334 lines
11 KiB
Python
Executable File
334 lines
11 KiB
Python
Executable File
#!/usr/bin/env python
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#
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# Copyright 2019 Banco Bilbao Vizcaya Argentaria, S.A.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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from urllib.parse import urlparse
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from uuid import uuid4
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import asyncio
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import io
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import logging
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import os
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import shlex
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import sys
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from aiohttp import web, StreamReader
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log = logging.getLogger('kapow')
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########################################################################
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# Resource Management #
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########################################################################
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CONNECTIONS = {}
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class Connection:
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"""
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Manages the lifecycle of a Kapow! connection.
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Behaves like a memory for the "fields" available in HTTP
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connections.
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"""
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def __init__(self, request):
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self._stream = None
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self._body = io.BytesIO()
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self._status = 200
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self._headers = dict()
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self._cookies = dict()
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self.request = request
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async def get(self, key):
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"""Get the content of the field `key`."""
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res = urlparse(key)
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def nth(n):
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"""Return the nth element in a path."""
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return res.path.split('/')[n]
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if res.path == 'request/method':
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return self.request.method.encode('utf-8')
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elif res.path == 'request/body':
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return self.request.content
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elif res.path == 'request/path':
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return self.request.path.encode('utf-8')
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elif res.path.startswith('request/matches/'):
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return self.request.match_info[nth(2)].encode('utf-8')
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elif res.path.startswith('request/params/'):
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return self.request.rel_url.query[nth(2)].encode('utf-8')
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elif res.path.startswith('request/headers/'):
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return self.request.headers[nth(2)].encode('utf-8')
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elif res.path.startswith('request/cookies/'):
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return self.request.cookies[nth(2)].encode('utf-8')
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elif res.path.startswith('request/form/'):
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return (await self.request.post())[nth(2)].encode('utf-8')
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elif res.path.startswith('request/files/'):
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name = nth(2)
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content = nth(3) # filename / content
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field = (await self.request.post())[name]
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if content == 'filename':
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try:
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return field.filename.encode('utf-8')
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except Exception:
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return b''
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elif content == 'content':
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try:
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return field.file.read()
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except Exception:
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return b''
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else:
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raise ValueError(f'Unknown content type {content!r}')
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else:
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raise ValueError('Unknown path')
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async def set(self, key, content):
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"""Set the field `key` with the value in `content`."""
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res = urlparse(key)
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def nth(n):
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return res.path.split('/')[n]
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if res.path == 'response/status':
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self._status = int((await content.read()).decode('utf-8'))
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elif res.path == 'response/body':
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self._body.write(await content.read())
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elif res.path.startswith('response/headers/'):
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clean = (await content.read()).rstrip(b'\n').decode('utf-8')
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self._headers[nth(2)] = clean
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elif res.path.startswith('response/cookies/'):
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clean = (await content.read()).rstrip(b'\n').decode('utf-8')
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self._cookies[nth(2)] = clean
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elif res.path == 'response/stream':
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if self._stream is None:
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self._stream = web.StreamResponse(status=self._status,
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reason="OK",
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headers=self._headers)
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for name, value in self._cookies.items():
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self._stream.set_cookie(name, value)
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await self._stream.prepare(self.request)
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chunk = await content.readany()
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while chunk:
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await self._stream.write(chunk)
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chunk = await content.readany()
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else:
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raise ValueError(f'Unknown path {res.path!r}')
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async def append(self, key, content):
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"""Append to field `key` the value in `content`."""
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raise NotImplementedError()
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async def build_response(self):
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"""Return the appropriate aiohttp.web.*Response."""
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if self._stream is None:
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response = web.Response(body=self._body.getvalue(),
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status=self._status,
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headers=self._headers)
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for name, value in self._cookies.items():
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response.set_cookie(name, value)
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return response
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else:
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await self._stream.write_eof()
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return self._stream
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async def get_field(request):
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"""Get the value of some HTTP field in the given connection."""
