Ruby/rails port of Cocoon/hibernate

[andrew]

Hi,
I’m currently running an apache/jboss cocoon/flow/hibernate/ajax
paypal (directpayment) project and am looking into the possibility of
porting it across to ruby/rails. For that reason I would like to know
the following:

1. Can I call my java classes or would I be looking at a complete
   rewrite in ruby?
2. How effective is ruby in terms of seperation of concerns regarding
   design from content?
3. I have a number of hibernate maps accessing various postgresql
   tables. Can I reverse engineer those tables into rails (maps?) ?
4. In cocoons mvc (flowscript) it is possible to instantiate and call
   class methods from within the document at the same time as directing
   flow. Is this possible in ruby/rails?

–
Regards

Andrew

[andrew]

Ok, to start with, I don’t really understand what #4 means, but I think
I
can address the other well enough:
#1: If the application is fairly complex, you’d probably be looking at a
full re-write… however, there is a project called JRuby that is
attempting
to change that statement. It allows you to run Ruby scripts on the JVM,
and
it allows you to reach out to existing Java code and call things in
it…
however, it’s support for Rails isn’t 100% atm… it can do basic stuff,
moving on up into intermediate, but extremely complex code is better
left
outside of JRuby atm.
#2: Excellent. It is on par with the best of any other framework I have
ever known in this regard.
#3: Using Rails, you generally don’t have to do much of anything to
support
already existing tables… Rails just reads in the schema info from the
DB,
and auto-generates all kinds of nifty things for you… the minor
exception
to this is that if you aren’t using the default names that Rails likes
in
your DB (it wants the primary key auto-increment id field to be named
id,
etc) you have to specify them in your file like so:
class User < ActiveRecord::Base
set_primary_key “userid”
end

Many people find On LAMP’s Rolling with Ruby on Rails tutorial a great
place
to find out what Rails can offer: the revisited tutorial is particularly
good in this respect:

Radar - O’Reilly

[andrew]

Hi Luke,
many thanks for the information you have provided thus far.

In regards to my question 4, an example might suffice:
(myArtistDetails.js)

importClass(Packages.test.Artist); Flows equivalent of package test;
import
Artist;

function artistDetails() {

try {
    artistID = cocoon.parameters.artistID;//either use defined or

specified from dB
artist = Artist.getArtist(artistID); //Artist id passed into
class
method

    artist_name = artist.getArtistName();//artist name is obtained 

from
the Artist class
artist_info = artist.getArtistInfo();// as above

}catch(e) {
}

cocoon.sendPageAndWait("artistDetails2.xml",{"artistID":artistID,"artist_name":artist_name,"artist_info":artist_info});

//MVC: flow is directed to rtistDetails2.xml with associated values
}

In the above flow (MVC) document a java class is imported, its method
interrogated and corresponding values passed onto the next document in
line.
How would this be handled in Ruby/Rails, such that an action on a web
page
causes artistDetaills() to be called and then directed on to
artistDetails2.xml?

Am I correct in thinking that rails is a mapping technology much like
hibernate?

–
Regards

Andrew

[andrew]

Hi Andrew,

I come from a JBoss/J2EE/Java background and I have been working on my
first RoR project for the last several months… all-in-all it is a
pleasure! If you are new to RoR, it will take a bit to get used to the
syntax but once you do, it is amazing how quickly one can get things
done and do it in a structured, test-oriented way.

RoR has ActiveRecord that is analagous to Hibernate or EJB3. It
supports many of the features and maps relationships nicely. Some of
the features I don’t see (someone please correct me if I am wrong)
are:

• lazy-loading/eager-loading ability
• object caching (like JBoss Cache)

In your situation, I wonder, rather than do a total immediate rewrite,
seeing you are using JBoss, why not keep JBoss as your object/db
broker with Hibernate and extend it out using Web Services and call
that from a RoR front-end? That way, you could migrate slowly rather
than wholesale.

Scott

[andrew]

It can be used as such, although I’m not sure that I would call that
it’s
default application.
And you could do exactly what you’re asking using AJAX and Rails’s links
to
it… it is one of the major aspects of Rails that promotes it above and
beyond most of the other frameworks available… you could even have it
load
up the artistDetails2.xml file into the page it’s already on, instead of
directing them to yet another page.

