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Extensions to req and res

wkrk offers a few handy methods to allow you to compose responses in an easy way. Also, we offer you with some new methods to get data from the current request object.

Extension to the Response Object​

error​

Sets the status code to 500 and sends the provided parameter as the response body.

res.error('There has been an error')

It calls .send internally, so it follows the same serialization rules.

get​

Returns the associated header from the response object:

res.set("Content-Type", "text/png")
res.get("Content-Type") // "text/png"

json​

Created a response with the json format and headers:

res.json({ username: "giovannibenussi" });

The code above sets the Content-Type automatically to application/json and transform que provided parameter to a JSON string.

It will consider any previous state set to the response object:

res.set('x-debug', 'abcdefghijklm')
res.status(200).json({ username: "giovannibenussi" });

redirect​

Redirects the request to the specified URL:

res.redirect('https://www.giovannibenussi.com/')

The default status code for this method is 307 (temporary redirect). However, it also accepts a custom status code as a second parameter:

res.redirect('https://www.giovannibenussi.com/', 308)

As opposed to Response.redirect, it accepts relative paths:

res.redirect('/welcome')
res.redirect('./posts')
res.redirect('../users')

send​

Creates a response with the provided parameter as the response body:

res.send('hello world');

Parameters are converted to their JSON representation (except for strings) prior returning a response, so you can provide any serializable parameter:

res.send({ hello: 'world' }); // object
res.send([1, 2, 3, 4]); // array 
res.send(1); // number

This method automatically sets the Content-Type header if not present depending on its type according to the following rules:

  • string: Content-Type is set to text/html.
  • serializable object: Content-Type is set to application/json.

set​

Sets the associated header for the response object:

res.set("Content-Type", "text/png")
res.get("Content-Type") // "text/png"

You can also provide an object to set multiple headers at once:

res.set({
  'Content-Disposition', 'inline; filename="image.png"',
  'Content-Type', 'text/png'
})

status​

Sets the response status code:

res.status(200).json({ username: "giovannibenussi" });

statusCode​

Returns the status code of the response object:

res.status(500)
res.statusCode // 500

type​

Sets the Content-Type associated with the provided name, extension, or filename:

res.type("json") // application/json
res.type(".md") // text/markdown
res.type("static/index.html") // text/html

Type mapping is provided by the mime/lite package.

How Extensions Work​

We have custom wrappers for the req and res objects. We provide methods like json and send that generates a native Response object so you can return those in your handlers.

req and res are instances of ExtendedRequest and ExtendedResponse from our library wkrk-extended:

req.constructor.class // ExtendedRequest
res.constructor.class // ExtendedResponse

In the real world, you'll call methods on this objects that returns a native Request object:

// both return an instance of the native `Response` object
res.json({ username: "giovannibenussi" });
res.send('hello world');

This allows you to use this objects in your handlers seamlessly:

export default {
  get(req, res) {
    return res.status(200).json({ name: "Giovanni" });
  },
  post(req, res) {
    return res.status(200).json({ success: true });
  }
};