feat: more options for UI middleware

- refactored UI middleware
  * factorized chore middleware to remove duplicated code
  * factorized UI middleware options: to avoid breaking changes in the
    options types, there is a decode/encode to a common structure
  * added more options:
    * allows to fully customize the UI template
  * added more unit tests

- Spec middleware: added support for optional SpecOption argument
  * allows to serve the spec from a custom path / document name

- serving with or without trailing "/" (cf. issue #238)
  * replaced path.Join() by path.Clean(), which is the intended behavior
    (i.e. serve the path, irrespective of the presence of a trailing
    slash)
  * generalized this behavior to all UI and Spec middleware, not just
    swaggerUI

- API Context:
  * exposed middleware to serve RapiDoc UI
  * allowed new UIOption (...UIOption) to the APIHandler, etc middleware
  * coordinated UI / Spec middleware to be consistent when non-default
    path/document URL is served

* fixes #192
* fixes #226

Signed-off-by: Frederic BIDON <fredbi@yahoo.com>

middleware/context.go

@@ -18,6 +18,8 @@ import (
 	stdContext "context"
 	"fmt"
 	"net/http"
+	"net/url"
+	"path"
 	"strings"
 	"sync"
 
@@ -584,45 +586,92 @@ func (c *Context) Respond(rw http.ResponseWriter, r *http.Request, produces []st
 	c.api.ServeErrorFor(route.Operation.ID)(rw, r, errors.New(http.StatusInternalServerError, "can't produce response"))
 }
 
-func (c *Context) APIHandlerSwaggerUI(builder Builder) http.Handler {
+// APIHandlerSwaggerUI returns a handler to serve the API.
+//
+// This handler includes a swagger spec, router and the contract defined in the swagger spec.
+//
+// A spec UI (SwaggerUI) is served at {API base path}/docs and the spec document at /swagger.json
+// (these can be modified with uiOptions).
+func (c *Context) APIHandlerSwaggerUI(builder Builder, opts ...UIOption) http.Handler {
 	b := builder
 	if b == nil {
 		b = PassthroughBuilder
 	}
 
-	var title string
-	sp := c.spec.Spec()
-	if sp != nil && sp.Info != nil && sp.Info.Title != "" {
-		title = sp.Info.Title
-	}
+	specPath, uiOpts, specOpts := c.uiOptionsForHandler(opts)
+	var swaggerUIOpts SwaggerUIOpts
+	fromCommonToAnyOptions(uiOpts, &swaggerUIOpts)
+
+	return Spec(specPath, c.spec.Raw(), SwaggerUI(swaggerUIOpts, c.RoutesHandler(b)), specOpts...)
+}
 
-	swaggerUIOpts := SwaggerUIOpts{
-		BasePath: c.BasePath(),
-		Title:    title,
+// APIHandlerRapiDoc returns a handler to serve the API.
+//
+// This handler includes a swagger spec, router and the contract defined in the swagger spec.
+//
+// A spec UI (RapiDoc) is served at {API base path}/docs and the spec document at /swagger.json
+// (these can be modified with uiOptions).
+func (c *Context) APIHandlerRapiDoc(builder Builder, opts ...UIOption) http.Handler {
+	b := builder
+	if b == nil {
+		b = PassthroughBuilder
 	}
 
-	return Spec("", c.spec.Raw(), SwaggerUI(swaggerUIOpts, c.RoutesHandler(b)))
+	specPath, uiOpts, specOpts := c.uiOptionsForHandler(opts)
+	var rapidocUIOpts RapiDocOpts
+	fromCommonToAnyOptions(uiOpts, &rapidocUIOpts)
+
+	return Spec(specPath, c.spec.Raw(), RapiDoc(rapidocUIOpts, c.RoutesHandler(b)), specOpts...)
 }
 
-// APIHandler returns a handler to serve the API, this includes a swagger spec, router and the contract defined in the swagger spec
-func (c *Context) APIHandler(builder Builder) http.Handler {
+// APIHandler returns a handler to serve the API.
+//
+// This handler includes a swagger spec, router and the contract defined in the swagger spec.
+//
+// A spec UI (Redoc) is served at {API base path}/docs and the spec document at /swagger.json
+// (these can be modified with uiOptions).
+func (c *Context) APIHandler(builder Builder, opts ...UIOption) http.Handler {
 	b := builder
 	if b == nil {
 		b = PassthroughBuilder
 	}
 
