context.ViewData(key,value) and ViewLayout(layout) http://support.iris-go.com/d/27-using-middleware-to-inject-properties-for-templates/3

Nothing that you couldn't do before.


Former-commit-id: 658ec25d8045d25a76f87c8f992e67e64006e287

HISTORY.md

@@ -8,13 +8,21 @@
 
 
 ## 6.1.4 -> 6.2.0 (√Νεxτ)
+
+
+_Update: 28 March 2017_
+
+- **View**: Provide an easier method on the community's question about "injecting" additional data outside of the route's main handler which calls the .Render, via middleware. 
+	- As discussed [above](http://support.iris-go.com/d/27-using-middleware-to-inject-properties-for-templates). 
+	- Click [here](https://github.com/kataras/iris/tree/v6/_examples/intermediate/view/context-view-data) for an example.
+
 _Update: 18 March 2017_
 
-- **Sessions**: Enchance the community feature request about custom encode and decode methods for the cookie value(sessionid) as requested [here](http://support.iris-go.com/d/29-mark-cookie-for-session-as-secure).
+- **Sessions**: Enchance the community's feature request about custom encode and decode methods for the cookie value(sessionid) as requested [here](http://support.iris-go.com/d/29-mark-cookie-for-session-as-secure).
 
 _Update: 12 March 2017_
 
-- Enhance Custom http errors with gzip and static files handler, as requested/reported [here](http://support.iris-go.com/d/17-fallback-handler-for-non-matched-routes/9).
+- Enhance Custom http errors with gzip and static files handler, as requested/reported [here](http://support.iris-go.com/d/17-fallback-handler-for-non-matched-routes).
 - Enhance per-party custom http errors (now it works on any wildcard path too).
 - Add a third parameter on `app.OnError(...)` for custom http errors with regexp validation, see [status_test.go](https://github.com/kataras/iris/blob/v6/status_test.go) for an example.
 - Add a `context.ParamIntWildcard(...)` to skip the first slash, useful for wildcarded paths' parameters.

README.md

@@ -129,6 +129,76 @@ Feature Overview
 - Feels like you used iris forever, thanks to its Fluent API
 - And many others...
 
