Use pluggy to hook into Xpublish

Works with  xpublish-community/xpublish#146

pyproject.toml

@@ -1,7 +1,42 @@
 [build-system]
-requires = ["setuptools>=42", "wheel", "setuptools_scm[toml]>=3.4"]
+requires = ["setuptools>=61", "wheel", "setuptools_scm[toml]>=3.4"]
 build-backend = "setuptools.build_meta"
 
+[project]
+name = "xpublish_opendap"
+description = ""
+readme = "README.md"
+requires-python = ">=3.9"
+keywords = []
+license = { file = "LICENSE.txt" }
+
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Intended Audience :: Science/Research",
+    "Operating System :: OS Independent",
+    "License :: OSI Approved :: BSD License",
+    "Programming Language :: Python",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Topic :: Scientific/Engineering",
+]
+
+dynamic = ["version", "dependencies"]
+
+[tool.setuptools]
+packages = ["xpublish_opendap"]
+
+[tool.setuptools.dynamic]
+dependencies = { file = ["requirements.txt"] }
+
+[tool.setuptools_scm]
+write_to = "xpublish_opendap/_version.py"
+
+[project.entry-points."xpublish.plugin"]
+opendap = "xpublish_opendap.plugin:OpenDapPlugin"
+
 [tool.interrogate]
 ignore-init-method = true
 ignore-init-module = false

requirements.txt

@@ -1,3 +1,3 @@
 opendap-protocol<1.2.0
 xarray
-xpublish<=0.1.0
+xpublish

xpublish_opendap/__init__.py

@@ -2,9 +2,9 @@
 xpublish_opendap provides an OpenDAP router for Xpublish
 """
 
-from xpublish_opendap.router import dap_router
+from xpublish_opendap.plugin import OpenDapPlugin
 
-__all__ = ["dap_router"]
+__all__ = ["OpenDapPlugin"]
 
 try:
     from ._version import __version__

xpublish_opendap/plugin.py

@@ -0,0 +1,85 @@
+"""
+xpublish_opendap
+
+OpenDAP router for Xpublish
+"""
+import logging
+from typing import List
+from urllib import parse
+
+import cachey
+import opendap_protocol as dap
+import xarray as xr
+from fastapi import APIRouter, Depends, Request
+from fastapi.responses import StreamingResponse
+from xpublish import Plugin, hookimpl
+
+from .dap_xarray import dap_dataset
+
+logger = logging.getLogger("uvicorn")
+
+
+
+class OpenDapPlugin(Plugin):
+    name = "opendap"
+
+    dataset_router_prefix = "/opendap"
+    dataset_router_tags: List[str] = ["opendap"]
+
+    @hookimpl
+    def dataset_router(self):
+        router = APIRouter(prefix=self.dataset_router_prefix, tags=self.dataset_router_tags)
+
+        def get_dap_dataset(
+            dataset_id: str,
+            ds: xr.Dataset = Depends(self.dependencies.dataset),
+            cache: cachey.Cache = Depends(self.dependencies.cache),
+        ):
+            """
+            Get a dataset that has been translated to opendap
+            """
+            cache_key = f"opendap_dataset_{dataset_id}"
+            dataset = cache.get(cache_key)
+
+            if dataset is None:
+                dataset = dap_dataset(ds, dataset_id)
+
+                cache.put(cache_key, dataset, 99999)
+
+            return dataset
+
+        def dap_constraint(request: Request) -> str:
+            """Parse DAP constraints from request"""
+            constraint = parse.unquote(request.url.components[3])
+
+            return constraint
+
+        @router.get(".dds")
+        def dds_response(
+            constraint=Depends(dap_constraint), dataset: dap.Dataset = Depends(get_dap_dataset),
+        ):
+            """OpenDAP DDS response (types and dimension metadata)"""
+            return StreamingResponse(
+                dataset.dds(constraint=constraint), media_type="text/plain",
+            )
+
+        @router.get(".das")
+        def das_response(
+            constraint=Depends(dap_constraint), dataset: dap.Dataset = Depends(get_dap_dataset),
+        ):
+            """OpenDAP DAS response (attribute metadata)"""
+            return StreamingResponse(
+                dataset.das(constraint=constraint), media_type="text/plain",
+            )
+
+
+        @router.get(".dods")
+        def dods_response(
+            constraint=Depends(dap_constraint), dataset: dap.Dataset = Depends(get_dap_dataset),
+        ):
+            """OpenDAP dods response (data access)"""
+            return StreamingResponse(
+                dataset.dods(constraint=constraint), media_type="application/octet-stream",
+            )
+
+        return router