cachemgr.pyc_dis

Cache服务器模块,可以完成图片的缓存处理功能. 很好用的.

#! /usr/bin/env python
# emacs-mode: -*- python-*-

import md5
import string
import os
import urlparse
import logging
import os.path
import time
import stat
import twisted.web.client
import config
import const
miCacheFileMode = ((stat.S_IRWXO | stat.S_IRWXU) | stat.S_IRWXG)
miCacheReqCounter = 0
miCacheHitCounter = 0
miCacheTime = config.image_cache_default_min
if (miCacheTime == 999):
    miCacheTime = ((((10 * 12) * 30) * 24) * 60)
log = logging.getLogger(const.CONST_APP_LOGGER)
class Image:

    def __init__(self, asContent = None, aiRWidth = None, aiRHeight = None, asColor = None, asSrc = None):
        self.csContent = asContent
        self.csColor = asColor
        self.csSrc = asSrc
        self.ciCacheTime = 999
        self.cbStaticImage = True
        self.cbCacheable = True
        self.csRSize = None
        self.csType = None
        self.csScheme = None
        self.ciPort = None
        self.ciRWidth = aiRWidth
        self.ciRHeight = aiRHeight
        self.ciAWidth = None
        self.ciAHeight = None
        self.ciFWidth = None
        self.ciFHeight = None
        self.csFormat = None
        self.csCacheLoc = None



    def cnSetASize(self, aiWidth, aiHeight):
        """
    设定图片的实际大小
    """
        self.ciAWidth = aiWidth
        self.ciAHeight = aiHeight
        liWidthRatio = (float(self.ciAWidth) / self.ciRWidth)
        liHeightRatio = (float(self.ciAHeight) / self.ciRHeight)
        liRatio = max(liWidthRatio, liHeightRatio)
        if (liRatio <= 1):
            self.ciFWidth = self.ciAWidth
            self.ciFHeight = self.ciAHeight
        else:
            self.ciFWidth = int((self.ciAWidth / liRatio))
            self.ciFHeight = int((self.ciAHeight / liRatio))



    def csGetContent(self):
        """
    读取图片的内容
    """
        if ((not self.csContent) and self.csCacheLoc):
            self.csContent = open(self.csCacheLoc, "rb").read()
        return self.csContent



    def cnSetRSize(self, asSize):
        self.csRSize = asSize
        lsSep = "x"
        (lsWidth, lsHeight,) = asSize.split(lsSep)
        self.ciRWidth = int(lsWidth)
        self.ciRHeight = int(lsHeight)
        if (self.ciRWidth == 0):
            self.ciRWidth = 1
        if (self.ciRHeight == 0):
            self.ciRHeight = 1



    def cnSetColor(self, asColor):
        self.csColor = asColor



    def cnParseURL(self):
        if (self.csSrc[-9:-3] == ":cache"):
            self.ciCacheTime = int(self.csSrc[-3:])
            self.csSrc = self.csSrc[:-9]
        (self.csScheme, self.csHost, self.ciPort, self.csPath,) = twisted.web.client._parse(self.csSrc)
        lsSuffix = self.csPath[-4:]
        if (lsSuffix.lower() not in config.mlStaticImage):
            self.cbStaticImage = False
        if (self.csScheme == "https"):
            self.cbStaticImage = False
        if (lsSuffix.lower() in config.mlNoCacheSuffix):
            self.cbStaticImage = False
            self.cbCacheable = False
        if (self.csPath.find("?") != -1):
            self.cbStaticImage = False
            if (config.cache_dynamic_url_image == 0):
                self.cbCacheable = False
            else:
                self.cbCacheable = True



    def cnSetCacheControl(self, alPragma, alCacheControl, alLastModified, alETag):
        """
    对于从web上获得的图片处理其header中对cache管理的信息
    """
        for value in alPragma:
            if (value.lower() == "no-cache"):
                self.cbCacheable = False
                return

        if ((len(alLastModified) != 0) or (len(alETag) != 0)):
            self.cbCacheable = True
            return
        if (len(alCacheControl) == 0):
            self.cbCacheable = False
        for value in alCacheControl:
            if (value.lower() in config.mlNoCacheControl):
                self.cbCacheable = False
                return
            elif (value.lower() in config.mlYesCacheControl):
                self.cbCacheable = True
                return





