What is kview

Kview is simple but useful wrapper for Kasia.go templates, which helps to modularize content of dynamic website. It allows you to easily describe the relationship between modules of your website.

Build the structure of your web service

You can build a web page from blocks. Every block is associated with different template file.

Example:

// Web pages declared as global variables
var home_view, edit_view kview.View

// Create the web service hierarchy
func webInit() {
    // Load site layout. 
    layout := kview.New("layout.kt")

    // Example layout consists of header, menu, two columns and footer. The
    // left column can contain very different information. Therefore, for
    // any page it will be defined by the different template. The right
    // column shows always the same type of information, so will be defined
    // once for all pages (the same applies to the menu).

    // Load the menu
    menu := kview.New("menu.kt")

    // Load the right column
    right  := kview.New("right.kt")

    // Add components to the right column
    right.Div("Info",       kview.New("right/info.kt"))
    right.Div("Commercial", kview.New("right/commercial.kt"))

    // Create the first page as layout copy. It is efficient operation
    // (references are copied, not the data itself).
    home_view = layout.Copy()

    // Add page components
    home_view.Div("Menu",  menu)
    home_view.Div("Left",  kview.New("left/home.kt", utils))
    home_view.Div("Right", right)

    // Create the second page.
    edit_view = layout.Copy()
    edit_view.Div("Menu",  menu)
    edit_view.Div("Left",  kview.New("left/edit.kt")
    edit_view.Div("Right", right)
}

The structure of the service is ready. The (optional) utils variable used in Left div may contains your utility functions/variables:

var utils = map[string]interface{} {
    "contains": strings.Contains,
    "addf": func(a, b float64) float64 {return a + b},
	"pi": 3.14159,
}

You can use them in left/home.kt template as follows:

$a + $pi = $addf(a, pi)

$if contains(s, "abc"):
    The s variable contains 'abc' substring.
$else:
    The s doesn't contain 'abc' substring.
$end

Some useful functions are provided by default:

• len(interface{}) int - it returns length of array/slice or -1,
• fmt(format string, a ...interface{}) string - works like fmt.Sprintf (in fact it is fmt.Sprintf),
• join(a []string, sep string) string - works like strings.Join,
• add, sub, mul, div, mod (a, b int) int - arithmetic operations,
• and, or (a, b bool), not(a bool) bool - logical operations.

Publishing your web service

To publish the service created with kview you can use the web.go framework:

func home(web_ctx *web.Context) {
    // ...
    // tpl_ctx contains the data needed to display the page
    home_view.Exec(web_ctx, tpl_ctx)
}

func edit(web_ctx *web.Context) {
    // ...
    edit_view.Exec(web_ctx, tpl_ctx)
}

func main() {
    webInit()

    web.Get("/", home)
    web.Get("/edit", edit)
    web.Run("0.0.0.0:80")
}

the http package:

func home(con http.ResponseWriter, req *http.Request) {
    // ...
    home_view.Exec(con, tpl_ctx) 
}

func edit(con http.ResponseWriter, req *http.Request) {
    // ...
    edit_view.Exec(con, tpl_ctx)
}

func main() {
    webInit()

    http.HandleFunc("/", home)
    http.HandleFunc("/edit", edit)
    // ...
    http.ListenAndServe("0.0.0.0:80", nil)
}

or other available framework like twister.

In the template, nested blocks are visible under the name you given them. You can render them using Render method (rather than Nested method in pure kasia.go):

<div id='Left'>$Left.Render(ctx.left)</div>
<div id='Right'>$Right.Render(ctx.right)</div>

You can find a working example in the examples directory. This simple application consists of:

• three files with Go code (the chrootuid.go file is irrelevant for our considerations - contains code for change application root directory and its privileges),
• templates tree (in templates directory),
• CSS style sheet (in static directory).

How to install and run example application

Instal web.go:

$ goinstall github.com/hoisie/web.go

Next install kview:

$ goinstall github.com/ziutek/kview

This command implicitly install kasia.go too.

Next you can build and run an example application:

$ cd $GOROOT/src/pkg/github.com/ziutek/kview/examples
$ make
$ ./simple

Next launch your browser and open the URL: http://127.0.0.1:9999

You can try this link first, if you want to see a sample application in action.