Very basic middleware and route matching functionality

1 files changed, 168 insertions, 11 deletions

diff --git a/modules/caddyhttp/caddyhttp.go b/modules/caddyhttp/caddyhttp.go
index 529c1f7..059af62 100644
--- a/modules/caddyhttp/caddyhttp.go
+++ b/modules/caddyhttp/caddyhttp.go
@@ -2,6 +2,7 @@ package caddyhttp
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"log"
 	"net"
@@ -30,23 +31,56 @@ type httpModuleConfig struct {
 }
 
 func (hc *httpModuleConfig) Run() error {
-	// fmt.Printf("RUNNING: %#v\n", hc)
+	// TODO: Either prevent overlapping listeners on different servers, or combine them into one
+
+	// TODO: A way to loop requests back through, so have them start the matching over again, but keeping any mutations
 
 	for _, srv := range hc.Servers {
+		// set up the routes
+		for i, route := range srv.Routes {
+			// matchers
+			for modName, rawMsg := range route.Matchers {
+				val, err := caddy2.LoadModule("http.matchers."+modName, rawMsg)
+				if err != nil {
+					return fmt.Errorf("loading matcher module '%s': %v", modName, err)
+				}
+				srv.Routes[i].matchers = append(srv.Routes[i].matchers, val.(RouteMatcher))
+			}
+
+			// middleware
+			for j, rawMsg := range route.Apply {
+				mid, err := caddy2.LoadModuleInlineName("http.middleware", rawMsg)
+				if err != nil {
+					return fmt.Errorf("loading middleware module in position %d: %v", j, err)
+				}
+				srv.Routes[i].middleware = append(srv.Routes[i].middleware, mid.(MiddlewareHandler))
+			}
+
+			// responder
+			if route.Respond != nil {
+				resp, err := caddy2.LoadModuleInlineName("http.responders", route.Respond)
+				if err != nil {
+					return fmt.Errorf("loading responder module: %v", err)
+				}
+				srv.Routes[i].responder = resp.(Handler)
+			}
+		}
+
 		s := &http.Server{
 			ReadTimeout:       time.Duration(srv.ReadTimeout),
 			ReadHeaderTimeout: time.Duration(srv.ReadHeaderTimeout),
+			Handler:           srv,
 		}
 
 		for _, lnAddr := range srv.Listen {
-			proto, addrs, err := parseListenAddr(lnAddr)
+			network, addrs, err := parseListenAddr(lnAddr)
 			if err != nil {
 				return fmt.Errorf("parsing listen address '%s': %v", lnAddr, err)
 			}
 			for _, addr := range addrs {
-				ln, err := caddy2.Listen(proto, addr)
+				ln, err := caddy2.Listen(network, addr)
 				if err != nil {
-					return fmt.Errorf("%s: listening on %s: %v", proto, addr, err)
+					return fmt.Errorf("%s: listening on %s: %v", network, addr, err)
 				}
 				go s.Serve(ln)
 				hc.servers = append(hc.servers, s)
@@ -67,10 +101,117 @@ func (hc *httpModuleConfig) Cancel() error {
 	return nil
 }
 
