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What Is The Use Of Put In Postman

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Understanding the PUT Request in Postman for API Testing

The PUT request is a fundamental HTTP method used in API testing. It plays a crucial role in modifying existing resources on a server. This guide will delve into the practical aspects of utilizing the PUT request in Postman for API testing, illustrating its power with clear examples.

The Essence of PUT: Updating Resources

The core purpose of the PUT method is to completely replace an existing resource with the data provided in the request body. This is distinct from the PATCH method, which allows for partial updates. Imagine you’re editing a document; PUT replaces the entire document with a new version, while PATCH only modifies specific sections.

Practical Examples: PUT in Action

Let’s examine how PUT is used in API testing scenarios.

Example: Updating User Information

Assume we have an API endpoint for managing user profiles. To modify a user’s details, we would use the PUT method.

Step 1: Define the Endpoint The endpoint for updating a user might look like this: https://api.example.com/users/{userId}

Step 2: Build the Request Body In the request body, we specify the new user data:

{
  "firstName": "UpdatedFirstName",
  "lastName": "UpdatedLastName",
  "email": "updated.email@example.com"
}

Step 3: Send the PUT Request Using Postman, we create a PUT request targeting the endpoint, replacing {userId} with the actual user ID. The body contains the updated user details.

Example: Postman Request

Method: PUT URL: https://api.example.com/users/123 Body:

{
  "firstName": "UpdatedFirstName",
  "lastName": "UpdatedLastName",
  "email": "updated.email@example.com"
}

Examining the Response

The response from the PUT request will provide crucial information regarding the update process. A successful update typically returns a 200 OK status code.

Example Response:

{
  "message": "User updated successfully.",
  "userId": 123
}

PUT vs. PATCH: Choosing the Right Method

While both PUT and PATCH are used for updates, a key distinction lies in their scope:

  • PUT: Replaces the entire resource with the new data.
  • PATCH: Applies partial updates to specific fields.

Choosing between these methods depends on the update needs. If you’re changing the entire resource (like updating an entire user profile), PUT is the suitable choice. If only modifying a few fields (like changing a user’s address), PATCH is more appropriate.

Verifying Updates with Assertions

Postman allows you to write assertions to validate the success of the PUT request. Assertions ensure that the API response matches expected conditions.

Example: Assertion for Successful Update

pm.test("User updated successfully", () => {
  pm.response.to.have.status(200);
  pm.expect(pm.response.json().message).to.equal("User updated successfully.");
});

This assertion checks for a successful status code (200) and validates that the message “User updated successfully.” is present in the response.

Conclusion

The PUT request constitutes a powerful tool within the arsenal of API testing. By understanding its role in resource updates, you can effectively test the modifications made to your API’s data. Utilizing Postman for creating and validating PUT requests, along with assertions, ensures the accuracy and consistency of your API’s functionality.

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