Use gorilla/mux to route HTTP requests (#11)

* Add basic routing based on matched paths
* Make /sync and /send use the right API paths

src/github.com/matrix-org/dendrite/clientapi/clientapi.go

@@ -1,31 +1,19 @@
 package main
 
 import (
+	"github.com/matrix-org/dendrite/clientapi/routing"
 	"net/http"
 	"os"
 
 	log "github.com/Sirupsen/logrus"
-
-	"github.com/matrix-org/dendrite/clientapi/readers"
-	"github.com/matrix-org/dendrite/clientapi/writers"
-	"github.com/matrix-org/util"
-	"github.com/prometheus/client_golang/prometheus"
 )
 
-// setup registers HTTP handlers with the given ServeMux. It also supplies the given http.Client
-// to clients which need to make outbound HTTP requests.
-func setup(mux *http.ServeMux, httpClient *http.Client) {
-	mux.Handle("/metrics", prometheus.Handler())
-	mux.Handle("/api/send", prometheus.InstrumentHandler("send_message", util.MakeJSONAPI(&writers.SendMessage{})))
-	mux.Handle("/api/sync", prometheus.InstrumentHandler("sync", util.MakeJSONAPI(&readers.Sync{})))
-}
-
 func main() {
 	bindAddr := os.Getenv("BIND_ADDRESS")
 	if bindAddr == "" {
 		log.Panic("No BIND_ADDRESS environment variable found.")
 	}
 	log.Info("Starting clientapi")
-	setup(http.DefaultServeMux, http.DefaultClient)
+	routing.Setup(http.DefaultServeMux, http.DefaultClient)
 	log.Fatal(http.ListenAndServe(bindAddr, nil))
 }

src/github.com/matrix-org/dendrite/clientapi/readers/sync.go

@@ -3,16 +3,12 @@ package readers
 import (
 	"net/http"
 
-	log "github.com/Sirupsen/logrus"
 	"github.com/matrix-org/util"
 )
 
-// Sync handles HTTP requests to /sync
-type Sync struct{}
-
-// OnIncomingRequest implements util.JSONRequestHandler
-func (s *Sync) OnIncomingRequest(req *http.Request) (interface{}, *util.HTTPError) {
-	logger := req.Context().Value(util.CtxValueLogger).(*log.Entry)
+// Sync implements /sync
+func Sync(req *http.Request) (interface{}, *util.HTTPError) {
+	logger := util.GetLogger(req.Context())
 	logger.Info("Doing stuff...")
 	return nil, &util.HTTPError{
 		Code:    404,

src/github.com/matrix-org/dendrite/clientapi/routing/routing.go

@@ -0,0 +1,49 @@
+package routing
+
+import (
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/matrix-org/dendrite/clientapi/readers"
+	"github.com/matrix-org/dendrite/clientapi/writers"
+	"github.com/matrix-org/util"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const pathPrefixR0 = "/_matrix/client/r0"
+
+// Setup registers HTTP handlers with the given ServeMux. It also supplies the given http.Client
+// to clients which need to make outbound HTTP requests.
+func Setup(servMux *http.ServeMux, httpClient *http.Client) {
+	apiMux := mux.NewRouter()
+	r0mux := apiMux.PathPrefix(pathPrefixR0).Subrouter()
+	r0mux.Handle("/sync", make("sync", wrap(func(req *http.Request) (interface{}, *util.HTTPError) {
+		return readers.Sync(req)
+	})))
+	r0mux.Handle("/rooms/{roomID}/send/{eventType}",
+		make("send_message", wrap(func(req *http.Request) (interface{}, *util.HTTPError) {
+			vars := mux.Vars(req)
+			return writers.SendMessage(req, vars["roomID"], vars["eventType"])
+		})),
+	)
+
+	servMux.Handle("/metrics", prometheus.Handler())
+	servMux.Handle("/api/", http.StripPrefix("/api", apiMux))
+}
+
+// make a util.JSONRequestHandler into an http.Handler
+func make(metricsName string, h util.JSONRequestHandler) http.Handler {
+	return prometheus.InstrumentHandler(metricsName, util.MakeJSONAPI(h))
+}
+
+// jsonRequestHandlerWrapper is a wrapper to allow in-line functions to conform to util.JSONRequestHandler
+type jsonRequestHandlerWrapper struct {
+	function func(req *http.Request) (interface{}, *util.HTTPError)
+}
+
+func (r *jsonRequestHandlerWrapper) OnIncomingRequest(req *http.Request) (interface{}, *util.HTTPError) {
+	return r.function(req)
+}
+func wrap(f func(req *http.Request) (interface{}, *util.HTTPError)) *jsonRequestHandlerWrapper {
+	return &jsonRequestHandlerWrapper{f}
+}

src/github.com/matrix-org/dendrite/clientapi/writers/sendmessage.go

@@ -3,18 +3,13 @@ package writers
 import (
 	"net/http"
 
