API reference

req.get(name)

Reads the first query-string value with this name. Parameter: a string key. Returns: a string or undefined. To read all matching values, call req.getAll(name).

const name = req.get('name') || 'world'

req.formData(options?)

Reads URL-encoded or multipart form data. Returns: a promise of form values, including request-owned uploads. The request body and upload limits apply.

const values = await req.formData()

h(value)

Escapes a value for HTML text or a quoted attribute. Parameter: the value to display. Returns: an escaped string.

<p><?= h(req.get('name') || 'world') ?></p>

<p>&lt;b&gt;Clover&lt;/b&gt;</p>

Note: h() is not an escaping helper for JavaScript, CSS, or arbitrary URLs.

include(path, locals?)

Renders a local file into the current response. Parameters: a path relative to the calling file, and an optional input object. Returns: a promise. Await it. Inputs are available as locals in the included file. Includes share request context and can nest up to 32 levels deep.

await include('./_welcome.cow', { name: 'Clover' })

res.json(value?)

With a value, sends a JSON response and finishes it. With no argument, selects the JSON content type without finishing. Set other response metadata before output is committed.

res.json({ hello: 'herd' })

{"hello":"herd"}

res.status(code)

Sets the HTTP response status before headers are committed. Parameter: a valid status code. You can chain it with a response method.

res.status(404).send('Not found')

More page APIs

API	Purpose
`req.method()`	Read the HTTP method.
`req.header(name)`	Read a request header.
`req.json()`	Read the request body as JSON.
`echo(...values)`	Append response output.
`res.setHeader(name, value)`	Set an outgoing header.
`res.redirect(location, status?)`	Finish with a redirect.
`cow.signal`	Observe request cancellation.
`cow.onCleanup(callback)`	Register request cleanup.
`cow.track(promise)`	Track asynchronous work within the request.

See the guides for sessions, SQLite, uploads, streaming, and their detailed behavior. This reference covers core page APIs. Version-zero APIs can change.