Response template queries
Imposter allows you to respond with a template - that is, a file or content containing placeholders, which are replaced with values at runtime. See the templates page for more information.
You can also use a JsonPath expression to query an object when using a placeholder.
This is useful if you have an object, such as a request body or object within a store, and wish to render a child property of the object instead of the whole object.
Using JsonPath in placeholders
The JsonPath placeholder syntax is as follows:
<placeholder expression>:<JsonPath expression>
Here is an example that queries the request body:
${context.request.body:$.name}
In this example, the request body is parsed as a JSON object, then the JsonPath expression $.name is executed. The request body looks like this:
{
"name": "Alice",
"occupation": "Programmer"
}
The result of the query is the string Alice, which is then substituted into the template.
Similarly, you could refer to other properties of the body - occupation would look like this:
Your occupation is: ${context.request.body:$.occupation}
Example using stores
This example fetches an item in a store, and returns the name property using a JsonPath expression.
Learn more about stores.
This will return the name property from the person item in the request store:
${stores.request.person:$.name}
This retrieves the item named person from the request store. The item must be an object, or a string representation of a valid JSON object.
The person item looks like this:
{
"name": "Alice",
"occupation": "Programmer"
}
Since this item is an object, we can use JsonPath to query the name property - hence the expression $.name in the template placeholder.
Templating performance
Using JsonPath in placeholder templates is computationally expensive, as it requires parsing and querying of an item rather than just value substitution.