Support templating more complex captures into JSON request bodies

[colinwd]

Problem to solve

While we can easily capture complex variables via jsonpath, the ability to use them is limited at the moment:

GET http://localhost:3000/car/1

HTTP 200
[Captures]
features: jsonpath "$.car.features" # Array of strings


PUT http://localhost:3000/car/2
{
    "features": {{features}}
}

HTTP 200

Output:

error: Unrenderable variable
  --> array-var.hurl:10:19
   |
10 |     "features": {{features}}
   |                   ^^^^^^^^ variable <features> with value [wheels engine doors] can not be rendered

Proposal

I have done some initial digging through the code to see what it might take to support this, and noted that it's likely not a trivial modification. The current templating code, as we can see in the error message above, outputs strings without any surrounding quotes, and modifying that would be a breaking change for that component's public API.

I'd love to support getting this into place, but wanted to make sure any changes are in line with existing project guidelines and direction. Some guidance on how this might fit into the project as it is today would be very welcome.

Tasks to complete

1. Update Templating Body docs to accurately reflect that templating primitives does currently work for JSON bodies! Happy to submit a separate, initial PR for this.
2. Modify existing (or add new?) JSON templating code to support complex types - mainly arrays and objects.
3. Lots of unit tests.
4. Update docs to reflect new feature.

Let me know if this is something that will fit into the current roadmap! Thanks!

[fabricereix]

Hi @colinwd,
Thanks for your suggestion.
We could indeed support more rendering, specifically in a JSON body for arrays and objects.
As suggested, you can already submit a PR for the doc for the existing behaviour.

For this enhancement, we will have to make sure that:

• this impacts only JSON body (and not other bodies)
• the rendering errors are still correct. We will still have values that will never be renderable in a JSON such collections from XML.

Before implementing, we can update this issue with real usecase/concrete example that we will use for integration testing.

[janstrohschein]

I found this issue because we upgraded from Hurl version 2 to version 4 and now our response body content cant be rendered anymore. Have there been some changes in how the response is handled?

[Captures]
client_id: jsonpath "$[?(@.clientId=='{{client_id}}')].id"

Output in version 2: e654bfe8-1195-44e2-9f56-bb9ec83fe14e
Output in version 4: [e654bfe8-1195-44e2-9f56-bb9ec83fe14e]

[fabricereix]

This must be related to #1469
You now have to get explicitly the first element, simple add nth 0 after your jsonpath query

client_id: jsonpath "$[?(@.clientId=='{{client_id}}')].id" nth 0

[janstrohschein]

Thank you very much! That solved it 👍