From d8421bcddcfc93e38fc0b5f2d789b80bf329519b Mon Sep 17 00:00:00 2001
From: Kegan Dougal <kegan@matrix.org>
Date: Thu, 16 Feb 2017 17:32:20 +0000
Subject: [PATCH] Add basic routing based on matched paths

---
 .../dendrite/clientapi/clientapi.go           | 16 +-----
 .../dendrite/clientapi/routing/routing.go     | 56 +++++++++++++++++++
 2 files changed, 58 insertions(+), 14 deletions(-)
 create mode 100644 src/github.com/matrix-org/dendrite/clientapi/routing/routing.go

diff --git a/src/github.com/matrix-org/dendrite/clientapi/clientapi.go b/src/github.com/matrix-org/dendrite/clientapi/clientapi.go
index 989dbf3b2..b646904d9 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/clientapi.go
+++ b/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))
 }
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go b/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go
new file mode 100644
index 000000000..177187a2b
--- /dev/null
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go
@@ -0,0 +1,56 @@
+package routing
+
+import (
+	"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"
+	"net/http"
+	"strings"
+)
+
+const pathPrefixR0 = "/_matrix/client/r0"
+
+// Return true if this path should be handled by this handler
+type matcher func(path string) bool
+
+type lookup struct {
+	Matches matcher
+	Handler http.Handler
+}
+
+func newLookup(name string, m matcher, h util.JSONRequestHandler) lookup {
+	return lookup{
+		Matches: m,
+		Handler: prometheus.InstrumentHandler(name, util.MakeJSONAPI(h)),
+	}
+}
+
+func matchesString(str string) func(path string) bool {
+	return func(path string) bool {
+		return path == str
+	}
+}
+
+// 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) {
+	var r0lookups []lookup
+	r0lookups = append(r0lookups, newLookup("sync", matchesString("/sync"), &readers.Sync{}))
+
+	mux.Handle("/metrics", prometheus.Handler())
+	mux.HandleFunc("/api/", func(w http.ResponseWriter, req *http.Request) {
+		clientServerPath := strings.TrimPrefix(req.URL.Path, "/api")
+		if strings.HasPrefix(clientServerPath, pathPrefixR0) {
+			apiPath := strings.TrimPrefix(clientServerPath, pathPrefixR0)
+			for _, lookup := range r0lookups {
+				if lookup.Matches(apiPath) {
+					lookup.Handler.ServeHTTP(w, req)
+					return
+				}
+			}
+		}
+		w.WriteHeader(404)
+		w.Write([]byte(`{"error":"Not found","errcode":"M_NOT_FOUND"}`))
+	})
+}