-	log "github.com/Sirupsen/logrus"
 	"github.com/matrix-org/util"
 )
 
-// SendMessage handles HTTP requests to /rooms/$room_id/send/$event_type
-type SendMessage struct {
-}
-
-// OnIncomingRequest implements util.JSONRequestHandler
-func (s *SendMessage) OnIncomingRequest(req *http.Request) (interface{}, *util.HTTPError) {
-	logger := req.Context().Value(util.CtxValueLogger).(*log.Entry)
-	logger.Info("Doing stuff...")
+// SendMessage implements /rooms/{roomID}/send/{eventType}
+func SendMessage(req *http.Request, roomID, eventType string) (interface{}, *util.HTTPError) {
+	logger := util.GetLogger(req.Context())
+	logger.WithField("roomID", roomID).WithField("eventType", eventType).Info("Doing stuff...")
 	return nil, &util.HTTPError{
 		Code:    404,
 		Message: "Not implemented yet",

vendor/manifest

@@ -86,7 +86,7 @@
 		{
 			"importpath": "github.com/matrix-org/util",
 			"repository": "https://github.com/matrix-org/util",
-			"revision": "0f4d9cce82badc0741ff1141dcf079312cb4d2f0",
+			"revision": "0bbc3896e02031e7e7338948b73ce891aa73ab2b",
 			"branch": "master"
 		},
 		{

vendor/src/github.com/matrix-org/util/json.go

@@ -12,11 +12,33 @@ import (
 	log "github.com/Sirupsen/logrus"
 )
 
-// ContextKeys is a type alias for string to namespace Context keys per-package.
-type ContextKeys string
+// contextKeys is a type alias for string to namespace Context keys per-package.
+type contextKeys string
 
-// CtxValueLogger is the key to extract the logrus Logger.
-const CtxValueLogger = ContextKeys("logger")
+// ctxValueRequestID is the key to extract the request ID for an HTTP request
+const ctxValueRequestID = contextKeys("requestid")
+
+// GetRequestID returns the request ID associated with this context, or the empty string
+// if one is not associated with this context.
+func GetRequestID(ctx context.Context) string {
+	id := ctx.Value(ctxValueRequestID)
+	if id == nil {
+		return ""
+	}
+	return id.(string)
+}
+
+// ctxValueLogger is the key to extract the logrus Logger.
+const ctxValueLogger = contextKeys("logger")
+
+// GetLogger retrieves the logrus logger from the supplied context. Returns nil if there is no logger.
+func GetLogger(ctx context.Context) *log.Entry {
+	l := ctx.Value(ctxValueLogger)
+	if l == nil {
+		return nil
+	}
+	return l.(*log.Entry)
+}
 
 // JSONRequestHandler represents an interface that must be satisfied in order to respond to incoming
 // HTTP requests with JSON. The interface returned will be marshalled into JSON to be sent to the client,
@@ -34,12 +56,12 @@ type JSONError struct {
 
 // Protect panicking HTTP requests from taking down the entire process, and log them using
 // the correct logger, returning a 500 with a JSON response rather than abruptly closing the
-// connection. The http.Request MUST have a CtxValueLogger.
+// connection. The http.Request MUST have a ctxValueLogger.
 func Protect(handler http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, req *http.Request) {
 		defer func() {
 			if r := recover(); r != nil {
-				logger := req.Context().Value(CtxValueLogger).(*log.Entry)
+				logger := req.Context().Value(ctxValueLogger).(*log.Entry)
 				logger.WithFields(log.Fields{
 					"panic": r,
 				}).Errorf(
@@ -56,18 +78,20 @@ func Protect(handler http.HandlerFunc) http.HandlerFunc {
 