def mlSrcToFile(asBaseDir, asSrc, aiHashLevel, aiFirstLevel, asPrefix = "", asSuffix = "", aiNameLen = 16):
    """
  根据字符串, 生成hash文件的路径
  asBaseDir，最上曾层的路径
  asSrc, 用于生成hash文件的源字符串, 可以是 url 或者其它的任意字符串
  aiHashLevel, 支持 0,1,2,3三种层次的hash层次
  aiFirstLevel, 第一层次的hash目录分为多少个子目录，例如可以制造出16x256的目录结构
  asPrefix, 文件名前面，可以增加任意前缀
  asSuffix, 文件名后面，可以增加任意后缀
  aiNameLen, 文件名的md5部分，的长度可选
  返回 ：
  路径:例如4/16
  文件名:例如"e98u723lasdzx98u"
  全路径:路径+文件名
  """
    lsPath = ""
    lsFileName = ""
    llPath = [asBaseDir]
    lsMD5 = md5.new(asSrc).hexdigest()[:aiNameLen]
    lsFileName = ((asPrefix + lsMD5) + asSuffix)
    if (aiHashLevel >= 1):
        llPath.append(`(int(lsFileName[:2], 16) % aiFirstLevel)`)
    if (aiHashLevel >= 2):
        llPath.append(`int(lsFileName[2:4], 16)`)
    if (aiHashLevel >= 3):
        llPath.append(`int(lsFileName[4:6], 16)`)
    lsPath = string.join(llPath, os.sep)
    return ((lsPath + os.sep) + lsFileName)


class CacheManager:
    """
  管理resize的cache
  """

    def __init__(self):
        self.csPath = config.image_cache_path



    def csGetSrcCache(self, aoImage):
        """
    获取一个图片的转换前cache
    """
        global miCacheHitCounter
        global miCacheReqCounter
        return
        miCacheReqCounter += 1
        lsResultPath = None
        liCacheTime = min(aoImage.ciCacheTime, miCacheTime)
        lsFullPath = mlSrcToFile(self.csPath, aoImage.csSrc, config.image_cache_hash_level, config.image_cache_first_level)
        liSize = -1
        try:
            liSize = os.path.getsize(lsFullPath)
        except:
            pass
        if (liSize != -1):
            if (liSize == 0):
                liCacheTime = config.image_cache_error_min
            liCacheTime = (liCacheTime * 60)
            if ((time.time() - os.path.getmtime(lsFullPath)) < liCacheTime):
                lsResultPath = lsFullPath
            else:
                log.debug(("%s cache expired" % lsFullPath))
        if lsResultPath:
            miCacheHitCounter += 1
        return lsResultPath



    def cbWriteCache(self, aoImage):
        """
    写一幅图片的cache
    """
        return
        lbRet = True
        log.debug(("save cache for %s,size(%d)" % (aoImage.csSrc,
         len(aoImage.csContent))))
        if (not aoImage.cbCacheable):
            log.debug("dynamic image,ignore saving")
            return True
        lsFullPath = mlSrcToFile(self.csPath, aoImage.csSrc, config.image_cache_hash_level, config.image_cache_first_level)
        try:
            lsDir = os.path.dirname(lsFullPath)
            if (not os.path.exists(lsDir)):
                os.makedirs(lsDir)
            open(lsFullPath, "wb").write(aoImage.csContent)
        except Exception,e:
            import traceback
            traceback.print_exc()
            lbRet = False
            log.error(("write failed,exception is %s" % e))
        return lbRet



    def cbWriteZeroCache(self, aoImage):
        """
    对错误的图片保存空的cache
    """
        lsContent = aoImage.csContent
        aoImage.csContent = ""
        lbRet = self.cbWriteCache(aoImage)
        aoImage.csContent = lsContent
        return lbRet



    def cnCheckCache(self, aoImage):
        """
    检查图片的cache情况，如果有转换后图片，则返回转换后图片
    如果没有返回转换前图片，如果还没有只能返回空
    返回:
    (转换前图片,转换后图片)
    """
        if (not aoImage.cbCacheable):
            log.debug("dynamic image,no cache apply")
            return (None, None)
        lsSrc = self.csGetSrcCache(aoImage)
        if (lsSrc is None):
            log.debug(("cache miss:%s(%s)" % (aoImage.csSrc,
             lsSrc)))
        else:
            log.debug(("cache hit:%s(%s)" % (aoImage.csSrc,
             lsSrc)))
        return (lsSrc,
         None)



CacheMgr = CacheManager()
if (__name__ == "__main__"):
    print mlSrcToFile("abcd", 2, 16)

# local variables:
# tab-width: 4