dnsimple: handle ExchangeAuthorizationForToken error response

dnsimple/oauth.go

@@ -1,6 +1,9 @@
 package dnsimple
 
 import (
+	"encoding/json"
+	"fmt"
+	"net/http"
 	"net/url"
 	"strings"
 )
@@ -32,18 +35,50 @@ type ExchangeAuthorizationRequest struct {
 	GrantType string `json:"grant_type,omitempty"`
 }
 
+// ExchangeAuthorizationError represents a failed request to exchange
+// an authorization code for an access token.
+type ExchangeAuthorizationError struct {
+	// HTTP response
+	HttpResponse *http.Response
+
+	ErrorCode        string `json:"error"`
+	ErrorDescription string `json:"error_description"`
+}
+
+// Error implements the error interface.
+func (r *ExchangeAuthorizationError) Error() string {
+	return fmt.Sprintf("%v %v: %v %v",
+		r.HttpResponse.Request.Method, r.HttpResponse.Request.URL,
+		r.ErrorCode, r.ErrorDescription)
+}
+
 // ExchangeAuthorizationForToken exchanges the short-lived authorization code for an access token
 // you can use to authenticate your API calls.
 func (s *OauthService) ExchangeAuthorizationForToken(authorization *ExchangeAuthorizationRequest) (*AccessToken, error) {
 	path := versioned("/oauth/access_token")
-	accessToken := &AccessToken{}
 
-	_, err := s.client.post(path, authorization, accessToken)
+	req, err := s.client.NewRequest("POST", path, authorization)
 	if err != nil {
 		return nil, err
 	}
 
-	return accessToken, nil
+	resp, err := s.client.HttpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		errorResponse := &ExchangeAuthorizationError{}
+		errorResponse.HttpResponse = resp
+		json.NewDecoder(resp.Body).Decode(errorResponse)
+		return nil, errorResponse
+	}
+
+	accessToken := &AccessToken{}
+	err = json.NewDecoder(resp.Body).Decode(accessToken)
+
+	return accessToken, err
 }
 
 // AuthorizationOptions represents the option you can use to generate an authorization URL.

dnsimple/oauth_test.go

@@ -40,6 +40,32 @@ func TestOauthService_ExchangeAuthorizationForToken(t *testing.T) {
 	}
 }
 
+func TestOauthService_ExchangeAuthorizationForToken_Error(t *testing.T) {
+	setupMockServer()
+	defer teardownMockServer()
+
+	mux.HandleFunc("/v2/oauth/access_token", func(w http.ResponseWriter, r *http.Request) {
+		httpResponse := httpResponseFixture(t, "/oauthAccessToken/error-invalid_request.http")
+
+		w.WriteHeader(httpResponse.StatusCode)
+		io.Copy(w, httpResponse.Body)
+	})
+
+	_, err := client.Oauth.ExchangeAuthorizationForToken(&ExchangeAuthorizationRequest{Code: "1234567890", ClientID: "a1b2c3", ClientSecret: "thisisasecret", GrantType: "authorization_code"})
+	if err == nil {
+		t.Fatalf("Oauth.ExchangeAuthorizationForToken() expected to return an error")
+	}
+
+	switch v := err.(type) {
+	case *ExchangeAuthorizationError:
+		if want := `Invalid "state": value doesn't match the "state" in the authorization request`; v.ErrorDescription != want {
+			t.Errorf("Oauth.ExchangeAuthorizationForToken() error is %v, want %v", v, want)
+		}
+	default:
+		t.Fatalf("Oauth.ExchangeAuthorizationForToken() error type unknown: %v", v.Error())
+	}
+}
+
 func TestOauthService_AuthorizeURL(t *testing.T) {
 	clientID := "a1b2c3"
 	client.BaseURL = "https://api.host.test"

fixtures.http/oauthAccessToken/error-invalid_request.http

@@ -0,0 +1,16 @@
+HTTP/1.1 400 Bad Request
+Server: nginx
+Date: Mon, 08 Feb 2016 21:24:19 GMT
+Content-Type: application/json; charset=utf-8
+Transfer-Encoding: chunked
+Connection: keep-alive
+X-RateLimit-Limit: 30
+X-RateLimit-Remaining: 29
+X-RateLimit-Reset: 1454970259
+ETag: W/"def417b4ade951f8148bb6a4fa3fcf5a"
+Cache-Control: max-age=0, private, must-revalidate
+X-Request-Id: e8c544cf-fcc3-4762-a200-60c0320a2575
+X-Runtime: 0.105600
+Strict-Transport-Security: max-age=31536000
+
+{"error":"invalid_request","error_description":"Invalid \"state\": value doesn't match the \"state\" in the authorization request"}