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Improve & update release process to reflect recent changes (#3242)
[etc/vim.git] / src / blackd / __init__.py
1 import asyncio
2 import logging
3 from concurrent.futures import Executor, ProcessPoolExecutor
4 from datetime import datetime
5 from functools import partial
6 from multiprocessing import freeze_support
7 from typing import Set, Tuple
8
9 try:
10     from aiohttp import web
11
12     from .middlewares import cors
13 except ImportError as ie:
14     raise ImportError(
15         f"aiohttp dependency is not installed: {ie}. "
16         + "Please re-install black with the '[d]' extra install "
17         + "to obtain aiohttp_cors: `pip install black[d]`"
18     ) from None
19
20 import click
21
22 import black
23 from _black_version import version as __version__
24 from black.concurrency import maybe_install_uvloop
25
26 # This is used internally by tests to shut down the server prematurely
27 _stop_signal = asyncio.Event()
28
29 # Request headers
30 PROTOCOL_VERSION_HEADER = "X-Protocol-Version"
31 LINE_LENGTH_HEADER = "X-Line-Length"
32 PYTHON_VARIANT_HEADER = "X-Python-Variant"
33 SKIP_STRING_NORMALIZATION_HEADER = "X-Skip-String-Normalization"
34 SKIP_MAGIC_TRAILING_COMMA = "X-Skip-Magic-Trailing-Comma"
35 PREVIEW = "X-Preview"
36 FAST_OR_SAFE_HEADER = "X-Fast-Or-Safe"
37 DIFF_HEADER = "X-Diff"
38
39 BLACK_HEADERS = [
40     PROTOCOL_VERSION_HEADER,
41     LINE_LENGTH_HEADER,
42     PYTHON_VARIANT_HEADER,
43     SKIP_STRING_NORMALIZATION_HEADER,
44     SKIP_MAGIC_TRAILING_COMMA,
45     PREVIEW,
46     FAST_OR_SAFE_HEADER,
47     DIFF_HEADER,
48 ]
49
50 # Response headers
51 BLACK_VERSION_HEADER = "X-Black-Version"
52
53
54 class InvalidVariantHeader(Exception):
55     pass
56
57
58 @click.command(context_settings={"help_option_names": ["-h", "--help"]})
59 @click.option(
60     "--bind-host", type=str, help="Address to bind the server to.", default="localhost"
61 )
62 @click.option("--bind-port", type=int, help="Port to listen on", default=45484)
63 @click.version_option(version=black.__version__)
64 def main(bind_host: str, bind_port: int) -> None:
65     logging.basicConfig(level=logging.INFO)
66     app = make_app()
67     ver = black.__version__
68     black.out(f"blackd version {ver} listening on {bind_host} port {bind_port}")
69     web.run_app(app, host=bind_host, port=bind_port, handle_signals=True, print=None)
70
71
72 def make_app() -> web.Application:
73     app = web.Application(
74         middlewares=[cors(allow_headers=(*BLACK_HEADERS, "Content-Type"))]
75     )
76     executor = ProcessPoolExecutor()
77     app.add_routes([web.post("/", partial(handle, executor=executor))])
78     return app
79
80
81 async def handle(request: web.Request, executor: Executor) -> web.Response:
82     headers = {BLACK_VERSION_HEADER: __version__}
83     try:
84         if request.headers.get(PROTOCOL_VERSION_HEADER, "1") != "1":
85             return web.Response(
86                 status=501, text="This server only supports protocol version 1"
87             )
88         try:
89             line_length = int(
90                 request.headers.get(LINE_LENGTH_HEADER, black.DEFAULT_LINE_LENGTH)
91             )
92         except ValueError:
93             return web.Response(status=400, text="Invalid line length header value")
94
95         if PYTHON_VARIANT_HEADER in request.headers:
96             value = request.headers[PYTHON_VARIANT_HEADER]
97             try:
98                 pyi, versions = parse_python_variant_header(value)
99             except InvalidVariantHeader as e:
100                 return web.Response(
101                     status=400,
102                     text=f"Invalid value for {PYTHON_VARIANT_HEADER}: {e.args[0]}",
103                 )
104         else:
105             pyi = False
106             versions = set()
107
108         skip_string_normalization = bool(
109             request.headers.get(SKIP_STRING_NORMALIZATION_HEADER, False)
