November 2, 2006

Repensando a web com Rails

Fabio Akita has just contacted me to say that his new book "Repensando a web com Rails" has been released for the Brazilian market. The book is primarily about Ruby on Rails, but contains a section on SAP integration with Rails, which I helped (a little) with
Congratualtions Fabio - Hope it sells well.

Posted by PiersHarding at 1:27 PM

October 31, 2006

Ruby and the SOAP RunTime (SRT) Handler

Following on from my previous post about Ruby, Ruby on Rails, and SAP Web Services Integration - I would like to show how to switch to using the SOAP RunTime (SRT) Handler, which makes available SAP Web Services via Virtual Interfaces.

Steps

Create the SAP Web Service

We need to create a web service that exposes the function modules that were used in the UserAdmin Rails application. To do this - go to transaction SE80, go to the Enterprise Services tab, and create a Virtual Interface of type Funciton Group called Z_USERADMIN. Include into this the function modules:

Activate this, and then create a Web Services definiton - again, using SE80, go to the Enterprise Services tab, and create a Web Services definition called Z_USERADMIN - referencing the previously activated Vitual Interface Z_USERADMIN.
Finally - activate this in the ICF configuration (SICF), by using transaction WSCONFIG, referencing the Web Service definition Z_USERADMIN created above.
There is an excellent discussion of the details of this process by Thomas Jung, here, and here.

Modify model sap_user.rb

Now for the final part - in the UserAdmin Rails application, edit the SapUser model file app/models/sap_user.rb. This needs to switch from referencing the method "function_module" for loading the functions, to using "resources", as outlined below: 
require_gem "sap4rails"

class SapUser < SAP4Rails::WS::Base

# You must define a list of RESOURCES to preload
   resources "http://seahorse.local.net:8000/sap/bc/srt/rfc/sap/Z_USERADMIN"
...
Now you can test it as in the previous weblogs.

Unicode!

One thing that I neglected to say in my previous post, is a major advantage of using sapwas for accessing SAP is that it has comprehensive Unicode support - free of charge (but not of pain) :-) .

Round Up

For me - this rounds up SAP Web Services and Ruby - you can either access them in Ruby directly by using the library sapwas, or taking advantage of the Rails integration provided by sap4rails.

Posted by PiersHarding at 11:12 AM

October 23, 2006

sap4rails 0.07 - SAP RFC and auto-reconnect

I released sap4rails 0.07 this week, which corrects a problem with RFC connections not reconnecting correctly (this is using saprfc as the driver - there is no similar issue wtih the sapwas driver, which uses stateless HTTP). This is especially important when the R/3 (ABAP) application server your Rails application is connected to goes down temporarily (or indeed any other temporary communication disturbance). Before an RFC call is executed, the conection is ping checked, and then a single reconnection attempt is tried if the ping fails. If the reconnect fails then an error is raised so it is a good idea to wrap your code in a rescue block, to deal with the situation in your local conditions. Here is an example log: 

...
[SapUser] missing_method: Z_BAPI_USER_GETLIST
[SapUser] ifaces: ["SUSR_USER_LOCKSTATE_GET", "BAPI_USER_GET_DETAIL", "BAPI_USER_UNLOCK", "BAPI_USER_LOCK", "Z_BAPI_USER_GETLIST"]
in check connect...
Think Im connected - lets check ...
RFC PING[]...
Something wrong with connection(1) - do it again ...
new connection(2) ...
allready connected ...
[SapUser] missing_method: Z_BAPI_USER_GETLIST
[SapUser] ifaces: ["SUSR_USER_LOCKSTATE_GET", "BAPI_USER_GET_DETAIL", "BAPI_USER_UNLOCK", "BAPI_USER_LOCK", "Z_BAPI_USER_GETLIST"]
in check connect...
Think Im connected - lets check ...
RFC PING[true]...
...

Here you can see the first RFC_PING return nil, and the second after reconnect return [true].

Posted by PiersHarding at 3:05 PM

October 18, 2006

sapwas for Ruby and HTTPS

sapwas for Ruby now enables SAP Web Services to be called via HTTPS. This first requires you to setup SSL support in NW4 - which isn't too much trouble if you follow Gregors' excellent advice here. Once that is in place, then it is just a matter of structuring the URL coorectly, as described in this example: 

require "SAP/WAS"

@was = SAP::WAS.new(:url => "https://seahorse.local.net:8443/sap/bc/srt/rfc/sap/Z_RFC_READ_REPORT_01",
                    :lang   => "EN",
                    :client => "010",
                    :user   => "developer",
                    :passwd => "developer",
                    :trace  => true)

# get a list of users
irep = @was.RFC_READ_REPORT
irep.program.value = 'SAPLGRAP'
irep.call()
puts "qtab no rows are: #{irep.qtab.rows.length.to_s}"
puts "qtab rows are: #{irep.qtab.rows.inspect}"

sapwas fully integrates with sap4rails as an alternative driver for accessing either RFCs or SAP SOAP based Web Services, and is available here.

Posted by PiersHarding at 10:48 AM

October 15, 2006

Ruby, Ruby on Rails, and SAP Web Services Integration

Something I like about Scripting Languages is the way they revel in having "more than one way to skin a cat". So, in this spirit I have built a complementary interface to saprfc (for Ruby) called sapwas, that facilitates RFC calls via SAP Web Services. This has been integrated into sap4rails, and the attached example demonstrates how to substitue Web Services for RFC integration in Ruby on Rails.

SAP Web Services vs RFC?

Other than curiosity, there is another motivation for trying this out - Since there has been discussion of late on the merits of RFC and Web Service technology such as SOAP, I thought that inorder to do the subject justice I would do some further (tangible) investigation.

To me, the most obvious way to draw a comparison, is to develop comparable examples of each, with the only difference being the substitution of the technology in question.

This led to me focusing on a recent article I wrote: Ruby on Rails with AJAX, to use as a base line.

Activating the SAP Web Service support

If we take the example above (Ruby on Rails with AJAX), then the changes are as follows:

Install sapwas

Download either the source distribution, or the gem file by following the sapwas project download links. Gem files are easier to deal with - all you need to do is: 

gem install sapwas-<version>.gem

And its done (use gem uninstall to remove if its there allready).

You will probably need to install http-access2 inorder to get the basic authentication working correctly. This is a requirement of the SOAP4R library.

Upgrade sap4rails

Download either the source distribution, or the gem file for sap4rails by following the project download links. First remove the old version, and install the new: 

gem uninstall sap4rails
gem install sap4rails-<version>.gem

If you have used the source distribution previously, then you will have to manually remove the previous one, and install again (the usual ruby setup.rb dance - gems are soo much easier :-).

Modify the SapUser model

In the Rails application, edit the app/models/sap_user.rb, and change the super class for SapUser: 

class SapUser < SAP4Rails::WS::Base
...

Set your Rails configuration

Modify the config/sap.yml file - you really should only need to add in the :url line depicted below, but check anyway: 

  client: "010"
  url: "http://seahorse.local.net:8000/sap/bc/soap/rfc"
  user: developer
  passwd: developer
  lang: EN

note on WAS configuration

You must ensure that /sap/bc/soap/rfc is configured/activated correctly in transaction SICF.

Go!

Once you have completed these changes, you can then test the Rails application as described in Ruby on Rails with AJAX - it should function in exactly the same manner - wasn't that easy!

Now you have it working - I'll leave you to draw your own conclussions on it's merits :-)

Posted by PiersHarding at 6:11 PM