Capture values

Capture stores response values in a run-level dictionary. Later requests can interpolate them with ${captured:KEY} inside $pattern.

- CreateThing:
    Method: POST
    URLPath: /things
    Body: { name: demo }
    Capture:
      thingId: body.id
      etag: headers.ETag
      elapsed: duration_ms
- ReadThing:
    Method: GET
    URLPath: /things/placeholder
    Headers:
      If-Match: { $pattern: "${captured:etag}" }
    Query:
      id: { $pattern: "${captured:thingId}" }

Simple paths

Path	Value
status	HTTP or AMQP status
duration_ms	Operation duration in milliseconds
headers.NAME	Response metadata/header, matched case-insensitively
body	Entire parsed body
body.field	Dot path into parsed JSON
body[N].field	Indexed array path

Missing paths capture null. Captures are most predictable in sequential sequences; do not create ordering dependencies between concurrently executed requests.

JSONPath

Use $jsonpath for filters, wildcards, or aggregation:

Capture:
  firstId: { $jsonpath: "$.items[*].id::first" }
  allIds: { $jsonpath: "$.items[*].id" }
  count: { $jsonpath: "$.items[*]::count" }
  total: { $jsonpath: "$.items[*].score::sum" }

Suffixes are ::first, ::last, ::count, ::sum, ::avg, ::min, and ::max. Without a suffix, one match returns a scalar and multiple matches return a list.

Expectations are evaluated before captures for the same response. A capture from one request is therefore available only to later requests.