+	specPath, uiOpts, specOpts := c.uiOptionsForHandler(opts)
+	var redocOpts RedocOpts
+	fromCommonToAnyOptions(uiOpts, &redocOpts)
+
+	return Spec(specPath, c.spec.Raw(), Redoc(redocOpts, c.RoutesHandler(b)), specOpts...)
+}
+
+func (c Context) uiOptionsForHandler(opts []UIOption) (string, uiOptions, []SpecOption) {
 	var title string
 	sp := c.spec.Spec()
 	if sp != nil && sp.Info != nil && sp.Info.Title != "" {
 		title = sp.Info.Title
 	}
 
-	redocOpts := RedocOpts{
-		BasePath: c.BasePath(),
-		Title:    title,
+	// default options (may be overridden)
+	optsForContext := []UIOption{
+		WithUIBasePath(c.BasePath()),
+		WithUITitle(title),
+	}
+	optsForContext = append(optsForContext, opts...)
+	uiOpts := uiOptionsWithDefaults(optsForContext)
+
+	// If spec URL is provided, there is a non-default path to serve the spec.
+	// This makes sure that the UI middleware is aligned with the Spec middleware.
+	u, _ := url.Parse(uiOpts.SpecURL)
+	var specPath string
+	if u != nil {
+		specPath = u.Path
+	}
+
+	pth, doc := path.Split(specPath)
+	if pth == "." {
+		pth = ""
 	}
 
-	return Spec("", c.spec.Raw(), Redoc(redocOpts, c.RoutesHandler(b)))
+	return pth, uiOpts, []SpecOption{WithSpecDocument(doc)}
 }
 
 // RoutesHandler returns a handler to serve the API, just the routes and the contract defined in the swagger spec

middleware/context_test.go

@@ -17,6 +17,7 @@ package middleware
 import (
 	stdcontext "context"
 	"errors"
+	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -32,8 +33,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-const applicationJSON = "application/json"
-
 type stubBindRequester struct {
 }
 
@@ -131,28 +130,226 @@ func TestContentType_Issue174(t *testing.T) {
 	assert.Equal(t, http.StatusOK, recorder.Code)
 }
 
+const (
+	testHost = "https://localhost:8080"
+
+	// how to get the spec document?
+	defaultSpecPath = "/swagger.json"
+	defaultSpecURL  = testHost + defaultSpecPath
+	// how to get the UI asset?
+	defaultUIURL = testHost + "/api/docs"
+)
+
 func TestServe(t *testing.T) {
 	spec, api := petstore.NewAPI(t)
 	handler := Serve(spec, api)
 
-	// serve spec document
-	request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, "http://localhost:8080/swagger.json", nil)
-	require.NoError(t, err)
+	t.Run("serve spec document", func(t *testing.T) {
+		request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, defaultSpecURL, nil)
+		require.NoError(t, err)
 
-	request.Header.Add("Content-Type", runtime.JSONMime)
-	request.Header.Add("Accept", runtime.JSONMime)
-	recorder := httptest.NewRecorder()
+		request.Header.Add("Content-Type", runtime.JSONMime)
+		request.Header.Add("Accept", runtime.JSONMime)
+		recorder := httptest.NewRecorder()
 
-	handler.ServeHTTP(recorder, request)
-	assert.Equal(t, http.StatusOK, recorder.Code)
+		handler.ServeHTTP(recorder, request)
+		assert.Equal(t, http.StatusOK, recorder.Code)
+	})
 
-	request, err = http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, "http://localhost:8080/swagger-ui", nil)
-	require.NoError(t, err)
+	t.Run("should not find UI there", func(t *testing.T) {
+		request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, testHost+"/swagger-ui", nil)
+		require.NoError(t, err)
+		recorder := httptest.NewRecorder()
 
-	recorder = httptest.NewRecorder()
+		handler.ServeHTTP(recorder, request)
+		assert.Equal(t, http.StatusNotFound, recorder.Code)
+	})
 
