Hire Purchase: Module Development example in openerp 5.0.0.1

In this tutorial, I will share how module develops in openerp. First I will explain the functionality of hire purchase (what we are going to develop), second I will develop hire purchase module in openerp. A simple explanation of hire purchase module is sale of goods in installment. In my example, I will ignore the interest portion of hire purchase. I just spread the price of good in number of monthly installment. I can say that, this module is a demo version of hire purchased without installment. In future I will extend this module with interest. In this tutorial I will focus on step by step development of module in openerp.
What hire purchase is read out the wiki about hire purchase, for detail of hire purchase also read wikieducator.

In this tutorial I will cover; how to create openerp objects (in .py file), interaction with object using openerp views (tree and form), openerp wizards and menuitem.

Step 1:

Create the following files and folders.

a. Folder having named ‘hirepurchase’ and 2nd folder having name ‘wizard’ in ‘hirepurchase’ folder.

b. Create the files in hirepurchase folder, i.e. __init__.py, __terp__.py, hirepurchase_view.xml and hirepurchase.py.

c. Create the files in wizard folder, i.e. __init__.py and wizard_pay_hirepurchaseinvoice.py

File structure: hirepurchase folder contains one folder (wizard) and four files (__init__.py, __terp__.py, hirepurchase_view.xml and hirepurchase.py). Wizard folder contains two files (__init__.py and wizard_pay_hirepurchaseinvoice.py)

Step 2:

Open the __init__.py in gedit (linux) or notepad (windows). Write the following code.

import hirepurchase

Step 3:

Open the __terp__.py in gedit (linux) or notepad (windows). Write the following code.

{
        "name" : "hirepurchase",
        "version" : "0.1",
        "author" : "Mohsin",
        "website" : "http://mohsinpage.wordpress.com",
        "category" : "Accounting",
        "description": """  """,
        "depends" : ['base','account','base_report_designer'],
        "init_xml" : [ ],
        "demo_xml" : [ ],
        "update_xml" : ['hirepurchase_view.xml'],
        "installable": True
}

Name of module will be ‘hireurchase’. Hirepuchase depends on the on other two modules i.e. base and account. Hirepurchase module use an xml file having name hirepurchase.xml, in this xml file we will declare different type of views available in openerp like tree, form, button and menuitem etc other then wizards.

Step 3:
Open the hirepurchase.py in gedit (linux) or notepad (windows). Write the following code.

from osv import osv, fields
import netsvc
import wizard

l = netsvc.Logger()

class account_hirepurchase(osv.osv):
    def onchange_invoice_id(self, cr, uid, ids,invoice, context={}):
#        l.notifyChannel("MyLog: in method= ",netsvc.LOG_INFO,'')
        res = {'value': {}}
        if not invoice:
            return res
        else:
            rec_of_invoice=self.pool.get('account.invoice').browse(cr,uid,invoice,context=context)
            res['value']['total_amount'] = rec_of_invoice.residual
            return res

    _name = 'account.hirepurchase'
    _columns = {
        'name': fields.many2one('res.partner','Partner',domain=[('active','=','TRUE'),('customer','=','TRUE')]),
        'invoice': fields.many2one('account.invoice','Invoice',domain="[('state','=','open'),('partner_id','=',name)]"),
        'number_installment': fields.integer('Installments'),
        'total_amount': fields.float('Residual Amount'),
        'hirepurchase_lines': fields.one2many('account.hirepurchaseline','hirepurchaseid'),
        'status': fields.selection([('unpaid', 'Un Paid'),
                                   ('partial_paid', 'Partial Paid'),('fully_paid', 'Fully Paid')], 'Status',
                                   required=True, help="""Help Text"""),
    }

    def create_installment(self,cr, uid, ids, context={}):
        current_form_obj=self.browse(cr, uid, ids, context)[0]
        if not current_form_obj:
            return False
        else:
            n=int(current_form_obj.number_installment)
            i=1
            while i<=n:
                self.pool.get('account.hirepurchaseline').create(cr,uid,{
                'hirepurchaseid':current_form_obj.id,
                'due_amount':current_form_obj.total_amount/n,
                'installment_no':i,
                'status':'due',
                })
                i=i+1
        return True
account_hirepurchase()

class account_hirepurchaseline(osv.osv):
    _name = 'account.hirepurchaseline'
    _rec_name='installment_no'
    _columns = {
        'hirepurchaseid': fields.many2one('account.hirepurchase','Hire Purchase ID',ondelete='cascade'),
        'due_amount': fields.float('Amount Due'),
        'installment_no': fields.integer('Installment No'),
        'status': fields.selection([('due', 'Due'),
                                   ('paid', 'Paid')], 'Status',
                                   required=True, help="""Help Text"""),
        'voucher': fields.many2one('account.move','Payment Voucher',ondelete='restrict'),
    }
account_hirepurchaseline()

