Some of the testings with Ext.isNumber are as follows..
Ext.isNumber(null)) false
Ext.isNumber(undefined) false
Ext.isNumber('') false
Ext.isNumber('1') false
(Ext.isNumber(1)) true
Ext.isNumber('1.234')false
(Ext.isNumber(1.234))true
(Ext.isNumber('1AS')false
(Ext.isNumber('AS1')false
Ext.isNumber('.1132')false
(Ext.isNumber(.132))true
Ext.isNumber('asdf')false
asdf is not defined [Break on this error] console.log("(Ext.isNumber(adsf))"+Ext.isNumber(asdf));
Monday, October 4, 2010
Saturday, October 2, 2010
JavaScript isNumeric / Number validation
/* Takes input string and returns true if it is number else returns false */
function IsNumeric(sText){
/* Dont copy paste this code directly as it is containing logical errors */
/* Hint to find the bug in this code : If I pass number to this function it fails. */
var ValidChars = "0123456789.";
var IsNumber=true;
var Char;
for (i = 0; i < sText.length && IsNumber == true; i++)
{
Char = sText.charAt(i);
if (ValidChars.indexOf(Char) == -1)
{
IsNumber = false;
}
}
return IsNumber;
}
I used the above code to validate my input string .
Problem comes when we pass null or undefined strings. we need to add a validation for that.
But after adding that validation I thought it's perfect .But still there was one flaw
That is, If I pass a number to this function it fails because sText.length wont work on a number :(
The final code after doing some modifications to the above code is
function IsNumeric(sText){
if(sText == undefined || sText == null ) return false;
sText=''+sText //if input is not a string then we are making it to string.
//Otherwise sText.length wont work.
var ValidChars = "0123456789.";
var Char;
for (i = 0; i < sText.length ; i++)
{
Char = sText.charAt(i);
if (ValidChars.indexOf(Char) == -1)
{
return false;
}
}
return true;
}
To realize this I wasted good amount of time..So to save others time I am writing this blog..
Happy Coding and have fun :)
function IsNumeric(sText){
/* Dont copy paste this code directly as it is containing logical errors */
/* Hint to find the bug in this code : If I pass number to this function it fails. */
var ValidChars = "0123456789.";
var IsNumber=true;
var Char;
for (i = 0; i < sText.length && IsNumber == true; i++)
{
Char = sText.charAt(i);
if (ValidChars.indexOf(Char) == -1)
{
IsNumber = false;
}
}
return IsNumber;
}
I used the above code to validate my input string .
Problem comes when we pass null or undefined strings. we need to add a validation for that.
But after adding that validation I thought it's perfect .But still there was one flaw
That is, If I pass a number to this function it fails because sText.length wont work on a number :(
The final code after doing some modifications to the above code is
function IsNumeric(sText){
if(sText == undefined || sText == null ) return false;
sText=''+sText //if input is not a string then we are making it to string.
//Otherwise sText.length wont work.
var ValidChars = "0123456789.";
var Char;
for (i = 0; i < sText.length ; i++)
{
Char = sText.charAt(i);
if (ValidChars.indexOf(Char) == -1)
{
return false;
}
}
return true;
}
To realize this I wasted good amount of time..So to save others time I am writing this blog..
Happy Coding and have fun :)
Friday, October 1, 2010
Ping may fail even if the system is in network
Generally we use PING IP command to test the connectivity of a system.
If it fails we think it's not reachable But it's not true always.
I faced the same situation today..
There is a system for which I can do ssh -p 2021 root@XXXXXX
If it fails we think it's not reachable But it's not true always.
I faced the same situation today..
There is a system for which I can do ssh -p 2021 root@XXXXXX
But for the same box I can't ping.
Learning is ping uses icmp 'echo-request' . If it is blocked in that server we can't ping...
Learning is ping uses icmp 'echo-request' . If it is blocked in that server we can't ping...
Thursday, September 23, 2010
Installing Ubuntu Linux On windows 7 or Vista Dual boot
My Brother's HP laptop contains only Vista now he want to install Ubuntu on it.
Possible solutions 1) format the entire hard disk install ubuntu linux.
2) use the Dual boot option. [ will discuss here ]
To get the Dual boot option with windows we need to install windows first as far as I know.
We need to delete a logical drive from windows to install linux. But The laptop is containing only one drive.So we need to make the partition with out corrupting the existing geniuen windows.
Go to administrative tool in that we can see Disk management there we can see windows hard disk drive C (guess) Right click on that click on shrink volume..So to create new drive give some 30 gb ( I gave 50 gb).
By using shrink option operating system won't get corrupted and by which we can create a drive..Thanks to shrink partition.
Now delete the newly created drive from windows, that's it.
This newly created and deleted partition is used to install ubuntu..