-	handler.ServeHTTP(recorder, request)
-	assert.Equal(t, 404, recorder.Code)
+	t.Run("should find UI here", func(t *testing.T) {
+		request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, defaultUIURL, nil)
+		require.NoError(t, err)
+		recorder := httptest.NewRecorder()
+
+		handler.ServeHTTP(recorder, request)
+		assert.Equal(t, http.StatusOK, recorder.Code)
+
+		htmlResponse := recorder.Body.String()
+		assert.Containsf(t, htmlResponse, "<title>Swagger Petstore</title>", "should default to the API's title")
+		assert.Containsf(t, htmlResponse, "<redoc", "should default to Redoc UI")
+		assert.Containsf(t, htmlResponse, "spec-url='/swagger.json'>", "should default to /swagger.json spec document")
+	})
+}
+
+func TestServeWithUIs(t *testing.T) {
+	spec, api := petstore.NewAPI(t)
+	ctx := NewContext(spec, api, nil)
+
+	const (
+		alternateSpecURL  = testHost + "/specs/petstore.json"
+		alternateSpecPath = "/specs/petstore.json"
+		alternateUIURL    = testHost + "/ui/docs"
+	)
+
+	uiOpts := []UIOption{
+		WithUIBasePath("ui"), // override the base path from the spec, implies /ui
+		WithUIPath("docs"),
+		WithUISpecURL("/specs/petstore.json"),
+	}
+
+	t.Run("with APIHandler", func(t *testing.T) {
+		t.Run("with defaults", func(t *testing.T) {
+			handler := ctx.APIHandler(nil)
+
+			t.Run("should find UI", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, defaultUIURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+
+				htmlResponse := recorder.Body.String()
+				assert.Containsf(t, htmlResponse, "<redoc", "should default to Redoc UI")
+			})
+
+			t.Run("should find spec", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, defaultSpecURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+			})
+		})
+
+		t.Run("with options", func(t *testing.T) {
+			handler := ctx.APIHandler(nil, uiOpts...)
+
+			t.Run("should find UI", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, alternateUIURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+
+				htmlResponse := recorder.Body.String()
+				assert.Contains(t, htmlResponse, fmt.Sprintf("<redoc spec-url='%s'></redoc>", alternateSpecPath))
+			})
+
+			t.Run("should find spec", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, alternateSpecURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+			})
+		})
+	})
+
+	t.Run("with APIHandlerSwaggerUI", func(t *testing.T) {
+		t.Run("with defaults", func(t *testing.T) {
+			handler := ctx.APIHandlerSwaggerUI(nil)
+
+			t.Run("should find UI", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, defaultUIURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+
+				htmlResponse := recorder.Body.String()
+				assert.Contains(t, htmlResponse, fmt.Sprintf(`url: '%s',`, strings.ReplaceAll(defaultSpecPath, `/`, `\/`)))
+			})
+
+			t.Run("should find spec", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, defaultSpecURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+			})
+		})
+
+		t.Run("with options", func(t *testing.T) {
+			handler := ctx.APIHandlerSwaggerUI(nil, uiOpts...)
+
+			t.Run("should find UI", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, alternateUIURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+
+				htmlResponse := recorder.Body.String()
+				assert.Contains(t, htmlResponse, fmt.Sprintf(`url: '%s',`, strings.ReplaceAll(alternateSpecPath, `/`, `\/`)))
+			})
+
+			t.Run("should find spec", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, alternateSpecURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+			})
+		})
+	})
+
+	t.Run("with APIHandlerRapiDoc", func(t *testing.T) {
+		t.Run("with defaults", func(t *testing.T) {
+			handler := ctx.APIHandlerRapiDoc(nil)
+
+			t.Run("should find UI", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, defaultUIURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+
+				htmlResponse := recorder.Body.String()
+				assert.Contains(t, htmlResponse, fmt.Sprintf("<rapi-doc spec-url=%q></rapi-doc>", defaultSpecPath))
+			})
+
+			t.Run("should find spec", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, defaultSpecURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+			})
+		})
+
+		t.Run("with options", func(t *testing.T) {
+			handler := ctx.APIHandlerRapiDoc(nil, uiOpts...)
+
+			t.Run("should find UI", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, alternateUIURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+
+				htmlResponse := recorder.Body.String()
+				assert.Contains(t, htmlResponse, fmt.Sprintf("<rapi-doc spec-url=%q></rapi-doc>", alternateSpecPath))
+			})
+			t.Run("should find spec", func(t *testing.T) {
+				request, err := http.NewRequestWithContext(stdcontext.Background(), http.MethodGet, alternateSpecURL, nil)
+				require.NoError(t, err)
+				recorder := httptest.NewRecorder()
+
+				handler.ServeHTTP(recorder, request)
+				assert.Equal(t, http.StatusOK, recorder.Code)
+			})
+		})
+	})
 }
 
 func TestContextAuthorize(t *testing.T) {