Day29 Lab 2 - Object storage数据压缩

资料的压缩最好是能做在前端，因为网路最慢的地方就是前後端的沟通了，现在的压缩演算法有很多，举凡gzip、PKzip、LZW、zlib等等

我们的Lab追求简单，於是使用了python本身就有的zlib，压缩和解压缩的使用非常简单，如下

def compress(data):
   return zlib.compress(data)

def decompress(data):
   print(data)
   return zlib.decompress(data)

https://github.com/kaichiachen/python-simple-object-storage/blob/master/utils/utils.py#L53

然後我们分别在upload object的时候进行压缩

content = compress(content.encode()) # content type will be byte after compress
hash = sha256(content)
size = len(content)
chunk = 10
for i in range(0, size, chunk):
   res = requests.post(f"{server_url}/objects/{name}", files={
                                                         'obj': content[i:i+chunk],
                                                         'hash':hash,
                                                         'version': args.version,
                                                         'start': i,
                                                         'length': chunk,
                                                         'size': size})

以及download的时候解压缩

while len(content)<size:
      try:
         content += requests.get(f"{server_url}/objects/{name}?version={version}&start={start}").content
      except KeyboardInterrupt:
         sys.exit()
      except Exception as e:
         start = len(content)
         print('Something wrong, downloading again...', e)
   try:
      print(f'Get content: {decompress(content).decode()}')
   except Exception as e:
      print(f'Something wrong: {e}')

於是乎，从使用者的角度来看，看起来就只是上传下载Object而已，性能的优化都在前端做好了