Templating in Response Body

Beeceptor implements Handlerbars to provide dynamic mocked responses. This helps a mocking rule to utilize attributes from request payload and query parameters to generate a dynamic response.

This feature is available with paid plans only and takes your API mocking experience near to realistic.

Using Templates in Response Body

Beeceptor parses incoming request for request payload and query parameters as a JSON objects. This objects are available to template engine to be substituted response. Here are a few facts you should know before you start using this.

• The template engine uses Handlerbars's syntax.
• Request payload is parsed only if the entering Content-Type is set to one of below.
  • JSON payload - application/json
  • Form URL encoded - application/x-www-form-urlencoded
• By default, template engine is off. You need to explicitly mark a rule to enable usage of Handlebars template.

When there are syntax errors in defining template, a response with 561 status code is returned. You should review the template syntax and correct it.

Handlebars Syntax

A handlebars expression is enclosed between {{ and }}. When the template is executed, these expressions are replaced with values from a request object. Beeceptor uses special Handlebars helpers to extract request parameters.

Helpers

Beeceptor supports following two types of template syntax.

Helper Name	Description
body	Extracts request payload/body from either JSON or Form URL Encoded. Both of these are built into JSON object to be used in template. This typically works for POST, PATCH and PUT types of HTTP verbs. Syntax: {{body 'path' 'default-value'}}
queryParam	Extracts query parameters and builds a JSON object to be used in template. This works for all HTTP verbs. Syntax: {{queryParam 'path' 'default-value'}}

Parameter details:

• The path is a required parameter in the above syntax.
• The default-value is optional, falls back to empty string.
• The path parameter allows accessing deep properties using a flat representation string. Some examples are keyName, parent.child, keyName.1.childKey. This works for JSON Objects and JSON Arrays as object roots.
• If no value is found corresponding to given path, the default-value is returned.

Example

Consider a following example with mocking rule and request payload:

Mocking template defined in a rule:

{
     "type": "{{queryParam 'type'}}",
     "address": "{{body 'address'}}",
     "age": {{body 'age' '0'}},
     "full_name": "{{body 'name.first'}} - {{body 'name.last'}}"
}

Request payload entering with application/json content-type at server path /my-rule?type=individual :

{
    "address": "80, Pearl Residency, MG Road, India",
    "age": 99,
    "name": {"first": "Arti", "last": "Jain"}
}

Beeceptor generated response body for this request:

{
  "type": "individual",
  "address": "80, Pearl Residency, MG Road, India",
  "age": 99,
  "full_name": "Arti - Jain"
}