use go module for dependencies (#594)

common/httpapi.go

@@ -0,0 +1,117 @@
+package common
+
+import (
+	"net/http"
+	"time"
+
+	"github.com/matrix-org/dendrite/clientapi/auth"
+	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+	opentracing "github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+// MakeAuthAPI turns a util.JSONRequestHandler function into an http.Handler which authenticates the request.
+func MakeAuthAPI(
+	metricsName string, data auth.Data,
+	f func(*http.Request, *authtypes.Device) util.JSONResponse,
+) http.Handler {
+	h := func(req *http.Request) util.JSONResponse {
+		device, err := auth.VerifyUserFromRequest(req, data)
+		if err != nil {
+			return *err
+		}
+
+		return f(req, device)
+	}
+	return MakeExternalAPI(metricsName, h)
+}
+
+// MakeExternalAPI turns a util.JSONRequestHandler function into an http.Handler.
+// This is used for APIs that are called from the internet.
+func MakeExternalAPI(metricsName string, f func(*http.Request) util.JSONResponse) http.Handler {
+	h := util.MakeJSONAPI(util.NewJSONRequestHandler(f))
+	withSpan := func(w http.ResponseWriter, req *http.Request) {
+		span := opentracing.StartSpan(metricsName)
+		defer span.Finish()
+		req = req.WithContext(opentracing.ContextWithSpan(req.Context(), span))
+		h.ServeHTTP(w, req)
+	}
+
+	return http.HandlerFunc(withSpan)
+}
+
+// MakeInternalAPI turns a util.JSONRequestHandler function into an http.Handler.
+// This is used for APIs that are internal to dendrite.
+// If we are passed a tracing context in the request headers then we use that
+// as the parent of any tracing spans we create.
+func MakeInternalAPI(metricsName string, f func(*http.Request) util.JSONResponse) http.Handler {
+	h := util.MakeJSONAPI(util.NewJSONRequestHandler(f))
+	withSpan := func(w http.ResponseWriter, req *http.Request) {
+		carrier := opentracing.HTTPHeadersCarrier(req.Header)
+		tracer := opentracing.GlobalTracer()
+		clientContext, err := tracer.Extract(opentracing.HTTPHeaders, carrier)
+		var span opentracing.Span
+		if err == nil {
+			// Default to a span without RPC context.
+			span = tracer.StartSpan(metricsName)
+		} else {
+			// Set the RPC context.
+			span = tracer.StartSpan(metricsName, ext.RPCServerOption(clientContext))
+		}
+		defer span.Finish()
+		req = req.WithContext(opentracing.ContextWithSpan(req.Context(), span))
+		h.ServeHTTP(w, req)
+	}
+
+	return http.HandlerFunc(withSpan)
+}
+
+// MakeFedAPI makes an http.Handler that checks matrix federation authentication.
+func MakeFedAPI(
+	metricsName string,
+	serverName gomatrixserverlib.ServerName,
+	keyRing gomatrixserverlib.KeyRing,
+	f func(*http.Request, *gomatrixserverlib.FederationRequest) util.JSONResponse,
+) http.Handler {
+	h := func(req *http.Request) util.JSONResponse {
+		fedReq, errResp := gomatrixserverlib.VerifyHTTPRequest(
+			req, time.Now(), serverName, keyRing,
+		)
+		if fedReq == nil {
+			return errResp
+		}
+		return f(req, fedReq)
+	}
+	return MakeExternalAPI(metricsName, h)
+}
+
+// SetupHTTPAPI registers an HTTP API mux under /api and sets up a metrics
+// listener.
+func SetupHTTPAPI(servMux *http.ServeMux, apiMux http.Handler) {
+	servMux.Handle("/metrics", promhttp.Handler())
+	servMux.Handle("/api/", http.StripPrefix("/api", apiMux))
+}
+
+// WrapHandlerInCORS adds CORS headers to all responses, including all error
+// responses.
+// Handles OPTIONS requests directly.
+func WrapHandlerInCORS(h http.Handler) http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
+		w.Header().Set("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, Authorization")
+
+		if r.Method == http.MethodOptions && r.Header.Get("Access-Control-Request-Method") != "" {
+			// Its easiest just to always return a 200 OK for everything. Whether
+			// this is technically correct or not is a question, but in the end this
+			// is what a lot of other people do (including synapse) and the clients
+			// are perfectly happy with it.
+			w.WriteHeader(http.StatusOK)
+		} else {
+			h.ServeHTTP(w, r)
+		}
+	})
+}