feat(http/middleware): add idiomatic http-compatible middleware

http/middleware/middleware.go

@@ -0,0 +1,55 @@
+// Copyright 2025 AJ ONeal <aj@therootcompany.com> (https://therootcompany.com)
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package middleware
+
+import (
+	"net/http"
+	"slices"
+)
+
+// Middleware receives and returns and http.HandlerFunc
+type Middleware func(http.HandlerFunc) http.HandlerFunc
+
+// MiddlewareChain enables inline chaining
+type MiddlewareChain struct {
+	middlewares []Middleware
+}
+
+// New creates a reusable MiddlewareChain with 0 or more middleware
+func New(middlewares ...Middleware) MiddlewareChain {
+	return MiddlewareChain{middlewares: middlewares}
+}
+
+// Use appends additional middleware to the chain
+func (c MiddlewareChain) Use(middlewares ...Middleware) MiddlewareChain {
+	newMiddlewares := make([]Middleware, len(c.middlewares), len(c.middlewares)+len(middlewares))
+	copy(newMiddlewares, c.middlewares)
+	newMiddlewares = append(newMiddlewares, middlewares...)
+
+	return MiddlewareChain{middlewares: newMiddlewares}
+}
+
+// Handle composes middleware with the final handler
+func (c MiddlewareChain) Handle(handler http.HandlerFunc) http.HandlerFunc {
+	if handler == nil {
+		panic("mw.New(...).Use(...).Handle(-->this<--) requires a handler")
+	}
+
+	middlewares := make([]Middleware, len(c.middlewares))
+	copy(middlewares, c.middlewares)
+	slices.Reverse(middlewares)
+
+	// Apply middleware in forward order
+	result := handler
+	for _, m := range middlewares {
+		result = m(result)
+	}
+
+	return result
+}