#!/usr/bin/env python
# coding: utf-8
"""
请求处理器基类
提供所有请求处理器共用的基础功能
"""
from hashlib import sha256
from http.cookies import SimpleCookie
from http.client import responses as http_status_codes
from os import urandom
from .._json import loads # noqa: F401 # 对外再导出（保持模块符号面）
from .response import (
DEFAULT_STATUS_MESSAGE,
default_content_type,
json_content_type,
server_info,
)
from .form import parse_form, parse_header # noqa: F401 # parse_form 为对外再导出
from .base_request import RequestPropertiesMixin as _RequestPropertiesMixin
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class BaseRequestHandler(_RequestPropertiesMixin):
"""
请求处理器基类，提供通用的请求处理功能
所有 WSGI/ASGI/Socket 请求处理器共享的属性和方法集中在此，
减少子类间的代码重复。
"""
def __init__(self, app, environ):
self._app = app
self._environ = environ
self._headers_responsed = False
self._status_code = 200
self._get = {}
self._post = {}
self._body = ""
self._files = {}
self._session_id = None
self._session = None
self._session_modified = False
self._session_loaded = False
self._template_lookup = None
# 初始化 _headers 属性，用于存储响应头
self._headers = []
# 预构建请求头缓存，避免每次访问 headers property 时遍历 environ
self._request_headers = self._build_request_headers(environ)
# ==================== 模板渲染 ====================
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def render_template(self, template_name, **kwargs):
"""
渲染模板
模板上下文中会自动注入翻译函数 ``_`` / ``gettext`` / ``ngettext``。
未启用国际化（或当前无请求 locale）时，这些函数为恒等函数，
渲染结果与未注入前完全一致。
Args:
template_name: 模板文件名
**kwargs: 模板变量
Returns:
渲染后的 HTML 字符串
"""
import os
# 延迟初始化模板查找器
if self._template_lookup is None:
# 获取模板目录路径
template_dir = getattr(self._app.config, 'template_dir', 'templates')
if not os.path.isabs(template_dir):
# 如果是相对路径，相对于当前工作目录
template_dir = os.path.join(os.getcwd(), template_dir)
# 创建模板查找器
# 在开发模式下禁用缓存，确保模板修改后立即生效
debug_mode = getattr(self._app, 'debug', False) if self._app else False
from mako.lookup import TemplateLookup
self._template_lookup = TemplateLookup(
directories=[template_dir],
input_encoding='utf-8',
encoding_errors='replace',
cache_enabled=not debug_mode
)
try:
# 注入翻译函数（幂等，不覆盖调用方显式传入的同名变量）
kwargs = self._inject_translations(kwargs)
# 获取模板
template = self._template_lookup.get_template(template_name)
# 渲染模板
content = template.render(**kwargs)
# 直接返回渲染后的内容，不设置 Content-Type
# Content-Type 会在 _response 方法中设置
return content
except Exception as e:
# 模板渲染失败，返回错误信息
import traceback
error_detail = traceback.format_exc()
error_content = (
f"<h1>Template Error</h1><p>Failed to render template '{template_name}': "
f"{str(e)}</p><pre>{error_detail}</pre>"
)
# 直接返回错误内容，不设置 Content-Type
# Content-Type 会在 _response 方法中设置
return error_content
@staticmethod
def _inject_translations(kwargs):
"""
向模板上下文注入翻译函数
使用延迟导入，避免 i18n 模块与 handlers 模块形成循环依赖。
Args:
kwargs: 模板变量
Returns:
注入翻译函数后的模板变量
"""
try:
from ..i18n import inject_translations
except ImportError:
return kwargs
return inject_translations(kwargs)
# ==================== 会话管理 ====================
def _new_session_id(self):
"""
生成新的会话 ID（SHA256 随机值）
使用 SHA-256 哈希算法生成唯一的会话 ID。
SHA-256 的碰撞概率约为 2^-128，在实际应用中几乎不可能发生碰撞，
因此无需每次检查存储中是否已存在该 ID。
Returns:
str: 64字符的十六进制会话 ID
"""
token = urandom(32)
session_id = sha256(token).hexdigest()
return session_id
def _build_session_cookie_header(self, session_key):
"""
构建会话 Cookie 头部
Args:
session_key: 会话 ID
Returns:
Set-Cookie 头部值
"""
app = self._app
session_name = app.config.session_name
session_secure = app.config.session_secure
session_http_only = app.config.session_http_only
session_same_site = app.config.session_same_site
cookie_header = SimpleCookie()
cookie_header[session_name] = session_key
cookie_header[session_name]['path'] = "/"
if session_secure:
cookie_header[session_name]['secure'] = True
if session_http_only:
cookie_header[session_name]['httponly'] = True
if session_same_site:
cookie_header[session_name]['samesite'] = session_same_site
return str(cookie_header[session_name])
def _save_session_to_store(self):
"""
保存会话到存储并返回 session_key。
Returns:
session_key 如果会话已加载且有 ID，否则 None
"""
app = self._app
session_key = None
if self._session_loaded:
session_key = self._session_id or self.session.id
if self._session_modified:
app.sessions.put(session_key, self.session)
return session_key
# ==================== 响应构建 ====================
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def start_response(self, status_code=200, headers=None):
if self._headers_responsed:
raise ValueError("Http headers already responsed.")
