Fix HttpOperator pagination with str data

airflow/providers/http/operators/http.py

@@ -56,12 +56,17 @@ class HttpOperator(BaseOperator):
     :param pagination_function: A callable that generates the parameters used to call the API again,
         based on the previous response. Typically used when the API is paginated and returns for e.g a
         cursor, a 'next page id', or a 'next page URL'. When provided, the Operator will call the API
-        repeatedly until this callable returns None. Also, the result of the Operator will become by
-        default a list of Response.text objects (instead of a single response object). Same with the
-        other injected functions (like response_check, response_filter, ...) which will also receive a
-        list of Response object. This function receives a Response object form previous call, and should
-        return a dict of parameters (`endpoint`, `data`, `headers`, `extra_options`), which will be merged
-        and will override the one used in the initial API call.
+        repeatedly until this callable returns None. The result of the Operator will become by default a
+        list of Response.text objects (instead of a single response object). Same with the other injected
+        functions (like response_check, response_filter, ...) which will also receive a list of Response
+        objects. This function receives a Response object form previous call, and should return a nested
+        dictionary with the following optional keys: `endpoint`, `data`, `headers` and `extra_options.
+        Those keys will be merged and/or override the parameters provided into the HttpOperator declaration.
+        Parameters are merged when they are both a dictionary (e.g.: HttpOperator.headers will be merged
+        with the `headers` dict provided by this function). When merging, dict items returned by this
+        function will override initial ones (e.g: if both HttpOperator.headers and `headers` have a 'cookie'
+        item, the one provided by `headers` is kept). Parameters are simply overridden when any of them are
+        string (e.g.: HttpOperator.endpoint is overridden by `endpoint`).
     :param response_check: A check against the 'requests' response object.
         The callable takes the response object as the first positional argument
         and optionally any number of keyword arguments available in the context dictionary.
@@ -101,7 +106,7 @@ def __init__(
         *,
         endpoint: str | None = None,
         method: str = "POST",
-        data: Any = None,
+        data: dict[str, Any] | str | None = None,
         headers: dict[str, str] | None = None,
         pagination_function: Callable[..., Any] | None = None,
         response_check: Callable[..., bool] | None = None,
@@ -271,9 +276,16 @@ def _merge_next_page_parameters(self, next_page_params: dict) -> dict:
         :param next_page_params: A dictionary containing the parameters for the next page.
         :return: A dictionary containing the merged parameters.
         """
+        data: str | dict | None = None  # makes mypy happy
+        next_page_data_param = next_page_params.get("data")
+        if isinstance(self.data, dict) and isinstance(next_page_data_param, dict):
+            data = merge_dicts(self.data, next_page_data_param)
+        else:
+            data = next_page_data_param or self.data
+
         return dict(
             endpoint=next_page_params.get("endpoint") or self.endpoint,
-            data=merge_dicts(self.data, next_page_params.get("data", {})),
+            data=data,
             headers=merge_dicts(self.headers, next_page_params.get("headers", {})),
             extra_options=merge_dicts(self.extra_options, next_page_params.get("extra_options", {})),
         )

airflow/providers/http/triggers/http.py

@@ -56,7 +56,7 @@ def __init__(
         method: str = "POST",
         endpoint: str | None = None,
         headers: dict[str, str] | None = None,
-        data: Any = None,
+        data: dict[str, Any] | str | None = None,
         extra_options: dict[str, Any] | None = None,
     ):
         super().__init__()

tests/providers/http/operators/test_http.py

@@ -127,7 +127,7 @@ def pagination_function(response: Response) -> dict | None:
                 iterations += 1
                 return dict(
                     endpoint=response.json()["endpoint"],
-                    data={},
+                    data="",
                     headers={},
                     extra_options={},
                 )