models.py

class SaleOrder(models.Model):

    _inherit = 'sale.order'

    @api.model
    def create(self, values):
        record = super(SaleOrder, self).create(values)
        import urllib2
        import json
        req = urllib2.Request('http://localhost:3000/send-message/', data=json.dumps({
            'message': '{} - {}'.format(record.partner_id.name, record.amount_total)
        }), headers={
            'Content-type': 'application/json'
        })
        urllib2.build_opener().open(req)
        return record