IO error: not a gzipped file in python

Question

I'm programming a RPG game, so I have the function load_map , with an XML map, I have to decode and decompress the layer. This is the code:

# Decodifica una cadena en base64 y luego la descomprime.
def decode(cadena):
    # Decodificar.
    cadena = base64.decodestring(cadena)

    # Descomprimir.
    copmressed_stream = StringIO.StringIO(cadena)
    gzipper = gzip.GzipFile(fileobj=copmressed_stream)
    cadena = gzipper.read()

    # Convertir.
    salida = []
    for idx in xrange(0, len(cadena), 4):
        val = ord(str(cadena[idx])) | (ord(str(cadena[idx + 1])) << 8) | \
        (ord(str(cadena[idx + 2])) << 16) | (ord(str(cadena[idx + 3])) << 24)
        salida.append(val)

    return salida

The error is in cadena=gzipper.read() . Why am I getting this error, and how can I fix it?

Answer 1

add exception catch such as try...except... will be good. you can make sure your test file-type is gzip by shell command as icktoofay. Certianly , command 'file test.gzip' will work.