• Question (Q): Why Django build-in Web Server (development server) works VERY SLOWLY on Windows 7 ? And how to fix this?
  Answer (A): seems it’s all about DNS… To fix this just open C:\Windows\system32\drivers\etc\hosts file (in notepad for example) and uncomment (i.e. remove “#”) in the following line: 127.0.0.1 localhost

• to be continue…

Because Evejob Project developed in few frameworks, we need to make clear “terminology” differences used by different frameworks as well as different strategies to develop MVC applications using such frameworks.
Let’s start from MVC frameworks:
1) ASP.NET MVC as we see from name is “Model-View-Controller” framework (powered by .NET framework), so use actually concepts of “Models”, “Views” and “Controllers”. “Views” and “Controllers” concepts defined by framework itself (i.e. you need to inherit controllers from System.Web.Mvc.Controller class and inherit views from System.Web.Mvc.ViewPage to use build-in view engine). It is also possible in ASP.NET MVC to attach third-party View Engine (just google and you will found at least few). But “Models” concept in ASP.NET MVC is true “concept” – you don’t need to inherit from some base class or implement some interface to made a models in ASP.NET MVC! Instead framework provide you will full flexibility to create your own domain model and select any persistent framework if you need to persist your model entities. You can use for example Entity Framework, Linq to SQL, any other ORM or even POCO to implement your models!
2) Ruby On Rails is true “Model-View-Controller” framework and more so it uses “convention over configuration” principle. This mean that you actually have already defined conventions where to put your model entities, where to put controllers and where to put views (templates) and how to implement them (from what class you need to inherit etc). Sure while it is still possible to made some changes and even use another ORMs etc, build-in (OK, read instead “installed by default with Rails”) ActiveRecord ORM is enough for most cases (OK, at least in most simple cases ). The same things with templates (views) – you can use build in template engines (provided by ActiveView module) or add your own – at the time I write this exists not less then 20! different third-party template engines in addition to build-in (sure you can always build your own if need and made 21-th)!
3) Grails is really “Model-View-Controller” framework, was build with same principles like RoR, but because Grails work on top of Spring and Hibernate, developers initially get BEST build-in enterprise infrastructure from Java world! And sure in Grails infrastructure was extended so much (thanks to power of Groovy), that it looks like it most powerful MVC framework to the moment (this is just my personal opinion – I don’t want to start a war here )!

So frameworks listed above all follow MVC terminology where you actually create your own Models (Domain Models possible with Persistence), implement Controller (with actions) and create presentation using Views (that is actually powered by some build-in or custom template engine).

One framework – Django – that we use for Evejob project made use of a little different terminology (instead of MVC): Model-View-Template.
Model term is used for same purposes like Model in MVC – it is simply domain model (provided usually by build-in to Django ORM, but also possible to use your own ORM… just note that it require little more “tuning / hacking” than in other frameworks).
View in Django play the same role as Controller in MVC.
And “Template” term in MVT actually used instead of “View” from MVC (while Template terms actually also used in MVC in sense that view CAN be represented as result of Template rendering)
What I found from my experience that this difference in terminology does NOT make any actually impact on development process!
More so, actually most MVCs that available in the market used mostly in “MTC” mode – i.e. “Model-Template-Controller”.
What does it means? It means that Controllers actually render Templates in MOST of the cases! Sure in case if you use MVC framework to build for example Web Services, you will probably not render any Templates and your controllers (controllers in MVC or your Views in MVT) actually more likely will return JSON or XML directly (OK… XML it is possible also to build using Templates sometimes – look how it is done in Grails for example! But let’s think here that we want to return raw XML from Controller without any template engine). Sometimes you also can return JavaScript or any other format etc directly from Views in MVT or from Controllers in MVC.
What is good in MVT is “order” of letters that give better understanding for developers that first time here about this pattern – “Model” <-> “View” <-> “Template”. This way logical flow going – i.e. views are in the “middle” of this logical flow! (using this principle it was better initially probably call MVC as MCV, i.e. “Model” <-> “Controller” <-> “View” , so “Controllers” become in the middle, center of logic). It related only to logical structure, because in MVC pattern, Model accessible (and used) actually in both Controller and View, same like in MVT both Views and Templates share same Model! You can read a short overview of MVC at Wikipedia article for example if want little more information)
But as I tell before – main thing is “understanding” how pattern works, not how we call it! And “idea” of implementation of this patter in Django and other frameworks is exactly same even so name is not!

