Allow to parse more backend kwargs to pydap backend (#6276)

* propose implementation of #6274

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* minor fix

* Add tests for new method PydapDataStore._update_default_params

* minor fix

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* add entry in whats-new.rst

* Minor change

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Define open_dataset_params for cleaner solution

* remove import of inspect lib

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update xarray/backends/pydap_.py

Co-authored-by: Mathias Hauser <mathause@users.noreply.github.com>

* update whats-new

* Set pydap backend arguments explicitly

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* set defaults in PydapDataStore.open rather than entry point

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Co-authored-by: Jonas Gliss <jonas.gliss@statkraft.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Mathias Hauser <mathause@users.noreply.github.com>

doc/whats-new.rst

@@ -28,6 +28,10 @@ New Features
   and ``Microsecond``. (:issue:`6134`, :pull:`6135`).
   By `Aaron Spring <https://github.com/aaronspring>`_.
 
+- Enbable to provide more keyword arguments to `pydap` backend when reading
+  OpenDAP datasets (:issue:`6274`).
+  By `Jonas Gliß <https://github.com/jgliss>`.
+
 
 Breaking changes
 ~~~~~~~~~~~~~~~~

xarray/backends/pydap_.py

@@ -86,9 +86,40 @@ def __init__(self, ds):
         self.ds = ds
 
     @classmethod
-    def open(cls, url, session=None):
+    def open(
+        cls,
+        url,
+        application=None,
+        session=None,
+        output_grid=None,
+        timeout=None,
+        verify=None,
+        user_charset=None,
+    ):
+
+        if output_grid is None:
+            output_grid = True
+
+        if verify is None:
+            verify = True
+
+        if timeout is None:
+            from pydap.lib import DEFAULT_TIMEOUT
 
-        ds = pydap.client.open_url(url, session=session)
+            timeout = DEFAULT_TIMEOUT
+
+        if user_charset is None:
+            user_charset = "ascii"
+
+        ds = pydap.client.open_url(
+            url=url,
+            application=application,
+            session=session,
+            output_grid=output_grid,
+            timeout=timeout,
+            verify=verify,
+            user_charset=user_charset,
+        )
         return cls(ds)
 
     def open_store_variable(self, var):
@@ -123,12 +154,22 @@ def open_dataset(
         drop_variables=None,
         use_cftime=None,
         decode_timedelta=None,
+        application=None,
         session=None,
+        output_grid=None,
+        timeout=None,
+        verify=None,
+        user_charset=None,
     ):
 
         store = PydapDataStore.open(
-            filename_or_obj,
+            url=filename_or_obj,
+            application=application,
             session=session,
+            output_grid=output_grid,
+            timeout=timeout,
+            verify=verify,
+            user_charset=user_charset,
         )
 
         store_entrypoint = StoreBackendEntrypoint()