Update the WEBBPSF_PATH handling to automatically try to get the da…

…ta if it isn't set

webbpsf/tests/test_errorhandling.py

@@ -4,6 +4,7 @@
 import logging
 import os
 import os.path
+from pathlib import Path
 
 import pytest
 
@@ -48,7 +49,7 @@ def test_invalid_masks():
     assert _exception_message_starts_with(excinfo, "Instrument NIRCam doesn't have a pupil mask called 'JUNK'.")
 
 
-def test_get_webbpsf_data_path_invalid(monkeypatch):
+def test_get_webbpsf_data_path_invalid(monkeypatch, tmp_path):
     real_env_webbpsf_path = os.getenv('WEBBPSF_PATH')
     real_conf_webbpsf_path = conf.WEBBPSF_PATH
     real_webbpsf_path = real_env_webbpsf_path or real_conf_webbpsf_path
@@ -57,9 +58,19 @@ def test_get_webbpsf_data_path_invalid(monkeypatch):
     # config says to (and env var has been unset)
     monkeypatch.delenv('WEBBPSF_PATH')
     monkeypatch.setattr(conf, 'WEBBPSF_PATH', 'from_environment_variable')
-    with pytest.raises(EnvironmentError) as excinfo:
+
+    # Patch the function that gets the home directory so we don't overwrite the
+    # what is on the system
+    def mockreturn():
+        return Path(tmp_path)
+
+    monkeypatch.setattr(Path, "home", mockreturn)
+
+    with pytest.warns(UserWarning, match=r"Environment variable \$WEBBPSF_PATH is not set!\n.*") as excinfo:
         _ = utils.get_webbpsf_data_path()
-    assert 'Environment variable $WEBBPSF_PATH is not set!' in str(excinfo)
+
+    # Check that the data was downloaded
+    assert any((tmp_path / "data" / "webbpsf-data").iterdir())
 
     # Test that we can override the WEBBPSF_PATH setting here through
     # the config object even though the environment var is deleted

webbpsf/utils.py

@@ -180,6 +180,39 @@ def setup_logging(level='INFO', filename=None):
 """
 
 
+def auto_download_webbpsf_data():
+    import os
+    import tarfile
+    from pathlib import Path
+    from tempfile import TemporaryDirectory
+    from urllib.request import urlretrieve
+
+    # Create a default directory for the data files
+    default_path = Path.home() / "data" / "webbpsf-data"
+    default_path.mkdir(parents=True, exist_ok=True)
+
+    os.environ["WEBBPSF_PATH"] = str(default_path)
+
+    # Download the data files if the directory is empty
+    if not any(default_path.iterdir()):
+        warnings.warn("WebbPSF data files not found in default location, attempting to download them now...")
+
+        with TemporaryDirectory() as tmpdir:
+            # Download the data files to a temporary directory
+            url = "https://stsci.box.com/shared/static/qxpiaxsjwo15ml6m4pkhtk36c9jgj70k.gz"
+            filename = Path(tmpdir) / "webbpsf-data-LATEST.tar.gz"
+            urlretrieve(url, filename)
+
+            # Extract the tarball
+            with tarfile.open(filename, "r:gz") as tar:
+                tar.extractall(default_path.parent, filter="fully_trusted")
+
+        if not any(default_path.iterdir()):
+            raise IOError(f"Failed to get and extract WebbPSF data files to {default_path}")
+
+    return default_path
+
+
 def get_webbpsf_data_path(data_version_min=None, return_version=False):
     """Get the WebbPSF data path
 
@@ -201,7 +234,12 @@ def get_webbpsf_data_path(data_version_min=None, return_version=False):
     if path_from_config == 'from_environment_variable':
         path = os.getenv('WEBBPSF_PATH')
         if path is None:
-            raise EnvironmentError(f'Environment variable $WEBBPSF_PATH is not set!\n{MISSING_WEBBPSF_DATA_MESSAGE}')
+            message = (
+                'Environment variable $WEBBPSF_PATH is not set!\n'
+                f'{MISSING_WEBBPSF_DATA_MESSAGE} searching default location..s'
+            )
+            warnings.warn(message)
+            path = auto_download_webbpsf_data()
     else:
         path = path_from_config