Well, let’s start with the basics. Before you try your luck with the magnificent ‘bundle install’,  halt! Stop right there and do THIS first

1. Install Oracle Instantclient. Get started with that here. Its pretty straightforward and shouldn’t be a problem.

2. Post that, you need to set the environment variable LD_LIBRARY_PATH. Do it now by typing in :

export LD_LIBRARY_PATH="/usr/lib/oracle/11.2/client64/"

in your user profile file ie ‘.bashrc’ or ‘.bash_profile’. Reload it by typing:

source .bashrc

Also, check that this location does have the client installed. If not, find out where it is and create a soft link to here. ruby-oci8 expects to find it at this location “/usr/lib/oracle/….”.

3. Lastly, set this link:

sudo ln -s /usr/include/linux/ /usr/include/sysclient

One more thing, try typing:

echo $ORACLE_HOME

It should be set to where your Oracle is installed. If it isn’t set, set it in your user profile file again with ‘export’.

That’s it. We are done. Try running ‘bundle install‘ or ‘gem install ruby-oci8‘ and it should work. Well, it should. If it didn’t, well, I’m sure its Oracle, not you In any case, drop in a comment and maybe I can help. For the rest of the ‘process’, I’ve written a follow up post here. Happy DBing

development:

adapter: oracle_enhanced

host: localhost

database: xe

username: <schema_name>

password: <workspace_password>

> echo $ORACLE_HOME

> cd <$ORACLE_HOME>/product/11.2.0/xe/bin

> sqlplus

user-name: / as sysdba

password: <password to login to web interface used with username ‘admin’> (if prompted)

SQL> grant dba to <schema_name>;

SQL> exit

sqlplus

user-name: <schema_name_you granted dba to>

password: <schema password>

Have fun! And remember, Databases don’t bite

It was the ‘Hackers & Founders’ Delhi Hackathon (http://hfdelhi.in). Organized by the extremely helpful and proactive people at One97 (http://one97.com/) and ClearTax (http://cleartax.in/).

But enough with the details. So, here it is – the award winning ‘hack’

SayWhat?

A cross-platform (iOS/Android) mobile app featuring popular dialogues/sayings from Movies and Sitcoms. The player has to string together popular dialogues, one small piece at a time, with a visual aid from the movie/sitcom helping all along. Its based on a simple idea of finishing sentences in segments. The app was built using Ansca Mobile’s Corona framework (http://www.anscamobile.com/corona) which is an upcoming mobile development platform that builds on top of both RoR and Javascript. Two of my favorite tools

A few screenshots from the quick prototype built at the hackathon.

I have since, refactored and cleaned up code keeping in mind an eventual Google Marketplace/Apple Store release. Post-feedback from friends and some co-participants from the hackathon, I have been tweaking and adjusting game play trying to find the right balance between ease of play and challenge goals. The scoring criteria is a constant work in progress, as we discover the reward to effort ratio, as players ourselves. A few friends have been set in motion, hand picking the absolute best of known movie/sitcom quotes and I am hoping to be able to have a database of at least 500 quotes for the soft launch. The app UI is also being given some tactile love with details, small animations and audio feedback. Corona has amazing support for Facebook integration, and an ‘Extend challenge’/'Post Score’ optional functionality seems like an appropriate add-on by the time I manage to take this to the stores.

Anxious to see this listed on the app stores real soon. Say what?!

But I’ve moved past all those and hit a big solid roadblock on the jqGrid Inline Edit. The default behavior of inline editing is that if the edited row saves successfully with no errors, the grid can reload and reflect the newly updated record. If however, the server side validations (onSubmit aka Enter key press) failed, the edited row is restored to its last saved state, in non-edit mode. This results in the loss of any valid editing that the user has already done. You can read more about the problem here.

After struggling a bit and reading through the ‘grid.inlinedit.js’ file, I discovered this bit of code:

editRow : function(rowid,keys,oneditfunc,successfunc, url, extraparam, aftersavefunc,errorfunc, afterrestorefunc) {
// Compatible mode old versions
var settings = {
"keys" : keys || false,
"oneditfunc" : oneditfunc || null,
"successfunc" : successfunc || null,
"url" : url || null,
"extraparam" : extraparam || {},
"aftersavefunc" : aftersavefunc || null,
"errorfunc": errorfunc || null,
"afterrestorefunc" : afterrestorefunc|| null,
"restoreAfterErorr" : true
},
args = $.makeArray(arguments).slice(1), o;

if(args[0] && typeof(args[0]) == "object" && !$.isFunction(args[0])) {
o = $.extend(settings,args[0]);
} else {
o = settings;
}
// End compatible

What this really does is, introduces a backdoor solution to our problem. To be specific, the problem here is the ‘restoreAfterError’ parameter which is hardcoded as ‘true’. This attribute is responsible for the problem above. It forces the execution of the method that restores the errored out row. So, this attribute needs to be set to ‘false’ to let the errored out row remain in editable state with all changed values intact.

To do this, I did not want to change the signature of the ‘editRow’ method. And thankfully, I didn’t need to. Instead of the usual call :


jQuery("#grid_id").jqGrid('editRow',rowid, keys, oneditfunc, succesfunc, url, extraparam, aftersavefunc,errorfunc, afterrestorefunc);

Invoke the method like this instead:

grid.jqGrid('editRow', rowId, {"keys":true, "oneditfunc":"", "successfunc":Mmd.Callbacks.SuccessEdit, "url":url, "extraparam":{'_method': 'PUT'}, "aftersavefunc":Mmd.Callbacks.ReloadGrid, "errorfunc":Mmd.Callbacks.Error, "restoreAfterError":false});

This invocation sets the ‘args[0]‘ as an object (json: with ‘keys’ as the first key) and hence satisfies the ‘if’ condition. The ‘if’ path then sets the options as the json we send during method invocation. And this json sets the desired ‘restoreAfterError’ to false.