-func parseListenAddr(a string) (proto string, addrs []string, err error) {
-	proto = "tcp"
+type httpServerConfig struct {
+	Listen            []string        `json:"listen"`
+	ReadTimeout       caddy2.Duration `json:"read_timeout"`
+	ReadHeaderTimeout caddy2.Duration `json:"read_header_timeout"`
+	HiddenFiles       []string        `json:"hidden_files"` // TODO:... experimenting with shared/common state
+	Routes            []serverRoute   `json:"routes"`
+}
+
+func (s httpServerConfig) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var mid []Middleware // TODO: see about using make() for performance reasons
+	var responder Handler
+	mrw := &middlewareResponseWriter{ResponseWriterWrapper: &ResponseWriterWrapper{w}}
+
+	for _, route := range s.Routes {
+		matched := len(route.matchers) == 0
+		for _, m := range route.matchers {
+			if m.Match(r) {
+				matched = true
+				break
+			}
+		}
+		if !matched {
+			continue
+		}
+		for _, m := range route.middleware {
+			mid = append(mid, func(next HandlerFunc) HandlerFunc {
+				return func(w http.ResponseWriter, r *http.Request) error {
+					return m.ServeHTTP(mrw, r, next)
+				}
+			})
+		}
+		if responder == nil {
+			responder = route.responder
+		}
+	}
+
+	// build the middleware stack, with the responder at the end
+	stack := HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
+		if responder == nil {
+			return nil
+		}
+		mrw.allowWrites = true
+		return responder.ServeHTTP(w, r)
+	})
+	for i := len(mid) - 1; i >= 0; i-- {
+		stack = mid[i](stack)
+	}
+
+	err := stack.ServeHTTP(w, r)
+	if err != nil {
+		// TODO: error handling
+		log.Printf("[ERROR] TODO: error handling: %v", err)
+	}
+}
+
+type serverRoute struct {
+	Matchers map[string]json.RawMessage `json:"match"`
+	Apply    []json.RawMessage          `json:"apply"`
+	Respond  json.RawMessage            `json:"respond"`
+
+	// decoded values
+	matchers   []RouteMatcher
+	middleware []MiddlewareHandler
+	responder  Handler
+}
+
+// RouteMatcher is a type that can match to a request.
+// A route matcher MUST NOT modify the request.
+type RouteMatcher interface {
+	Match(*http.Request) bool
+}
+
+// Middleware chains one Handler to the next by being passed
+// the next Handler in the chain.
+type Middleware func(HandlerFunc) HandlerFunc
+
+// MiddlewareHandler is a Handler that includes a reference
+// to the next middleware handler in the chain. Middleware
+// handlers MUST NOT call Write() or WriteHeader() on the
+// response writer; doing so will panic. See Handler godoc
+// for more information.
+type MiddlewareHandler interface {
+	ServeHTTP(http.ResponseWriter, *http.Request, Handler) error
+}
+
+// Handler is like http.Handler except ServeHTTP may return an error.
+//
+// Middleware and responder handlers both implement this method.
+// Middleware must not call Write or WriteHeader on the ResponseWriter;
+// doing so will cause a panic. Responders should write to the response
+// if there was not an error.
+//
+// If any handler encounters an error, it should be returned for proper
+// handling. Return values should be propagated down the middleware chain
+// by returning it unchanged.
+type Handler interface {
+	ServeHTTP(http.ResponseWriter, *http.Request) error
+}
+
+// HandlerFunc is a convenience type like http.HandlerFunc.
+type HandlerFunc func(http.ResponseWriter, *http.Request) error
+
+// ServeHTTP implements the Handler interface.
+func (f HandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
+	return f(w, r)
+}
+
+func parseListenAddr(a string) (network string, addrs []string, err error) {
+	network = "tcp"
 	if idx := strings.Index(a, "/"); idx >= 0 {
-		proto = strings.ToLower(strings.TrimSpace(a[:idx]))
+		network = strings.ToLower(strings.TrimSpace(a[:idx]))
 		a = a[idx+1:]
 	}
 	var host, port string
@@ -101,8 +242,24 @@ func parseListenAddr(a string) (proto string, addrs []string, err error) {
 	return
 }
 
-type httpServerConfig struct {
-	Listen            []string        `json:"listen"`
-	ReadTimeout       caddy2.Duration `json:"read_timeout"`
-	ReadHeaderTimeout caddy2.Duration `json:"read_header_timeout"`
+type middlewareResponseWriter struct {
+	*ResponseWriterWrapper
+	allowWrites bool
 }
+
+func (mrw middlewareResponseWriter) WriteHeader(statusCode int) {
+	if !mrw.allowWrites {
+		panic("WriteHeader: middleware cannot write to the response")
+	}
+	mrw.ResponseWriterWrapper.WriteHeader(statusCode)
+}
+
+func (mrw middlewareResponseWriter) Write(b []byte) (int, error) {
+	if !mrw.allowWrites {
+		panic("Write: middleware cannot write to the response")
+	}
+	return mrw.ResponseWriterWrapper.Write(b)
+}
+
+// Interface guards
+var _ HTTPInterfaces = middlewareResponseWriter{}