Attach CSV To E-Mail With MIMEBase, Only Attaches 'bin' Document

I want to write a function to attach a csv file to an E-Mail with HTML text. Everything works fine. I sends the E-Mail with the text and the attachment with the right information.

Solution 1:

Email clients may use the content type of the attachment part to determine which program is used to open the attachment, so specifying a suitable content type may help.

This code uses the standard library's mimetypes module to try to guess the correct content type of the attachment, based on its name:

import mimetypes

mimetypes.init()

def send_mail(receiver, subject, filepath, attachname):
    ...

    mimetype, _ = mimetypes.guess_type(attachname)
    if mimetype is None:
        mimetype = 'application/octet-stream'
    type_, _, subtype = mimetype.partition('/')
    att = MIMEBase(type_, subtype)
    ...

The above code will generate these headers for the attachment:

b'Content-Type: text/x-comma-separated-values'
b'MIME-Version: 1.0'
b'Content-Transfer-Encoding: base64'
b'Content_Disposition: attachment; filename="test.csv"'

Whether a mac will open a csv with a spreadsheet application (I assume this is what you want) depends on the configuration of the machine (See this blog for an example). If you want to be sure open the file in a spreadsheet it might be more effective to convert it to a spreadsheet format and send the spreadsheet.