import os
import re
import urllib.parse
import pickle

class DiskCache:
    def __init__(self,cache_dir='cache'):
        self.cache_dir=cache_dir

    def __getitem__(self, item):
        '''獲取快取'''
        path=self.url_to_path(item)
        if os.path.exists(path):
            with open(path,'wb')as fp:
                return pickle.load(fp)
        else:
            raise KeyError(url+' dose not exist!')

    def __setitem__(self, key, value):
        '''儲存快取'''
        path=self.url_to_path(key)
        folder=os.path.dirname(path)        #返回dirname目錄
        if not os.path.exists(folder):      #沒有父目錄則建立父目錄
            os.makedirs(folder)
        with open(path,'wb') as fp:         #寫入子檔案
            fp.write(pickle.dumps(value))

    def url_to_path(self,url):
        '''為url建立path'''
        components=urllib.parse.urlparse(url)
        path=components.path
        # 主要是避免特殊情況,可以視情況而定
        '''
        if not path:
            path='/start'                       #如果url沒有path就建立一個
        elif path.endswith('/'):                
            path+='no_end'
        '''
        filename=components.netloc+path+components.query
        #替換檔名中的不合法部分
        filename=re.sub('[^/0-9a-zA-Z\-.,;_]','_',filename)
        filename='/'.join(segment[:255] for segment in filename.split('/'))#建立多級目錄
        return os.path.join(self.cache_dir,filename)

#新增壓縮減少磁碟佔用，但是會加大一點查詢時間，不過無關緊要
#在加一個快取過期
 

import os
import re
import urllib.parse
import pickle
import zlib
import datetime
from datetime import timedelta

class DiskCache:
    def __init__(self,cache_dir='cache',expire=timedelta(days=30)):
        self.cache_dir=cache_dir
        self.expire=expire

    def __getitem__(self, item):
        '''獲取快取'''
        path=self.url_to_path(item)
        if os.path.exists(path):
            with open(path,'wb')as fp:
                result,time=pickle.load(zlib.decompress(fp.read()))
                if self.has_expire(time):
                    raise KeyError(url+' has expired!')
                return result
        else:
            raise KeyError(url+' dose not exist!')

    def __setitem__(self, key, value):
        '''儲存快取'''
        path=self.url_to_path(key)
        folder=os.path.dirname(path)        #返回dirname目錄
        if not os.path.exists(folder):      #沒有父目錄則建立父目錄
            os.makedirs(folder)
        time=datetime.datetime.utcnow()
        with open(path,'wb') as fp:         #寫入子檔案
            fp.write(zlib.compress(pickle.dumps(value,time)))

    def has_expire(self,timestamp):
        return datetime.datetime.utcnow()>timestamp+self.expire

    def url_to_path(self,url):
        '''為url建立path'''
        components=urllib.parse.urlparse(url)
        path=components.path
        # 主要是避免特殊情況,可以視情況而定
        '''
        if not path:
            path='/start'                       #如果url沒有path就建立一個
        elif path.endswith('/'):                
            path+='no_end'
        '''
        filename=components.netloc+path+components.query
        #替換檔名中的不合法部分
        filename=re.sub('[^/0-9a-zA-Z\-.,;_]','_',filename)
        filename='/'.join(segment[:255] for segment in filename.split('/'))#建立多級目錄
        return os.path.join(self.cache_dir,filename)