How to change `location` header from absolute to relative on proxied page?

Edgio Q&A
,
1

On one project https://dev.testproject.com we have tons of proxied pages with upstream http://upstream.testproject.com

Few of pages return location header with absolute url starts with http://upstream.testproject.com

How could we change location header to relative one in proxy rule for router?

2

Seems like we have solution for that

.match({ path: '/your-path-here' }, async res => {
      cacheResponse(NO_CACHE)
      await res.proxy('legacy', {
        transformResponse: res => {
          const locationHeader = res.getHeaders().location
          if (res.statusCode === 302 && locationHeader) {
            res.setHeader(
              'location',
              locationHeader.replace(
                /^(?:https?:\/\/)?(?:www\.)?((?:(?!www\.|\.).)+\.[a-zA-Z0-9.]+)/g,
                ''
              )
            )
          }
        },
      })
    })
3

@freewayspb That code will run every request through serverless, which will be unnecessary and costly. Instead you can use a regex to refine the location header at the edge. See https://docs.layer0.co/docs/api/core/classes/router_responsewriter.responsewriter.html#updateresponseheader

new Router()
   .get('/some/path', ({ updateResponseHeader, proxy }) => {
     proxy('origin')
     updateResponseHeader('some-header', /some-.*-part/gi, 'some-replacement')
   })