Multipart Form-data body does not support {{variables}} templating (API Connect recipe)

[danydossantos63]

Summary

In the API Connect plugin (v1.4.2), when running the recipe (input dataset → one request per row), {{variables}} are correctly substituted in the URL, headers, query params, Raw body, and Form-data (Json) body — but not in the Multipart Form-data body. Row/column values injected via {{ColumnName}} are sent to the API literally (e.g. {{id_client}}) instead of the actual row value.

Environment

• Plugin: dss-plugin-api-connect
• Version: v1.4.2
• Component: recipe api-connect

Steps to reproduce

1. Create an API Connect recipe with an input dataset containing a column, e.g. id_client.
2. Add id_client to "Columns to use as variables".
3. Set HTTP method = POST and Body = Multipart Form-data.
4. Add a body entry: key client_id, value {{id_client}}.
5. Run the recipe.

Expected behavior

Each request sends the row value, e.g. client_id=42, consistent with Raw and Form-data (Json) bodies.

Actual behavior

Each request sends the literal template string client_id={{id_client}}; the variable is never resolved.

Root cause

In python-lib/rest_api_client.py, the Multipart body values are stored as tuples (None, v):

elif body_format in [DKUConstants.MULTIPART_FORM_DATA_BODY_FORMAT]:
    key_value_body = endpoint.get("key_value_body", {})
    self.requests_kwargs.update({"files": {k: (None, v) for k, v in get_dku_key_values(key_value_body).items()}})

The templating engine template_dict() (applied in request()) only resolves {{...}} inside str and dict values. Tuple contents are skipped, so Multipart values are never templated — unlike data (Raw) and json (Form-data), which are strings/dicts and get resolved.

Proposed fix

Template the Multipart values at build time using the already-populated self.presets_variables:

elif body_format in [DKUConstants.MULTIPART_FORM_DATA_BODY_FORMAT]:
    key_value_body = endpoint.get("key_value_body", {})
    self.requests_kwargs.update({"files": {
        k: (None, format_template(v, **self.presets_variables))
        for k, v in get_dku_key_values(key_value_body).items()
    }})

(format_template is already imported in rest_api_client.py.)

Additional note (documentation)

The recipe's variable-section help text (custom-recipes/api-connect/recipe.json) states "URL, headers and parameters can be templated using {{variables}}", omitting the body. It should be updated to include the body to avoid confusion.

Verification

End-to-end test (mocked HTTP layer, 2 input rows) after the fix:

POST -> MULTIPART: {'client_id': (None, '42'), 'nom': (None, 'Dupont'), 'statique': (None, 'const')}
POST -> MULTIPART: {'client_id': (None, '99'), 'nom': (None, 'Martin'), 'statique': (None, 'const')}

Variables are resolved per row; static values are preserved.

[alexbourret]

Hi @danydossantos63 ! Thanks for this, we'll update the plugin asap !