unfinished partial work

1 files changed, 177 insertions, 0 deletions

diff --git a/src/hydrilla/proxy/policies/base.py b/src/hydrilla/proxy/policies/base.py
new file mode 100644
index 0000000..3bde6f2
--- /dev/null
+++ b/src/hydrilla/proxy/policies/base.py
@@ -0,0 +1,177 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Base defintions for policies for altering HTTP requests.
+#
+# This file is part of Hydrilla&Haketilo.
+#
+# Copyright (C) 2022 Wojtek Kosior
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+#
+# I, Wojtek Kosior, thereby promise not to sue for violation of this
+# file's license. Although I request that you do not make use this code
+# in a proprietary program, I am not going to enforce this in court.
+
+"""
+.....
+"""
+
+# Enable using with Python 3.7.
+from __future__ import annotations
+
+import sys
+
+if sys.version_info >= (3, 8):
+    from typing import Protocol
+else:
+    from typing_extensions import Protocol
+
+import dataclasses as dc
+import typing as t
+import enum
+
+from abc import ABC, abstractmethod
+
+from immutables import Map
+
+from ...url_patterns import ParsedUrl
+from .. import state
+
+
+class PolicyPriority(int, enum.Enum):
+    """...."""
+    _ONE   = 1
+    _TWO   = 2
+    _THREE = 3
+
+DefaultGetValue = t.TypeVar('DefaultGetValue', object, None)
+
+class IHeaders(Protocol):
+    """...."""
+    def __getitem__(self, key: str) -> str:  ...
+
+    def get_all(self, key: str) -> t.Iterable[str]: ...
+
+    def get(self, key: str, default: DefaultGetValue = None) \
+        -> t.Union[str, DefaultGetValue]: ...
+
+    def items(self) -> t.Iterable[tuple[str, str]]: ...
+
+def encode_headers_items(headers: t.Iterable[tuple[str, str]]) \
+    -> t.Iterable[tuple[bytes, bytes]]:
+    """...."""
+    for name, value in headers:
+        yield name.encode(), value.encode()
+
+@dc.dataclass(frozen=True)
+class ProducedRequest:
+    """...."""
+    url:         str
+    method:      str
+    headers:     t.Iterable[tuple[bytes, bytes]]
+    body:        bytes
+
+@dc.dataclass(frozen=True)
+class RequestInfo:
+    """...."""
+    url:         ParsedUrl
+    method:      str
+    headers:     IHeaders
+    body:        bytes
+
+    def make_produced_request(self) -> ProducedRequest:
+        """...."""
+        return ProducedRequest(
+            url     = self.url.orig_url,
+            method  = self.method,
+            headers = encode_headers_items(self.headers.items()),
+            body    = self.body
+        )
+
+@dc.dataclass(frozen=True)
+class ProducedResponse:
+    """...."""
+    status_code: int
+    headers:     t.Iterable[tuple[bytes, bytes]]
+    body:        bytes
+
+@dc.dataclass(frozen=True)
+class ResponseInfo:
+    """...."""
+    url:         ParsedUrl
+    status_code: int
+    headers:     IHeaders
+    body:        bytes
+
+    def make_produced_response(self) -> ProducedResponse:
+        """...."""
+        return ProducedResponse(
+            status_code = self.status_code,
+            headers     = encode_headers_items(self.headers.items()),
+            body        = self.body
+        )
+
+class Policy(ABC):
+    """...."""
+    process_request:  t.ClassVar[bool] = False
+    process_response: t.ClassVar[bool] = False
+
+    priority: t.ClassVar[PolicyPriority]
+
+    @property
+    def anticache(self) -> bool:
+        return self.process_request or self.process_response
+
+    def consume_request(self, request_info: RequestInfo) \
+        -> t.Optional[t.Union[ProducedRequest, ProducedResponse]]:
+        """...."""
+        return None
+
+    def consume_response(self, response_info: ResponseInfo) \
+        -> t.Optional[ProducedResponse]:
+        """...."""
+        return None
+
+
+# mypy needs to be corrected:
+# https://stackoverflow.com/questions/70999513/conflict-between-mix-ins-for-abstract-dataclasses/70999704#70999704
+@dc.dataclass(frozen=True, unsafe_hash=True) # type: ignore[misc]
+class PolicyFactory(ABC):
+    """...."""
+    builtin: bool
+
+    @abstractmethod
+    def make_policy(self, haketilo_state: state.HaketiloState) \
+        -> t.Optional[Policy]:
+        """...."""
+        ...
+
+    def __lt__(self, other: 'PolicyFactory'):
+        """...."""
+        return sorting_keys.get(self.__class__.__name__, 999) < \
+            sorting_keys.get(other.__class__.__name__, 999)
+
+sorting_order = (
+    'PayloadResourcePolicyFactory',
+
+    'PayloadPolicyFactory',
+
+    'RuleBlockPolicyFactory',
+    'RuleAllowPolicyFactory',
+
+    'FallbackPolicyFactory'
+)
+
+sorting_keys = Map((cls, name) for name, cls in enumerate(sorting_order))