In this file we created two objects i.e. account.hirepurchase and account.hirepurchaseline.
Account.hirpurchase:

This object has following attributes and functionalities.
Name: its store the id of res.partner object means it’s the foreign key of res.partner object. One res.partner can occur many time in account.hirepurchase.
Invoice: All the account.invoice related to res.partner will be available to store its id in invoice column, means invoice is the foreign key of account.invoice in account.hirpurchase. Only the open invoice will be entertain in hire purchases.
Number_installment: according to rule of hire purchase, each res.partner is allowed to pay in installments for his purchases of above mention price. Company will decide the number of installment for above res.partner on his purchase. It’s an integer type of column
Total_amount: its store the total residual value receivable from res.partner for his purchase in above accout.invoice. It’s a float type of column
Status: status show the three values un paid, partially paid and fully paid. It’s a selection type of column.
Onchnage_invoice_id(): In the form of account.hirepurchase, when invoice will selected or change from available list of invoice then the residual value of selected invoice will be assign to the text box of total_amount of account.hirepurchase .
Create_installment(): In the form of account.hirepurchase, there is a button having name ‘create the installments’. When this button will click, this functionality will be call. This function will create a number of installments, amount for each installment and status of each installment.

Account.Purchaseline:

This object has following attributes.
Due_amount: each installment amount receivable for monthly basis from res.partner.
Installment_no: it will store the no of installment.
Status: its store the status of each installment either paid or due.
Voucher: when res.partner pays his installment, the id of that receipt voucher will be store in this column, with installment status paid.

Below is the example of account.hirepurchase and account.hirepurchaseline:

Object = Account.hirepurchase	Name: Ali Yaseen		Invoice: Purchase Computer
	Number_installment: 4		Total_amount: 25000
	Status: Partially Paid
	Functionality One: onchange_invoice_id()
	Functionality Two: create_installment()
Object = Account.hirepurchaseline	Due_amount	Installment_no	Status	voucher
	6250	1	Paid	Payment receipt
	6250	2	Due
	6250	3	Due
	6250	4	Due

Step 4:
Open the hirepurchase_view.xml in gedit (linux) or notepad (windows). Write the code in xml like below for tree, form, action & menuitem for account.hirepurchase object and similarly xml code for tree, form and action for account.hirepurchaseline.

Form of hire purchase

"    <record model="ir.ui.view" id="view_account_hirepurchase_form">
        <field name="name">Hire Purchase Form</field>
        <field name="model">account.hirepurchase</field>
        <field name="type">form</field>
        <field name="arch" type="xml">
            <form string="account.hirepurchase">
            	<separator colspan="4" string="Invoice"/>
                <field name="name" select="1"/>
                <field name="invoice" select="2"  on_change="onchange_invoice_id(invoice)"/>
                <field name="total_amount" select="0"/>
                <separator colspan="4" string="Create Installment"/>
                <field name="number_installment" select="0"/>
                <button name="create_installment" string="Create Installment" type="object"/>
                <field name="hirepurchase_lines" colspan="4" select="0" nolabel="1"/>
                <field name="status" colspan="4"/>
                
            </form>
        </field>
    </record>"

Tree of hire purchase

    <record model="ir.ui.view" id="view_account_hirepurchase_tree">
        <field name="name">Hire Purchase Tree</field>
        <field name="model">account.hirepurchase</field>
        <field name="type">tree</field>
        <field name="arch" type="xml">
            <tree string="account.hirepurchase">
                <field name="name"/>
                <field name="invoice"/>
                <field name="number_installment"/>
                <field name="total_amount"/>
				<field name="status"/>
            </tree>
        </field>
    </record>

