Automatically call griddap_initialize if a dataset_id exists

.pre-commit-config.yaml

@@ -50,14 +50,14 @@ repos:
     - id: add-trailing-comma
 
 - repo: https://github.com/astral-sh/ruff-pre-commit
-  rev: v0.7.2
+  rev: v0.8.0
   hooks:
     - id: ruff
       args: ["--fix", "--show-fixes"]
     - id: ruff-format
 
 - repo: https://github.com/nbQA-dev/nbQA
-  rev: 1.8.7
+  rev: 1.9.1
   hooks:
     - id: nbqa-check-ast
     - id: nbqa-black

erddapy/core/griddap.py

@@ -2,16 +2,13 @@
 
 from __future__ import annotations
 
-import functools
-
 import pandas as pd
 
 from erddapy.core.url import urlopen
 
 OptionalList = list[str] | tuple[str] | None
 
 
-@functools.lru_cache(maxsize=128)
 def _griddap_get_constraints(
     dataset_url: str,
     step: int,

erddapy/erddapy.py

@@ -34,13 +34,13 @@
 
 # Objects used by downstream packages
 __all__ = [
+    "ERDDAP",
     "_check_substrings",
     "_distinct",
     "_format_constraints_url",
     "_quote_string_constraints",
     "parse_dates",
     "urlopen",
-    "ERDDAP",
 ]
 
 if TYPE_CHECKING:
@@ -141,11 +141,11 @@ def __init__(
         self.response = response
 
         # Initialized only via properties.
-        self.constraints: dict | None = None
         self.server_functions: dict | None = None
-        self.dataset_id: OptionalStr = None
         self.requests_kwargs: dict = {}
         self.auth: tuple | None = None
+
+        self.constraints: dict | None = None
         self.variables: OptionalList | None = None
         self.dim_names: OptionalList | None = None
 
@@ -157,6 +157,16 @@ def __init__(
         self._dataset_id: OptionalStr = None
         self._variables: dict = {}
 
+    @property
+    def dataset_id(self) -> str:
+        """dataset_id property."""
+        return self._dataset_id
+
+    @dataset_id.setter
+    def dataset_id(self, value: str) -> None:
+        self._dataset_id = value
+        self.griddap_initialize(dataset_id=value)
+
     def griddap_initialize(
         self: ERDDAP,
         dataset_id: OptionalStr = None,
@@ -171,15 +181,12 @@ def griddap_initialize(
 
         """
         dataset_id = dataset_id if dataset_id else self.dataset_id
-        msg = f"Method only valid using griddap protocol, got {self.protocol}"
-        if self.protocol != "griddap":
-            raise ValueError(msg)
+        # Short-circuit for opendap and/or non-griddap datasets.
+        if self.protocol != "griddap" or self.response == "opendap":
+            return
         msg = f"Must set a valid dataset_id, got {self.dataset_id}"
         if dataset_id is None:
             raise ValueError(msg)
-        # Return the opendap URL without any slicing.
-        if self.response == "opendap":
-            return
 
         metadata_url = f"{self.server}/griddap/{self.dataset_id}"
         (

notebooks/01a-griddap.ipynb

@@ -71,8 +71,7 @@
     "CAVEAT: Note that ERDDAP can serve gridded data with longitudes in the 0–360 format or -180–180.\n",
     "The user must inspect the dataset and modify your query accordingly.\n",
     "\n",
-    "Information on the griddap dataset is fetched with `griddap_initialize`.\n",
-    "This fills in the `variables` and `constraints` properties for that dataset."
+    "Information on the griddap dataset is fetched automatically and the `variables` and `constraints` properties for that dataset are filled using ERDDAP's defaults."
    ]
   },
   {
@@ -83,24 +82,55 @@
    "source": [
     "import json\n",
     "\n",
-    "e.griddap_initialize()\n",
+    "constraints = json.dumps(e.constraints, indent=1)\n",
     "\n",
     "print(f\"variables in this dataset:\\n\\n{e.variables}\")\n",
-    "constraints = json.dumps(e.constraints, indent=1)\n",
     "print(f\"\\nconstraints of this dataset:\\n\\n{constraints}\")"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "The default behaviour is to use erddap standard subsetting to return all variables at the most recent timestep and every point of the remaining dimensions.\n",
+    "ERDDAP's standard subsetting return all variables at the most recent timestep and every point of the remaining dimensions.\n",
     "\n",
     "This can result in large data requests!\n",
     "However, the values of the constraints can be changed and variables dropped before data set is downloaded.\n",
     "Here we will download only one variable from that list."
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "e.constraints[\"latitude_step\"] = 10\n",
+    "e.constraints[\"longitude_step\"] = 10\n",
+    "\n",
+    "constraints = json.dumps(e.constraints, indent=1)\n",
+    "print(f\"\\nconstraints of this dataset:\\n\\n{constraints}\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The user can reset to the defaults with `griddap_initialize()`."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "e.griddap_initialize()\n",
+    "\n",
+    "constraints = json.dumps(e.constraints, indent=1)\n",
+    "print(f\"\\nconstraints of this dataset:\\n\\n{constraints}\")"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -258,13 +288,6 @@
     "e.dataset_id = \"etopo5_lon180\""
    ]
   },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "The data can be downloaded immediately, no need to run `griddap_initialize`\n"
-   ]
-  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -332,7 +355,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.5"
+   "version": "3.13.0"
   }
  },
  "nbformat": 4,