Ruby Mysql database connectivity

In this section I am going to tell you how do you get connected your MySQL database using Ruby.

Make sure that you have install mysql adapter
To verify you mysql file go to command prompt type irb -> require 'mysql' if it's return true that means the file is loaded.

Now use your fav editor let say scite.

require 'rubygems'
require 'mysql'

begin
#establish a connection.
mysql = Mysql.real_connect("hostname(e.g - localhost)", "username", "password", "databasename")
result = mysql.query("SELECT * FROM USERS;")
result.each do |row|
row.each do |col|
puts col
end
end
#the col object will return the value from the users table.
# if you want to insert a record. then
mysql.query("INSERT INTO users (email) VALUES ('example@example.com')")
#this is how you can edit delete the records...
rescue Exception => e
puts "I guess something went wrong. #{e}"
ensure
# clone the connection...
mysql.close if mysql
end

bash: cap: command not found

bash: cap: command not found

In this post I'll be talking about how to resolve the “bash: cap: command not found” issue. Even after installing Capistrano we get the following error “bash: cap: command not found” the reason behind this is that the path is not decalred in bash file, so to fix the problem you have to add the following line on code inside bashrc file

Step 1
#go to Terminal
#type
sudo gedit ~/.bashrc

Step 2
#Add the following line at the bottom of the file.
export PATH=$PATH:/home/user/.gem/ruby/1.8
#save and close
# To find the installation of you gem just run the following command
#gem list -d c
# capistrano (2.5.8)
# Authors: Jamis Buck, Lee Hambley
# Rubyforge: http://rubyforge.org/projects/capistrano
# Homepage: http://www.capify.org
# Installed at: /home/user/.gem/ruby/1.8

Step 3
#From command prompt
source ~/.bashrc

File Upload using AJAX and jQuery.

File Upload using AJAX and jQuery.

File upload using jQuery is preety simple.

NOTE: please include the jQuery Library afer prototype.js

As you can in the above example I had declared “jQuery.noConflict();” the reason behind this is to abvoid the conflict between jQuery library and prototype.js.

<% remote_form_for :some_random_name, @some_object, :url => {:action => 'testtest'},
:html => { :multipart => true, :id => "upload_form" } do |f| %>


<%= file_field_tag "test" "uploaded" %>
< id="button" class="button" value="Add File" type="button">
< id="save" class="save" value="Upload" type="submit">
<%end%>

Thats it.

How to integrate Comatose CMS in your rails application.

Comatose CMS Yet another Micro CMS, when your client may use to create and edit easily a static pages like privacy policy, terms & conditions, an FAQ, that kind of thing.

Installation of Camotose.
$ ./script/plugin install git://github.com/darthapo/comatose.git
$ ./script/generate comatose_migration
$ rake db:migrate

Once the above mentioned command is executed then configure your route file, at the bottom of your route file paste the below mention syntax
map.comatose_admin
map.comatose_root ''

That it now you to access the Camotose simply type
http://localhost:3000/comatose_admin

You can configure you comatose on your config/environment.rb file, but i'll suggest you to create a comatose.rb inside your config/initializers folder, and insert the following code.

Comatose.configure do |config|
config.admin_title = 'YOUR site name CMS SYSTEM' # it cab anything...
config.admin_helpers = []
config.admin_sub_title = 'Administration Pages'
config.content_type = 'utf-8'
config.default_filter = ''
#config.default_processor = :liquid
config.default_tree_level = 3
config.disable_caching = false
config.hidden_meta_fields = 'filter'
config.helpers = []
config.includes = []
# These are 'blockable' settings
config.authorization = Proc.new { true }
config.admin_get_author = Proc.new { request.env['REMOTE_ADDR'] }
config.after_setup = Proc.new { true }

# Includes AuthenticationSystem in the ComatoseAdminController
config.admin_includes << :authenticated_system

# Calls :login_required as a before_filter
config.admin_authorization = :login_required

end

Insert HTML Tag Using Javascript...

The below mention function will be use to insert a div tag along with input field, button when a user clicks on hyper link. Button will be used to hide the selected div. A user can create max 5 div.


function attachFile(id)
{
var count = new Array("1","2","3","4","5")
var hiddenCount = document.getElementById("Cnt").value;
var Comman = 1;


for(var j=1;j<=count.length;j++)
{
if (id == 'remove_' + j)
{
document.getElementById('div_' + j).style.display = "none";
return
}
}
Comman = parseInt(hiddenCount) + Comman;
if (Comman <= 5)
{
var varTag1 = document.createElement("INPUT");
// var varTagRemove = newElement("input",{type:"button",name:"Remove",id:"remove_"+Comman,value:"1"},{onclick:attachFile(this.id)});
var varTagRemove = document.createElement("INPUT");
varTagRemove.type="button";
varTagRemove.value = "Remove";
varTagRemove.id = "remove_"+Comman;
varTag1.type = "file";
varTag1.id = "file_"+Comman;;
var x = document.all;
var br = "br"
if(x)
br = "
"
var varTag2 = document.createElement(br);

document.getElementById("div_" + Comman).appendChild(varTag1);
document.getElementById("div_" + Comman).appendChild(varTagRemove);
document.getElementById("div_" + Comman).appendChild(varTag2);
var rm_test = document.getElementById("remove_" + Comman);
rm_test.onclick = function(){attachFile(this.id)};
document.getElementById('Cnt').value = Comman;

}
else
{
for (var i = 1; i <= count.length; i++)
{
if (document.getElementById("div_" + i).style.display == "none")
{
document.getElementById("div_" + i).style.display = "block";
return
}
}
//ALERT WILL BE CALLED WHEN THE COUNT OF FILE UPLOADER IS 5 AND ALL THE DIV DISPLAY PROPERTY IS
// BLOCK
alert("Limit is over");
}
}

Ruby: How "send" method works?

Invokes the method identified by symbol, passing it any arguments specified. You can use __send__ if the name send clashes with an existing method in obj.
For example.
Suppose that in you have a three different parameter
1.addnum
2.subnum
3.multinum

depends on the parameter you want to call the method to execute add/subtract/multiply. So what you can do

class Number

def mainfunction(methodname, val1, val2)
#THE BELOW MENTION SEND METHOD WILL CALL ANY ONE METHOD #DEPENDS ON THE FIRST PARAMETER
self.send(methodname, val1, val2)
end

def addnum(val1, val2)
val1 + val2
end

def subnum(val1, val2)
val1 + val2
end

def multinum(val1, val2)
val1 + val2
end
end

num = Number.new
num.mainfunction(“addnum”, 10 , 20) #output => 30

So this is just a very basic example to understand hoe send method work.

How to enable grant access to remote system for MySQL server?

In a few step you can allow remote system to access your MySQL server. To implement first you will need to configure your my.cnf which which is located at

/etc/mysql/my.cnf [Debian Linux Environment]
OR
/etc/my.cnf [Red Hat Linux/Fedora/Centos Linux]
OR
/var/db/mysql/my.cnf [FreeBSD]

access the file using

sudo gedit /etc/mysql/my.cnf

check for following line
bind-address in which the local ip address is assigned 127.0.0.1
bind-address = 127.0.0.1
So just replace the local ip address with your server ip address e.g. 192.168.XXX.XXX
bind-address = 192.168.XXX.XXX

Thats it now all you need to restart your MySQL server and assign a grant access to remote system.

To restart MySQL server
etc/init.d/mysql restart

To assigned a grant access
GRANT ALL ON user_database_name.* TO remote_user_name@'192.168.x.x' IDENTIFIED BY 'PASSWORD';

Thats it and it is done.. Now
the remote user can access your db..