self._status_code = int(status_code)
if headers is not None:
for header in headers:
if not isinstance(header, (list, tuple)):
header = header.encode("utf-8")
k, v = header.split(":")
k, v = k.strip(), v.strip()
else:
k, v = header
self._add_header(k, v)
self._headers_responsed = True
def _add_header(self, key, value):
self._headers.append((key, value))
def _add_response_headers(self, headers):
headers.extend(self._headers)
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def set_cookie(self, key, value, **kwargs):
cookie = SimpleCookie()
cookie[key] = value
for k, v in kwargs.items():
if not v:
continue
cookie[key][k] = v
self._headers.append(("Set-Cookie", str(cookie[key])))
def _redirect(self, url):
url = "/" if url is None else url
headers = [("Content-Type", "text/html; charset=utf-8"), ("Location", url)]
status_code = 302
status_text = "Found"
content = "%d %s" % (status_code, status_text)
return self._response(status_code, headers=headers, content=content)
def _build_response_headers(self, status_code, extra_headers=None, content=None):
"""
构建响应头列表
Args:
status_code: HTTP 状态码
extra_headers: 额外的响应头
content: 响应内容
Returns:
响应头列表
"""
# 创建响应头列表
response_headers = []
response_headers.append(("Server", server_info))
response_headers.append(("X-Content-Type-Options", "nosniff"))
response_headers.append(("X-Frame-Options", "SAMEORIGIN"))
response_headers.append(("X-XSS-Protection", "1; mode=block"))
# 添加 self._headers 中的内容
if hasattr(self, '_headers'):
response_headers.extend(self._headers)
# 添加传入的 headers 参数
if extra_headers:
response_headers.extend(extra_headers)
# 检查是否已经有 Content-Type 响应头
has_content_type = any(h[0].lower() == 'content-type' for h in response_headers)
# 如果没有 Content-Type 响应头，根据状态码和内容类型设置默认的 Content-Type
if not has_content_type:
if status_code >= 400:
response_headers.append(("Content-Type", "text/html; charset=utf-8"))
else:
from collections.abc import Iterable
# dict、list、tuple 类型设置为 application/json
if isinstance(content, (dict, list, tuple)):
response_headers.append(("Content-Type", json_content_type))
# HTML 字符串设置为 text/html
elif isinstance(content, str) and content.lstrip().startswith('<'):
response_headers.append(("Content-Type", "text/html; charset=utf-8"))
# 字节类型设置为 application/octet-stream
elif isinstance(content, bytes):
response_headers.append(("Content-Type", "application/octet-stream"))
# 其他可迭代对象设置为 text/plain
elif (
not isinstance(content, (str, bytes, type(None)))
and isinstance(content, Iterable)
):
response_headers.append(("Content-Type", "text/plain; charset=utf-8"))
# 其他类型使用默认的 text/html
else:
response_headers.append(("Content-Type", default_content_type))
# 检查是否已经有 Content-Length 或 Transfer-Encoding 头
has_content_length = any(h[0].lower() == 'content-length' for h in response_headers)
has_transfer_encoding = any(h[0].lower() == 'transfer-encoding' for h in response_headers)
# 处理不同类型的 content
from collections.abc import Iterable
if not has_content_length and not has_transfer_encoding:
if isinstance(content, (str, bytes)):
# 对于字符串或字节，计算长度并添加 Content-Length 头
if isinstance(content, str):
content_bytes = content.encode('utf-8')
content_length = len(content_bytes)
else:
content_length = len(content)
response_headers.append(("Content-Length", str(content_length)))
elif (
not isinstance(content, (dict, list, tuple, type(None)))
and isinstance(content, Iterable)
):
# 对于生成器等可迭代对象，使用 Transfer-Encoding: chunked
response_headers.append(("Transfer-Encoding", "chunked"))
return response_headers
def _prepare_response(self, status_code, extra_headers=None, content=None):
"""
准备响应的内部方法，处理会话和设置响应头
Args:
status_code: HTTP 状态码
extra_headers: 额外的响应头
content: 响应内容
Returns:
(status, response_headers, content): 状态行、响应头和内容
"""
status_code = int(status_code)
status_text = http_status_codes.get(status_code, "Unknown")
status = "%d %s" % (status_code, status_text)
# 构建响应头
response_headers = self._build_response_headers(status_code, extra_headers, content)
# 处理会话
self._process_session_response(response_headers)
