Allow configs to be initialised with zero values for Client and Transport.

google/appengine.go

@@ -3,6 +3,8 @@
 package google
 
 import (
+	"net/http"
+
 	"github.com/golang/oauth2"
 
 	"appengine"
@@ -25,11 +27,6 @@ type AppEngineConfig struct {
 // provided auth scopes.
 func NewAppEngineConfig(context appengine.Context, scopes []string) *AppEngineConfig {
 	return &AppEngineConfig{
-		Transport: &urlfetch.Transport{
-			Context:                       context,
-			Deadline:                      0,
-			AllowInvalidServerCertificate: false,
-		},
 		context: context,
 		scopes:  scopes,
 	}
@@ -38,7 +35,7 @@ func NewAppEngineConfig(context appengine.Context, scopes []string) *AppEngineCo
 // NewTransport returns a transport that authorizes
 // the requests with the application's service account.
 func (c *AppEngineConfig) NewTransport() *oauth2.Transport {
-	return oauth2.NewTransport(c.Transport, c, nil)
+	return oauth2.NewTransport(c.transport(), c, nil)
 }
 
 // FetchToken fetches a new access token for the provided scopes.
@@ -52,3 +49,10 @@ func (c *AppEngineConfig) FetchToken(existing *oauth2.Token) (*oauth2.Token, err
 		Expiry:      expiry,
 	}, nil
 }
+
+func (c *AppEngineConfig) transport() http.RoundTripper {
+	if c.Transport != nil {
+		return c.Transport
+	}
+	return &urlfetch.Transport{Context: c.context}
+}

google/appenginevm.go

@@ -12,7 +12,7 @@ import (
 // AppEngineConfig represents a configuration for an
 // App Engine application's Google service account.
 type AppEngineConfig struct {
-	// Transport is the round tripper to be used
+	// Transport is the http.RoundTripper to be used
 	// to construct new oauth2.Transport instances from
 	// this configuration.
 	Transport http.RoundTripper
@@ -25,16 +25,15 @@ type AppEngineConfig struct {
 // provided auth scopes.
 func NewAppEngineConfig(context appengine.Context, scopes []string) *AppEngineConfig {
 	return &AppEngineConfig{
-		Transport: http.DefaultTransport,
-		context:   context,
-		scopes:    scopes,
+		context: context,
+		scopes:  scopes,
 	}
 }
 
 // NewTransport returns a transport that authorizes
 // the requests with the application's service account.
 func (c *AppEngineConfig) NewTransport() *oauth2.Transport {
-	return oauth2.NewTransport(c.Transport, c, nil)
+	return oauth2.NewTransport(c.transport(), c, nil)
 }
 
 // FetchToken fetches a new access token for the provided scopes.
@@ -48,3 +47,10 @@ func (c *AppEngineConfig) FetchToken(existing *oauth2.Token) (*oauth2.Token, err
 		Expiry:      expiry,
 	}, nil
 }
+
+func (c *AppEngineConfig) transport() http.RoundTripper {
+	if c.Transport != nil {
+		return c.Transport
+	}
+	return http.DefaultTransport
+}

google/google.go

@@ -65,16 +65,12 @@ func NewServiceAccountConfig(opts *oauth2.JWTOptions) (*oauth2.JWTConfig, error)
 // from Google Compute Engine instance's metaserver. If no account is
 // provided, default is used.
 func NewComputeEngineConfig(account string) *ComputeEngineConfig {
-	return &ComputeEngineConfig{
-		Client:    http.DefaultClient,
-		Transport: http.DefaultTransport,
-		account:   account,
-	}
+	return &ComputeEngineConfig{account: account}
 }
 
 // NewTransport creates an authorized transport.
 func (c *ComputeEngineConfig) NewTransport() *oauth2.Transport {
-	return oauth2.NewTransport(c.Transport, c, nil)
+	return oauth2.NewTransport(c.transport(), c, nil)
 }
 
 // FetchToken retrieves a new access token via metadata server.
@@ -89,7 +85,7 @@ func (c *ComputeEngineConfig) FetchToken(existing *oauth2.Token) (token *oauth2.
 		return
 	}
 	req.Header.Add("X-Google-Metadata-Request", "True")
-	resp, err := c.Client.Do(req)
+	resp, err := c.client().Do(req)
 	if err != nil {
 		return
 	}
@@ -106,3 +102,17 @@ func (c *ComputeEngineConfig) FetchToken(existing *oauth2.Token) (token *oauth2.
 	}
 	return
 }
+
+func (c *ComputeEngineConfig) transport() http.RoundTripper {
+	if c.Transport != nil {
+		return c.Transport
+	}
+	return http.DefaultTransport
+}
+
+func (c *ComputeEngineConfig) client() *http.Client {
+	if c.Client != nil {
+		return c.Client
+	}
+	return http.DefaultClient
+}