initial skeleton for loading sample data

src/yt_napari/_ds_cache.py

@@ -9,6 +9,13 @@
 from yt_napari.logging import ytnapari_log
 
 
+def _load_sample(filename):
+    # TODO: check for pooch, pandas.
+    # TODO: catch key errors, etc.
+    ds = yt.load_sample(filename)
+    return ds
+
+
 class DatasetCache:
     def __init__(self):
         self.available = {}
@@ -53,7 +60,15 @@ def check_then_load(self, filename: str, cache_if_not_found: bool = True):
             ds_callable = getattr(_special_loaders, callable_name)
             ds = ds_callable()
         else:
-            ds = yt.load(filename)
+            # TODO: have this sample files registry come from yt,
+            # just setting up the napari side for now. Should
+            # also add a config option maybe to handle name
+            # conflicts between sample files and local files?
+            sample_files = ["IsolatedGalaxy"]
+            if filename in sample_files:
+                ds = _load_sample(filename)
+            else:
+                ds = yt.load(filename)
 
         if ytcfg.get("yt_napari", "in_memory_cache") and cache_if_not_found:
             self.add_ds(ds, filename)

src/yt_napari/_model_ingestor.py

@@ -758,14 +758,13 @@ def _process_validated_model(
     return layer_list, timeseries_layers
 
 
-def load_from_json(json_paths: List[str]) -> List[Layer]:
+def load_from_json_strs(json_strs: List[str]) -> List[Layer]:
     layer_lists = []  # we will concatenate layers across json paths
     timeseries_layers = []  # timeseries layers handled separately
-    for json_path in json_paths:
+    for json_str in json_strs:
         # InputModel is a pydantic class, the following will validate the json
-        with open(json_path, "r") as open_file:
-            model = InputModel.model_validate_json(open_file.read())
-
+        model = InputModel.model_validate_json(json_str)
+        print(model)
         # now that we have a validated model, we can use the model attributes
         # to execute the code that will return our array for the image
         layer_lists_j, timeseries_layers_j = _process_validated_model(model)
@@ -785,6 +784,14 @@ def load_from_json(json_paths: List[str]) -> List[Layer]:
     return out_layers
 
 
+def load_from_json(json_paths: List[str]) -> List[Layer]:
+    json_strs = []  # list of json strings
+    for json_path in json_paths:
+        with open(json_path, "r") as open_file:
+            json_strs.append(open_file.read())
+    return load_from_json_strs(json_strs)
+
+
 def _choose_ref_layer(
     layer_list: List[SpatialLayer], method: Optional[str] = "first_in_list"
 ) -> ReferenceLayer:

src/yt_napari/_sample_data.py

@@ -0,0 +1,50 @@
+import json
+
+from yt_napari import __version__
+from yt_napari._model_ingestor import load_from_json_strs
+
+isogaldict = {
+    "datasets": [
+        {
+            "filename": "IsolatedGalaxy",
+            "selections": {
+                "regions": [
+                    {
+                        "fields": [
+                            {
+                                "field_name": "Density",
+                                "field_type": "enzo",
+                                "take_log": True,
+                            }
+                        ],
+                        "left_edge": {
+                            "value": [
+                                0.4,
+                                0.4,
+                                0.4,
+                            ],
+                            "unit": "Mpc",
+                        },
+                        "right_edge": {
+                            "value": [
+                                0.6,
+                                0.6,
+                                0.6,
+                            ],
+                            "unit": "Mpc",
+                        },
+                        "resolution": [400, 400, 400],
+                    },
+                ]
+            },
+            "edge_units": "Mpc",
+        }
+    ]
+}
+
+
+def isogal():
+    isogaldict["$schema"] = f"yt-napari_{__version__}.json"
+    json_objs = [json.dumps(isogaldict)]
+    result = load_from_json_strs(json_objs)
+    return result

src/yt_napari/napari.yaml

@@ -14,6 +14,9 @@ contributions:
     - id: yt-napari.metadata_widget
       title: Inspect the metadata for a yt dataset
       python_name: yt_napari._widget_matadata:MetadataWidget
+    - id: yt-napari.data.isogal
+      title: Load Isolated Galaxy
+      python_name: yt_napari._sample_data:isogal
   readers:
     - command: yt-napari.get_reader
       accepts_directories: false
@@ -25,3 +28,7 @@ contributions:
       display_name: yt Time Series Reader
     - command: yt-napari.metadata_widget
       display_name: yt Metadata Explorer
+  sample_data:
+    - key: isogal
+      display_name: IsolatedGalaxy
+      command: yt-napari.data.isogal