+
+Table of Contents
+-----------
+
+<img align="right" src="http://iris-go.com/assets/book/cover_4.jpg" width="300" />
+
+* [Level: Beginner](_examples/beginner)
+    * [Hello World](_examples/beginner/hello-world/main.go)
+    * [Routes (using httprouter)](_examples/beginner/routes-using-httprouter/main.go)
+    * [Routes (using gorillamux)](_examples/beginner/routes-using-gorillamux/main.go)
+    * [Internal Application File Logger](_examples/beginner/file-logger/main.go)
+    * [Write JSON](_examples/beginner/write-json/main.go)
+    * [Read JSON](_examples/beginner/read-json/main.go)
+    * [Read Form](_examples/beginner/read-form/main.go)
+    * [Favicon](_examples/beginner/favicon/main.go)
+    * [File Server](_examples/beginner/file-server/main.go)
+    * [Send Files](_examples/beginner/send-files/main.go)
+    * [Stream Writer](_examples/beginner/stream-writer/main.go)
+    * [Listen UNIX Socket](_examples/beginner/listen-unix/main.go)
+    * [Listen TLS](_examples/beginner/listen-tls/main.go)
+    * [Listen Letsencrypt (Automatic Certifications)](_examples/beginner/listen-letsencrypt/main.go)
+* [Level: Intermediate](_examples/intermediate)
+    * [Send An E-mail](_examples/intermediate/e-mail/main.go)
+    * [Upload/Read Files](_examples/intermediate/upload-files/main.go)
+    * [Request Logger](_examples/intermediate/request-logger/main.go)
+    * [Profiling (pprof)](_examples/intermediate/pprof/main.go)
+    * [Basic Authentication](_examples/intermediate/basicauth/main.go)
+    * [HTTP Access Control](_examples/intermediate/cors/main.go)
+    * [Cache Markdown](_examples/intermediate/cache-markdown/main.go)
+    * [Localization and Internationalization](_examples/intermediate/i18n/main.go)
+    * [Recovery](_examples/intermediate/recover/main.go)
+    * [Graceful Shutdown](_examples/intermediate/graceful-shutdown/main.go)
+    * [Custom TCP Listener](_examples/intermediate/custom-listener/main.go)
+    * [Custom HTTP Server](_examples/intermediate/custom-httpserver/main.go)
+    * [View Engine](_examples/intermediate/view)
+        * [Overview](_examples/intermediate/view/overview/main.go)
+        * [Template HTML: Part Zero](_examples/intermediate/view/template_html_0/main.go)
+        * [Template HTML: Part One](_examples/intermediate/view/template_html_1/main.go)
+        * [Template HTML: Part Two](_examples/intermediate/view/template_html_2/main.go)
+        * [Template HTML: Part Three](_examples/intermediate/view/template_html_3/main.go)
+        * [Template HTML: Part Four](_examples/intermediate/view/template_html_4/main.go)
+        * [Inject Data Between Handlers](_examples/intermediate/view/context-view-data/main.go)
+        * [Embedding Templates Into Executable](_examples/intermediate/embedding-templates-into-app)
+        * [Custom Renderer](_examples/intermediate/view/custom-renderer/main.go)
+    * [Password Hashing](_examples/intermediate/password-hashing/main.go)
+    * [Sessions](_examples/intermediate/sessions)
+        * [Overview](_examples/intermediate/sessions/overview/main.go)
+        * [Encoding & Decoding the Session ID: Secure Cookie](_examples/intermediate/sessions/securecookie/main.go)
+        * [Standalone](_examples/intermediate/sessions/standalone/main.go)
+        * [With A Back-End Database](_examples/intermediate/sessions/database/main.go)
+    * [Flash Messages](_examples/intermediate/flash-messages/main.go)
+    * [Websockets](_examples/intermediate/websockets)
+        * [Ridiculous Simple](_examples/intermediate/websockets/ridiculous-simple/main.go)
+        * [Overview](_examples/intermediate/websockets/overview/main.go)
+        * [Connection List](_examples/intermediate/websockets/connectionlist/main.go)
+        * [Native Messages](_examples/intermediate/websockets/naive-messages/main.go)
+        * [Secure](_examples/intermediate/websockets/secure/main.go)
+        * [Custom Go Client](_examples/intermediate/websockets/custom-go-client/main.go)
+* [Level: Advanced](_examples/advanced)
+    * [Transactions](_examples/advanced/transactions/main.go)
+    * [HTTP Testing](_examples/advanced/httptest/main_test.go)
+    * [Watch & Compile Typescript source files](_examples/advanced/typescript/main.go)
+    * [Cloud Editor](_examples/advanced/cloud-editor/main.go)
+    * [Online Visitors](_examples/advanced/online-visitors/main.go)
+    * [URL Shortener using BoltDB](_examples/advanced/url-shortener/main.go)
+    * [Subdomains](_examples/advanced/subdomains)
+        * [Single](_examples/advanced/subdomains/single/main.go)
+        * [Multi](_examples/advanced/subdomains/multi/main.go)
+        * [Wildcard](_examples/advanced/subdomains/wildcard/main.go)
+
 Installation
 -----------
 

_examples/README.md

@@ -38,12 +38,13 @@ It doesn't contains "best ways" neither explains all its features. It's just a s
     * [Custom HTTP Server](intermediate/custom-httpserver/main.go)
     * [View Engine](intermediate/view)
         * [Overview](intermediate/view/overview/main.go)
-        * [Embedding Templates Into Executable](intermediate/embedding-templates-into-app)
         * [Template HTML: Part Zero](intermediate/view/template_html_0/main.go)
         * [Template HTML: Part One](intermediate/view/template_html_1/main.go)
         * [Template HTML: Part Two](intermediate/view/template_html_2/main.go)
         * [Template HTML: Part Three](intermediate/view/template_html_3/main.go)
         * [Template HTML: Part Four](intermediate/view/template_html_4/main.go)
+        * [Inject Data Between Handlers](intermediate/view/context-view-data/main.go)
+        * [Embedding Templates Into Executable](intermediate/embedding-templates-into-app)
         * [Custom Renderer](intermediate/view/custom-renderer/main.go)
     * [Password Hashing](intermediate/password-hashing/main.go)
     * [Sessions](intermediate/sessions)