110         )
111         skip_magic_trailing_comma = bool(
112             request.headers.get(SKIP_MAGIC_TRAILING_COMMA, False)
113         )
114         preview = bool(request.headers.get(PREVIEW, False))
115         fast = False
116         if request.headers.get(FAST_OR_SAFE_HEADER, "safe") == "fast":
117             fast = True
118         mode = black.FileMode(
119             target_versions=versions,
120             is_pyi=pyi,
121             line_length=line_length,
122             string_normalization=not skip_string_normalization,
123             magic_trailing_comma=not skip_magic_trailing_comma,
124             preview=preview,
125         )
126         req_bytes = await request.content.read()
127         charset = request.charset if request.charset is not None else "utf8"
128         req_str = req_bytes.decode(charset)
129         then = datetime.utcnow()
130
131         loop = asyncio.get_event_loop()
132         formatted_str = await loop.run_in_executor(
133             executor, partial(black.format_file_contents, req_str, fast=fast, mode=mode)
134         )
135
136         # Only output the diff in the HTTP response
137         only_diff = bool(request.headers.get(DIFF_HEADER, False))
138         if only_diff:
139             now = datetime.utcnow()
140             src_name = f"In\t{then} +0000"
141             dst_name = f"Out\t{now} +0000"
142             loop = asyncio.get_event_loop()
143             formatted_str = await loop.run_in_executor(
144                 executor,
145                 partial(black.diff, req_str, formatted_str, src_name, dst_name),
146             )
147
148         return web.Response(
149             content_type=request.content_type,
150             charset=charset,
151             headers=headers,
152             text=formatted_str,
153         )
154     except black.NothingChanged:
155         return web.Response(status=204, headers=headers)
156     except black.InvalidInput as e:
157         return web.Response(status=400, headers=headers, text=str(e))
158     except Exception as e:
159         logging.exception("Exception during handling a request")
160         return web.Response(status=500, headers=headers, text=str(e))
161
162
163 def parse_python_variant_header(value: str) -> Tuple[bool, Set[black.TargetVersion]]:
164     if value == "pyi":
165         return True, set()
166     else:
167         versions = set()
168         for version in value.split(","):
169             if version.startswith("py"):
170                 version = version[len("py") :]
171             if "." in version:
172                 major_str, *rest = version.split(".")
173             else:
174                 major_str = version[0]
175                 rest = [version[1:]] if len(version) > 1 else []
176             try:
177                 major = int(major_str)
178                 if major not in (2, 3):
179                     raise InvalidVariantHeader("major version must be 2 or 3")
180                 if len(rest) > 0:
181                     minor = int(rest[0])
182                     if major == 2:
183                         raise InvalidVariantHeader("Python 2 is not supported")
184                 else:
185                     # Default to lowest supported minor version.
186                     minor = 7 if major == 2 else 3
187                 version_str = f"PY{major}{minor}"
188                 if major == 3 and not hasattr(black.TargetVersion, version_str):
189                     raise InvalidVariantHeader(f"3.{minor} is not supported")
190                 versions.add(black.TargetVersion[version_str])
191             except (KeyError, ValueError):
192                 raise InvalidVariantHeader("expected e.g. '3.7', 'py3.5'") from None
193         return False, versions
194
195
196 def patched_main() -> None:
197     maybe_install_uvloop()
198     freeze_support()
199     black.patch_click()
200     main()
201
202
203 if __name__ == "__main__":
204     patched_main()