Support being given an oauth2 TokenSource

reddit/reddit-oauth.go

@@ -60,12 +60,15 @@ func (s *oauthTwoLeggedTokenSource) Token() (*oauth2.Token, error) {
 	return s.config.Token(s.ctx)
 }
 
+
 func oauthTransport(client *Client) http.RoundTripper {
 	httpClient := &http.Client{Transport: client.client.Transport}
 	ctx := context.WithValue(context.Background(), oauth2.HTTPClient, httpClient)
 
 	var tokenSource oauth2.TokenSource
-	if client.applicationOnlyOAuth {
+	if client.tknSource != nil {
+		tokenSource = client.tknSource
+	} else if client.applicationOnlyOAuth {
 		tokenSource = &oauthTwoLeggedTokenSource{
 			ctx: ctx,
 			config: &clientcredentials.Config{

reddit/reddit-options.go

@@ -5,6 +5,9 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+
+
+	"golang.org/x/oauth2"
 )
 
 // Opt is used to further configure a client upon initialization.
@@ -65,6 +68,13 @@ func WithApplicationOnlyOAuth(o bool) Opt {
 	}
 }
 
+func WithOAuthTokenSource(tkn oauth2.TokenSource) Opt {
+	return func(c *Client) error {
+		c.tknSource = tkn
+		return nil
+	}
+}
+
 // FromEnv configures the client with values from environment variables.
 // Supported environment variables:
 // GO_REDDIT_CLIENT_ID to set the client's id.

reddit/reddit.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"github.com/google/go-querystring/query"
+	"golang.org/x/oauth2"
 )
 
 const (
@@ -96,6 +97,7 @@ type Client struct {
 	Wiki       *WikiService
 
 	applicationOnlyOAuth bool
+	tknSource oauth2.TokenSource
 
 	onRequestCompleted RequestCompletionCallback
 }