apperceive

how to install mysql2 gem on windows

2014-12-13T11:01:00.004-08:00

There is a useful link in here stackoverflow.

Rails reads excel by using spreadsheet

2014-11-26T09:54:00.000-08:00

thanks to stackoverflow.com I found this fruitful example and I share it

# load the gem
require 'spreadsheet'

# In this example the model MyFile has_attached_file :attachment
@workbook = Spreadsheet.open(MyFile.first.attachment.to_file)

# Get the first worksheet in the Excel file
@worksheet = @workbook.worksheet(0)

# It can be a little tricky looping through the rows since the variable
# @worksheet.rows often seem to be empty, but this will work:
0.upto @worksheet.last_row_index do |index|
  # .row(index) will return the row which is a subclass of Array
  row = @worksheet.row(index)

  @contact = Contact.new
  #row[0] is the first cell in the current row, row[1] is the second cell, etc...
  @contact.first_name = row[0]
  @contact.last_name = row[1]

  @contact.save
end

While saving simple_form data, rails save values as NULL problem

2014-11-26T03:37:00.002-08:00

Problem solution is here.

The model you have are heavily populated with attr_accessor. attr_accessor is a way to create "virtual attributes" in Ruby / Rails, as it defines a custom getter and setter method, which will essentially define the "attributes" for use on the system

The problem you have is attr_accessor, in the simplest of terms, will not permit your data to be saved in the database. This will be one of the bigger issues you have - you need to get rid of any attr_accessors which override your database attributes.

It should be removed the attr_accessor methods from your model

How to capture packets

2014-11-20T05:46:00.000-08:00

While I surf the internet, I came across a web site(www.opensourceforu.com) about how to capture packets physical layer to application layer. I like this explanation:

Capturing packets means collecting data being transmitted on the network. Every time a network card receives an Ethernet frame, it checks if its destination MAC address matches its own. If it does, it generates an interrupt request. The routine that handles this interrupt is the network card’s driver; it copies the data from the card buffer to kernel space, then checks the ethertype field of the Ethernet header to determine the type of the packet, and passes it to the appropriate handler in the protocol stack. The data is passed up the layers until it reaches the user-space application, which consumes it.

Google Chrome using with proxy in Linux

2014-08-26T22:57:00.004-07:00

If you also reach internet via proxy, you can encounter this problem in Linux. Although you set up proxy server in console, you couldn't connect internet over Google Chrome. So you open a command prompt(especially bash) and write this command:
linux@linux:~/$chromium-browser --proxy-server=*.*.*.*:*

*.*.*.*:* = your proxy server ip and port

How to check whether a string contains a substring in Ruby

2014-08-22T07:30:00.002-07:00

If you look for a method in order to use while searching a string contains a substring, you could use this method;
a = "Skill"
if a.include? "ll"
puts "exist"
end

How to get exact number in a string with using ruby

2014-08-20T01:51:00.001-07:00

When I search a useful code block so as to find exact number in a string, I come accross this fruitful function in Ruby:

str.delete("^0-9.")

error: device unauthorized. Please check the confirmation dialog on your device.

2014-08-04T04:44:00.004-07:00

While encountering this error in linux shell, you could fix it by applying below instruction

unplug your device
(in shell) SDK_DIR=(android_sdk_directory)
cd $SDK_DIR/platform_tools
./adb start-server
plug device
confirm authorization

Convert pdf to image in linux

2014-08-02T05:50:00.002-07:00

If you look for a tool in order to convert a pdf document to a image, you could use a useful command:

convert document.pdf document.png

this little tool come in handy very much.

Quick ntfs format in Linux

2014-08-01T07:10:00.001-07:00

sudo mkfs.ntfs -f /dev/sdb1

NTFS is a journaling file system.Hence Don't forget unmount your disk before unplugged.

qemu-timer.o: undefined reference to symbol 'timer_settime@@GLIBC_2.3.3'

2014-08-01T05:10:00.002-07:00

Another good solution is here while compiling qemu.

../.././gcc/libgcc.mvars: No such file or directory

2014-08-01T04:24:00.003-07:00

This bug struggled me for a long time. Therefore, I found a good solution in here.

Fruitful Regex Hints

2014-08-01T00:45:00.002-07:00

Minimum 8 characters at least 1 Alphabet and 1 Number:

"^(?=.*[A-Za-z])(?=.*\d)[A-Za-z\d]{8,}$"

Minimum 8 characters at least 1 Alphabet, 1 Number and 1 Special Character:

"^(?=.*[A-Za-z])(?=.*\d)(?=.*[$@$!%*#?&])[A-Za-z\d$@$!%*#?&]{8,}$"

Minimum 8 characters at least 1 Uppercase Alphabet, 1 Lowercase Alphabet and 1 Number:

"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[a-zA-Z\d]{8,}$"

Minimum 8 characters at least 1 Uppercase Alphabet, 1 Lowercase Alphabet, 1 Number and 1 Special Character:

"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[$@$!%*?&])[A-Za-z\d$@$!%*?&]{8,}"

Minimum 8 and Maximum 10 characters at least 1 Uppercase Alphabet, 1 Lowercase Alphabet, 1 Number and 1 Special Character:

"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[$@$!%*?&])[A-Za-z\d$@$!%*?&]{8,10}"

How to monitor the services in Ubuntu 14.10

2014-07-31T05:46:00.004-07:00

To oversee ubuntu linux background daemons, following command is fruitful:
sudo initctl list

There is a detailed explanation for this init control tool in here

Ruby Quick Reference

2014-07-30T23:23:00.003-07:00

When hacking Ruby on Rails, Some strange code stick in my mind. Therefore, while searching good guide, I found this useful Ruby reference.

