WIP: Trait for HTTP request handler

[ensh63]

Trait HttpRequestHandler<ReturnType> is defined. This trait allows to implement HTTP request handler with arbitrary return type. Special auxiliary trait HttpHandlerWrapper<ReturnType> adds function to convert this return type to ngx_int_t. Two conversions are predefined: for Option<ngx_int_t> and for Result<ngx_int_t, E>. Conversion function may include any desired additional actions common for all handlers. For instance, convertor for Result<ngx_int_t, E> logs the error, if any.

Trait HttpRequestHandler<ReturnType> also includes associated type for the HTTP module and associated constant for the handler phase.

Handler registration is simplified to a single call of ngx::http::add_phase_handler::<H: crate::http::HttpHandlerWrapper<R>, R>() function which is implemented by default.

All examples are modified to use this trait.

There are some unclear moments:

• Should old handler macro be removed?
• If handler is defined as a separate struct, what can be done with data members of this structure? Are they usable at all?
• Is it needed to define a new set of constants for common return values or current approach with Status and into() is acceptable?

[Copilot]

Pull Request Overview

This PR introduces a trait-based approach for HTTP request handlers in nginx modules, simplifying handler registration and providing type-safe error handling. The new HttpRequestHandler trait allows handlers to return arbitrary types (Option<ngx_int_t> or Result<ngx_int_t, E>) with automatic conversion to nginx's native return type, replacing the previous macro-based approach.

Key changes:

• Added HttpRequestHandler trait with associated types for module and phase configuration
• Implemented automatic error logging for Result return types via HttpHandlerWrapper trait
• Introduced NgxHttpPhases enum for type-safe phase specification
• Migrated all example modules (curl, awssig, async) to use the new trait system

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/http/status.rs	Added From<HTTPStatus> implementation for ngx_int_t to support status code conversion
src/http/request.rs	Defined HttpRequestHandler and HttpHandlerWrapper traits with default implementations for Option and Result return types
nginx-sys/src/http.rs	Added NgxHttpPhases enum representing nginx HTTP processing phases
examples/curl.rs	Converted from macro-based handler to HttpRequestHandler trait implementation
examples/awssig.rs	Converted from macro-based handler to HttpRequestHandler trait implementation
examples/async.rs	Converted from macro-based handler to HttpRequestHandler trait implementation

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[bavshin-f5]

Result<HTTPStatus, E>?

Also, the bounds for E can be relaxed to Display. I doubt we'll need anything more.

[ensh63]

Bounds relaxed. I'm not sure about HTTPStatus here. Probably we need to have more generic status type, but this maybe out of the scope of current PR.