原因
Blog是一個(gè)更新并不很頻繁的一套系統(tǒng),但是每次刷新頁(yè)面都要更新數(shù)據(jù)庫(kù)反而很浪費(fèi)資源,添加靜態(tài)頁(yè)面生成是一個(gè)解決辦法,同時(shí)緩存是一個(gè)更好的主意,可以結(jié)合Memcached添加少量的代碼進(jìn)行緩存,而且免去去了每次更新文章都要重新生成靜態(tài)頁(yè)面,特別當(dāng)頁(yè)面特別多時(shí).
實(shí)現(xiàn)
主要通過(guò)頁(yè)面的uri進(jìn)行緩存,結(jié)合tornado.web.RequestHandler的prepare和on_finish方法函數(shù), prepare 主要是請(qǐng)求前執(zhí)行,on_finish()是請(qǐng)求結(jié)束之前執(zhí)行.在渲染模板時(shí)緩存頁(yè)面內(nèi)容,然后在請(qǐng)求前檢測(cè)是否有緩存,如果有直接輸出緩存,結(jié)束請(qǐng)求,在POST提交之后清空所有緩存,重新生成緩存,從而保證內(nèi)容實(shí)時(shí)性.由于登錄用戶和普通用戶的頁(yè)面不相同,所以不緩存登錄用戶頁(yè)面(代碼中沒(méi)有體現(xiàn),請(qǐng)自行實(shí)現(xiàn)).主要python代碼(省略了模板渲染的代碼):
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#!/usr/bin/env python# -*- coding:utf-8 -*-## Author : cold# E-mail : [email protected]# Date : 13/01/14 09:57:31# Desc : #import configimport pylibmcfrom tornado.web import RequestHandler#### 省略Cache類定義 #####class Memcached(object): _mc = pylibmc.client.Client(config.CACHE_HOST, binary = True) def __enter__(self): if config.CACHED: return Memcached else: return Cache() def __exit__(self, exc_type, exc_val, exc_tb): pass @classmethod def get_cache(cls): return cls._mc @classmethod def get(cls, key, default = None): r = cls._mc.get(key) if not r: r = default return r @classmethod def set(cls, key, value, timeout = 0): timeout = timeout if timeout else config.CACHE_TIMEOUT return cls._mc.set(key, value, timeout) @classmethod def delete(cls, key): return cls._mc.delete(key) @classmethod def flush(cls): return cls._mc.flush_all() def __getattr__(self, key): return Memcached.get(key) def __setattr__(self, key, value): return Memcached.set(key, value)class BaseHandler(RequestHandler): """ 繼承tornado請(qǐng)求基類,重寫 prepare和on_finish方法 """ cache = Memcached def render(self, template_path, *args, **kwargs): """ 渲染模板 """ # 省略渲染模板代碼 content = '' # 渲染模板后的內(nèi)容 if self.request.method == "GET" and CACHED and \ not self.request.path.startswith("/admin"): self.cache.set(self.request.uri, content) # 將渲染后的內(nèi)容緩存起來(lái) self.write(content) def prepare(self): super(BaseHandler, self).prepare() # 如果請(qǐng)求是GET方法,而且不是請(qǐng)求后臺(tái) if self.request.method == "GET" and CACHED and \ not self.request.path.startswith("/admin"): # 嘗試獲取當(dāng)前頁(yè)面的緩存 cache = self.cache.get(self.request.uri) # 獲取緩存則輸出頁(yè)面,結(jié)束請(qǐng)求 if cache: return self.finish(cache) def on_finish(self): """ 重寫結(jié)束請(qǐng)求前的方法函數(shù) """ if self.request.method == "POST": # 如果遇到POST提交則清空緩存 self.cache.flush() |
緩存系統(tǒng)在redis和Memcached選擇了很久,因?yàn)橹皇菃渭兊木彺骓?yè)面所以最后選擇了memcached,使用pylibmc python庫(kù).
測(cè)試
使用webbench 網(wǎng)站壓力測(cè)試對(duì)比了緩存前后的結(jié)果: 使用緩存前
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$ webbench -c 500 -t 30 http://www.linuxzen.com/Webbench - Simple Web Benchmark 1.5Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.Benchmarking: GET http://www.linuxzen.com/500 clients, running 30 sec.Speed=54 pages/min, 38160 bytes/sec.Requests: 27 susceed, 0 failed. |
使用緩存后:
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$ webbench -c 500 -t 30 http://www.linuxzen.com/Webbench - Simple Web Benchmark 1.5Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.Benchmarking: GET http://www.linuxzen.com/500 clients, running 30 sec.Speed=256 pages/min, 238544 bytes/sec.Requests: 128 susceed, 0 failed. |
明顯快了很多...