Action of hire purchase

    <record model="ir.actions.act_window" id="action_account_hirepurchase">
        <field name="name">Hire Purchases</field>
        <field name="res_model">account.hirepurchase</field>
        <field name="view_type">form</field>
        <field name="view_mode">tree,form</field>
    </record>

Menu of hire purchase

    <menuitem name="Financial Management/Invoices/Hire Purchases" id="menu_account_hirepurchase" action="action_account_hirepurchase"/>

Form of hire purchase lines

    <record model="ir.ui.view" id="view_account_hirepurchaseline_form">
        <field name="name">Hire Purchas Lines</field>
        <field name="model">account.hirepurchaseline</field>
        <field name="type">form</field>
        <field name="arch" type="xml">
            <form string="Hire Purchase Lines List">
                <field name="due_amount" select="2"/>
                <field name="installment_no" select="0"/>
				<field name="status" select="2"/>
				<field name="voucher"/>
            </form>
        </field>
    </record>

Tree of hire purchase lines

    <record model="ir.ui.view" id="view_account_hirepurchaseline_tree">
        <field name="name">Hire Purchase Lines</field>
        <field name="model">account.hirepurchaseline</field>
        <field name="type">tree</field>
        <field name="arch" type="xml">
            <tree string="Hire Purchase Lines List">
                <field name="due_amount"/>
                <field name="installment_no"/>
				<field name="status"/>
				<field name="voucher"/>
            </tree>
        </field>
    </record>

Action of hire purchase lines

    <record model="ir.actions.act_window" id="action_account_hirepurchaseline">
        <field name="name">Hire Purchase Lines</field>
        <field name="res_model">account.hirepurchaseline</field>
        <field name="view_type">form</field>
        <field name="view_mode">tree,form</field>
    </record>

So far, we can install this hire purchase module. But let me extent the functionality of this module, by introducing a wizards. Using this wizard, we don’t need to enter a receipt voucher. Just select the installment & bank book, this wizard will generate the receipt voucher in account.move.line .

Hire Purchase form, Hire Purchase Lines, Wizard

Hire Purchase Lines Form

Step 5:
Now in this step, we will create wizard, which will enter receipt voucher in account.move.line. First enter the accessing action in account.hirepurchase object of this wizard like below. This below line will be adding in same file hirepurchase_view.xml of hirepurchase folder.

    <wizard id="wizard_hirepurchaseinvoice_pay" model="account.hirepurchase" name="account.invoice.hirepurchasepay" string="Receipt Installment" groups="base.group_user"/>

Step 6:
Open the __init__.py of wizard folder not hirepurchase folder in gedit (for ubuntu) or noteoad (for windows). Write the below code.

import wizard_pay_hirepurchaseinvoice

Step 7:
Open the wizard_pay_hirepurchaseinvoice.pyof wizard folder in gedit (for ubuntu) or noteoad (for windows). Write the below code.

import wizard
import netsvc
import time
import pooler

l = netsvc.Logger()

installment_form = '''
<form>

'''

installment_fields = {
    'Installment': {'string': 'Installment', 'type': 'many2one', 'relation':'account.hirepurchaseline', 'required':True},

}

pay_form = '''
<form>

'''

pay_fields = {
    'amount': {'string': 'Amount paid', 'type':'float', 'required':True},
    'name': {'string': 'Entry Name', 'type':'char', 'size': 64, 'required':True},
    'date': {'string': 'Payment date', 'type':'date', 'required':True, 'default':lambda *args: time.strftime('%Y-%m-%d')},
    'journal_id': {'string': 'Journal/Payment Mode', 'type': 'many2one', 'relation':'account.journal', 'required':True, 'domain':[('type','=','cash')]},
    'voucher_type':{'string':"Voucher Type", 'type':'selection', 'selection':[('rec_voucher','Cash Receipt'),('bank_rec_voucher','Bank Receipt')],'required':True},
    'period_id': {'string': 'Period', 'type': 'many2one', 'relation':'account.period', 'required':True},
}
def _get_hirepurchase_id(self, cr, uid, data, context={}):
     l.notifyChannel("MyLog: = _get_hirepurchase_id",netsvc.LOG_INFO,data['id'])
     global hirepurchase_id
     l.notifyChannel("MyLog: = hirepurchase_id",netsvc.LOG_INFO,hirepurchase_id)
     hirepurchase_id=data['id']
     l.notifyChannel("MyLog: = hirepurchase_id",netsvc.LOG_INFO,hirepurchase_id)
     return {}