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id = request.match_info["id"]
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field = request.match_info["field"]
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try:
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connection = CONNECTIONS[id]
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except KeyError:
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response = web.HTTPNotFound()
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else:
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content = await connection.get(field)
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if isinstance(content, StreamReader):
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response = web.StreamResponse(status=200, reason="OK")
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await response.prepare(request)
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chunk = await content.readany()
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while chunk:
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await response.write(chunk)
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chunk = await content.readany()
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await response.write_eof()
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else:
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response = web.Response(body=content)
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return response
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async def set_field(request):
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"""Set the value of some HTTP field in the given connection."""
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id = request.match_info["id"]
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field = request.match_info["field"]
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try:
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connection = CONNECTIONS[id]
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except KeyError:
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response = web.HTTPNotFound()
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else:
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try:
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await connection.set(field, request.content)
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except ConnectionResetError:
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# Raised when trying to write to an already-closed stream.
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request.transport.close()
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else:
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response = web.Response(body=b'')
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return response
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async def append_field(request):
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pass
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########################################################################
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# Endpoint Execution #
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########################################################################
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def handle_route(entrypoint, command):
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"""
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Return an aiohttp route handler that will execute entrypoint and
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command in order to manage a Kapow! route.
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"""
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async def _handle(request):
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# Register a new connection to Kapow!
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id = "CONN_" + str(uuid4()).replace('-', '_')
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connection = CONNECTIONS[id] = Connection(request)
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# Run entrypoint + command passing the connection id
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executable, *params = shlex.split(entrypoint)
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args = ' '.join([executable]
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+ [shlex.quote(token) for token in params]
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+ [shlex.quote(command)])
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try:
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shell_task = await asyncio.create_subprocess_shell(
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args,
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env={**os.environ,
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"KAPOW_URL": "http://localhost:8080",
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"KAPOW_HANDLER_ID": id
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},
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stdin=asyncio.subprocess.DEVNULL)
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await shell_task.wait()
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except:
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raise
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else:
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# Respond when the command finish
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return await connection.build_response()
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finally:
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del CONNECTIONS[id]
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return _handle
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########################################################################
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# Route Management #
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########################################################################
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async def get_routes(request):
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"""Return the list of registered routes."""
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return web.json_response(list(request.app.router))
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async def append_route(request):
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"""Create a new Kapow! route."""
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request.app.router._frozen = False
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content = await request.json()
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name = "ROUTE_" + str(uuid4()).replace('-', '_')
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request.app.router.add_route(content["method"],
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content["url_pattern"],
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handle_route(content["entrypoint"],
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content["command"]),
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name=name)
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print(f'Route created {content["method"]} {content["url_pattern"]}')
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return web.json_response(name)
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async def delete_route(request):
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"""Delete the given Kapow! route."""
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id = request.match_info["id"]
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route = request.app.router._named_resources.pop(id)
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request.app.router._resources.remove(route)
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print(f'Route deleted {id}')
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return web.json_response(id)
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########################################################################
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# aiohttp webapp #
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########################################################################
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async def run_init_script(app):
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"""
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Run the init script if given, then wait for the shell to finish.
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"""
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if len(sys.argv) == 1:
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# No script given
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cmd = "/bin/bash"
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elif len(sys.argv) == 2:
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cmd = f"/bin/bash --init-file {sys.argv[1]}"
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else:
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print(f"Usage: {sys.argv[0]} <init-script>")
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os._exit(1)
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shell_task = await asyncio.create_subprocess_shell(
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cmd,
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env={**os.environ,
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"KAPOW_URL": "http://localhost:8080"
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})
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await shell_task.wait()
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await app.cleanup()
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os._exit(shell_task.returncode)
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async def start_background_tasks(app):
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loop = asyncio.get_running_loop()
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app["debug_tasks"] = loop.create_task(run_init_script(app))
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def kapow():
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"""Start aiohttp app."""
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app = web.Application(client_max_size=1024**3)
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app.add_routes([
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# Control API
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web.get('/routes', get_routes),
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web.post('/routes', append_route), # TODO: return route index
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# web.put('/routes', insert_route), # TODO: return route index
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web.delete('/routes/{id}', delete_route),
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# Data API
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web.get('/handlers/{id}/{field:.*}', get_field),
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web.put('/handlers/{id}/{field:.*}', set_field),
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])
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app.on_startup.append(start_background_tasks)
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web.run_app(app)
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if __name__ == '__main__':
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kapow()
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