Add SPDX license data

pyproject.toml

@@ -95,3 +95,4 @@ ignore = [
     "ISC001",
     "ISC002",
 ]
+per-file-ignores = { "src/packaging/_spdx.py" = ["E501"] }

tasks/__init__.py

@@ -4,6 +4,7 @@
 
 import invoke
 
-from . import check
+from . import check, licenses
 
 ns = invoke.Collection(check)
+ns.add_collection(licenses)

tasks/licenses.py

@@ -0,0 +1,91 @@
+import json
+import time
+from contextlib import closing
+from io import StringIO
+
+import httpx
+import invoke
+
+from .paths import SPDX_LICENSES
+
+LATEST_API = "https://api.github.com/repos/spdx/license-list-data/releases/latest"
+LICENSES_URL = (
+    "https://raw.githubusercontent.com/spdx/license-list-data/v{}/json/licenses.json"
+)
+EXCEPTIONS_URL = (
+    "https://raw.githubusercontent.com/spdx/license-list-data/v{}/json/exceptions.json"
+)
+
+
+def download_data(url):
+    for _ in range(600):
+        try:
+            response = httpx.get(url)
+            response.raise_for_status()
+        except Exception:
+            time.sleep(1)
+            continue
+        else:
+            return json.loads(response.content.decode("utf-8"))
+
+    message = "Download failed"
+    raise ConnectionError(message)
+
+
+@invoke.task
+def update(ctx):
+    print("Updating SPDX licenses...")
+
+    latest_version = download_data(LATEST_API)["tag_name"][1:]
+    print(f"Latest version: {latest_version}")
+
+    license_payload = download_data(LICENSES_URL.format(latest_version))["licenses"]
+    print(f"Licenses: {len(license_payload)}")
+
+    exception_payload = download_data(EXCEPTIONS_URL.format(latest_version))[
+        "exceptions"
+    ]
+    print(f"Exceptions: {len(exception_payload)}")
+
+    licenses = {}
+    for license_data in license_payload:
+        license_id = license_data["licenseId"]
+        license_key = license_id.casefold()
+        deprecated = license_data["isDeprecatedLicenseId"]
+        licenses[license_key] = {"id": license_id, "deprecated": deprecated}
+
+    exceptions = {}
+    for exception_data in exception_payload:
+        exception_id = exception_data["licenseExceptionId"]
+        exception_key = exception_id.casefold()
+        deprecated = exception_data["isDeprecatedLicenseId"]
+        exceptions[exception_key] = {"id": exception_id, "deprecated": deprecated}
+
+    with closing(StringIO()) as file_contents:
+        file_contents.write(
+            f"""\
+from __future__ import annotations
+
+VERSION = {latest_version!r}
+
+# fmt: off
+LICENSES: dict[str, dict[str, str | bool]] = {{
+"""
+        )
+
+        for normalized_name, data in sorted(licenses.items()):
+            file_contents.write(f"    {normalized_name!r}: {data!r},\n")
+
+        file_contents.write("}\n\nEXCEPTIONS: dict[str, dict[str, str | bool]] = {\n")
+
+        for normalized_name, data in sorted(exceptions.items()):
+            file_contents.write(f"    {normalized_name!r}: {data!r},\n")
+
+        file_contents.write("}\n# fmt: on\n")
+
+        # Replace default Python single quotes with double quotes to adhere
+        # to this project's desired formatting
+        contents = file_contents.getvalue().replace("'", '"')
+
+    with open(SPDX_LICENSES, "w", encoding="utf-8") as f:
+        f.write(contents)

tasks/paths.py

@@ -7,3 +7,4 @@
 PROJECT = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
 
 CACHE = os.path.join(PROJECT, ".cache")
+SPDX_LICENSES = os.path.join(PROJECT, "src", "packaging", "_spdx.py")

tasks/requirements.txt

@@ -1,3 +1,4 @@
 # The requirements required to invoke the tasks
 invoke
 progress
+httpx