text: #!/usr/bin/env python
  """
  Copyright 2012 GroupDocs.
  
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at
  
         http://www.apache.org/licenses/LICENSE-2.0
  
     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
  """
  import os
  import mimetypes
  import urlparse
  
  class FileStream(object):
      """This class encapsulates data needed either for file upload or download. All properties are initialized lazily on first access.
      
      To use this class for file upload initialize it with absolute path to file on your filesystem.
      
      To use this class for file download call fromHttp(response) method.
      """
      
      def __init__(self, filePath=None, response=None, stream=None):
          self.__response = response # used for file download
          self.__filePath = filePath # used for file upload
          self.__fileName = None
          self.__contentType = None
          self.__size = None
          self.__inputStream = stream
              
      @classmethod
      def fromFile(cls, filePath):
          """filePath is an absolute path to file on your filesystem.
          """
          return cls(filePath, None)
      
      @classmethod
      def fromStream(cls, stream, size, contentType="application/octet-stream"):
          """stream is a file-like object, i.e. stream = fopen(filename)
          """
          if not size or int(size) <= 0:
              raise ValueError('Invalid stream size provided')
          
          instance = cls(None, None, stream)
          instance.size = size
          instance.contentType = contentType
          return instance
      
      @classmethod
      def fromHttp(cls, response):
          """response is a file-like object with two additional methods: geturl() and info()
          """
          return cls(None, response)
      
      @property
      def fileName(self):
          if self.__fileName == None and self.__filePath != None:
              self.__fileName = os.path.basename(self.__filePath)
          elif self.__fileName == None and self.__response != None:
              self.__fileName = self.__getValueFromCD('filename') or self.__getFileNameFromUrl(self.__response.url)
          return self.__fileName
      
      @fileName.setter
      def fileName(self, value):
          self.__fileName = value
  
      @property
      def contentType(self):
          if self.__contentType == None and self.__filePath != None:
              self.__contentType = mimetypes.guess_type(self.__filePath)[0] or "application/octet-stream"
          elif self.__contentType == None and self.__response != None:
              self.__contentType = self.__response.info()['Content-Type'] if 'Content-Type' in self.__response.info() else None
          return self.__contentType
      
      @contentType.setter
      def contentType(self, value):
          self.__contentType = value
  
      @property
      def size(self):
          if self.__size == None and self.__filePath != None:
              self.__size = os.path.getsize(self.__filePath)
          elif self.__size == None and self.__response != None:
              self.__size = self.__getValueFromCD('size')
              if self.__size == None and 'Content-Length' in self.__response.info():
                  self.__size = self.__response.info()['Content-Length'] 
          return self.__size
      
      @size.setter
      def size(self, value):
          self.__size = value
  
      @property
      def inputStream(self):
          """returns file object
          """
          if self.__inputStream == None and self.__filePath != None:
              self.__inputStream = open(self.__filePath, "rb")
          elif self.__inputStream == None and self.__response != None:
              self.__inputStream = self.__response
          return self.__inputStream
      
      @inputStream.setter
      def inputStream(self, value):
          self.__inputStream = value
          
      def __getValueFromCD(self, key):
          headers = self.__response.info()
          if 'Content-Disposition' in headers:
              # If the response has Content-Disposition, try to get value from it
              cd = dict(map(
                  lambda x: x.strip().split('=') if '=' in x else (x.strip(),''),
                  headers['Content-Disposition'].split(';')))
              if key in cd:
                  value = cd[key].strip("\"'")
                  if value: return value
          return None
      
      def __getFileNameFromUrl(self, url):
          return os.path.basename(urlparse.urlsplit(url)[2])
          
  