Some interesting Django related links:

- Django Project Home

• http://www.djangosites.org – list of Django sites
• http://pinaxproject.com – a platform for rapidly developing websites
• http://cloud27.com – site that was build using Pinax
• http://www.django-cms.org/ – Django CMS
• http://code.google.com/p/django-tagging/ – A generic tagging application for Django projects, which allows association of a number of tags with anyModel instance and makes retrieval of tags simple.
• http://djangopluggables.com/ – 3-rd party Django applications
• http://www.djangosnippets.org/ – useful “snippets” of reusable Django code

OK, in Part #1 we already figure out what Models we need to create. Because Django support concept of “applications” inside one project, we can actually start creating models for 3 applications:

• Accounts (User profiles, registration, authentication / authorization etc)
• Companies (Companies catalog, profiles etc)
• Common (seems City and Country are good example of entities that will be used in other applications)

Django internally support following concepts that will be used in Accounts application:

1. Users
2. Groups (known in other frameworks as “User Roles”)
3. User Profile (you need to create your own model for it, but Django have special support for this)

cd c:\evejob\EvejobDJ
python manage.py startapp accounts

The same way, you can create now “common” and “companies” applications in EvejobDJ project.

Let’s take a look into possible simple “accounts” application model.py file:

from django.db import models
from django.contrib.auth.models import User
from django.utils.translation import ugettext_lazy as _
 
class UserProfile(models.Model):
 
    # required field - user that own profile
    user = models.ForeignKey(User, unique=True)
 
    # optional Job Title
    job_title = models.CharField(_("Job Title"), max_length=128, null = True, blank = True)
 
    # optional Phone Number
    phone = models.CharField(_("Phone"), max_length=16, null = True, blank = True)
 
    # Boolean stored as tinyint in MySQL database, but it's ok for now
    allow_site_to_contact_by_email = models.BooleanField(_("Allow site to contact me by email"))
    allow_site_partners_to_contact_by_email = models.BooleanField(_("Allow site partners to contact me by email"))
    allow_site_to_contact_by_phone = models.BooleanField(_("Allow site to contact me by phone"))
    allow_site_partners_to_contact_by_phone = models.BooleanField(_("Allow site partners to contact me by phone"))
 
    def __unicode__(self):
       return self.user.username

Let’s review now most important aspects of this code:

from django.contrib.auth.models import User

# required field - user that own profile
user = models.ForeignKey(User, unique=True)

from django.utils.translation import ugettext_lazy as _

    def __unicode__(self):
       return self.user

from django.db import models
from django.contrib.auth.models import User
import EvejobDJ.settings as settings
from django.utils.translation import ugettext_lazy as _
 
class Country(models.Model):
 
    # required Unique Company Name
    name = models.CharField(_("Name"), max_length=255, unique = True)
 
    def __unicode__(self):
       return '%s' % (self.name)
 
    class Meta:
       verbose_name = _('Country')
       verbose_name_plural = _('Countries')
 
class City(models.Model):
 
    # required Unique Company Name
    name = models.CharField(_("Name"), max_length=255, unique = True)
 
    country = models.ForeignKey(Country, unique = False)
 
    def __unicode__(self):
       return '%s' % (self.name)
 
    class Meta:
       verbose_name = _('City')
       verbose_name_plural = _('Cities')

    class Meta:
       verbose_name = _('City')
       verbose_name_plural = _('Cities')

from django.db import models
from django.contrib.auth.models import User
import EvejobDJ.settings as settings
from django.utils.translation import ugettext_lazy as _
 
class Company(models.Model):
 
    # required Unique Company Name
    name = models.CharField(_("Name"), max_length=255, unique = True)
 
    # user that create this company first time.
    creation_by = models.ForeignKey(User, unique = False)
 
    # when user create this company first time. Django Automatically set the field to now when Company created for the first time
    creation_date = models.DateTimeField(_("Create Date"), auto_now_add = True)
 
    city = models.ForeignKey('common.City', unique = False, null = True, blank = True)
    country = models.ForeignKey('common.Country', unique = False, null = True, blank = True)
 
    # logo = models.OneToOneField('CompanyLogo', related_name='logo', verbose_name = "company logo")
    # But this is not needed, as you always can get access to logo using something like
    # (read more http://docs.djangoproject.com/en/dev/topics/db/queries/#one-to-one-relationships)
    # e = Company.objects.get(id=2)
    # e.companylogo
 
    def __unicode__(self):
       return '%s' % (self.name)
 
    class Meta:
       verbose_name = _('Company')
       verbose_name_plural = _('Companies')
 
class CompanyLogo(models.Model):
 
    company = models.OneToOneField(Company, primary_key=True)
 