[andrew]

Hi Scott,
my appetite is definitely being whetted!! Please see my replies below:

I come from a JBoss/J2EE/Java background and I have been working on my
first RoR project for the last several months… all-in-all it is a
pleasure! If you are new to RoR, it will take a bit to get used to the
syntax but once you do, it is amazing how quickly one can get things
done and do it in a structured, test-oriented way.

From the various docs and examples I have seen it definitely does seem
like
a quick development environment!

RoR has ActiveRecord that is analagous to Hibernate or EJB3. It

supports many of the features and maps relationships nicely. Some of
the features I don’t see (someone please correct me if I am wrong)
are:

• lazy-loading/eager-loading ability
• object caching (like JBoss Cache)

OK! I am using hibernate with ehcache handling lazy object caching. Can
anyone else confirm whether ActiveRecord supports lazy-loading/object
caching?

In your situation, I wonder, rather than do a total immediate rewrite,

seeing you are using JBoss, why not keep JBoss as your object/db
broker with Hibernate and extend it out using Web Services and call
that from a RoR front-end? That way, you could migrate slowly rather
than wholesale.

Great idea! I will look into this as a viable option.

The five main areas of concern to me are as follows:

1. Database.
   I am using postgreSQL 8.1. Would rails be able to reverse engineer the
   required ActiveRecord maps from the dB schema? From what I understand of
   rails convention table names need to be pluralized. How would the
   reverse
   engineering process handle the fact that none of my table names are
   pluralized?!

2. Form validation
   I am using Ajax to handle all form validation in cocoon. In cocoon form
   dev/validation would be handled by:

a. Specifying that you wish Ajax to handle validation as so:

<ft:form-template action=“login.kont” name=“Form1” method=“POST”
ajax=“true”>

b. Defining your form widgets in a seperate document as so:
<ft:widget id=“password”>
<fi:styling size=“30”
type=“password”
class=“keyinbox” style=“background-color:#C9C4BD;” />
</ft:widget>

c. Defining your validation, against your widgest, in another document
as
so:

     <fd:field id="password" required="true">
      <fd:datatype base="string"/>
      <fd:validation>
        <fd:length min="5" max="20"/>
      </fd:validation>
     </fd:field>

3. Paypal API.

I have recently come across a ruby/rails Paypal (directpayment api) so
this
area is covered.

4. Image handling.

All artist images are stored in postgresql and read into the webapp as
svg
via Base64. Cocoon then allows for an svgTOpng or svgTOjpeg conversion
before the image is rendered to the page. As an example I have various
img
calls defined as such:

So in effect the img tag is making a call to the database which in turn
return the appropriate binary information, holds it in svg format before
converting it to either PNG or JPEG. How would ruby/rails handle this?

5. Email/Zip
   I have a process where by the artist track files (mp3) a user may have
   ordered are pulled out from their order/order_items object, read in the
   file
   system directory and then zipped up. This zip is then emailed to the
   user.
   How would ruby/rails handle this process?

–
Regards

Andrew

Scott

[andrew]

On 2/27/07, Scott [email protected] wrote:

RoR has ActiveRecord that is analagous to Hibernate or EJB3. It
supports many of the features and maps relationships nicely. Some of
the features I don’t see (someone please correct me if I am wrong)
are:

• lazy-loading/eager-loading ability

Eager loading, sure. You can put :include => blah on either your
associations or in the actual find calls to eager load whatever you
need.
Lazy loading:
By default, associations are lazy loaded. You can change this behaviour
as
stated above. There is no way, that I know of, to lazy load individual
fields (other than doing something like using a view to get a copy of
the
table that doesn’t have the fields, then doing direct sql queries to get
the
field in question).

• object caching (like JBoss Cache)

For this one, you can easily use memcache… Rails is set up to work
excellently with it, and there’s a lot of great help around to get you
set
up… it’s not exactly a Rails piece, but has been tightly integrated.

Also, in the current working version of Rails (called edge rails), all
actions (read: functions that you call that generally end up rendering
the
html to the user) are cached by default… two identical queries will
result
in only one trip to the DB.

