Request-derived URLs

REST and GraphQL payload URLs are derived from the request that produced the response. A simulator listening on a random port returns repository, issue, pull request, commit, ref, branch, and organization URLs that point back at that same host and port.

apiUrl controls the mounted API root and is included in API URLs:

const app = simulation({
  apiUrl: '/api/v3',
  initialState
});

A request to http://127.0.0.1:49152/api/v3/repos/acme/awesome-repo returns API links under http://127.0.0.1:49152/api/v3/... and web links under http://127.0.0.1:49152/....

Fixture URL fields are overrides. When a fixture explicitly seeds a URL, the projectors preserve it; when the field is omitted, the adapters derive it from the request. Nullable URL fields can still be set to null deliberately.

simulation({
  initialState: {
    users: [],
    organizations: [{login: 'acme'}],
    repositories: [
      {
        owner: 'acme',
        name: 'awesome-repo',
        html_url: 'https://docs.example.test/acme/awesome-repo',
        mirror_url: null
      }
    ],
    branches: [],
    blobs: []
  }
});

If a request has no usable Host header, Simulacat Core uses the absolute SIMULACAT_GITHUB_API_URL environment variable as a fallback base. Normal HTTP requests should not need that fallback because the request host is preferred.