yes you can give 'name': 'Invoice ' + 'today date' in return from wizard to print report.

for example: this is function is call from print button in wizard.

def print_report(self,cr, uid, ids, context=None):
        if context is None:
           context = {}
        data = self.read(cr, uid, ids)[0]
        self_browse = self.browse(cr, uid, ids)
        
        datas = {
            'ids': [data.get('id')],
            'model': 'sale.order',
            'form': data
            }
        return {
            'type': 'ir.actions.report.xml',
            'report_name': 'custom.invvoice.report',
            'datas': datas,
            'name': 'Invoice ' + self_browse[0].start_date + ' To ' + self_browse[0].end_date  
            }

I think you can use this module

https://github.com/OCA/reporting-engine/tree/8.0/report_custom_filename

Kind regard, 

For Odoo 9+:

Go to configuration, reports, look for the report you want, then use the Printed Report Filename field which can contain python expressions. Two variables can be used inside: object which is the object being printed, and time which is python time module. So you can input "object.name" without the quotes.

No need for extra module or code.

More here: http://gitlab.opengest.solutions/opengest/odoo/commit/da3d2fb1dc76654e630fba27ca3dcf03002d9431

Look for print_report_name

I have also the same problem..

Here is our solution to customize the sale order report PDF name with the « print » buttons.

https://www.odoo.com/forum/help-1/question/change-printed-file-name-in-webkit-report-in-odoo-59901

Hello,

I too faced the same problem of printing invoice pdf with Invoice number.pdf as its name.

I modified @Nikunj Nakum  answer and I got the result. Below given is the code

  #=================================================
  # Class             :    account_invoice (inherited)
  # Method          :    custom_invoice_print button
  # Description   :    This function prints the invoice and mark it as sent, so that
  #                            we can see more easily the next step of the workflow. 

  #                            Prints Invoice with invoice number as its name
  #================================================

  def custom_invoice_print(self, cr, uid, ids, context=None):
        self.write(cr, uid, ids, {'sent': True}, context=context)
        data = self.read(cr, uid, ids)[0]
        self_browse = self.browse(cr, uid, ids)
        datas = {
             'ids': ids,
             'model': 'account.invoice',
             'form': self.read(cr, uid, ids[0], context=context)
        }
        return {
            'type': 'ir.actions.report.xml',
            'report_name': 'account.invoice2',
            'datas': datas,
            'name': 'Invoice ' + self_browse[0].number  ,
            'nodestroy' : True
        }

Result:  Invoice INV14-09_018.pdf

The same problem for me!

I really want to have the same functionality as for "save as attachment" for all of the print buttons! Drives me nuts to always download the document twice just for the right file name...

Any idea?!?

# -*- coding: utf-8 -*-

import ast
import base64
import csv
import glob
import itertools
import logging
import operator
import datetime
import hashlib
import os
import re
import simplejson
import time
import urllib
import urllib2
import urlparse
import xmlrpclib
import zlib
from xml.etree import ElementTree
from cStringIO import StringIO

import babel.messages.pofile
import werkzeug.utils
import werkzeug.wrappers
try:
    import xlwt
except ImportError:
    xlwt = None

import openerp
import openerp.modules.registry
from openerp.tools.translate import _
from openerp.tools import config

from openerp.addons.web import http
openerpweb = http
from openerp.addons.web.controllers.main import Reports

def content_disposition(filename, req):
    filename = filename.encode('utf8')
    escaped = urllib2.quote(filename)
    browser = req.httprequest.user_agent.browser
    version = int((req.httprequest.user_agent.version or '0').split('.')[0])
    if browser == 'msie' and version < 9:
        return "attachment; filename=%s" % escaped
    elif browser == 'safari':
        return "attachment; filename=%s" % filename
    else:
        return "attachment; filename*=UTF-8''%s" % escaped

class change_main(Reports):