_examples/intermediate/view/context-view-data/main.go

@@ -0,0 +1,58 @@
+// this example will show you how you can set per-request data for a template outside of the main handler which calls
+// the .Render, via middleware.
+//
+// Remember: .Render has the "binding" argument which can be used to send data to the template at any case.
+package main
+
+import (
+	"time"
+
+	"gopkg.in/kataras/iris.v6"
+	"gopkg.in/kataras/iris.v6/adaptors/httprouter"
+	"gopkg.in/kataras/iris.v6/adaptors/view"
+)
+
+const (
+	DefaultTitle  = "My Awesome Site"
+	DefaultLayout = "layouts/layout.html"
+)
+
+func main() {
+	app := iris.New()
+	// output startup banner and error logs on os.Stdout
+	app.Adapt(iris.DevLogger())
+	// set the router, you can choose gorillamux too
+	app.Adapt(httprouter.New())
+	// set the view engine target to ./templates folder
+	app.Adapt(view.HTML("./templates", ".html").Reload(true))
+
+	app.UseFunc(func(ctx *iris.Context) {
+		// set the title, current time and a layout in order to be used if and when the next handler(s) calls the .Render function
+		ctx.ViewData("Title", DefaultTitle)
+		now := time.Now().Format(app.Config.TimeFormat)
+		ctx.ViewData("CurrentTime", now)
+		ctx.ViewLayout(DefaultLayout)
+
+		ctx.Next()
+	})
+
+	app.Get("/", func(ctx *iris.Context) {
+		ctx.ViewData("BodyMessage", "a sample text here... setted by the route handler")
+		if err := ctx.Render("index.html", nil); err != nil {
+			app.Log(iris.DevMode, err.Error())
+		}
+	})
+
+	app.Get("/about", func(ctx *iris.Context) {
+		ctx.ViewData("Title", "My About Page")
+		ctx.ViewData("BodyMessage", "about text here... setted by the route handler")
+
+		// same file, just to keep things simple.
+		if err := ctx.Render("index.html", nil); err != nil {
+			app.Log(iris.DevMode, err.Error())
+		}
+	})
+
+	// Open localhost:8080 and localhost:8080/about
+	app.Listen(":8080")
+}

_examples/intermediate/view/context-view-data/templates/index.html

@@ -0,0 +1,8 @@
+<h1>
+	Title: {{.Title}}
+</h1>
+<h3>{{.BodyMessage}} </h3>
+
+<hr/>
+
+Current time: {{.CurrentTime}}

_examples/intermediate/view/context-view-data/templates/layouts/layout.html

@@ -0,0 +1,10 @@
+<html>
+<head>
+<title>My WebsiteLayout</title>
+
+</head>
+<body>
+	<!-- Render the current template here -->
+	{{ yield }}
+</body>
+</html>

context.go

@@ -869,13 +869,6 @@ func (ctx *Context) TryWriteGzip(b []byte) (int, error) {
 // -------------------------------------------------------------------------------------
 // -------------------------------------------------------------------------------------
 
-const (
-	// NoLayout to disable layout for a particular template file
-	NoLayout = "@.|.@no_layout@.|.@"
-	// TemplateLayoutContextKey is the name of the user values which can be used to set a template layout from a middleware and override the parent's
-	TemplateLayoutContextKey = "templateLayout"
-)
-
 // getGzipOption receives a default value and the render options map and returns if gzip is enabled for this render action
 func getGzipOption(defaultValue bool, options map[string]interface{}) bool {
 	gzipOpt := options["gzip"] // we only need that, so don't create new map to keep the options.
@@ -933,8 +926,66 @@ func (ctx *Context) fastRenderWithStatus(status int, cType string, data []byte)
 	return
 }
 
+const (
+	// NoLayout to disable layout for a particular template file
+	NoLayout = "@.|.@no_layout@.|.@"
+	// ViewLayoutContextKey is the name of the user values which can be used to set a template layout from a middleware and override the parent's
+	ViewLayoutContextKey = "@viewLayout"
+	ViewDataContextKey   = "@viewData"
+
+	// conversions
+	// TemplateLayoutContextKey same as ViewLayoutContextKey
+	TemplateLayoutContextKey = ViewLayoutContextKey
+)
+
+// ViewLayout sets the "layout" option if and when .Render
+// is being called afterwards, in the same request.
+// Useful when need to set or/and change a layout based on the previous handlers in the chain.
+//
+// Look: .ViewData     | .Render
+//       .MustRender   | .RenderWithStatus also.
+//
+// Example: https://github.com/kataras/iris/tree/v6/_examples/intermediate/view/context-view-data/
+func (ctx *Context) ViewLayout(layoutTmplFile string) {
+	ctx.Set(ViewLayoutContextKey, layoutTmplFile)
+}
+
+// ViewData saves one or more key-value pair in order to be passed if and when .Render
+// is being called afterwards, in the same request.
+// Useful when need to set or/and change template data from previous hanadlers in the chain.
+//
+// If .Render's "binding" argument is not nil and it's not a type of map
+// then these data are being ignored, binding has the priority, so the main route's handler can still decide.
+// If binding is a map or iris.Map then theese data are being added to the view data
+// and passed to the template.
+//
+// After .Render, the data are not destroyed, in order to be re-used if needed (again, in the same request as everything else),
+// to manually clear the view data, developers can call:
+// ctx.Set(iris.ViewDataContextKey, iris.Map{})
+//
+// Look: .ViewLayout   | .Render
+//       .MustRender   | .RenderWithStatus also.
+//
+// Example: https://github.com/kataras/iris/tree/v6/_examples/intermediate/view/context-view-data/
+func (ctx *Context) ViewData(key string, value interface{}) {
+	v := ctx.Get(ViewDataContextKey)
+	if v == nil {
+		ctx.Set(ViewDataContextKey, Map{key: value})
+		return
+	}
+
+	if data, ok := v.(Map); ok {
+		data[key] = value
+	}
+}
+
 // RenderWithStatus builds up the response from the specified template or a serialize engine.
-// Note: the options: "gzip" and "charset" are built'n support by Iris, so you can pass these on any template engine or serialize engines
+// Note: the options: "gzip" and "charset" are built'n support by Iris, so you can pass these on any template engine or serialize engines.
+//
+// Look: .ViewData     | .Render
+//       .ViewLayout   | .MustRender also.
+//
+// Examples: https://github.com/kataras/iris/tree/v6/_examples/intermediate/view/
 func (ctx *Context) RenderWithStatus(status int, name string, binding interface{}, options ...map[string]interface{}) (err error) {
 	if _, shouldFirstStatusCode := ctx.ResponseWriter.(*responseWriter); shouldFirstStatusCode {
 		ctx.SetStatusCode(status)
@@ -957,6 +1008,38 @@ func (ctx *Context) RenderWithStatus(status int, name string, binding interface{
 		}
 	}
 