 // MakeJSONAPI creates an HTTP handler which always responds to incoming requests with JSON responses.
 // Incoming http.Requests will have a logger (with a request ID/method/path logged) attached to the Context.
-// This can be accessed via the const CtxValueLogger. The type of the logger is *log.Entry from github.com/Sirupsen/logrus
+// This can be accessed via GetLogger(Context). The type of the logger is *log.Entry from github.com/Sirupsen/logrus
 func MakeJSONAPI(handler JSONRequestHandler) http.HandlerFunc {
 	return Protect(func(w http.ResponseWriter, req *http.Request) {
+		reqID := RandomString(12)
 		// Set a Logger on the context
-		ctx := context.WithValue(req.Context(), CtxValueLogger, log.WithFields(log.Fields{
+		ctx := context.WithValue(req.Context(), ctxValueLogger, log.WithFields(log.Fields{
 			"req.method": req.Method,
 			"req.path":   req.URL.Path,
-			"req.id":     RandomString(12),
+			"req.id":     reqID,
 		}))
+		ctx = context.WithValue(ctx, ctxValueRequestID, reqID)
 		req = req.WithContext(ctx)
 
-		logger := req.Context().Value(CtxValueLogger).(*log.Entry)
+		logger := req.Context().Value(ctxValueLogger).(*log.Entry)
 		logger.Print("Incoming request")
 
 		res, httpErr := handler.OnIncomingRequest(req)
@@ -99,7 +123,7 @@ func MakeJSONAPI(handler JSONRequestHandler) http.HandlerFunc {
 }
 
 func jsonErrorResponse(w http.ResponseWriter, req *http.Request, httpErr *HTTPError) {
-	logger := req.Context().Value(CtxValueLogger).(*log.Entry)
+	logger := req.Context().Value(ctxValueLogger).(*log.Entry)
 	if httpErr.Code == 302 {
 		logger.WithField("err", httpErr.Error()).Print("Redirecting")
 		http.Redirect(w, req, httpErr.Message, 302)

vendor/src/github.com/matrix-org/util/json_test.go

@@ -73,12 +73,30 @@ func TestMakeJSONAPIRedirect(t *testing.T) {
 	}
 }
 
+func TestGetLogger(t *testing.T) {
+	log.SetLevel(log.PanicLevel) // suppress logs in test output
+	entry := log.WithField("test", "yep")
+	mockReq, _ := http.NewRequest("GET", "http://example.com/foo", nil)
+	ctx := context.WithValue(mockReq.Context(), ctxValueLogger, entry)
+	mockReq = mockReq.WithContext(ctx)
+	ctxLogger := GetLogger(mockReq.Context())
+	if ctxLogger != entry {
+		t.Errorf("TestGetLogger wanted logger '%v', got '%v'", entry, ctxLogger)
+	}
+
+	noLoggerInReq, _ := http.NewRequest("GET", "http://example.com/foo", nil)
+	ctxLogger = GetLogger(noLoggerInReq.Context())
+	if ctxLogger != nil {
+		t.Errorf("TestGetLogger wanted nil logger, got '%v'", ctxLogger)
+	}
+}
+
 func TestProtect(t *testing.T) {
 	log.SetLevel(log.PanicLevel) // suppress logs in test output
 	mockWriter := httptest.NewRecorder()
 	mockReq, _ := http.NewRequest("GET", "http://example.com/foo", nil)
 	mockReq = mockReq.WithContext(
-		context.WithValue(mockReq.Context(), CtxValueLogger, log.WithField("test", "yep")),
+		context.WithValue(mockReq.Context(), ctxValueLogger, log.WithField("test", "yep")),
 	)
 	h := Protect(func(w http.ResponseWriter, req *http.Request) {
 		panic("oh noes!")
@@ -97,3 +115,21 @@ func TestProtect(t *testing.T) {
 		t.Errorf("TestProtect wanted body %s, got %s", expectBody, actualBody)
 	}
 }
+
+func TestGetRequestID(t *testing.T) {
+	log.SetLevel(log.PanicLevel) // suppress logs in test output
+	reqID := "alphabetsoup"
+	mockReq, _ := http.NewRequest("GET", "http://example.com/foo", nil)
+	ctx := context.WithValue(mockReq.Context(), ctxValueRequestID, reqID)
+	mockReq = mockReq.WithContext(ctx)
+	ctxReqID := GetRequestID(mockReq.Context())
+	if reqID != ctxReqID {
+		t.Errorf("TestGetRequestID wanted request ID '%s', got '%s'", reqID, ctxReqID)
+	}
+
+	noReqIDInReq, _ := http.NewRequest("GET", "http://example.com/foo", nil)
+	ctxReqID = GetRequestID(noReqIDInReq.Context())
+	if ctxReqID != "" {
+		t.Errorf("TestGetRequestID wanted empty request ID, got '%s'", ctxReqID)
+	}
+}