  2. Choose SOAP as Protocol: Select “SOAP” from the dropdown menu next to the request name.
  3. Import WSDL: Click on the “Import WSDL” button, paste the WSDL file URL, and click “Import.”

This will automatically generate a pre-configured request with the necessary parameters and header information based on the WSDL.

Building SOAP Requests Manually

If you prefer manual construction, you can create SOAP requests manually.

Steps:

  1. Create a New Request: Create a new request in Postman and set the method to POST.
  2. Set the Endpoint: In the request URL field, enter the SOAP API endpoint.
  3. Add Headers: Add the following headers:
    • Content-Type: text/xml; charset=utf-8
    • SOAPAction: The SOAP action to be performed. You can find this information in the WSDL.
  4. Construct the XML Body: In the request body, define the XML structure using the schema defined in the WSDL. You can use an online XML validator to ensure the correctness of your XML.

Example SOAP Request:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
                xmlns:xsd="http://www.w3.org/2001/XMLSchema"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <soapenv:Body>
        <GetWeather xmlns="http://www.example.com/weather">
            <city>London</city>
            <country>UK</country>
        </GetWeather>
    </soapenv:Body>
</soapenv:Envelope>

Testing and Validating SOAP Responses

After sending the request, Postman will display the SOAP response, which is typically XML.

Steps:

  1. Inspect the Response: Examine the response for any errors, status codes, or relevant information.
  2. Validate against the Schema: Use an online XML validator to check if the response adheres to the expected schema defined in the WSDL.
  3. Extract and Assert Data: Utilize Postman’s assertion framework to verify the content and structure of the response. You can use the Test tab in Postman.

Example Assertion:

pm.test("Check status code", function () {
    pm.response.to.have.status(200);
});


pm.test("Verify response XML", function () {
    var responseSchema = {
        "type": "object",
        "properties": {
            "city": { "type": "string"},
            "country": { "type": "string"},
            "temperature": { "type": "number" }
        }
    };
    pm.expect(pm.response.json()).to.deep.equal(responseSchema);
});

Using SOAP APIs with Variables and Collections

Postman enables you to use variables and collections to enhance your testing workflow.

Working with Variables:

  1. Define Environment Variables: Store API credentials and dynamic parameters as environment variables.
  2. Use Variables in Requests: Replace hard-coded values in your request with environment variables using double curly braces (e.g., ${variable_name}).

Utilizing Collections:

  1. Organize Requests: Group related SOAP API requests into collections for better organization and reusability.
  2. Create Folders: Use folders within collections to categorize different API endpoints or functionalities.
  3. Run Collections: Execute collections to perform a series of tests and analyze the results.

Advanced SOAP API Testing Techniques

Using Webhooks:

  • Trigger SOAP API requests based on events using webhooks. This allows automating testing in response to specific actions.

Employing Mock Servers:

  • Mock SOAP APIs to isolate testing from external dependencies and ensure consistent test environments.

Integrating with CI/CD:

  • Integrate your SOAP API tests into your CI/CD pipeline for automated testing and continuous delivery.

Best Practices for SOAP API Testing with Postman

  1. Use WSDL for Structure: Always leverage the WSDL to guide your request construction and response validation.
  2. Test with Multiple Scenarios: Design tests that cover a wide range of scenarios, including positive, negative, and edge cases.
  3. Document Your Tests: Thorough documentation is crucial for understanding and maintaining your test suite.
  4. Use Assertions Effectively: Employ assertions to verify the correctness and expected behavior of the SOAP API.
  5. Leverage Collections and Environment Variables: Utilize these features to streamline testing and make it more efficient.

Using Postman for SOAP API testing offers a versatile and powerful approach to ensuring API quality. By following the steps outlined in this guide and embracing best practices, you can effectively test your SOAP APIs and deliver robust and reliable applications.

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