+	// optional, view data (useful for middleware, although user can already do that with ctx.Set/Get)
+	// check if user sets any view data
+	if v := ctx.Get(ViewDataContextKey); v != nil {
+		// if so, then check its type, to make sure
+		if data, ok := ctx.Get(ViewDataContextKey).(Map); ok {
+			if len(data) > 0 {
+				if binding != nil {
+					// if binding is passed to the Render function then
+					// two things can happen:
+					// if binding is a custom type, we ignore the data
+					// if binding is a map of interface{} or string then, add these to the view data
+					// finally, set the binding to the new data and pass it to the view engine, as we did before.
+
+					if irisMap, ok := binding.(Map); ok {
+						for key, val := range irisMap {
+							data[key] = val
+						} // a little of necessary duplication here...
+					} else if stdMap, ok := binding.(map[string]interface{}); ok {
+						for key, val := range stdMap {
+							data[key] = val
+						}
+					} else if stdMapStr, ok := binding.(map[string]string); ok {
+						for key, val := range stdMapStr {
+							data[key] = val
+						}
+					}
+				}
+				binding = data
+			}
+		}
+	}
+
 	// Find Content type
 	// if it the name is not a template file, then take that as the content type.
 	cType := contentHTML
@@ -999,7 +1082,12 @@ func (ctx *Context) RenderWithStatus(status int, name string, binding interface{
 
 // Render same as .RenderWithStatus but with status to iris.StatusOK (200) if no previous status exists
 // builds up the response from the specified template or a serialize engine.
-// Note: the options: "gzip" and "charset" are built'n support by Iris, so you can pass these on any template engine or serialize engine
+// Note: the options: "gzip" and "charset" are built'n support by Iris, so you can pass these on any template engine or serialize engine.
+//
+// Look: .ViewData     | .MustRender
+//       .ViewLayout   | .RenderWithStatus also.
+//
+// Examples: https://github.com/kataras/iris/tree/v6/_examples/intermediate/view/
 func (ctx *Context) Render(name string, binding interface{}, options ...map[string]interface{}) error {
 	errCode := ctx.ResponseWriter.StatusCode()
 	if errCode <= 0 {
@@ -1009,7 +1097,12 @@ func (ctx *Context) Render(name string, binding interface{}, options ...map[stri
 }
 
 // MustRender same as .Render but returns 503 service unavailable http status with a (html) message if render failed
-// Note: the options: "gzip" and "charset" are built'n support by Iris, so you can pass these on any template engine or serialize engine
+// Note: the options: "gzip" and "charset" are built'n support by Iris, so you can pass these on any template engine or serialize engine.
+//
+// Look: .ViewData     | .Render
+//       .ViewLayout   | .RenderWithStatus also.
+//
+// Examples: https://github.com/kataras/iris/tree/v6/_examples/intermediate/view/
 func (ctx *Context) MustRender(name string, binding interface{}, options ...map[string]interface{}) {
 	if err := ctx.Render(name, binding, options...); err != nil {
 		htmlErr := ctx.HTML(StatusServiceUnavailable,