Okay, so step 1 done. Phew! Now that’s only half the battle won. The second issue is that once the errored row stays in editable mode, it cannot be saved again by hitting ‘Enter’. Read more about this problem here.

Now the solution to this is tricky. It involves commenting out (or deleting!) this line of code:

$(ind).unbind("keydown");

This is line #274 for me and is a part of ‘saveRow’ method definition in the ‘grid.inlineedit.js’ file. Take this line out and the ‘Enter’ key stays bound to the errored out row now in editable mode to correct the error and save again.

Hope this helps

So, I ended up using this little trick. Ruby meta programming awesomeness helped, of course.

Consider a minimalistic Model called ‘User’ with an underlying ‘users’ table in the database.

User
Id, Login, Name, Email, Verified, Blocked, Available

I know the schema can be altered to take these 3 into a single field called “state” or something on those lines, but this is just a simple example. Here, the last 3 attributes are boolean. We need to define methods “is_verified?” , “is_blocked?” , “is_available?”.

Usually, we would define 3 instance methods or named_scopes to achieve the objective. Like so:

def is_verified?
self.verified
end

def is_available?
self.available
end


Annoying, right? Let’s try this:

def self.boolean_attributes
self.columns_hash.reject{|k,v| (v.type.to_s != 'boolean') }.keys
end

self.boolean_attributes.each do |boolean_attribute|
define_method "is_#{boolean_attribute}?" do
!!self.send(boolean_attribute)
end
end


There. If there are 12 boolean attributes, you have 12 methods defined dynamically! And if you change the schema, you still have “is_{new_attribute}?” in place automatically.

Here’s what I’m talking about:
In console,

time_string = "2010-07-21 11:52:31"
helper.time_ago_in_words(time_string) # => about 5 hours


The catch here is that the “5 hours” duration is incorrect. This was hardly 5 minutes ago! So, the problem here was in time zones.
By default,

time_string.to_time # => Wed Jul 21 11:52:31 UTC 2010

Notice the time zone offset. It has been set to “UTC” by default. But the original time zone of this string time was different. And the tricky part is, it was different for different environments. So how’d we get past this? Here’s the entire snippet:

def custom_time_ago_in_words(time_str)
time = time_str.to_time + (-Time.zone_offset(Time.now.zone))
"#{time_ago_in_words(time)} ago"
end

This essentially adjusts the time according to the server time zone and gives correct output as “5 minutes ago”.

1. If we want to assign an entire AR object to a local hash:
A direct assignment is possible with “attributes”

local_hash = session_user.attributes

the ‘local_hash’ now has an attribute-value hash of the session_user object, an ActiveRecord object of model User ]

2. If we need the local_hash to have only a subset of the AR object attributes:

desired_keys = ['address' , 'zipcode' , 'city' , 'country']
local_array = session_user.attributes.select{|key,value| desired_keys.include?(key) }
local_hash = Hash[*local_array.flatten]

the ‘local_hash’ now has only the desired attribute values. This can easily be extended by simply adding more keys to ‘desired_keys’.
Instead of what I usually see,

local_hash = {
'address' => session_user.address,
'zipcode' => session_user.zipcode,
'city' => session_user.city,
'country' => session_user.country
}

What do you think of this snippet? Is there a shorter/smarter way of doing this? Think on!

In case of YAML, the spaces between array elements makes a difference. A much needed code snippet :

A file ‘myfile.yml’

array: [ 1 , 2 ,3, 4]
array_spaces: [1 , 2 , 3 , 4]

Loading this file in ‘irb’:

>> f =YAML.load_file('myfile.yml')
=> {"array"=>[1, "2 ,3", 4], "array_spaces"=>[1, 2, 3, 4]}
>> f["array"]
=> [1, "2 ,3", 4]
>> f["array"].size
=> 3
>> f["array_spaces"]
=> [1, 2, 3, 4]
>> f["array_spaces"].size
=> 4


Now that’s not Ruby-ish. But then, as a seasoned co-developer pointed out, YAML should be language agnostic. I still find it a bit odd, though. Hmmm, interesting. Point taken.

Always begin by looking at RoR guides:
Ruby on Rails guides

The BEST Ruby on Rails resource that gives a consolidated set from many relevant RoR resources:
Drink Rails

The renowned railscasts
Railscasts

RoR @SlideShare
Ruby @SlideShare
Rails @SlideShare

Awesome RoR screen casts. Short and concise.
Ruby Plus

Not very frequently updated, but has good content.
Monkey on Rails

Elaborate content on a wide variety of RoR subjects. By Yehuda Katz is a member of the Ruby on Rails core team.
Katz Got Your Tongue

Usually covered by “drinkrails”. Good resource.
Lindsaar Net

Updated, concise and good information resource.
Rails Dispatch

Latest on Rails. Tonnes of new and interesting stuff.
Rails Inside

Short concise everyday Rails tips.
Rails Quick Tips

The latest developments in Rails, all in one place
Riding Rails

Rails notes. Solutions to every day “how-tos”.
Rails Notes

Get your Ruby right with quick Ruby tips.
Ruby Quick Tips

Awesome Ruby resource. 5 minutes of Ruby goodness.
Ruby5

Another amazing Ruby resource. Concise episodes. Really useful.
Ruby Pulse Episodes

A good collection.
Rails Coach