fix: url encode UAA oAuth client credentials

Although this header was base64 encoded, the oAuth spec requires
that is also be url encoded. This was causing client credentials
that contained special characters (e.g. `+`) to be rejected by UAA.

See:
> The client identifier is encoded using the
   "application/x-www-form-urlencoded" encoding algorithm per
   Appendix B, and the encoded value is used as the username; the client
   password is encoded using the same algorithm and used as the
   password.

https://tools.ietf.org/html/rfc6749#section-2.3.1

Related:
golang/oauth2#320

[#171268188](https://www.pivotaltracker.com/story/show/171268188_

cfroutesync/uaaclient/client.go

@@ -3,6 +3,7 @@ package uaaclient
 import (
 	"fmt"
 	"net/http"
+	"net/url"
 	"strings"
 )
 
@@ -20,12 +21,14 @@ type jsonClient interface {
 
 func (c *Client) GetToken() (string, error) {
 	reqURL := fmt.Sprintf("%s/oauth/token", c.BaseURL)
-	bodyString := fmt.Sprintf("client_id=%s&grant_type=client_credentials", c.Name)
+	bodyString := fmt.Sprintf("grant_type=client_credentials")
+
 	request, err := http.NewRequest("POST", reqURL, strings.NewReader(bodyString))
 	if err != nil {
 		return "", err
 	}
-	request.SetBasicAuth(c.Name, c.Secret)
+
+	request.SetBasicAuth(url.QueryEscape(c.Name), url.QueryEscape(c.Secret))
 	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 
 	type getTokenResponse struct {

cfroutesync/uaaclient/client_test.go

@@ -50,7 +50,7 @@ var _ = Describe("Client", func() {
 			Expect(receivedRequest.Method).To(Equal("POST"))
 			Expect(receivedRequest.URL.RawQuery).To(BeEmpty())
 			receivedBytes, _ := ioutil.ReadAll(receivedRequest.Body)
-			Expect(receivedBytes).To(Equal([]byte("client_id=some-name&grant_type=client_credentials")))
+			Expect(receivedBytes).To(Equal([]byte("grant_type=client_credentials")))
 
 			authHeader := receivedRequest.Header["Authorization"]
 			Expect(authHeader).To(HaveLen(1))
@@ -60,6 +60,30 @@ var _ = Describe("Client", func() {
 			Expect(contentType).To(Equal("application/x-www-form-urlencoded"))
 		})
 
+		Context("when the client credentials contain special characters", func() {
+			It("escapes the characters before constructing the basic auth header", func() {
+				client = &uaaclient.Client{
+					BaseURL:    "https://some.base.url",
+					Name:       "some=+/name",
+					Secret:     "some%!@secret",
+					JSONClient: jsonClient,
+				}
+
+				_, err := client.GetToken()
+				Expect(err).NotTo(HaveOccurred())
+				Expect(jsonClient.MakeRequestCallCount()).To(Equal(1))
+				receivedRequest, _ := jsonClient.MakeRequestArgsForCall(0)
+				Expect(receivedRequest.Method).To(Equal("POST"))
+				Expect(receivedRequest.URL.RawQuery).To(BeEmpty())
+				receivedBytes, _ := ioutil.ReadAll(receivedRequest.Body)
+				Expect(receivedBytes).To(Equal([]byte("grant_type=client_credentials")))
+
+				authHeader := receivedRequest.Header["Authorization"]
+				Expect(authHeader).To(HaveLen(1))
+				Expect(authHeader[0]).To(Equal("Basic c29tZSUzRCUyQiUyRm5hbWU6c29tZSUyNSUyMSU0MHNlY3JldA=="))
+			})
+		})
+
 		Context("when the json client returns an error", func() {
 			BeforeEach(func() {
 				jsonClient.MakeRequestReturns(errors.New("potato"))