    @openerpweb.httprequest
    def index1(self, req, action, token):
        
        action = simplejson.loads(action)

        report_srv = req.session.proxy("report")
        context = dict(req.context)
        
        context.update(action["context"])

        report_data = {}
        report_ids = context["active_ids"]
        if 'report_type' in action:
            report_data['report_type'] = action['report_type']
        if 'datas' in action:
            if 'ids' in action['datas']:
                report_ids = action['datas'].pop('ids')
            report_data.update(action['datas'])

        report_id = report_srv.report(
            req.session._db, req.session._uid, req.session._password,
            action["report_name"], report_ids,
            report_data, context)

        report_struct = None
        while True:
            report_struct = report_srv.report_get(
                req.session._db, req.session._uid, req.session._password, report_id)
            if report_struct["state"]:
                break

            time.sleep(self.POLLING_DELAY)

        report = base64.b64decode(report_struct['result'])
        if report_struct.get('code') == 'zlib':
            report = zlib.decompress(report)
        report_mimetype = self.TYPES_MAPPING.get(
            report_struct['format'], 'octet-stream')
        file_name = action.get('name', 'report')
        if 'name' not in action:
            reports = req.session.model('ir.actions.report.xml')
            res_id = reports.search([('report_name', '=', action['report_name']),],
                                    0, False, False, context)
            if len(res_id) > 0:
                file_name = reports.read(res_id[0], ['name'], context)['name']
            else:
                file_name = action['report_name']
        file_name = '%s.%s' % (file_name, report_struct['format'])
        
        ########################################################
        # PATCH TO PRINT PARTNER-ID AND INVOICE NO IN FILE NAME
        if context['active_model'] in ['sale.order','purchase.order','account.invoice']:
            model1 =req.session.model(context['active_model'])
            read=model1.read(context['active_id'],[],context)
            if read['name']!=False:
                file_name = read['name'] + ' ' + read['partner_id'][1]
                print file_name
                file_name = '%s.%s' % (file_name, report_struct['format'])
            # PATCH END
        #########################################################
        
        return req.make_response(report,
             headers=[
                 ('Content-Disposition', content_disposition(file_name, req)),
                 ('Content-Type', report_mimetype),
                 ('Content-Length', len(report))],
             cookies={'fileToken': token})
        
        
    Reports.index=index1

In Existing Report Module after adding the below code able to generate Invoice Number in PDF File.

server\openerp\report\report_sxw.py in the create_single_pdf method.

    def create_single_pdf(self, cr, uid, ids, data, report_xml, context=None):
        if not context:
            context={}
        logo = None
        context = context.copy()
        title = report_xml.name
        rml = report_xml.report_rml_content
        model = context.get('active_model')
        record_id = context.get('active_id')    
        pool = pooler.get_pool(cr.dbname)
        invoice_obj = pool.get('account.invoice')
        type = report_xml.report_type
        if model == 'account.invoice' and record_id:
            invoice_val = invoice_obj.browse(cr, uid, record_id)     
            orderreference_type = invoice_val.reference or invoice_val.origin + report_xml.report_type
            type = orderreference_type.replace("pdf", ".pdf");        
        # if no rml file is found
        if not rml:
            return False
        rml_parser = self.parser(cr, uid, self.name2, context=context)
        objs = self.getObjects(cr, uid, ids, context)
        rml_parser.set_context(objs, data, ids, report_xml.report_type)
        processed_rml = etree.XML(rml)
        if report_xml.header:
            rml_parser._add_header(processed_rml, self.header)
        processed_rml = self.preprocess_rml(processed_rml,report_xml.report_type)
        if rml_parser.logo:
            logo = base64.decodestring(rml_parser.logo)
        create_doc = self.generators[report_xml.report_type]
        pdf = create_doc(etree.tostring(processed_rml),rml_parser.localcontext,logo,title.encode('utf8'))
        return pdf, type
        #return pdf, report_xml.report_type
      

Note: Core Report Module added extra code (Invoice Number in PDF File). But Better way to override  create_single_pdf method in a custom module.