Ubuntu 14.10 MATE nm-applet appearing problem

2014-07-28T02:29:00.001-07:00

When you install a new Ubuntu 14.10 MATE, you couldn't see network manager applet in your top panel. To be enable it, you should edit /etc/xdg/autostart/nm-applet.desktop
[Desktop Entry]
Name=Network
Comment=Manage your network connections
Icon=nm-device-wireless
Exec=nm-applet
Terminal=false
Type=Application
NoDisplay=true
NotShowIn=KDE;
X-GNOME-Bugzilla-Bugzilla=GNOME
X-GNOME-Bugzilla-Product=NetworkManager
X-GNOME-Bugzilla-Component=nm-applet
X-GNOME-UsesNotifications=true
#AutostartCondition=GNOME3 unless-session gnome <---Comment out

X-Ubuntu-Gettext-Domain=nm-applet

Furthermore, if you run below instructions in your terminal, you will enable nm-applet every log in.

mkdir -v ~/.config/autostart

cp /etc/xdg/autostart/nm-applet.desktop ~/.config/autostart

How to set/unset git proxy

2014-07-16T22:38:00.001-07:00

To set proxy server with git:

http_proxy=http://$server_ip:$server_port/
git config --global http.proxy $http_proxy

To unset proxy server with git:

git config --global --unset $http_proxy

Ubuntu 13.04 launcher remove

2013-07-21T02:19:00.004-07:00

I realize that I didn't write anything here for a long time. I bought a new ultrabook. After installing ubuntu 13.04, I am really fed up with launcher. Therefore I decided to remove it. While I was wandering web sites, I came across a nice recommendation. And here you could see it. I think it is useful for people who want to remove launcher. For now, that's it...

Android SMS sending over adb

2012-07-23T03:58:00.003-07:00

I found really useful link to this event. http://www.madurax86.com/send-sms-using-android-adb Thanks for person who wrote that script.

Mevlana quotes

2012-05-28T05:46:00.001-07:00

Thanks to this web site, I learnt much more than I know Mevlana quotes. I want to share some of them here.

Your task is not to seek for love, but merely to seek and find all the barriers within yourself that you have built against it.
The eye goes blind when it only wants to see why
Love is the cure,
for your pain will keep giving birth to more pain
until your eyes constantly exhale love
as effortlessly as your body yields its scent.
We Are All the Same
Listen to the reeds as they sway apart;
Hear them speak of lost friends.
At birth, you were cut from your bed,
Crying and grasping in separation.
Everyone listens, knowing your song.

You yearn for others who know your name,
And the words to your lament.
We are all the same, all the same,
Longing to find our way back;
Back to the one, back to the only one.
Be like a river in generosity and giving help. Be like a sun in tenderness and pity. Be like night when covering other's faults. Be like a dead when furious and angry. Be like earth in modesty and humbleness. Be like a sea in tolerance. Be as you are or as you look like.

Learning

2012-05-22T10:40:00.002-07:00

"Learning is finding out what you already know, Doing is demonstrating that you know it, Teaching is reminding others that they know it as well as you do. We are all learners, doers, and teachers."

Richard David Bach

Sarcasm

2012-05-19T06:49:00.000-07:00

I hate sarcasm because It hurts people. I mean Oscar Wilde realised this, however He said "sarcasm is the lowest form of wit". I certainly agree with him. True wit helps the others and improves others' opinions.

An author recommendation

2012-05-17T11:04:00.000-07:00

I would like to write a sentence from William Engdahl's Seeds of Destruction book. According to book, Henry Kissinger's statement that "If you control the oil, you control the nations; if you control the food, you control the people." You should read this book and As I do, You should follow William Engdahl's the other books.

android emulator hanged error after powering off

2012-05-14T11:36:00.005-07:00

When you go into Android Emulator, you press power button. You wait to close emulator. But something happens strange. Your emulator hangs. To correct this situation, you may try to this power off site. There's offers:

---> just close your emulator window
---> launch AVD Manager from eclipse
---> press Start button
---> check "Wipe user data"
---> click "Launch" and you will get clean and initial state of emulator

This is work for me.

Suse 12.1 auto load modules on boot

2012-05-14T11:36:00.003-07:00

If you want to load suse linux modules at boot, you must edit into /etc/sysconfig/kernel file MODULES_LOADED_ON_BOOT="(add here what module you want to load)" line.