This is documentation for the next version of Alloy. For the latest stable release, go to the latest version.
json_path
The json_path
function lookup values using jsonpath syntax.
The function expects two strings. The first string is the JSON string used look up values. The second string is the JSONPath expression.
json_path
always returns a list of values. If the JSONPath expression doesn’t match any values, an empty list is returned.
A common use case of json_path
is to decode and filter the output of a local.file
or remote.http
component to an Alloy syntax value.
Remember to escape double quotes when passing JSON string literals to
json_path
.For example, the JSON value
{"key": "value"}
is properly represented by the string"{\"key\": \"value\"}"
.
Examples
> json_path("{\"key\": \"value\"}", ".key")
["value"]
> json_path("[{\"name\": \"Department\",\"value\": \"IT\"},{\"name\":\"TestStatus\",\"value\":\"Pending\"}]", "[?(@.name == \"Department\")].value")
["IT"]
> json_path("{\"key\": \"value\"}", ".nonexists")
[]
> json_path("{\"key\": \"value\"}", ".key")[0]
value