Follow the above link to install ubuntu
Select the option "Use the largest contigous space" ( it will take the disk space which we have deleted above by shirnking/some how ) .
Done.
Linux installation on windows ..Here Shrinking is the Helping point..With out knowing shrink I have formatted a windows some time back :(.. recently I came to know So to help others I mam doing this post. ..Comment here if it helps you :)
Forgot to tell you while installing on my Brother HP laptop ,it was containing HP recovery back up which is of around 10gb in size .which was not allowing us to install linux so we have taken that backup into my laptop and deleted that recovery files..Then only we were able to install .I don't know what we did was wrong or right But we were happy by doing that.. :)
Wednesday, September 1, 2010
To Check Port is open or not
Before trying to connect a remote server it is better to check that sever is listening at the expected port ( Example mysql listens at 3306 and ssh 20 )
>telnet ip port
For example ip address 123.34.23.37 and I want to do ssh which listen by default 22
So need to check whether port 22 is listening then command would be :
>telnet 123.34.23.37 22
Above command will return some junk characters then it means open.
Otherwise it will return "telnet: Unable to connect to remote host: Connection refused"
that means its not opened..
Possible reasons : firewall is blocking or no service at that port to listen.
>telnet ip port
For example ip address 123.34.23.37 and I want to do ssh which listen by default 22
So need to check whether port 22 is listening then command would be :
>telnet 123.34.23.37 22
Above command will return some junk characters then it means open.
Otherwise it will return "telnet: Unable to connect to remote host: Connection refused"
that means its not opened..
Possible reasons : firewall is blocking or no service at that port to listen.
Remote Access to Mysql ubuntu
This link was good
http://ubuntu-commands.blogspot.com/2008/11/how-do-i-enable-remote-access-to-mysql.html
Copy & Pasted & EDITED the content from above link here ( for my reference)
By default, MySQL database server remote access disabled for security reasons. However, some time you need to provide the remote access to database server from home or from web server.
MySQL Remote Access
You need type the following commands which will allow remote connections:
Step # 1: Login over ssh if server is outside your IDC
First, login over ssh to remote MySQL database server
Step # 2: Enable networking
Once connected you need edit the mysql configuration file my.cfg using text editor such as vi.
* If you are using Debian Linux file is located at /etc/mysql/my.cnf location
* If you are using Red Hat Linux/Fedora/Centos Linux file is located at /etc/my.cnf location
* If you are using FreeBSD you need to create a file /var/db/mysql/my.cnf
# vi /etc/my.cnf
Step # 3: Once file opened, locate line that read as follows
[mysqld]
Make sure line skip-networking is commented (or remove line) and add following line
bind-address=YOUR-SERVER-IP
For example, if your MySQL server IP is 65.55.55.2 then entire block should be look like as follows:
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
language = /usr/share/mysql/English
bind-address = 65.55.55.2
# skip-networking
....
..
....Where,
* bind-address : IP address to bind to.
* skip-networking : Don’t listen for TCP/IP connections at all. All interaction with mysqld must be made via Unix sockets. This option is highly recommended for systems where only local requests are allowed. Since you need to allow remote connection this line should removed from file or put it in comment state.
Step# 4 Save and Close the file
Restart your mysql service to take change in effect:# /etc/init.d/mysql restart
Step # 5 Grant access to remote IP address
# mysql -u root -p mysqlGrant access to new database
If you want to add new database called foo for user bar and remote IP 202.54.10.20 then you need to type following commands at mysql> prompt:mysql> CREATE DATABASE foo;
mysql> GRANT ALL ON foo.* TO bar@'202.54.10.20' IDENTIFIED BY 'PASSWORD';
How Do I Grant access to existing database?
Let us assume that you are always making connection from remote IP called 202.54.10.20 for database called webdb for user webadmin, To grant access to this IP address type the following command At mysql> prompt for existing database:mysql> update db set Host='202.54.10.20' where Db='webdb';
mysql> update user set Host='202.54.10.20' where user='webadmin';
Step # 5: Logout of MySQL
Type exit command to logout mysql:mysql> exit
Step # 6: Open port 3306
You need to open port 3306 using iptables or BSD pf firewall.