In your situation, I wonder, rather than do a total immediate rewrite,

[andrew]

My personal experience with Cocoon / JBoss / etc tells me to NEVER just
port
code from these frameworks to Rails. Rewrite the application in Rails,
from
scratch, redoing even the database if you are allowed to. The end result
will be a pure-Rails site, which is vastly easier to develop and
maintain
than any Java solutions have ever been or will ever be. If you go trying
to
copy the way said Java solutions do things, you will end up with an
unmaintainable mess, if you finish it at all. Rails works best when you
let
Rails do what it wants to do.

As for specific answers:

2. Look into RJS. This acts much in the same way as what Cocoon seems to
   do,
   defining partials of HTML code that get pushed to the client.

3. Check out the fleximage plugin:
   http://agilewebdevelopment.com/plugins/fleximage Should take care of all
   your needs with this.

Jason

[andrew]

Hi jason,

My personal experience with Cocoon / JBoss / etc tells me to NEVER just
port

code from these frameworks to Rails.

Yes, I agree whole heartedly! I’m just trying to ascertain what what
technology within the ruby/rails framework will allow me to achieve the
same
functionality as I currently have with the cocoon/hibernate framework

2. Look into RJS. This acts much in the same way as what Cocoon seems to
   do,

defining partials of HTML code that get pushed to the client.

I will look into RJS.

4. Check out the fleximage plugin:

http://agilewebdevelopment.com/plugins/fleximage Should take care of all
your needs with this.

The plugin looks fantastic. Thanks for that headsup!

–
Regards

Andrew

Jason

[andrew]

Hi Luke,
you are a diamond my friend!

All I need to know now is what is the best resource/documentation
available
in terms of hooking together a ruby/rails/ajax/rjs/activerecord project?
Is
there a ruby/rails/ajax/rjs/activerecord for dummies type publication
available?

One further question if I may, in terms of persisting an objet retrieved
from a dB table? Currently I retrieve the hibernate dB object and store
it
in a session object. I take it that ruby/rails/activerecord would
function
in much the same way?

I just came across some activerecord code:

class Order < ActiveRecord::Base
has_many :items
end

That’s it?! One line of code to setup a one-to-many relationship between
an
order and order items table?!!!

Regards

Andrew

[andrew]

OK! I am using hibernate with ehcache handling lazy object caching. Can

anyone else confirm whether ActiveRecord supports lazy-loading/object
caching?

See my other message

1. Database.
   I am using postgreSQL 8.1. Would rails be able to reverse engineer the
   required ActiveRecord maps from the dB schema? From what I understand of
   rails convention table names need to be pluralized. How would the reverse
   engineering process handle the fact that none of my table names are
   pluralized?!

Easy: you can tell your models specifically what table name to use, and
it
will just go ahead and use them.
In essence, you create a model… say you have a person table, and you
want
a Person model.
class Person < ActiveRecord::Base
set_table_name ‘person’
end
This will still draw in all your fields automatically and create
accessors
for them and etc… one other want to consider is the id field… Rails
wants it to be named just flat out ‘id’, but a lot of people do
something
like ‘person_id’… you can use set_id_field

2. Form validation

                                  <fi:styling size="30"
      </fd:validation>
     </fd:field>

Ajax + Rails = super, super, super easy.

3. Paypal API.

I have recently come across a ruby/rails Paypal (directpayment api) so
this area is covered.

Definitely look into Active Merchant: it does Paypal and a TON of other
stuff… so if you switch, you’re still covered.

4. Image handling.

return the appropriate binary information, holds it in svg format before
converting it to either PNG or JPEG. How would ruby/rails handle this?

You completely got me on this one… I’m sure it’s probably possible,
but I
don’t have a clue.

5. Email/Zip

I have a process where by the artist track files (mp3) a user may have
ordered are pulled out from their order/order_items object, read in the file
system directory and then zipped up. This zip is then emailed to the user.
How would ruby/rails handle this process?

ActionMailer is your friend… ruby comes with standard zipping stuff
built
in, and ActionMailer is EXTREMELY easy to use to mail.

–

[andrew]

That’s it?! One line of code to setup a one-to-many relationship
between an order and order items table?!!!

You’d probably also want another line of code to do the other half of
the mapping:

class Item < ActiveRecord::Base
belongs_to :order
end

So, two lines of code. Terrible, ennit.

• donald

[andrew]

On 2/28/07, Andrew M. [email protected] wrote:

Hi Luke,
you are a diamond my friend!

