Initial version

Author: sirosen

.flake8

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+[flake8]
+exclude = .git,.tox,__pycache__,.eggs,dist,.venv*,docs,build,_build
+# we enforce 80 char width with `black` "loosely", so flake8 should be set to
+# not fail on up to 90 chars of width
+max-line-length = 90
+
+# based on the flake8 conf for `black` itself:
+#   https://github.com/ambv/black/blob/master/.flake8
+#
+# W503/W504 conflict, black causes E203
+ignore = W503,W504,E203,

.gitignore

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+.venv
+*.egg-info
+__pycache__

.pre-commit-config.yaml

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+repos:
+- repo: https://github.com/pre-commit/pre-commit-hooks.git
+  rev: v3.1.0
+  hooks:
+    - id: check-merge-conflict
+    - id: trailing-whitespace
+- repo: https://github.com/python/black
+  rev: 20.8b1
+  hooks:
+    - id: black
+      name: "Autoformat python files"
+      types: [python]
+      language_version: python3
+- repo: https://gitlab.com/pycqa/flake8
+  rev: 3.8.4
+  hooks:
+    - id: flake8
+      name: "Lint python files"
+      types: [python]
+      language_version: python3
+      additional_dependencies: ['flake8-bugbear==20.11.1']
+- repo: https://github.com/timothycrosley/isort
+  rev: 5.6.4
+  hooks:
+    - id: isort
+      name: "Sort python imports"
+      types: [python]
+      language_version: python3

.pre-commit-hooks.yaml

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+- id: check-jsonschema
+  name: Validate files with jsonschema
+  entry: check-jsonschema
+  language: python
+  types_or: [json,yaml]

LICENSE

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+   Copyright 2021, Stephen Rosen
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

README.md

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+# check-jsonschema
+
+A pre-commit hook for checking files against a JSONSchema.
+The schema may be specified as a local or remote (HTTP or HTTPS) file.
+
+Remote files are automatically downloaded and cached if possible.
+
+## Example Usage: Validate GitHub Workflows with Schemastore
+
+Add this hook to your pre-commit config:
+
+```yaml
+- repo: https://github.com/sirosen/check-jsonschema
+  rev: 0.1.0
+  hooks:
+    - id: check-workflows
+      name: "Lint GitHub Workflows"
+      language: python
+      files: ^\.github/workflows/.*\.yaml$
+      args: ["--schemafile", "https://json.schemastore.org/github-workflow"]
+```

check_jsonschema/__init__.py

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+import argparse
+import contextlib
+import json
+import os
+import platform
+import time
+import urllib.request
+
+from identify import identify
+import jsonschema
+import ruamel.yaml
+
+yaml = ruamel.yaml.YAML(typ="safe")
+
+
+sysname = platform.system()
+# on windows, try to get the appdata env var
+# this *could* result in CACHE_DIR=None, which is fine, just skip caching in
+# that case
+if sysname == "Windows":
+    CACHE_DIR = os.getenv("LOCALAPPDATA", os.getenv("APPDATA"))
+# macOS -> app support dir
+elif sysname == "Darwin":
+    CACHE_DIR = os.path.expanduser("~/Library/Application Support")
+# default for unknown platforms, namely linux behavior
+# use XDG env var and default to ~/.cache/
+else:
+    CACHE_DIR = os.getenv("XDG_CACHE_HOME", os.path.expanduser("~/.cache/"))
+
+if CACHE_DIR:
+    CACHE_DIR = os.path.join(CACHE_DIR, "jsonschema_validate")
+
+
+@contextlib.contextmanager
+def cached_open(file_url, filename):
+    if not CACHE_DIR:
+        with urllib.request.urlopen(file_url) as fp:
+            yield fp
+    else:
+        try:
+            os.makedirs(CACHE_DIR)
+        except FileExistsError:
+            pass
+
+        if not filename:
+            filename = file_url.split("/")[-1]
+        dest = os.path.join(CACHE_DIR, filename)
+
+        # connect, but don't read yet
+        conn = urllib.request.urlopen(file_url)
+
+        # download and cache to disk based on the mtime of the local file if it
+        # exists (check mtime before download for speed) or just download if missing
+        do_download = True
+        if os.path.exists(dest):
+            # get both timestamps as epoch times
+            local_mtime = os.path.getmtime(dest)
+            remote_mtime = time.mktime(
+                time.strptime(conn.headers["last-modified"], "%a, %d %b %Y %H:%M:%S %Z")
+            )
+            do_download = local_mtime < remote_mtime
+        if do_download:
+            with open(dest, "wb") as fp:
+                fp.write(conn.read())
+
+        conn.close()
+
+        with open(dest, "r") as fp:
+            yield fp
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--schemafile",
+        required=True,
+        help=(
+            "REQUIRED. "
+            "The path to a file containing the jsonschema to use or an "
+            "HTTP(S) URI for the schema. If a remote file is used, "
+            "it will be downloaded and cached locally based on mtime."
+        ),
+    )
+    parser.add_argument(
+        "--cache-filename",
+        help=(
+            "The name to use for caching a remote schema. "
+            "Defaults to the last slash-delimited part of the URI."
+        ),
+    )
+    parser.add_argument("instancefiles", nargs="+", help="JSON or YAML files to check.")
+    args = parser.parse_args()
+
+    if args.schemafile.startswith("https://") or args.schemafile.startswith("http://"):
+        with cached_open(args.schemafile, args.cache_filename) as fp:
+            schema = json.load(fp)
+    else:
+        with open(args.schemafile) as f:
+            schema = json.load(f)
+
+    for instancefile in args.instancefiles:
+        tags = identify.tags_from_path(instancefile)
+        if "yaml" in tags:
+            loader = yaml.load
+        elif "json" in tags:
+            loader = json.load
+        else:
+            raise ValueError(
+                f"cannot check {instancefile} as it is neither yaml nor json"
+            )
+        with open(instancefile) as f:
+            doc = loader(f)
+
+        jsonschema.validate(instance=doc, schema=schema)
+    print("ok -- validation done")

check_jsonschema/cli.py

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+[metadata]
+name = check-jsonschema
+version = 0.1.0
+description = A pre-commit hook for validating files against jsonschemas.
+long_description = file: README.md
+long_description_content_type = text/markdown
+url = https://github.com/sirosen/check-jsonschema
+author = Stephen Rosen
+author_email = [email protected]
+
+classifiers =
+    Development Status :: 3 - Alpha
+    Intended Audience :: Developers
+    License :: OSI Approved :: Apache Software License
+    Programming Language :: Python :: 3
+
+[options]
+python_requires = >=3.6.2
+install_requires =
+    ruamel.yaml==0.16.12
+    jsonschema<4.0
+    identify<2.0
+packages = find:
+
+[options.entry_points]
+console_scripts =
+    check-jsonschema = check_jsonschema.cli:main
+
+[bdist_wheel]
+universal = True
+
+
+[isort]
+profile = black

setup.cfg

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+from setuptools import setup
+
+setup()