# 标记响应头已发送
self._headers_responsed = True
# 如果 content 为 None，设置默认的错误信息
if content is None:
content = DEFAULT_STATUS_MESSAGE % {
"code": status_code,
"message": status_text,
"explain": status_text,
}
return status, response_headers, content
def _process_session_response(self, response_headers):
"""
处理会话相关的响应
Args:
response_headers: 响应头列表
"""
session_key = self._save_session_to_store()
# 设置 session cookie（只有在会话已加载时）
if session_key:
session_name = self._app.config.session_name
session_secure = self._app.config.session_secure
session_http_only = self._app.config.session_http_only
session_same_site = self._app.config.session_same_site
cookie_header = SimpleCookie()
cookie_header[session_name] = session_key
cookie_header[session_name]['path'] = "/"
if session_secure:
cookie_header[session_name]['secure'] = True
if session_http_only:
cookie_header[session_name]['httponly'] = True
if session_same_site:
cookie_header[session_name]['samesite'] = session_same_site
response_headers.append(("Set-Cookie", str(cookie_header[session_name])))
def _response(self, status_code, headers=None, content=None):
"""
生成响应的兼容方法
Args:
status_code: HTTP 状态码
headers: 响应头
content: 响应内容
Returns:
(status, response_headers, content)
"""
return self._prepare_response(status_code, headers, content)
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def handle_response(self, result):
"""
处理响应结果，支持 Response 对象
"""
from .response import Response
if isinstance(result, Response):
self._status_code = result.status_code
for header, value in result.headers:
self._add_header(header, value)
return result.content
return result
def _process_route_result(self, result, app):
"""
处理路由处理器的返回结果，统一处理 Response 对象、
已发送头部的响应、和普通返回值。
Args:
result: 路由处理器的返回值
app: 应用实例
Returns:
经过 middleware 处理的响应元组
"""
from .response import Response
from http.client import responses as http_status_codes
# 处理 Response 对象
if isinstance(result, Response):
return self._handle_response_object(result, app, http_status_codes)
if self._headers_responsed:
return self._handle_headers_responsed(result, app, http_status_codes)
return self._handle_normal_result(result, app, http_status_codes)
def _handle_response_object(self, result, app, http_status_codes):
"""处理 Response 对象类型的返回值"""
session_key = self._save_session_to_store()
if session_key and self._session_modified:
app.sessions.put(session_key, self.session)
if session_key:
result.headers.append(("Set-Cookie", self._build_session_cookie_header(session_key)))
status_code = result.status_code
status_text = http_status_codes.get(status_code, "Unknown")
status = "%d %s" % (status_code, status_text)
return app.middleware_manager.process_response(
self, (status, result.headers, result.content)
)
def _handle_headers_responsed(self, result, app, http_status_codes):
"""处理已经调用过 start_response 的情况"""
session_key = self._save_session_to_store()
if session_key and self._session_modified:
app.sessions.put(session_key, self.session)
if session_key:
self.set_cookie(
app.config.session_name, session_key,
path="/",
secure=app.config.session_secure,
httponly=app.config.session_http_only,
samesite=app.config.session_same_site
)
status_code = int(self._status_code)
status_text = http_status_codes.get(status_code, "Unknown")
status = "%d %s" % (status_code, status_text)
response_headers = [("Server", server_info)]
response_headers.extend(self._headers)
return app.middleware_manager.process_response(
self, (status, response_headers, result)
)
def _handle_normal_result(self, result, app, http_status_codes):
"""处理普通返回值"""
return app.middleware_manager.process_response(
self, self._response(self._status_code, content=result)
)
def _process_route_error(self, app):
"""处理路由执行过程中的异常"""
from ..utils import log_error, render_error
log_error(app.logger)
if app.config.debug:
content = render_error()
return app.middleware_manager.process_response(
self, self._response(500, content=content)
)
return app.middleware_manager.process_response(self, self._response(500))
__all__ = [
'BaseRequestHandler',
]