A sample iptables rule to open Linux iptables firewall
/sbin/iptables -A INPUT -i eth0 -p tcp --destination-port 3306 -j ACCEPT
OR only allow remote connection from your web server located at 10.5.1.3:
/sbin/iptables -A INPUT -i eth0 -s 10.5.1.3 -p tcp --destination-port 3306 -j ACCEPT
OR only allow remote connection from your lan subnet 192.168.1.0/24:
/sbin/iptables -A INPUT -i eth0 -s 192.168.1.0/24 -p tcp --destination-port 3306 -j ACCEPT
A sample FreeBSD / OpenBSD pf rule ( /etc/pf.conf)
pass in on $ext_if proto tcp from any to any port 3306
OR allow only access from your web server located at 10.5.1.3:
pass in on $ext_if proto tcp from 10.5.1.3 to any port 3306 flags S/SA synproxy state
Step # 7: Test it
From remote system or your desktop type the command:
$ mysql -u webadmin –h 65.55.55.2 –p
Where,
* -u webadmin: webadmin is MySQL username
* -h IP or hostname: 65.55.55.2 is MySQL server IP address or hostname (FQDN)
* -p : Prompt for password
You can also use telnet to connect to port 3306 for testing purpose:$ telnet 65.55.55.2 3306
Create a user at % ( only this user can remotely connect)
mysql>CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%'
-> WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;
to create user http://dev.mysql.com/doc/refman/5.1/en/adding-users.html
http://ubuntu-commands.blogspot.com/2008/11/how-do-i-enable-remote-access-to-mysql.html
Copy & Pasted & EDITED the content from above link here ( for my reference)
By default, MySQL database server remote access disabled for security reasons. However, some time you need to provide the remote access to database server from home or from web server.
MySQL Remote Access
You need type the following commands which will allow remote connections:
Step # 1: Login over ssh if server is outside your IDC
First, login over ssh to remote MySQL database server
Step # 2: Enable networking
Once connected you need edit the mysql configuration file my.cfg using text editor such as vi.
* If you are using Debian Linux file is located at /etc/mysql/my.cnf location
* If you are using Red Hat Linux/Fedora/Centos Linux file is located at /etc/my.cnf location
* If you are using FreeBSD you need to create a file /var/db/mysql/my.cnf
# vi /etc/my.cnf
Step # 3: Once file opened, locate line that read as follows
[mysqld]
Make sure line skip-networking is commented (or remove line) and add following line
bind-address=YOUR-SERVER-IP
For example, if your MySQL server IP is 65.55.55.2 then entire block should be look like as follows:
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
language = /usr/share/mysql/English
bind-address = 65.55.55.2
# skip-networking
....
..
....Where,
* bind-address : IP address to bind to.
* skip-networking : Don’t listen for TCP/IP connections at all. All interaction with mysqld must be made via Unix sockets. This option is highly recommended for systems where only local requests are allowed. Since you need to allow remote connection this line should removed from file or put it in comment state.
Step# 4 Save and Close the file
Restart your mysql service to take change in effect:# /etc/init.d/mysql restart
Step # 5 Grant access to remote IP address
# mysql -u root -p mysqlGrant access to new database
If you want to add new database called foo for user bar and remote IP 202.54.10.20 then you need to type following commands at mysql> prompt:mysql> CREATE DATABASE foo;
mysql> GRANT ALL ON foo.* TO bar@'202.54.10.20' IDENTIFIED BY 'PASSWORD';
How Do I Grant access to existing database?
Let us assume that you are always making connection from remote IP called 202.54.10.20 for database called webdb for user webadmin, To grant access to this IP address type the following command At mysql> prompt for existing database:mysql> update db set Host='202.54.10.20' where Db='webdb';
mysql> update user set Host='202.54.10.20' where user='webadmin';
Step # 5: Logout of MySQL
Type exit command to logout mysql:mysql> exit
Step # 6: Open port 3306
You need to open port 3306 using iptables or BSD pf firewall.
A sample iptables rule to open Linux iptables firewall
/sbin/iptables -A INPUT -i eth0 -p tcp --destination-port 3306 -j ACCEPT
OR only allow remote connection from your web server located at 10.5.1.3:
/sbin/iptables -A INPUT -i eth0 -s 10.5.1.3 -p tcp --destination-port 3306 -j ACCEPT
OR only allow remote connection from your lan subnet 192.168.1.0/24:
/sbin/iptables -A INPUT -i eth0 -s 192.168.1.0/24 -p tcp --destination-port 3306 -j ACCEPT
A sample FreeBSD / OpenBSD pf rule ( /etc/pf.conf)
pass in on $ext_if proto tcp from any to any port 3306
OR allow only access from your web server located at 10.5.1.3:
pass in on $ext_if proto tcp from 10.5.1.3 to any port 3306 flags S/SA synproxy state
Step # 7: Test it
From remote system or your desktop type the command:
$ mysql -u webadmin –h 65.55.55.2 –p
Where,
* -u webadmin: webadmin is MySQL username
* -h IP or hostname: 65.55.55.2 is MySQL server IP address or hostname (FQDN)
* -p : Prompt for password
You can also use telnet to connect to port 3306 for testing purpose:$ telnet 65.55.55.2 3306
Create a user at % ( only this user can remotely connect)
mysql>CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%'
-> WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;
to create user http://dev.mysql.com/doc/refman/5.1/en/adding-users.html
Wednesday, July 21, 2010
Connecting to Linux server with port
Genearally we do "ssh root@ip"
and then password ..