    # user that create this logo first time.
    creation_by = models.ForeignKey(User, unique = False)
 
    # when user create this logo first time. Django Automatically set the field to now when logo created for the first time
    creation_date = models.DateTimeField(_("Create Date"), auto_now_add = True)
 
    caption = models.CharField(blank=True, null = True, max_length=100)
 
    image = models.ImageField(upload_to=settings.COMPANY_LOGO_RELATIVE_ROOT)
 
    def __unicode__(self):
       return '%s' % (self.company.name)
 
    class Meta:
       verbose_name = _('Company Logo')
       verbose_name_plural = _('Companies Logos')

INSTALLED_APPS = (
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.flatpages',
    'common',
    'accounts',
    'companies',
)

Django

We will need to use MySQL for Python project for connection from Django Python code to MySQL database. Because I (and hope you also) use Windows 7 64 bit with Python 64 bit, needs to found and install 64 bit version of such library. On original project site, for some reason I could not found (at least in the moment when I write post), so I get it from different site:  http://www.codegood.com/download/3/. Just download and install it (it will automatically found your Python installation if you follow all steps that I write in previous posts).

Let’s configure now, EvejobDJ project to use MySQL database.

First, needs to create “EvejobDJ” database schema using one of the administration tools, for example, described in Part #7 – just create it visually or issue following SQL command:

CREATE DATABASE EvejobDJ;

Open “settings.py” file in root folder of EvejobDJ project inside IntelliJ IDEA IDE and change database engine parameters to following:

DATABASE_ENGINE = 'mysql'           # 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.
DATABASE_NAME = 'evejobdj'         # Or path to database file if using sqlite3.
DATABASE_USER = 'root'                # Not used with sqlite3.
DATABASE_PASSWORD = ''             # Not used with sqlite3.
DATABASE_HOST = ''                     # Set to empty string for localhost. Not used with sqlite3.
DATABASE_PORT = ''                     # Set to empty string for default. Not used with sqlite3.

Now it is time to test connection and create default tables in database (for authentication, sessions etc):

cd C:\Evejob\EvejobDJ
python manage.py syncdb

Hopefully you will get something like this in response:

As you see you will need to create default “superuser” (I just put “admin” as his username and “info at evejob.com” as his email) because Django authentication app enabled by default.

Now you can check in MySQL database administration tool that you really create tables (screenshot from free MySQL Administrator that you probably install with MySQL GUI Tools):

Ruby On Rails

To use MySQL in Ruby On Rails (RoR) we need to install MySQL Adapter, for example:

ruby -S gem install mysql

But here we get into trouble – binaries of this gem (mysql) does not work correctly on Windows 64 bit and on project site there is no version for 64 bit OS…
While on some “Unix” OS it is possible to fix this issue (for example build gem from source…), on Windows it is simply not possible…
Ah, OK, OK… it is possible, but just too complex / time consuming – don’t want to spend time on this NOW and leave this time to focus on coding of Evejob… maybe somebody or author of gem will fix this issue later!

Note: other available adapters for MySQL from Ruby seems also have same problems… at least by now.

So let’s just temporary switch to PostgreSQL for Ruby on Rails version of Evejob.

To setup PostgreSQL for EvejobRoR development it takes just few minutes:

• Download and install latest PostgreSQL from http://www.enterprisedb.com/products/pgdownload.do#windows. Installation is trivial same like for MySQL (sure same – configuration is NOT trivial for production usage!). Make sure that you remember password that you put for “postgres” login role (default database user name).
• Create “EvejobRoR_development” database in PgAdmin (this app comes with PostgreSQL… very similar to MySQL Administrator) and select “postgres” role as owner for this database.
• Open EvejobRoR project in IntelliJ IDEA and copy file “config\database.yml” to “config\database_mysql.yml” (we will need it again when fix issue with MySQL + Ruby)
• Edit file “config\database.yml” and enter here following information (make sure you put your password instead of my fake “admin”):

  development:
    adapter: postgresql
    encoding: utf8
    reconnect: false
    database: EvejobRoR_development
    pool: 5
    username: postgres
    password: admin
    host: localhost
   
  test:
    adapter: postgresql
    encoding: utf8
    reconnect: false
    database: EvejobRoR_test
    pool: 5
    username: postgres
    password: admin
    host: localhost
   
  production:
    adapter: postgresql
    encoding: utf8
    reconnect: false
    database: EvejobRoR_production
    pool: 5
    username: postgres
    password:  admin
    host: localhost

