Handler #

For routing is to tell which function to return a response to.

The function for returning a Response is Handler.

Handler is a callback function which accept Context, helping you access powerful API for accessing data and modifying the response.

The params from the previous example also come from Handler

// Structure
app.get(path, handler, hook?)

// Usage
app.get('/id/:id', (context) => context.params.id)

Context #

Context's properties consists of

• request: Raw Request for accessing data as web standard type
• body: Body which come with the request query: Parsed path query as a simple object
• params: Path parameters as a simple object
• store: A global mutable store for KingWorld instance
• set: Response representation
  • status: response status
  • headers: response headers
  • redirect: redirect to new path

And a few helper methods for convenient usage: status: Function to set HTTP response status code redirect: Function to redirect to different path setHeader: Syntax sugar for setting specific header value

For both context, you can easily access in Handler function:

app.post('/', ({ body, set }) => {
    const signed = signIn(body)
    
    if(signed)
        return 'Welcome back'
    else {
        set.status = 403
        return 'Invalid username or password'
    }
})

Response #

Returning value from Handler, KingWorld will try to map returned value into Response.

For eaxmple, to return an object, you should stringify the content first and then set response header of Content-Type to application/json.

Which look something like this:

new Response(JSON.stringify({
    'vtuber': [
        'Shirakami Fubuki',
        'Inugami Korone'
    ]
}, {
    headers: {
        'Content-Type': 'application/json'
    }
})

But KingWorld handle that for you.

You simply return an object, and KingWorld will map your value to a correct response for you.

app.get('/', () => ({
    'vtuber': [
        'Shirakami Fubuki',
        'Inugami Korone'
    ]
}))

Ofcourse, as KingWorld map the value to Response.

But you can also return a Response if you really want to.

app.get('/', () => new Response(
    JSON.stringify({
        'vtuber': [
            'Shirakami Fubuki',
            'Inugami Korone'
        ]
    }, {
        headers: {
            'Content-Type': 'application/json'
        }
    })
)