Response templating

Response templating is a feature that allows you to specify the response that the mock service will return when it matches a request.

  response: # optional
    randomize: <bool> # optional
    header: <mapping> # optional
    trailer: <mapping> # optional, gRPC and HTTP/2 only
    body|stream: <mapping | sequence> # optional
    status: <OK|CANCELLED|UNKNOWN|...> # optional, both gRPC and HTTP
    statusDetails: <scalar> # optional, gRPC only, default empty

Randomize response

Set response.randomize flag to true if you need to generate a random response. Check out our Data generation article.

Header and trailer templating

Headers are treated as a regular mapping property with key-value pairs, so the templating is the same as for the body payload. It supports all templating operators and scripting features.

Example:

- method: greet.Greeter/SayHello
  response:
    header:
      Expires: "{{ date.now | date.add_days 2 | date.to_string '%a, %d %b %Y %T %Z' }}"
    trailer:
      user-defined-status: OK

Body and stream templating

The body property is used to specify the body for unary gRPC and HTTP calls.
The stream property is used to specify the stream for gRPC server streaming calls only.

Note that the response is converted to a target format eventually, which depends on a mock service protocol:

protobuf for gRPC service
JSON for HTTP service

Examples:

- method: greet.Greeter/SayHello
  response:
    body:
      message: "Hello Joe!"

- method: greet.Greeter/SayHello
  response:
    body:
      message: "Hello {{request.body.name}}!"

Operators

repeat

Useful for producing dynamic arrays or streaming responses:

Definition:

<property>:
  repeat:
    count: <scalar> # number of items of output array
    item: <mapping> # item to generate

Exposed runtime variables:

{{ repeat.index }} - index of the current item (0, 1, 2, etc)
{{ repeat.item }} - reference to the current item
{{ repeat.count }} - declared count of items
{{ repeat.items }} - list of items

Examples:

myArray:
  repeat:
    count: "{{ faker.random.number 2 10 }}"
    item:
      id: "{{ repeat.index }}"
      firstName: "{{ faker.name.first_name female }}"
      lastName: "{{ faker.name.last_name female }}"
      fullName: "{{ repeat.item.firstName }} {{ repeat.item.lastName }}"
      login: "{{ faker.internet.user_name repeat.item.firstName repeat.item.lastName }}"
      email: "{{ faker.internet.email repeat.item.firstName repeat.item.lastName }}"
      avatar: "{{ faker.internet.avatar }}"
      balance: "{{ faker.finance.amount }}"

will produce

{
  "myArray": [{
      "login": "Aniyah_Lueilwitz",
      "firstName": "Aniyah",
      "lastName": "Lueilwitz",
      "fullName": "Aniyah Lueilwitz",
      "email": "Aniyah.Lueilwitz@gmail.com",
      "avatar": "https://cloudflare-ipfs.com/ipfs/Qmd3W5DuhgHirLHGVixi6V76LhCkZUz6pnFt5AJBiyvHye/avatar/521.jpg",
      "balance": 213.2
    }, {
      "id": 1,
      "login": "Jaiden54",
      "firstName": "Jaiden",
      "lastName": "Windler",
      "fullName": "Jaiden Windler",
      "email": "Jaiden55@yahoo.com",
      "avatar": "https://cloudflare-ipfs.com/ipfs/Qmd3W5DuhgHirLHGVixi6V76LhCkZUz6pnFt5AJBiyvHye/avatar/477.jpg",
      "balance": 986.69
    }, {
      "id": 2,
      "login": "Bertrand52",
      "firstName": "Bertrand",
      "lastName": "Marvin",
      "fullName": "Bertrand Marvin",
      "email": "Bertrand.Marvin@gmail.com",
      "avatar": "https://cloudflare-ipfs.com/ipfs/Qmd3W5DuhgHirLHGVixi6V76LhCkZUz6pnFt5AJBiyvHye/avatar/173.jpg",
      "balance": 595.65
    }
  ]
}

fromJsonFile

Loads a property value from a JSON file.

Definition:

<property>:
  fromJsonFile: <fileName>

Example:

# loading a whole response body from a json file
  response:
    body:
      fromJsonFile: "/body.json"

# loading a data property from a json file
  response:
    body:
      id: 1
      data:
        fromJsonFile: "/data.json"

# load a data property from a dynamically resolved json file
- url: /post/{id}  
  method: GET
  response:
    body:
      id: "{{ request.url_path.id }}"
      data:
        fromJsonFile: "/data-{{ request.url_path.id }}.json"

fromYamlFile

Loads a property value from a YAML file.

<property>:
  fromYamlFile: <fileName>

Status code and details

The status (or statusCode) property accepts gRPC codes in both text and numeric format as defined in the page below:

https://grpc.github.io/grpc/core/md_doc_statuscodes.html

Definition:

  response:
    status: <OK|CANCELLED|UNKNOWN|...> # optional, both gRPC and HTTP, default OK
    statusDetails: <scalar> # optional, gRPC only, default empty

Examples:

  response:
    status: OK

  response:
    status: NOT_FOUND
    statusDetails: "Page not found"

  response:
    status: 1 # CANCELLED
    statusDetails: "Request has been cancelled"