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How To Test Soap Api Using Postman

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How to Test SOAP APIs Using Postman

Postman is a popular tool for API testing, but it’s primarily designed for REST APIs. However, with some configuration and understanding, you can use Postman to effectively test SOAP APIs. Here’s a comprehensive guide:

Understanding SOAP APIs

SOAP (Simple Object Access Protocol) is a messaging protocol used for exchanging structured information between applications. It relies on XML for data transmission and uses the HTTP protocol for transport. SOAP APIs typically involve a request and a response, both formatted in XML.

Setting up Postman for SOAP API Testing

  1. Create a New Request: Open Postman and create a new request. Choose the POST method as SOAP APIs often use POST requests.

  2. Setting the Header: Add the necessary headers to the request:

    • Content-Type: application/soap+xml

    • Accept: application/soap+xml

    • SOAPAction: This header specifies the specific action to be performed. This is crucial for SOAP API calls to differentiate the intended action.

  3. Body:

    • Choose XML: In the body section, select raw and XML as the format.

    • Paste Your XML: Paste the XML request body for your SOAP API.

    • Example:

      <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
        <soapenv:Header>
          <wsu:Timestamp>
            <wsu:Created>2023-12-07T10:00:00.000Z</wsu:Created>
            <wsu:Expires>2023-12-07T10:10:00.000Z</wsu:Expires>
          </wsu:Timestamp>
        </soapenv:Header>
        <soapenv:Body>
          <ns:GetWeather xmlns:ns="http://example.com/weather/">
            <ns:city>London</ns:city>
          </ns:GetWeather>
        </soapenv:Body>
      </soapenv:Envelope>

Testing SOAP APIs with Postman: A Practical Example

Let’s test a sample SOAP API for retrieving weather information. For this example, we’ll use a hypothetical weather service at https://www.sample-weather.com/webservices/weather.asmx.

1. Construct the XML Request

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tem="http://tempuri.org/">
   <soapenv:Header/>
   <soapenv:Body>
      <tem:GetWeather>
         <tem:cityName>London</tem:cityName>
      </tem:GetWeather>
   </soapenv:Body>
</soapenv:Envelope>

2. Set Up the Postman Request

  • Method: POST
  • URL: https://www.sample-weather.com/webservices/weather.asmx
  • Headers:
    • Content-Type: application/soap+xml
    • Accept: application/soap+xml
    • SOAPAction: "http://tempuri.org/GetWeather"
  • Body: Paste the XML request from above.

3. Sending the Request

Click Send in Postman.

4. Analyze the Response

Postman will display the SOAP response as XML data. Check the response for:

  • Success: If the request was successfully processed, the response will contain the expected weather information.
  • Errors: If the request failed, the response will include error details in the XML format.

How to Test SOAP API Authentication

Many SOAP APIs require authentication. Postman provides various ways to achieve this:

  • Basic Authentication: Use the “Authorization” tab in Postman to provide the username and password.
  • OAuth 2.0: Use the “Authorization” tab to configure OAuth 2.0 authentication.
  • API Keys: You can set up a global variable in Postman to hold your API key and use it in the request headers.

Using Postman Collection for SOAP API Testing

Organizing your SOAP API tests is crucial for efficiency and maintainability. Postman Collections allow you to group requests, manage environments, and perform automated tests.

  • Create a New Collection: Click on the “Collections” tab in Postman and create a new collection for your SOAP API tests.
  • Add Requests: Add individual requests to the collection, each representing a different functionality of your SOAP API.
  • Organize with Folders: Group related requests into folders to structure your collection.
  • Utilize Environments: Define different environments to manage different API endpoints, API keys, or authentication credentials.
  • Run Tests with Runner: Postman’s Runner tool enables automated execution of your collection, allowing you to create comprehensive test suites.

Key Considerations for SOAP API Testing with Postman

  • XML Understanding: Familiarity with XML syntax is essential to construct requests and analyze responses.
  • SOAPAction Header: Ensure that the SOAPAction header correctly identifies the action you’re trying to perform.
  • Error Handling: Pay close attention to the error messages and codes returned in the SOAP response.
  • Automation: Consider using scripts and automation techniques to streamline your testing process.

In Conclusion:

Postman, despite its focus on REST APIs, can be a valuable tool for testing SOAP APIs. By understanding the fundamentals of SOAP, XML, and Postman’s features, you can effectively test, document, and automate your SOAP API testing workflow.

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