• Execute following commands:

  ruby -S gem install postgres-pr

  This will install PostgreSQL adapter for Ruby (gem “postgres-pr” works on Windows x64)

  Now you can try to execute database “migration” that will hopefully create some stuff in development database:

  cd c:\Evejob\EvejobRoR
  c:\ruby\bin\rake db:migrate

  It will be to simple if this will work for you from first attempt! On my machine, I was need to made small “hack” to made this work, i.e. to add following code into new_rails_defaults.rb file in “config\initializers” folder and run db:migrate again:

  def PGconn.quote_ident(name)
      %("#{name}")
  end

  (look for more info about this “hack” here)

If you complete everything, you can check that db:migrate actually create one table (”schema_migrations”) in your development database:

Grails

Let’s configure last version of Evejob which going to use MySQL database – EvejobGoG.

First, needs to create “evejobGoG_development”, “evejobGoG_test” and “evejobGoG_production” empty databases. You can do this trivial task using MySQL Administrator GUI Tool for example.

Next step is to let know Grails how to connect to just created MySQL databases. Because Grails runs on Groovy and Groovy itself runs in JVM we can use MySQL Connector/J from MySQL site: http://dev.mysql.com/downloads/connector/j/

Download “zip” file, unpack it to temporary folder and copy mysql-connector-java-x.x.xx-bin.jar file to the C:\evejob\EvejobGoG\lib folder.

Now open EvejobGoG project in IntelliJ IDEA and found DataSource.groovy file located in “EvejobGoG\Grails-app\conf” folder. Let’s change some settings in this file:

dataSource {
	pooled = true
	driverClassName = "com.mysql.jdbc.Driver" //"org.hsqldb.jdbcDriver"
	username = "root"
	password = ""
    dialect = "org.hibernate.dialect.MySQL5InnoDBDialect"
}
hibernate {
    cache.use_second_level_cache=true
    cache.use_query_cache=true
    cache.provider_class='com.opensymphony.oscache.hibernate.OSCacheProvider'
}
// environment specific settings
environments {
	development {
		dataSource {
			dbCreate = "update" // one of 'create', 'create-drop','update'
			url = "jdbc:mysql://localhost/evejobGoG_development" // "jdbc:hsqldb:mem:devDB"
		}
	}
	test {
		dataSource {
			dbCreate = "update"
			url = "jdbc:mysql://localhost/evejobGoG_test" // "jdbc:hsqldb:mem:testDb"
		}
	}
	production {
		dataSource {
			dbCreate = "update"
			url = "jdbc:mysql://localhost/evejobGoG_production" // "jdbc:hsqldb:file:prodDb;shutdown=true"
		}
	}
}

Now Grails know how to connect to MySQL. Unfortunately, there is no build-in database migrations functionality in Grails framework yet, so our next step is to install some plug-ins that can help us to maintain database schema versions and migrations. While exists few of such plug-ins, I think most “featured” is LiquiBase (but also you can take a look into “Autobase” if you prefer to dial with DSL instead of XML… just take a note that this plugin works only with Grails, while LiquiBase can be used with Ant, Maven, Spring etc or even independently as database change management solution)

To install LiquiBase do following (you can read more regarding Grails integration with LiquidBase here):

cd C:\evejob\EvejobGoG
grails install-plugin liquibase

Now check that you have following folder (that is empty by now):

C:\evejob\EvejobGoG\grails-app\migrations

If you don’t have folder yet, just create it before continue with migrations – this folder will be used to save migrations change log etc..

Now it’s time to generate change log and migrate database (that is empty for now) to initial version:

grails generate-changelog grails-app\migrations\changelog.xml
grails migrate

After first command (”generate-changelog”) LiquiBase will create initial version of database change log and save it to the “C:\evejob\EvejobGoG\grails-app\migrations\changelog.xml” file. It will looks something like following:

Second command (”grails migrate”) will actually made migration in database. In our case because our domain is empty, LiquiBase will just create changes maintenance tables: “databasechangelog” and “databasechangeloglock”. You can check now this using MySQL Administrator:

If all steps above completed successfully you finish setup EvejobGoG Grails project to use MySQL Database and have ability to migrate databases!