remove any trailing slash that may passed on StaticEmbeddedHandler (although all examples shows the correct way but you never know)

Former-commit-id: 50ab9ddb2e738b4061622ac9ebcfec30e0cdecfa

context/response_recorder.go

@@ -85,7 +85,9 @@ func (w *ResponseRecorder) EndResponse() {
 // possible to maximize compatibility.
 func (w *ResponseRecorder) Write(contents []byte) (int, error) {
 	w.chunks = append(w.chunks, contents...)
-	return len(w.chunks), nil
+	// Remember that we should not return all the written length within `Write`:
+	// see https://github.com/kataras/iris/pull/931
+	return len(contents), nil
 }
 
 // Writef formats according to a format specifier and writes to the response.

core/router/api_builder.go

@@ -629,7 +629,7 @@ func (api *APIBuilder) StaticContent(reqPath string, cType string, content []byt
 
 // StaticEmbedded  used when files are distributed inside the app executable, using go-bindata mostly
 // First parameter is the request path, the path which the files in the vdir will be served to, for example "/static"
-// Second parameter is the (virtual) directory path, for example "./assets"
+// Second parameter is the (virtual) directory path, for example "./assets" (no trailing slash),
 // Third parameter is the Asset function
 // Forth parameter is the AssetNames function.
 //
@@ -646,6 +646,10 @@ func (api *APIBuilder) StaticEmbedded(requestPath string, vdir string, assetFn f
 // it sends gzip response only, so the client must be aware that is expecting a gzip body
 // (browsers and most modern browsers do that, so you can use it without fair).
 //
+// First parameter is the request path, the path which the files in the vdir will be served to, for example "/static"
+// Second parameter is the (virtual) directory path, for example "./assets" (no trailing slash),
+// Third parameter is the GzipAsset function
+// Forth parameter is the GzipAssetNames function.
 //
 // Example: https://github.com/kataras/iris/tree/master/_examples/file-server/embedding-gziped-files-into-app
 func (api *APIBuilder) StaticEmbeddedGzip(requestPath string, vdir string, gzipAssetFn func(name string) ([]byte, error), gzipNamesFn func() []string) *Route {

core/router/fs.go

@@ -42,6 +42,14 @@ func StaticEmbeddedHandler(vdir string, assetFn func(name string) ([]byte, error
 		if vdir[0] == '/' || vdir[0] == os.PathSeparator { // second check for /something, (or ./something if we had dot on 0 it will be removed
 			vdir = vdir[1:]
 		}
+
+		// check for trailing slashes because new users may be do that by mistake
+		// although all examples are showing the correct way but you never know
+		// i.e "./assets/" is not correct, if was inside "./assets".
+		// remove last "/".
+		if trailingSlashIdx := len(vdir) - 1; vdir[trailingSlashIdx] == '/' {
+			vdir = vdir[0:trailingSlashIdx]
+		}
 	}
 
 	// collect the names we are care for,