add a new 'Context.GzipReader(bool) method and 'iris.GzipReader' middleware as requested at #1528

Former-commit-id: 7665545069bf1784d17a9db1e5f9f5f8df4b0c43

_examples/http_request/read-gzip/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"github.com/kataras/iris/v12"
+)
+
+func main() {
+	app := newApp()
+	app.Logger().SetLevel("debug")
+
+	app.Listen(":8080")
+}
+
+type payload struct {
+	Message string `json:"message"`
+}
+
+func newApp() *iris.Application {
+	app := iris.New()
+
+	// GzipReader is a middleware which enables gzip decompression,
+	// when client sends gzip compressed data.
+	//
+	// A shortcut of:
+	// func(ctx iris.Context) {
+	//	ctx.GzipReader(true)
+	//	ctx.Next()
+	// }
+	app.Use(iris.GzipReader)
+
+	app.Post("/", func(ctx iris.Context) {
+		// Bind incoming gzip compressed JSON to "p".
+		var p payload
+		if err := ctx.ReadJSON(&p); err != nil {
+			ctx.StopWithError(iris.StatusBadRequest, err)
+			return
+		}
+
+		// Send back the message as plain text.
+		ctx.WriteString(p.Message)
+	})
+
+	return app
+}