docs/tests/unit/static-assets.js

import nock from 'nock'
import { expect, jest } from '@jest/globals'

import { checkCachingHeaders } from '../helpers/caching-headers.js'
import { setDefaultFastlySurrogateKey } from '../../middleware/set-fastly-surrogate-key.js'
import archivedEnterpriseVersionsAssets from '../../middleware/archived-enterprise-versions-assets.js'

function mockRequest(path, { headers }) {
  const _headers = Object.fromEntries(
    Object.entries(headers || {}).map(([key, value]) => [key.toLowerCase(), value])
  )
  return {
    path,
    url: path,
    get: (header) => {
      return _headers[header.toLowerCase()]
    },
    set: (header, value) => {
      _headers[header.toLowerCase()] = value
    },

    headers,
  }
}
const mockResponse = () => {
  const res = {}
  res.status = 404
  res.statusCode = 404
  res.json = (payload) => {
    res._json = payload
  }
  res.send = (body) => {
    res.status = 200
    res.statusCode = 200
    res._send = body
  }
  res.headers = {}
  res.set = (key, value) => {
    if (typeof key === 'string') {
      res.headers[key.toLowerCase()] = value
    } else {
      for (const [k, value] of Object.entries(key)) {
        res.headers[k.toLowerCase()] = value
      }
    }
  }
  res.removeHeader = (key) => {
    delete res.headers[key]
  }
  res.hasHeader = (key) => {
    return key in res.headers
  }
  return res
}

describe('archived enterprise static assets', () => {
  // Sometimes static assets are proxied. The URL for the static asset
  // might not indicate it's based on archived enterprise version.

  jest.setTimeout(60 * 1000)

  beforeAll(async () => {
    // The first page load takes a long time so let's get it out of the way in
    // advance to call out that problem specifically rather than misleadingly
    // attributing it to the first test
    // await get('/')

    const sampleCSS = '/* nice CSS */'

    nock('https://github.github.com')
      .get('/help-docs-archived-enterprise-versions/2.21/_next/static/foo.css')
      .reply(200, sampleCSS, {
        'content-type': 'text/css',
        'content-length': sampleCSS.length,
      })
    nock('https://github.github.com')
      .get('/help-docs-archived-enterprise-versions/2.21/_next/static/only-on-proxy.css')
      .reply(200, sampleCSS, {
        'content-type': 'text/css',
        'content-length': sampleCSS.length,
      })
    nock('https://github.github.com')
      .get('/help-docs-archived-enterprise-versions/2.3/_next/static/only-on-2.3.css')
      .reply(200, sampleCSS, {
        'content-type': 'text/css',
        'content-length': sampleCSS.length,
      })
    nock('https://github.github.com')
      .get('/help-docs-archived-enterprise-versions/2.3/_next/static/fourofour.css')
      .reply(404, 'Not found', {
        'content-type': 'text/plain',
      })
    nock('https://github.github.com')
      .get('/help-docs-archived-enterprise-versions/2.3/assets/images/site/logo.png')
      .reply(404, 'Not found', {
        'content-type': 'text/plain',
      })
  })

  afterAll(() => nock.cleanAll())

  it('should proxy if the static asset is prefixed', async () => {
    const req = mockRequest('/enterprise/2.21/_next/static/foo.css', {
      headers: {
        Referrer: '/enterprise/2.21',
      },
    })
    const res = mockResponse()
    const next = () => {
      throw new Error('did not expect this to ever happen')
    }
    setDefaultFastlySurrogateKey(req, res, () => {})
    await archivedEnterpriseVersionsAssets(req, res, next)
    expect(res.statusCode).toBe(200)
    checkCachingHeaders(res, false, 60)
  })

  it('should proxy if the Referrer header indicates so on home page', async () => {
    const req = mockRequest('/_next/static/only-on-proxy.css', {
      headers: {
        Referrer: '/enterprise/2.21',
      },
    })
    const res = mockResponse()
    const next = () => {
      throw new Error('did not expect this to ever happen')
    }
    setDefaultFastlySurrogateKey(req, res, () => {})
    await archivedEnterpriseVersionsAssets(req, res, next)
    expect(res.statusCode).toBe(200)
    checkCachingHeaders(res, false, 60)
  })

  it('should proxy if the Referrer header indicates so on sub-page', async () => {
    const req = mockRequest('/_next/static/only-on-2.3.css', {
      headers: {
        Referrer: '/en/enterprise-server@2.3/some/page',
      },
    })
    const res = mockResponse()
    const next = () => {
      throw new Error('did not expect this to ever happen')
    }
    setDefaultFastlySurrogateKey(req, res, () => {})
    await archivedEnterpriseVersionsAssets(req, res, next)
    expect(res.statusCode).toBe(200)
    checkCachingHeaders(res, false, 60)
  })

  it('might still 404 even with the right referrer', async () => {
    const req = mockRequest('/_next/static/fourofour.css', {
      headers: {
        Referrer: '/en/enterprise-server@2.3/some/page',
      },
    })
    const res = mockResponse()
    let nexted = false
    const next = () => {
      nexted = true
    }
    setDefaultFastlySurrogateKey(req, res, next)
    await archivedEnterpriseVersionsAssets(req, res, next)
    expect(res.statusCode).toBe(404)
    // It did't exit in that middleware but called next() to move on
    // with any other middlewares.
    expect(nexted).toBe(true)
  })

  it('404 on the proxy but actually present here', async () => {
    const req = mockRequest('/assets/images/site/logo.png', {
      headers: {
        Referrer: '/en/enterprise-server@2.3/some/page',
      },
    })
    const res = mockResponse()
    let nexted = false
    const next = () => {
      nexted = true
    }
    setDefaultFastlySurrogateKey(req, res, () => {})
    await archivedEnterpriseVersionsAssets(req, res, next)
    // It tried to go via the proxy, but it wasn't there, but then it
    // tried "our disk" and it's eventually there.
    expect(nexted).toBe(true)
  })
})