more doc

docs/src/migrations/v3.0.0.md

@@ -84,6 +84,37 @@ stac = StacApi(
 )
 ```
 
+## APIRequest - GET Request Model
+
+Most of the **GET** endpoints are configured with `stac_fastapi.types.search.APIRequest` base class.
+
+e.g the BaseSearchGetRequest, default for the `GET - /search` endpoint:
+
+```python
+@attr.s
+class BaseSearchGetRequest(APIRequest):
+    """Base arguments for GET Request."""
+
+    collections: Annotated[Optional[str], Query()] = attr.ib(
+        default=None, converter=str2list
+    )
+    ids: Annotated[Optional[str], Query()] = attr.ib(default=None, converter=str2list)
+    bbox: Annotated[Optional[BBox], Query()] = attr.ib(default=None, converter=str2bbox)
+    intersects: Annotated[Optional[str], Query()] = attr.ib(default=None)
+    datetime: Annotated[Optional[DateTimeType], Query()] = attr.ib(
+        default=None, converter=str_to_interval
+    )
+    limit: Annotated[Optional[int], Query()] = attr.ib(default=10)
+```
+
+We use [*python attrs*](https://www.attrs.org/en/stable/) to construct those classes. **Type Hint** for each attribute is important and should be defined using `Annotated[{type}, fastapi.Query()]` form.
+
+```python
+@attr.s
+class SomeRequest(APIRequest):
+    user_number: Annotated[Optional[int], Query(alias="user-number")] = attr.ib(default=None)
+```
+
 ## Filter extension
 
 `default_includes` attribute has been removed from the `ApiSettings` object. If you need `defaults` includes you can overwrite the `FieldExtension` models (see https://github.com/stac-utils/stac-fastapi/pull/706).