[CXF-8991] Enhancement: Determine Content Type for Empty Requests with Consideration for `application/json`

• Type: Improvement
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 3.6.3
• Component/s: Core
• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Krzysztof Grabowski
• Created: 27/Mar/24 12:20
• Updated: 27/Mar/24 14:36
• Resolved: 27/Mar/24 14:36

Description

Summary: In Apache CXF version 3.6.3, the handling of content type for empty requests defaults to a specific behavior that may not accommodate all use cases, specifically when dealing with JSON content types. This enhancement proposal aims to extend the determineContentType() method functionality to better support scenarios where application/json content type should be inferred or explicitly set for empty requests.

Problem: Currently, when making empty requests (no request body), the HttpURLConnection does not set the Content-Type header unless explicitly defined by the user. This behavior is controlled by the setProtocolHeadersInConnection method, which defaults to setting the content type to / or dropping it entirely for GET requests or when the SET_EMPTY_REQUEST_CT_PROPERTY is explicitly set to false. This approach does not account for situations where an empty request should imply a specific content type, such as application/json, which is a common use case in RESTful APIs.

Proposed Improvement: I suggest enhancing the determineContentType() method to include logic that checks the request context or headers for indications that application/json should be used as the content type for empty requests. This would involve:

• Extending the logic within determineContentType() to infer application/json when appropriate, possibly based on additional headers or request properties indicating that the request is intended to be interpreted as a JSON request

Benefits:

• Aligns Apache CXF's handling of content types for empty requests with common RESTful API practices.
• Provides more intuitive behavior for API consumers and developers, reducing the need for workarounds to explicitly set content types for empty JSON requests.
• Enhances the framework's flexibility in handling various content types, particularly for APIs that predominantly use JSON.

Impact: This change is expected to improve Apache CXF's usability for developers working with JSON-centric APIs, making it easier to comply with API contracts that expect specific content types for all requests, including those without a body.

---

Issue Links

• links to: GitHub Pull Request #1771