fix(dart_frog): add default handler for disallowed http methods (#1)

[felangel]

Status

READY

Description

• fix(dart_frog): add default handler for disallowed http methods
  • This fixes a bug where previously requests made to a dart frog server with arbitrary http methods would result in a 500 (internal server error). With the changes in the PR, that case would result in a 405 (method not allowed)

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• 📝 Documentation
• 🗑️ Chore

Summary by CodeRabbit

• New Features
  • Enhanced HTTP request handling to clearly flag unsupported methods, resulting in a descriptive "Method Not Allowed" (405) response when an invalid HTTP method is used.

[coderabbitai]

Walkthrough

The changes introduce explicit error handling for unsupported HTTP methods. A new exception class, UnsupportedHttpMethodException, is added to signal when an unsupported method is encountered in the Request class. In the Router class, a new parameter methodNotAllowedHandler and related logic (including a default handler and response class) are implemented to return a 405 status on such cases. Additionally, new test cases validate the behavior for both request and router components when handling unsupported HTTP methods.

Changes

File(s)	Change summary
packages/dart_frog/lib/.../request.dart and packages/dart_frog/lib/.../router.dart	Added error handling for unsupported HTTP methods. In request.dart, introduced UnsupportedHttpMethodException. In router.dart, added methodNotAllowedHandler, _defaultMethodNotAllowed, and _MethodNotAllowedResponse.
packages/dart_frog/test/.../request_test.dart and packages/dart_frog/test/.../router_test.dart	Added tests to verify that unsupported HTTP methods throw the new exception and trigger the 405 response via the router’s method not allowed handler, including repeated invocations.

Sequence Diagram(s)

sequenceDiagram
    participant Client
    participant Router
    participant Request
    participant Handler as methodNotAllowedHandler

    Client->>Router: Send HTTP request (unsupported method)
    Router->>Request: Retrieve method property
    Request-->>Router: Throw UnsupportedHttpMethodException
    Router->>Handler: Invoke methodNotAllowedHandler
    Handler-->>Router: Return 405 Method Not Allowed response
    Router->>Client: Send 405 response

Loading

Poem

Hop, hop, I’m a coding rabbit on the run,
Skipping past bugs under the bright coding sun.
Unsupported methods now cause no dismay,
With custom exceptions leading the way.
My ears perk up at each fixed 405 call,
A joyful code hop for one and for all!

---

📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between acc6829 and c29cadc.

📒 Files selected for processing (4)

• packages/dart_frog/lib/src/request.dart (2 hunks)
• packages/dart_frog/lib/src/router.dart (5 hunks)
• packages/dart_frog/test/src/request_test.dart (2 hunks)
• packages/dart_frog/test/src/router_test.dart (2 hunks)

⏰ Context from checks skipped due to timeout of 90000ms (1)

• GitHub Check: pana / build

🔇 Additional comments (10)

packages/dart_frog/test/src/request_test.dart (1)

47-59: Great test coverage for the new functionality!

This test verifies that the Request class properly throws UnsupportedHttpMethodException when an unsupported HTTP method is encountered, with the correct error message listing all supported methods.

packages/dart_frog/lib/src/request.dart (2)

3-18: Well-structured exception class with good documentation

The UnsupportedHttpMethodException implementation is clean and provides a detailed error message that will help developers understand what methods are supported.

---

132-135: Good implementation of method verification

The use of firstWhere with an orElse parameter is an elegant way to implement this validation, throwing the appropriate exception when an unsupported HTTP method is encountered.

packages/dart_frog/test/src/router_test.dart (2)

94-100: Excellent test case for unsupported HTTP methods

This test confirms that requests with unsupported HTTP methods (like 'FOO') correctly return a 405 Method Not Allowed status with the appropriate message.

---

455-473: Complete test coverage for the methodNotAllowed response

These tests thoroughly validate the behavior of the methodNotAllowed response, ensuring it can be reused and properly modified with copyWith().

packages/dart_frog/lib/src/router.dart (5)

39-46: Good API design with backward compatibility

Adding the optional methodNotAllowedHandler parameter with a default implementation maintains backward compatibility while providing flexibility for custom handlers.

---

176-184: Proper exception handling for unsupported methods

This implementation correctly catches the UnsupportedHttpMethodException and invokes the appropriate handler, improving the framework's error handling capabilities.

---

227-229: Simple and effective default handler

The default handler returns a sentinel response, following the same pattern as the _defaultNotFound handler for consistency.

---

237-243: Well-documented static field

The documentation for the methodNotAllowed static field clearly explains its purpose and usage, which will help developers understand the API.

---

268-289: Complete implementation of the method not allowed response

The _MethodNotAllowedResponse class follows the same pattern as _RouteNotFoundResponse, ensuring consistent behavior for method not allowed responses.

While there's some code duplication between this and _RouteNotFoundResponse, it maintains a clear separation of concerns that makes the code more maintainable.

---

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