snapshot of https://github.com/go-chi/chi.git (master, 2026-09-15; blobs > 131072B omitted)

chain.go

@@ -0,0 +1,49 @@
+package chi
+
+import "net/http"
+
+// Chain returns a Middlewares type from a slice of middleware handlers.
+func Chain(middlewares ...func(http.Handler) http.Handler) Middlewares {
+	return Middlewares(middlewares)
+}
+
+// Handler builds and returns a http.Handler from the chain of middlewares,
+// with `h http.Handler` as the final handler.
+func (mws Middlewares) Handler(h http.Handler) http.Handler {
+	return &ChainHandler{h, chain(mws, h), mws}
+}
+
+// HandlerFunc builds and returns a http.Handler from the chain of middlewares,
+// with `h http.Handler` as the final handler.
+func (mws Middlewares) HandlerFunc(h http.HandlerFunc) http.Handler {
+	return &ChainHandler{h, chain(mws, h), mws}
+}
+
+// ChainHandler is a http.Handler with support for handler composition and
+// execution.
+type ChainHandler struct {
+	Endpoint    http.Handler
+	chain       http.Handler
+	Middlewares Middlewares
+}
+
+func (c *ChainHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	c.chain.ServeHTTP(w, r)
+}
+
+// chain builds a http.Handler composed of an inline middleware stack and endpoint
+// handler in the order they are passed.
+func chain(middlewares []func(http.Handler) http.Handler, endpoint http.Handler) http.Handler {
+	// Return ahead of time if there aren't any middlewares for the chain
+	if len(middlewares) == 0 {
+		return endpoint
+	}
+
+	// Wrap the end handler with the middleware chain
+	h := middlewares[len(middlewares)-1](endpoint)
+	for i := len(middlewares) - 2; i >= 0; i-- {
+		h = middlewares[i](h)
+	}
+
+	return h
+}