Merge pull request #169 from monzo/add-router-endpoint-pattern

Add router endpoint pattern method to Typhon Request

Author: RohanPadmanabhan

request.go

@@ -183,7 +183,7 @@ func (r *Request) BodyBytes(consume bool) ([]byte, error) {
 // Send round-trips the request via the default Client. It does not block, instead returning a ResponseFuture
 // representing the asynchronous operation to produce the response. It is equivalent to:
 //
-//  r.SendVia(Client)
+//	r.SendVia(Client)
 func (r Request) Send() *ResponseFuture {
 	return Send(r)
 }
@@ -213,6 +213,16 @@ func (r Request) ResponseWithCode(body interface{}, statusCode int) Response {
 	return rsp
 }
 
+// RequestPathPattern finds the router entry pattern that matches the request
+func (r Request) RequestPathPattern() string {
+	return routerPathPatternForRequest(r)
+}
+
+// RequestMethod returns the HTTP method of the request
+func (r Request) RequestMethod() string {
+	return r.Method
+}
+
 func (r Request) String() string {
 	if r.URL == nil {
 		return "Request(Unknown)"

request_test.go

@@ -7,6 +7,7 @@ import (
 	"encoding/json"
 	"io/ioutil"
 	"math"
+	"net/http"
 	"strings"
 	"testing"
 
@@ -223,6 +224,27 @@ func TestRequestSetMetadata(t *testing.T) {
 	assert.Equal(t, []string{"data"}, req.Request.Header["meta"])
 }
 
+func TestRouterEndpointPattern(t *testing.T) {
+	req := NewRequest(context.Background(), http.MethodGet, "/foo/some-url-identifier", nil)
+	assert.Equal(t, "", req.RequestPathPattern()) // should be empty if request has not been served by a router
+
+	router := Router{}
+	routerEndpointPattern := "/foo/:id"
+	router.GET(routerEndpointPattern, func(req Request) Response {
+		// as we are currently serving the request, we should be able to get the router endpoint pattern
+		assert.Equal(t, routerEndpointPattern, req.RequestPathPattern())
+		return req.Response(nil)
+	})
+
+	rsp := req.SendVia(router.Serve()).Response()
+	require.NoError(t, rsp.Error) // check we didn't get a "route not found" error
+}
+
+func TestRequestMethod(t *testing.T) {
+	req := NewRequest(context.Background(), http.MethodGet, "", nil)
+	assert.Equal(t, http.MethodGet, req.RequestMethod())
+}
+
 func jsonStreamMarshal(v interface{}) ([]byte, error) {
 	var buffer bytes.Buffer
 	writer := bufio.NewWriter(&buffer)

router.go

@@ -13,10 +13,12 @@ import (
 // directly means we'd get a collision with any other package that does the same.
 // https://play.golang.org/p/MxhRiL37R-9
 type routerContextKeyType struct{}
+type routerRequestPatternContextKeyType struct{}
 
 var (
-	routerContextKey   = routerContextKeyType{}
-	routerComponentsRe = regexp.MustCompile(`(?:^|/)(\*\w*|:\w+)`)
+	routerContextKey               = routerContextKeyType{}
+	routerRequestPatternContextKey = routerRequestPatternContextKeyType{}
+	routerComponentsRe             = regexp.MustCompile(`(?:^|/)(\*\w*|:\w+)`)
 )
 
 type routerEntry struct {
@@ -44,6 +46,13 @@ func RouterForRequest(r Request) *Router {
 	return nil
 }
 
+func routerPathPatternForRequest(r Request) string {
+	if v := r.Context.Value(routerRequestPatternContextKey); v != nil {
+		return v.(string)
+	}
+	return ""
+}
+
 func (r *Router) compile(pattern string) *regexp.Regexp {
 	re, pos := ``, 0
 	for _, m := range routerComponentsRe.FindAllStringSubmatchIndex(pattern, -1) {
@@ -116,14 +125,15 @@ func (r Router) Lookup(method, path string) (Service, string, map[string]string,
 // Serve returns a Service which will route inbound requests to the enclosed routes.
 func (r Router) Serve() Service {
 	return func(req Request) Response {
-		svc, _, ok := r.lookup(req.Method, req.URL.Path, nil)
+		svc, pathPattern, ok := r.lookup(req.Method, req.URL.Path, nil)
 		if !ok {
 			txt := fmt.Sprintf("No handler for %s %s", req.Method, req.URL.Path)
 			rsp := NewResponse(req)
 			rsp.Error = terrors.NotFound("no_handler", txt, nil)
 			return rsp
 		}
 		req.Context = context.WithValue(req.Context, routerContextKey, &r)
+		req.Context = context.WithValue(req.Context, routerRequestPatternContextKey, pathPattern)
 		rsp := svc(req)
 		if rsp.Request == nil {
 			rsp.Request = &req