CDN源码开发,cn2香港vps,云拨号vps,外贸VPS主机托管,rn vps

🗣 Wd提问: CDN源码开发

🤖 Ai回答:
我来为您介绍CDN源码开发的核心概念和实现要点。

CDN核心架构组件

1、负载均衡器 (Load Balancer)
python
import hashlib
import random
from typing import List, Dict

class LoadBalancer:
def __init__(self):
self.servers = []
self.algorithm = round_robin
self.current_index = 0

def add_server(self, server_info: Dict):
添加边缘服务器
self.servers.append(server_info)

def get_server_consistent_hash(self, key: str) Dict:
一致性哈希算法
if not self.servers:
return None

简化的一致性哈希实现
hash_value = int(hashlib.md5(key.encode()).hexdigest(), 16)
server_index = hash_value % len(self.servers)
return self.servers[server_index]

def get_server_round_robin(self) Dict:
轮询算法
if not self.servers:
return None

server = self.servers[self.current_index]
self.current_index = (self.current_index + 1) % len(self.servers)
return server

2、缓存管理器 (Cache Manager)
python
import time
import threading
from collections import OrderedDict

class CacheManager:
def __init__(self, max_size: int = 1000):
self.cache = OrderedDict()
self.max_size = max_size
self.lock = threading.Lock()
self.stats = {
'hits': 0,
'misses': 0,
'evictions': 0
}

def get(self, key: str):
获取缓存内容
with self.lock:
if key in self.cache:
移动到末尾（LRU）
value, expiry = self.cache.pop(key)
if time.time() < expiry:
self.cache[key] = (value, expiry)
self.stats['hits'] += 1
return value
else:
del self.cache[key]
self.stats['misses'] += 1
return None

def set(self, key: str, value, ttl: int = 3600):
设置缓存
with self.lock:
检查缓存大小限制
if len(self.cache) = self.max_size:
删除最老的条目
self.cache.popitem(last=False)
self.stats['evictions'] += 1

expiry = time.time() + ttl
self.cache[key] = (value, expiry)

移动到末尾
self.cache.move_to_end(key)

def invalidate(self, key: str):
使缓存失效
with self.lock:
if key in self.cache:
del self.cache[key]

3、边缘节点服务 (Edge Server)
python
import asyncio
import aiohttp
from aiohttp import web
import json

class EdgeServer:
def __init__(self, origin_url: str, port: int = 8080):
self.origin_url = origin_url
self.port = port
self.cache_manager = CacheManager()
self.load_balancer = LoadBalancer()

async def handle_request(self, request):
处理HTTP请求
path = request.path
cache_key = f{request.method}:{path}

首先检查本地缓存
cached_response = self.cache_manager.get(cache_key)
if cached_response:
return web.Response(
body=cached_response['body'],
headers=cached_response['headers'],
status=cached_response['status']
)

缓存未命中，向源站或上级节点请求
try:
response_data = await self.fetch_from_origin(path)

缓存响应
cache_ttl = self.extract_cache_ttl(response_data['headers'])
self.cache_manager.set(cache_key, response_data, cache_ttl)

return web.Response(
body=response_data['body'],
headers=response_data['headers'],
status=response_data['status']
)
except Exception as e:
return web.Response(text=fError: {str(e)}, status=500)

async def fetch_from_origin(self, path: str):
从源站获取数据
async with aiohttp.ClientSession() as session:
async with session.get(f{self.origin_url}{path}) as response:
body = await response.read()
return {
'body': body,
'headers': dict(response.headers),
'status': response.status
}

def extract_cache_ttl(self, headers: dict) int:
从响应头提取缓存时间
cache_control = headers.get('Cache-Control', '')
if 'max-age=' in cache_control:
try:
max_age = int(cache_control.split('max-age=')[1].split(',')[0])
return min(max_age, 86400) 最大24小时
except:
pass
return 3600 默认1小时

def start_server(self):
启动服务器
app = web.Application()
app.router.add_route('*', '/{tail:.*}', self.handle_request)

web.run_app(app, port=self.port)

4、内容路由系统 (Content Router)
python
import geoip2.database
from ipaddress import ip_address

class ContentRouter:
def __init__(self, geo_db_path: str = None):
self.geo_reader = None
if geo_db_path:
self.geo_reader = geoip2.database.Reader(geo_db_path)
self.routing_rules = {}

def add_routing_rule(self, pattern: str, servers: List[str]):
添加路由规则
self.routing_rules[pattern] = servers

def select_server_by_geo(self, client_ip: str) str:
基于地理位置选择最优服务器
if not self.geo_reader:
return None

try:
response = self.geo_reader.city(client_ip)
country = response.country.iso_code

简单的地理路由逻辑
if country == 'CN':
return cn-edge-server
elif country in ['US', 'CA']:
return na-edge-server
else:
return global-edge-server
except:
return default-edge-server

def select_server_by_latency(self, client_ip: str, servers: List[str]) str:
基于延迟选择服务器
实现延迟测试逻辑
latencies = {}
for server in servers:
latency = self.measure_latency(client_ip, server)
latencies[server] = latency

返回延迟最低的服务器
return min(latencies, key=latencies.get) if latencies else servers[0]

def measure_latency(self, client_ip: str, server: str) float:
测量延迟（简化实现）
实际实现应该进行网络探测
return random.uniform(10, 200)

5、监控和统计系统
python
import time
from collections import defaultdict, deque
import json

class CDNMonitor:
def __init__(self):
self.metrics = defaultdict(lambda: deque(maxlen=1000))
self.start_time = time.time()

def record_hit(self, edge_server: str, content_type: str):
记录缓存命中
metric_key = f{edge_server}:hit:{content_type}
self.metrics[metric_key].append(time.time())

def record_miss(self, edge_server: str, content_type: str):
记录缓存未命中
metric_key = f{edge_server}:miss:{content_type}
self.metrics[metric_key].append(time.time())

def record_bandwidth(self, edge_server: str, bytes_sent: int):
记录带宽使用
metric_key = f{edge_server}:bandwidth
self.metrics[metric_key].append((time.time(), bytes_sent))

def get_stats(self, edge_server: str = None) dict:
获取统计信息
stats = {}

for key, values in self.metrics.items():
if edge_server and not key.startswith(edge_server):
continue

if ':hit:' in key or ':miss:' in key:
stats[key] = len(values)
elif ':bandwidth' in key:
total_bytes = sum(bytes_sent for _, bytes_sent in values)
stats[key] = total_bytes

return stats

def get_cache_hit_rate(self, edge_server: str) float:
计算缓存命中率
hits = len(self.metrics[f{edge_server}:hit])
misses = len(self.metrics[f{edge_server}:miss])

if hits + misses == 0:
return 0.0

return hits / (hits + misses)

6、完整的CDN节点实现
python
class CDNNode:
def __init__(self, config: dict):
self.config = config
self.edge_server = EdgeServer(config['origin_url'], config['port'])
self.cache_manager = CacheManager(config.get('cache_size', 1000))
self.content_router = ContentRouter(config.get('geo_db_path'))
self.monitor = CDNMonitor()
self.is_parent_node = config.get('is_parent', False)

Ai作答

📣 商家广告：