limiting the size and type of data in ir.attachment field odoo 12

Question

I need to create a ir.attachment field to upload datas by the user side,but i have to restrict the data type and size,how can i achieve it

my python field is :-

test = fields.Many2many('ir.attachment',string='Test')

Answer 1

You can use constrains to check test field.

Use mimetype and file_size fields to check the data type and size, the attachment size shown in the many2many list is computed using binaryToBinsize function from core/utils.js which divides the length by 1.37 then convert it to human size (divide by 1024 repeatedly).

Example:

Force users to select only text files smaller than 10M

@api.one
@api.constrains('test')
def _check_attachments(self):
    for attachment in self.test:
        if attachment.mimetype != 'text/plain' or attachment.file_size > 10 * 1024 * 1024:
            raise ValidationError("Only text files smaller than 10M are allowed!")

To prevent users from creating attachments that are not plain text files smaller than 10M using the test field list:

Pass file_size and mimetype in the context:

<field name="test" context="{'file_size': 10*1024*1024, 'mimetype': 'text/plain'}">

And add the constraints in the ir.attachment model.

Example:

def human_size(size):
    units = "Bytes,Kb,Mb,Gb,Tb,Pb,Eb,Zb,Yb".split(',')
    i = 0
    while size >= 1024:
        size /= 1024
        i += 1
    return "%.4g %s " % (size, units[i])


class IrAttachment(models.Model):
    _inherit = 'ir.attachment'

    @api.one
    @api.constrains('mimetype', 'file_size')
    def _check_mimetype_file_size(self):
        if 'mimetype' in  self.env.context and self.env.context['mimetype'] != self.mimetype:
            raise ValidationError("Only text files can be uploaded!")
        if 'file_size' in self.env.context and self.env.context['file_size'] < self.file_size:
            raise ValidationError("Only text files smaller than %s are allowed!" % human_size(self.env.context['file_size']))