All I need to know now is what is the best resource/documentation available
in terms of hooking together a
ruby/rails/ajax/rjs/activerecord project? Is there a
ruby/rails/ajax/rjs/activerecord for dummies type
publication available?

You’ll want the Agile Web D. with Rails book from the
Pragmatic Programmers. IT covers all the technologies plus a lot more
and also contains a very useful reference to the rails framework.

–max

One further question if I may, in terms of persisting an objet retrieved
from a dB table? Currently I retrieve the hibernate dB object and store it
in a session object. I take it that ruby/rails/activerecord would function
in much the same way?

Yes, you can do that. However it’s of course better pracice not to
store any application state (even temporary) in the session.

I just came across some activerecord code:

class Order < ActiveRecord::Base
has_many :items
end

That’s it?! One line of code to setup a one-to-many relationship between an
order and order items table?!!!

Yes! And if you like that one, wait until you find out about the
really cool stuff

–max

[andrew]

Hi Max,

You’ll want the Agile Web D. with Rails book from the
Pragmatic Programmers. IT covers all the technologies plus a lot more
and also contains a very useful reference to the rails framework.

thanks for that recommendation. I will look it up.

–
Regards

Andrew

–max

[andrew]

Hi Donald,

class Item < ActiveRecord::Base
belongs_to :order
end

Stop it! When I think how long it took me before I got a handle on
hibernate
map/classes!!!

2 lines?! It’s just not right!!!

–
Regards

Andrew

[andrew]

I love that everyone moving from a different framework (with the
possible
exception of things like Django) has these moments: the “oh my god it’s
so
easy” ones.

You want to see something freaking amazing?
This is code I wrote on this list the other day, and it just flipped my
lid
that it was so easy to do this.
Say you want a tree of categories. such that you have a parent with
multiple
children, who can have multiple children, etc.

First, if you want the super easy route, do this
class Category < ActiveRecord::Base
acts_as_tree
end

and put the field “parent_id” in your table… and you’re done.
You can then do
category.children
category.children.parent
childcategory.siblings
etc, etc.

If you want to roll your own, it’s one more line (of course, this
doesn’t
give you all the fancy extra functions)

class Category < ActiveRecord::Base
belongs_to :parent, class_name => ‘Category’, foreign_key =>
‘parent_id’
has_many :sub_categories, class_name => ‘Category’, foreign_key =>
‘parent_id’
end

Done… you can now do:
category.sub_categories
childcategory.parent
childcategory.parent.sub_categories - self (returns siblings)

Amazing, eh?

[andrew]

On Feb 27, 2007, at 10:02 AM, Andrew M. wrote:

Yes, I agree whole heartedly! I’m just trying to ascertain what
what technology within the ruby/rails framework will allow me to
achieve the same functionality as I currently have with the cocoon/
hibernate framework

there is no equivalent to the Cocoon flowscript (with the
continuations and all)… not that its a blocker, just be aware that
coding forms is different

-pete

[andrew]

On Feb 27, 9:18 pm, “Luke I.” [email protected] wrote:

I love that everyone moving from a different framework (with the possible
exception of things like Django) has these moments: the “oh my god it’s so
easy” ones.

Yeah. I was excited when EJB3 came out after years of EJB2/xDoclet.
Now, I won’t even consider working on anything except RoR. Unless, I
get paid enough, of course.

class Category < ActiveRecord::Base
Amazing, eh?
That is very cool. I have a similar thing in the app I am working on
now, I am going to give that a whirl. Thanks!

[andrew]

On 2/28/07, Luke I. [email protected] wrote:

I love that everyone moving from a different framework (with the possible
exception of things like Django) has these moments: the “oh my god it’s so
easy” ones.

I also like the two-line ajax autocompletion:

in the view:

<%= autto_complete_field :user, :name %>

in the controller:

auto_complete_for :user, :name

Done.

Some of the plugins do amazing things too, such as acts_as_versioned.
One line of code to get a complete versioned history of every update
to a model, complete with rollback to a previous version. The code?

class WikiPage << ActiveRecord::Base
acts_as_versioned
end

and then

wiki_page.revert_to(wiki_page.version-1) # get previous version

–max

[andrew]

Hi,
does the postgres-pr interface support SSL and if so is it set to
support
SSL by default or do I need to configure a ruby/rails document to
activate
it?

–
Regards

Andrew