python用gzip压缩string字符串，支持python2.6

压缩

def gzip_compress(buf, compresslevel=6):
    out = StringIO.StringIO()
    f = gzip.GzipFile(fileobj=out, mode="w", compresslevel=compresslevel)
    f.write(buf)
    f.close()
    res = out.getvalue()
    return res

解压缩

def gzip_decompress(buf):
    obj = StringIO.StringIO(buf)
    f = gzip.GzipFile(fileobj=obj)
    result = f.read()
    f.close()
    return result