Why does it work ?

[Michel Combe]

I'm trying to send a mail with an attached file. 
I use the following code and *it works* but I don't understand why and I 
hate that.

for filename in os.listdir(dir):
    path = os.path.join(dir, filename)
    if not os.path.isfile(path):
        continue
    ctype, encoding = mimetypes.guess_type(path)
    if ctype is None or encoding is not None:
        ctype = 'application/octet-stream'
    maintype, subtype = ctype.split('/', 1)
    if maintype == 'text':
        fp = open(path)
        msg = MIMEText(fp.read(), _subtype=subtype)
        fp.close()
    msg.add_header('Content-Disposition', 'attachment', filename=filename)
    outer.attach(msg)

In the "dir" directory, I have 2 text files :
- "texte.txt" which is the text I want inside the body of the message and 
- "fichier.txt" which is the file I want attached.

Why is "texte.txt" the only file that I find in the body of the message. 
Both files are text, so the MIMEText instruction shoud be executed for both 
files, No ?
Also add_header should be executed for both files resulting in 2 attached 
files ?
Which instruction says what is included in the body and what is attached to 
the mail ?

I must say I'm not sure of what MIMEText and add_header exactly do. I read 
the doc but it was not too clear for me.

Thanks for your help
Michel Combe