set-link

Link header middleware for express with multiple value and attribute support.

Usage

The middleware doesn't require any parameters. Just add it to the express app like this:

const setLink = require('set-link')

const app = express()

app.use(setLink)

.setLink must be called with the link IRI and the relationship:

app.use((req, res) => {
  res.setLink('http://example.org/context', 'http://www.w3.org/ns/json-ld#context')

  // Link: <http://example.org/context>; rel="http://www.w3.org/ns/json-ld#context"
})

It's also possible to add additional attributes using a key value map:

app.use((req, res) => {
  res.setLink('http://example.org/context', 'http://www.w3.org/ns/json-ld#context', {
    title: 'example title',
    type: 'application/ld+json'
  })
  
  // Link: <http://example.org/context>; rel="http://www.w3.org/ns/json-ld#context"; title="example title"; type="application/ld+json"
})

If there is already a link header, the new one will be appended:

app.use((req, res, next) => {
  res.set('link', '<http://example.org/api>; rel="http://www.w3.org/ns/hydra/core#apiDocumentation"')
  res.setLink('http://example.org/context', 'http://www.w3.org/ns/json-ld#context')

  // Link: <http://example.org/api>; rel="http://www.w3.org/ns/hydra/core#apiDocumentation", <http://example.org/context>; rel="http://www.w3.org/ns/json-ld#context"
})