Rule generator

Return a canned JSON body for one endpoint while everything else passes through: test error handling or develop against an API that does not exist yet.

Describe it as: "Mock a 200 JSON response {"status": "ok"} for any request to api.example.com/health, without contacting the server"

rules:
- filter:
    typeKind: FilterCollection
    children:
    - typeKind: HostFilter
      pattern: api.example.com
      operation: Exact
    - typeKind: PathFilter
      pattern: /health
      operation: Exact
    operation: And
  action:
    typeKind: MockedResponseAction
    response:
      statusCode: 200
      headers: []
      body:
        origin: FromString
        type: Json
        text: '{"status": "ok"}'
  actions: []

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Point a mobile app or third-party client at the code running on your machine without rebuilding it or editing hosts files.

Describe it as: "Redirect all traffic going to api.example.com to my local dev server on localhost port 3000"

rules:
- filter:
    typeKind: HostFilter
    pattern: api.example.com
    operation: Exact
  action:
    typeKind: ForwardAction
    url: http://localhost:3000
  actions: []

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Add latency to a single dependency to see how your app behaves when a CDN or API slows down, while the rest of the traffic stays fast.

Describe it as: "Simulate a slow network by delaying every response from cdn.example.com by 3 seconds"

rules:
- filter:
    typeKind: HostFilter
    pattern: cdn.example.com
    operation: Exact
  action:
    typeKind: DelayAction
    duration: 3000
    scope: ResponseHeaderReceivedFromRemote
  actions: []

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Add Access-Control-Allow-Origin and related CORS headers to any API's responses on the fly, with no server change and no separate CORS proxy, so your local frontend can call it directly.

Describe it as: "Add the response header Access-Control-Allow-Origin: * to every response coming from api.example.com"

rules:
- filter:
    typeKind: HostFilter
    pattern: api.example.com
    operation: Exact
  action:
    typeKind: AddResponseHeaderAction
    headerName: Access-Control-Allow-Origin
    headerValue: '*'
  actions: []

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Force one endpoint to return a server error with a JSON body while the rest of the traffic passes through: verify retries, fallbacks and error messages without breaking the real backend.

Describe it as: "Return a 500 Internal Server Error with a JSON body {"error": "internal"} for every request to api.example.com/orders, so I can test my app's error handling"

rules:
- filter:
    typeKind: FilterCollection
    children:
    - typeKind: HostFilter
      pattern: api.example.com
      operation: Exact
    - typeKind: PathFilter
      pattern: /orders
      operation: Exact
    operation: And
  action:
    typeKind: MockedResponseAction
    response:
      statusCode: 500
      headers:
      - name: Content-Type
        value: application/json
      body:
        origin: FromString
        type: Text
        text: '{"error": "internal"}'
  actions: []

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