Properly handle unversioned requests in path based version mux.

Author: raphael

mux.go

@@ -65,25 +65,30 @@ type (
 )
 
 // NewMux creates a top level mux using the default goa mux implementation.
+// The default versioning handling assumes that the base path for the API is "/api" and the
+// base paths for each version "/:version/api". Use SelectVersion to specify a different scheme
+// if the service exposes a versioned API with different base paths.
 func NewMux() ServeMux {
 	return &DefaultMux{
 		defaultVersionMux: &defaultVersionMux{
 			router:  httprouter.New(),
 			handles: make(map[string]HandleFunc),
 		},
-		selectVersion: PathSelectVersionFunc("/:version/"),
+		selectVersion: PathSelectVersionFunc("/:version/", "api"),
 	}
 }
 
 // PathSelectVersionFunc returns a SelectVersionFunc that uses the given path pattern to extract the
 // version from the request path. Use the same path pattern given in the DSL to define the API base
 // path, e.g. "/api/:version".
-func PathSelectVersionFunc(pattern string) SelectVersionFunc {
+// If the pattern matches zeroVersion then the empty version is returned (i.e. the unversioned
+// controller handles the request).
+func PathSelectVersionFunc(pattern, zeroVersion string) SelectVersionFunc {
 	rgs := design.WildcardRegex.ReplaceAllLiteralString(pattern, `/([^/]+)`)
 	rg := regexp.MustCompile("^" + rgs)
 	return func(req *http.Request) (version string) {
 		match := rg.FindStringSubmatch(req.URL.Path)
-		if len(match) > 1 {
+		if len(match) > 1 && match[1] != zeroVersion {
 			version = match[1]
 		}
 		return

mux_test.go

@@ -0,0 +1,54 @@
+package goa_test
+
+import (
+	"net/http"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"github.com/raphael/goa"
+)
+
+var _ = Describe("PathSelectVersionFunc", func() {
+	var pattern, zeroVersion string
+	var request *http.Request
+
+	var fn goa.SelectVersionFunc
+	var version string
+
+	JustBeforeEach(func() {
+		fn = goa.PathSelectVersionFunc(pattern, zeroVersion)
+		version = fn(request)
+	})
+
+	Context("using the default settings", func() {
+		BeforeEach(func() {
+			pattern = "/:version/"
+			zeroVersion = "api"
+		})
+
+		Context("and a versioned request", func() {
+			BeforeEach(func() {
+				var err error
+				request, err = http.NewRequest("GET", "/v1/foo", nil)
+				Ω(err).ShouldNot(HaveOccurred())
+			})
+
+			It("routes to the versioned controller", func() {
+				Ω(version).Should(Equal("v1"))
+			})
+		})
+
+		Context("and an unversioned request", func() {
+			BeforeEach(func() {
+				var err error
+				request, err = http.NewRequest("GET", "/api/foo", nil)
+				Ω(err).ShouldNot(HaveOccurred())
+			})
+
+			It("routes to the unversioned controller", func() {
+				Ω(version).Should(Equal(""))
+			})
+		})
+	})
+
+})