如何将文件附加到从Flask Form收到的Flask Mail中？

Question

I am developing a website in Python Flask. What I have to do is to get uploaded file in one of the forms and attach it to mail. I tried solution given in similar question but it gives following error:

AttributeError: 'str' object has no attribute 'filename'

What am I doing wrong? I am beginner in python and flask. Here's my code:

class UploadForm(Form):
    branch = StringField('branch', validators = [DataRequired()])
    year = StringField('year', validators = [DataRequired()])
    sub = StringField('sub', validators = [DataRequired()])
    paper = FileField('Logo', validators = [Required()])

def uploadPaper(form):
    msg = Message('New upload request', sender = ADMINS[0], recipients = ADMINS)
    msg.body = 'text body'
    msg.html = 'Branch: ' + form.branch.data + '<br />' + 'Year: ' + form.year.data + '<br />' + 'Subject: ' + form.sub.data
    msg.attach(form.paper.data.filename, 'application/octect-stream', form.paper.data.read())
    with app.app_context():
        mail.send(msg)
    return "success"

I am calling uploadPaper() function on validating the form.

Answer 1

Well, the error you've got means you're trying to read a file from a string.

AttributeError: 'str' object has no attribute 'filename'

This happens because your uploadPaper() function is returning a string (Or 'str') instead of a 'file' object. Since Python is object-oriented, your script is probably trying to read the "filename" attribute from the file object.

I can also see in your function that there is an object with the attribute you're trying to use, here at

msg.attach(form.paper.data.filename, 'application/octect-stream', form.paper.data.read())

It looks like the form.paper.data object has the property "filename" you're trying to user later on.

Why don't you try return form.paper.data instead of return "success" ?