Add OAuth config

Adding 0Auth config values based on this PR from echo-swagger:
swaggo/echo-swagger#25

swagger.go

@@ -30,6 +30,22 @@ type Config struct {
 	Layout                   SwaggerLayout
 	DefaultModelsExpandDepth ModelsExpandDepthType
 	ShowExtensions           bool
+
+	// The information for OAuth2 integration, if any.
+	OAuth *OAuthConfig
+}
+
+// OAuthConfig stores configuration for Swagger UI OAuth2 integration. See
+// https://swagger.io/docs/open-source-tools/swagger-ui/usage/oauth2/ for further details.
+type OAuthConfig struct {
+	// The ID of the client sent to the OAuth2 IAM provider.
+	ClientId string
+
+	// The OAuth2 realm that the client should operate in. If not applicable, use empty string.
+	Realm string
+
+	// The name to display for the application in the authentication popup.
+	AppName string
 }
 
 // URL presents the url pointing to API definition (normally swagger.json or swagger.yaml).
@@ -113,6 +129,12 @@ func AfterScript(js string) func(*Config) {
 	}
 }
 
+func OAuth(config *OAuthConfig) func(*Config) {
+	return func(c *Config) {
+		c.OAuth = config
+	}
+}
+
 type SwaggerLayout string
 
 const (
@@ -176,7 +198,6 @@ func newConfig(configFns ...func(*Config)) *Config {
 
 // Handler wraps `http.Handler` into `http.HandlerFunc`.
 func Handler(configFns ...func(*Config)) http.HandlerFunc {
-
 	config := newConfig(configFns...)
 
 	// create a template with name
@@ -334,6 +355,13 @@ window.onload = function() {
     defaultModelsExpandDepth: {{.DefaultModelsExpandDepth}},
     showExtensions: {{.ShowExtensions}}
   })
+  {{if .OAuth}}
+  ui.initOAuth({
+    clientId: "{{.OAuth.ClientId}}",
+    realm: "{{.OAuth.Realm}}",
+    appName: "{{.OAuth.AppName}}"
+  })
+  {{end}}
 
   window.ui = ui
   {{- if .AfterScript}}

swagger_test.go

@@ -40,7 +40,6 @@ func (s *mockedSwag) ReadDoc() string {
 }
 
 func TestWrapHandler(t *testing.T) {
-
 	tests := []struct {
 		RootFolder   string
 		InstanceName string
@@ -110,6 +109,24 @@ func TestWrapHandler(t *testing.T) {
 	}
 }
 
+func TestConfigWithOAuth(t *testing.T) {
+	router := http.NewServeMux()
+	router.Handle("/", Handler(OAuth(&OAuthConfig{
+		ClientId: "my-client-id",
+		Realm:    "my-realm",
+		AppName:  "My App Name",
+	})))
+
+	w := performRequest(http.MethodGet, "/index.html", router)
+	assert.Equal(t, 200, w.Code)
+	body := w.Body.String()
+	assert.Contains(t, body, `ui.initOAuth({
+    clientId: "my-client-id",
+    realm: "my-realm",
+    appName: "My App Name"
+  })`)
+}
+
 func performRequest(method, target string, h http.Handler) *httptest.ResponseRecorder {
 	r := httptest.NewRequest(method, target, nil)
 	w := httptest.NewRecorder()
@@ -199,7 +216,6 @@ func TestPersistAuthorization(t *testing.T) {
 }
 
 func TestConfigURL(t *testing.T) {
-
 	type fixture struct {
 		desc  string
 		cfgfn func(c *Config)
@@ -293,7 +309,6 @@ func TestConfigURL(t *testing.T) {
 }
 
 func TestUIConfigOptions(t *testing.T) {
-
 	type fixture struct {
 		desc string
 		cfg  *Config
@@ -390,7 +405,7 @@ func TestUIConfigOptions(t *testing.T) {
 				DefaultModelsExpandDepth: ShowModel,
 			},
 			exp: `window.onload = function() {
-  
+
   const ui = SwaggerUIBundle({
     url: "doc.json",
     deepLinking:  true ,
@@ -406,9 +421,11 @@ func TestUIConfigOptions(t *testing.T) {
       SwaggerUIBundle.plugins.DownloadUrl
     ],
     layout: "StandaloneLayout",
-    defaultModelsExpandDepth:  1 
+    defaultModelsExpandDepth:  1 ,
+    showExtensions:  false
   })
 
+
   window.ui = ui
 }`,
 		},
@@ -445,7 +462,7 @@ func TestUIConfigOptions(t *testing.T) {
     // Some plugin
   });
 
-  
+
   const ui = SwaggerUIBundle({
     url: "swagger.json",
     deepLinking:  false ,
@@ -466,9 +483,11 @@ func TestUIConfigOptions(t *testing.T) {
     onComplete: () => { window.ui.setBasePath('v3'); },
     showExtensions: true,
     layout: "StandaloneLayout",
-    defaultModelsExpandDepth:  -1 
+    defaultModelsExpandDepth:  -1 ,
+	showExtensions: true
   })
 
+
   window.ui = ui
   const someOtherCode = function(){
     // Do something
@@ -572,3 +591,23 @@ func TestShowExtensions(t *testing.T) {
 	cfg = newConfig(ShowExtensions(false))
 	assert.False(t, cfg.ShowExtensions)
 }
+
+func TestOAuth(t *testing.T) {
+	var cfg Config
+	expected := OAuthConfig{
+		ClientId: "my-client-id",
+		Realm:    "my-realm",
+		AppName:  "My App Name",
+	}
+	OAuth(&expected)(&cfg)
+	assert.Equal(t, expected.ClientId, cfg.OAuth.ClientId)
+	assert.Equal(t, expected.Realm, cfg.OAuth.Realm)
+	assert.Equal(t, expected.AppName, cfg.OAuth.AppName)
+}
+
+func TestOAuthNil(t *testing.T) {
+	var cfg Config
+	var expected *OAuthConfig
+	OAuth(expected)(&cfg)
+	assert.Equal(t, expected, cfg.OAuth)
+}