def _get_amount_of_installment(self, cr, uid, data, context={}):
     form=data['form']
#     installment_id=form.get('Installment',False)
     installment=pooler.get_pool(cr.dbname).get('account.hirepurchaseline').browse(cr, uid, form.get('Installment',False), context)
     ids = pooler.get_pool(cr.dbname).get('account.period').find(cr, uid, context=context)
     period_id = False
     if len(ids):
         period_id = ids[0]
#     l.notifyChannel("MyLog: = installment_id",netsvc.LOG_INFO,installment_id)
     return {
        'period_id':period_id,
        'amount': installment.due_amount
        }

def _voucher_entry(self, cr, uid, data, context={}):
    form=data['form']
    move_obj=pooler.get_pool(cr.dbname).get('account.move')
    move_line_obj=pooler.get_pool(cr.dbname).get('account.move.line')
    journal=pooler.get_pool(cr.dbname).get('account.journal').browse(cr, uid, form.get('journal_id',True), context)
    l.notifyChannel("MyLog: = form.get('name',True) = ",netsvc.LOG_INFO,data['id'])
    partner =pooler.get_pool(cr.dbname).get('account.hirepurchase').browse(cr, uid, data['id'], context)
    move={'name':"/",'ref':form.get('Installment',True),'period_id':form.get('period_id',True),'journal_id':form.get('journal_id',True),'type':form.get('voucher_type',True),'date':form.get('date',True),'to_check':False}
    new_move_id=move_obj.create(cr,uid,move,context)
    l.notifyChannel("MyLog: = partner = ",netsvc.LOG_INFO,partner.name.property_account_receivable.id)
    move_line=[
        {'account_id':journal.default_debit_account_id.id,'partner_id':partner.name.id,'period_id':form.get('period_id',True),'date':form.get('date',True),'centralization':'normal','journal_id':form.get('journal_id',True),'name':'Cash Receipt','credit':'0.00','state':'draft','move_id':new_move_id,'debit':form.get('amount',True),'ref':form.get('Installment',True)},
        {'account_id':partner.name.property_account_receivable.id,'partner_id':partner.name.id,'period_id':form.get('period_id',True),'date':form.get('date',True),'centralization':'normal','journal_id':form.get('journal_id',True),'name':'A/C Receivable','credit':form.get('amount',True),'state':'draft','move_id':new_move_id,'debit':'0.00','ref':form.get('Installment',True)},
            ]
    l.notifyChannel("MyLog: move_line = ",netsvc.LOG_INFO,move_line)
    for r in move_line:
        new_move_line_id=move_line_obj.create(cr,uid,r,context)
    hire_purchase_line_obj=pooler.get_pool(cr.dbname).get('account.hirepurchaseline')
    vals={'status':'paid','voucher':new_move_id}
    hire_purchase_line_obj.write(cr,uid,form.get('Installment',True),vals,context=None)
    return {}

class wizard_pay_hirepurchaseinvoice(wizard.interface):
    states = {
        'init': {
            'actions': [],
            'result': {'type':'state', 'state':'show_form'}
        },
        'show_form': {
            'actions': [],
            'result': {'type':'form', 'arch':installment_form, 'fields':installment_fields, 'state':[('end','Cancel'),('next','Next')]}
        },
        'next': {
            'actions': [_get_amount_of_installment],
            'result': {'type':'form', 'arch':pay_form, 'fields':pay_fields, 'state':[('end','Cancel'),('pay','Payment')]}
        },
        'pay': {
            'actions': [_voucher_entry],
            'result': {'type':'state', 'state':'end'}
        }

    }
wizard_pay_hirepurchaseinvoice('account.invoice.hirepurchasepay')

Wizard First Form: Select the installment for receipt voucher

Wizard from 2: Receipt Voucher.

Step 8:
Copy the folder in addons of openerp, update module list in openerp. Install this module. This module is a beta version, its more functionality will be share soon.

Receipt voucher entered after wizard step