Is an HTTP PUT request required to include a body?

Yes, HTTP PUT requests typically include a request body, which contains the data to be uploaded for updating the resource. PUT requests are designed to allow clients to upload updates to a specified resource on the server, typically requiring the complete resource content to be provided in the request.

For example, consider a RESTful service for saving user information, where a user's details can be accessed via a URI such as /users/1234. If we need to update this user's information, we might initiate a PUT request to this URI, including the complete user information in the request body formatted as JSON, as shown below:

json
PUT /users/1234 HTTP/1.1
Host: example.com
Content-Type: application/json

{
    "id": "1234",
    "name": "John Doe",
    "email": "john.doe@example.com"
}

In this example, the PUT request sends the complete user information as a JSON object to the server. Upon receiving this data, the server typically uses it to replace the existing data stored at /users/1234.

Note that while PUT requests commonly include a request body to provide a new version of the resource, this is not mandatory. Theoretically, a PUT request could omit the request body, depending on specific application requirements and API design. However, in practice, PUT requests without a request body are relatively uncommon.