Here the serve is listening 22 port ..So no need to mention.
But if you are trying to connect a sever which is listening at different port
let us say 2022 then we need to try "ssh -p 2022 root@ip"
then it will ask password..
We can find more details on man page of ssh.
Thanks
Murthy Kavali
and then password ..
Here the serve is listening 22 port ..So no need to mention.
But if you are trying to connect a sever which is listening at different port
let us say 2022 then we need to try "ssh -p 2022 root@ip"
then it will ask password..
We can find more details on man page of ssh.
Thanks
Murthy Kavali
Friday, April 16, 2010
Virtual Host in Ubuntu linux
My Ubuntu version:
cat /proc/version
Linux version 2.6.31-14-generic (buildd@rothera) (gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu8) ) #48-Ubuntu SMP Fri Oct 16 14:04:26 UTC 2009
/etc/init.d/apache2 restart
* Restarting web server apache2 [Fri Apr 16 1:29:16 2010] [warn] VirtualHost 127.0.0.1:80 overlaps with VirtualHost 127.0.0.1:80, the first has precedence, perhaps you need a NameVirtualHost directive
... waiting [Fri Apr 16 01:29:17 2010] [warn] VirtualHost 127.0.0.1:80 overlaps with VirtualHost 127.0.0.1:80, the first has precedence, perhaps you need a NameVirtualHost directive
if you face the above error.
That means while setting the vhosts we create a simple file like zoo.com in /etc/apache2/sites-available
content in zoo.com file will be
<>
ServerName zoo.com
ServerAdmin "info@tasmeemme.com"
DocumentRoot /var/www/vhosts/zoo
CustomLog /var/www/vhosts/logs/access_log plesklog
ErrorLog /var/www/vhosts/statistics/logs/error_log
< >
then create a soft link to that file in /etc/apache2/sites-enabled with same name as zoo.com
restart apache.
Now I guess everything works fine.
But the problem comes once you add one more file with the same iP and port.
Example create ram.com with same content as zoo.com
then restart apache you will get the below error
VirtualHost 127.0.0.1:80 overlaps with VirtualHost 127.0.0.1:80,
So both are lisetening at the same ip address,That is the issue to resolve this.
add differnt ip address to sites.
example
127.0.0.1 localhost
127.0.0.9 ram.com
127.0.0.10 kavali.com
127.0.0.13 zoo.com
something like this in /etc/hosts file
Ping above sites .. you will get reply with out network or may be very fast response that means it's correct.
Change the zoo.com file in /etc/apache2/sites-available with change ip address.
with the ip you entered in hosts file.
Restart apache ..This time you won't get any error.
Thanks
Murthy Kavali
cat /proc/version
Linux version 2.6.31-14-generic (buildd@rothera) (gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu8) ) #48-Ubuntu SMP Fri Oct 16 14:04:26 UTC 2009
/etc/init.d/apache2 restart
* Restarting web server apache2 [Fri Apr 16 1:29:16 2010] [warn] VirtualHost 127.0.0.1:80 overlaps with VirtualHost 127.0.0.1:80, the first has precedence, perhaps you need a NameVirtualHost directive
... waiting [Fri Apr 16 01:29:17 2010] [warn] VirtualHost 127.0.0.1:80 overlaps with VirtualHost 127.0.0.1:80, the first has precedence, perhaps you need a NameVirtualHost directive
if you face the above error.
That means while setting the vhosts we create a simple file like zoo.com in /etc/apache2/sites-available
content in zoo.com file will be
<
ServerName zoo.com
ServerAdmin "info@tasmeemme.com"
DocumentRoot /var/www/vhosts/zoo
CustomLog /var/www/vhosts/logs/access_log plesklog
ErrorLog /var/www/vhosts/statistics/logs/error_log
<
then create a soft link to that file in /etc/apache2/sites-enabled with same name as zoo.com
restart apache.
Now I guess everything works fine.
But the problem comes once you add one more file with the same iP and port.
Example create ram.com with same content as zoo.com
then restart apache you will get the below error
VirtualHost 127.0.0.1:80 overlaps with VirtualHost 127.0.0.1:80,
So both are lisetening at the same ip address,That is the issue to resolve this.
add differnt ip address to sites.
example
127.0.0.1 localhost
127.0.0.9 ram.com
127.0.0.10 kavali.com
127.0.0.13 zoo.com
something like this in /etc/hosts file
Ping above sites .. you will get reply with out network or may be very fast response that means it's correct.
Change the zoo.com file in /etc/apache2/sites-available with change ip address.
with the ip you entered in hosts file.
Thanks
Murthy Kavali
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