From 4ca9948b1148eb9d9550b56663a73d5564bef296 Mon Sep 17 00:00:00 2001
From: "Gerasimos (Makis) Maropoulos" <kataras2006@hotmail.com>
Date: Thu, 4 Jul 2019 01:57:40 +0300
Subject: [PATCH] add override context methods on Routing

---
 Home.md                             |   1 +
 Routing-override-context-methods.md | 103 ++++++++++++++++++++++++++++
 _Sidebar.md                         |   1 +
 3 files changed, 105 insertions(+)
 create mode 100644 Routing-override-context-methods.md

diff --git a/Home.md b/Home.md
index 1057810..972a9f8 100644
--- a/Home.md
+++ b/Home.md
@@ -17,6 +17,7 @@ This wiki is the main source of documentation for **developers** working with (o
     * [[Handle HTTP errors|Routing-error-handlers]]
     * [[Subdomains|Routing-subdomains]]
     * [[Wrap the Router|Routing-wrap-the-router]]
+    * [[Override Context Methods]|Routing-override-context-methods]
     * [[Dependency Injection|Routing-dependency-injection]]
 * [[API Versioning]]
 * [[Cookies]]
diff --git a/Routing-override-context-methods.md b/Routing-override-context-methods.md
new file mode 100644
index 0000000..4c4c5dd
--- /dev/null
+++ b/Routing-override-context-methods.md
@@ -0,0 +1,103 @@
+In this section you will learn how to override the existing [Context](https://godoc.org/github.com/kataras/iris/context#Context)'s methods.
+
+The [Context](https://godoc.org/github.com/kataras/iris/context#Context) is an interface. However on other frameworks you don't have that functionality of overriding it even if it's used as an interface. With Iris you can **attach** your implementation to the **context pool** itself using the `app.ContextPool.Attach` method.
+
+1. Let's get started by importing the `"github.com/kataras/iris/context"` which is required here.
+2. Secondly, create your own Context implementation.
+3. Add the `Do` and `Next` methods where they just call the `context.Do` and `context.Next` package-level functions.
+4. Use the Application's `ContextPool` to set it as the Context implementation that should be used for the route's handlers.
+
+Example Code:
+
+Please read the _comments_ too.
+
+```go
+package main
+
+import (
+    "reflect"
+
+    "github.com/kataras/iris"
+    // 1.
+    "github.com/kataras/iris/context"
+)
+
+// 2.
+// Create your own custom Context, put any fields you'll need.
+type MyContext struct {
+    // Embed the `context.Context` - 
+    // It's totally optional but you will need this if you
+    // don' want to override all the context's methods!
+    context.Context
+}
+
+// Optionally: validate MyContext implements context.Context on compile-time.
+var _ context.Context = &MyContext{}
+
+// 3.
+func (ctx *MyContext) Do(handlers context.Handlers) {
+    context.Do(ctx, handlers)
+}
+
+
+// 3.
+func (ctx *MyContext) Next() {
+    context.Next(ctx)
+}
+
+// [Override any context's method you want here...]
+// Like the HTML below:
+
+func (ctx *MyContext) HTML(htmlContents string) (int, error) {
+    ctx.Application().Logger().Infof("Executing .HTML function from MyContext")
+
+    ctx.ContentType("text/html")
+    return ctx.WriteString(htmlContents)
+}
+
+func main() {
+    app := iris.New()
+
+    // 4.
+    app.ContextPool.Attach(func() context.Context {
+        return &MyContext{
+            // If you use the embedded Context,
+            // call the `context.NewContext` to create one:
+            Context: context.NewContext(app),
+        }
+    })
+
+    // Register a view engine on .html files inside the ./view/** directory.
+    app.RegisterView(iris.HTML("./view", ".html"))
+
+    // Register your route, as you normally do
+    app.Handle("GET", "/", recordWhichContextForExample,
+    func(ctx context.Context) {
+        // use the context's overridden HTML method.
+        ctx.HTML("<h1> Hello from my custom context's HTML! </h1>")
+    })
+
+    // This will be executed by the
+    // MyContext.Context embedded default context
+    // when MyContext is not directly define the View function by itself.
+    app.Handle("GET", "/hi/{firstname:alphabetical}",recordWhichContextForExample,
+    func(ctx context.Context) {
+        firstname := ctx.Values().GetString("firstname")
+
+        ctx.ViewData("firstname", firstname)
+        ctx.Gzip(true)
+
+        ctx.View("hi.html")
+    })
+
+    app.Run(iris.Addr(":8080"))
+}
+
+// Should always print "($PATH) Handler is executing from 'MyContext'"
+func recordWhichContextForExample(ctx context.Context) {
+    ctx.Application().Logger().Infof("(%s) Handler is executing from: '%s'",
+        ctx.Path(), reflect.TypeOf(ctx).Elem().Name())
+
+    ctx.Next()
+}
+```
\ No newline at end of file
diff --git a/_Sidebar.md b/_Sidebar.md
index a15e7c5..d55e5a3 100644
--- a/_Sidebar.md
+++ b/_Sidebar.md
@@ -12,6 +12,7 @@
     * [[Handle HTTP errors|Routing-error-handlers]]
     * [[Subdomains|Routing-subdomains]]
     * [[Wrap the Router|Routing-wrap-the-router]]
+    * [[Override Context Methods]|Routing-override-context-methods]
     * [[Dependency Injection|Routing-dependency-injection]]
 * [[API Versioning]]
 * [[Cookies]]