Edison Sandbox

When to use $_SESSION vs $_COOKIE

2011-09-07T11:11:00.003+08:00

A critical feature in web programming is the ability to seamlessly pass data from one page load to the next. It's used most commonly when dealing with user logins, but also for passing error messages, shopping carts, etc.
Storing data across pages using PHP is done with two variables in the global scope, called $_SESSION and $_COOKIE, and although accomplishing the same end goal, the both go about it in very different ways. The purpose of this article is to give a brief look into the differences between cookies and sessions, when it's better to use one versus the other, and the pros and cons of the two.
The difference is in how each store data. Cookies store data locally in the user's browser, while sessions store data on the webserver.

Session Basics

Sessions are simply server-side cookies each with a corresponding client side cookie that contains only a reference to its server-side counterpart. When a user visits a page, the client sends the reference code to the server, and PHP will then match that reference code to a server-side cookie and load the data in the server's cookie into the $_SESSION superglobal.

Pros

Can store very large amounts of data easily.
Save bandwidth by passing only a reference to the session each pageload. A client-side cookie has to pass all of its data.
Data is stored on the web server. This makes sessions secure, because the data cannot be viewed or edited by the client.

Cons

Ends when the browser is closed unless you've configured php.ini to extend sessions' cookie lifetime. Cannot last forever.

Cookie Basics

Cookie data is sent to the web server every page load. PHP reads and stores the value into the $_COOKIE superglobal. When a cookie is created, you can give it a lifespan. After that lifespan runs out, it will expire.

Pros

Can last as long as the website needs. They will still be there even if the browser is closed and reopened.
Useful for "remember me" logins
Useful for storing temporary user settings. For example, if a user is browsing a paginated list of items, sorted a certain way, the sorting setting can be stored in a cookie.

Cons

Stored in the users filesystem. This means that the user can tamper with it and view it.
Can only store a limited amount of data.
Must pass all data to the webserver each pageload. This takes up more bandwidth.

Cookies in Action

Creating a cookie

The function definition:
bool setcookie ( string name [, string value [, int expire [, string path [, string domain [, int secure]]]]])

Using a cookie

Deleting a cookie

Setting a cookie with no value is the same as deleting it. This will not remove the file from the client computer. To do this, you can set the cookie expiration date to a time in the past, and the browser will take care of it.

Sessions in Action

Creating a session

This must be called near the top of your code before any output. When you call this function, PHP will check to see if the user sent a session cookie. If so, it will load the session data into $_SESSION. If not, it will create a new session file on the server and send the ID back to the client.

Setting a value

Reading a session value

Removing session data

Ending a session

The Bottom Line

Sessions are cookies where the data is stored on the server. Cookies are stored in the users filesystem (typically in their "Temporary Internet Files" folder). Both have their advantages, but on any given day, you'll probably find yourself using sessions much more commonly.

PHP Documentation

簡繁體中文對照表

2011-09-06T12:31:00.002+08:00

簡繁體中文對照表

IT用語對照表

Programming 相关词汇及用语
原文简中繁中补充说明
abstract 抽象抽象简繁相同
algorithm 算法演算法
application 应用程序應用程式
argument 参数;引数;自变量引數
array 数组陣列差异大
asynchronous 异步非同步差异大
attribute 属性屬性简繁相同
boolean 布尔值布林值
class 类類別
class library 类库類別庫
code 代码;源代码程式碼
comment;annotate 注释註釋
component 组件元件差异大
constant 常量常數
constructor 构造函数建構函數;建構子
CSS 样式表樣式表简繁相同
data structure 数据结构資料結構
deadlock 死锁;死结死結
debug 调试除錯;偵錯差异大
delegate 委托委派
DLL (Dynamic Link Library) 动态链接库文件組件;動態鏈結程式庫差异大
Design Pattern 设计模式設計樣式
distributed 分布式分散式
encapsulation 封装封裝简繁相同
enumerator 枚举列舉
event 事件事件简繁相同
field 字段欄位
framework 框架框架简繁相同
function 函数;函式函數;函式简繁相同
generic(s) 泛型泛型简繁相同
implement 实现實作 (interface)
inherit 继承繼承简繁相同
instance 实例實體;執行個體
instantiate 实例化實體化;具現化
interface 接口介面差异大
iterator 迭代器迭代器简繁相同
loop 循环迴圈差异大
message 消息訊息
method 方法方法简繁相同
namespace 命名空间命名空間简繁相同
Object-Oriented 面向对象物件導向差异大
object 对象物件差异大
operator 运算符運算子
overload 重载多載
override 重写覆寫
paging 分页分頁简繁相同
parameter 参数參數简繁相同
persistence 持久化永續差异大
polymorphism 多态多型
process 进程行程;程序非指商业流程
program 程序程式
programmer 程序员程式設計師
programming 编程程式設計;寫程式
property 属性屬性简繁相同
queue 队列佇列
refactor 重构重構;重建简繁相同
reference type 引用类型參考型別差异大
reflection 反射反射简繁相同
Regular Expression 正则表达式規則運算式
return 返回傳回
reuse 复用重用;複用
serialization 序列化序列化简繁相同
source code 源代码原始碼
static 静态靜態简繁相同
string 字符串;字符字串
strong type 强类型強型別
struct 結構結構简繁相同
synchronization 同步同步简繁相同
thread 线程執行緒差异大
transaction 事务交易差异大
type 类型型別
value type 值类型實值型別
variable 变量變數

Database 相关词汇及用语
原文简中繁中补充说明
access 存取存取简繁相同
cluster index 聚集索引;集簇索引叢集索引
column 列;字段行簡繁相反
connection 联机連線差异大
data 数据資料
database 数据库資料庫
data access 数据访问資料存取
disconnection 脱机離線差异大
index 索引索引简繁相同
information 信息;資訊資訊
mapping 映射
OLTP 联机事务处理線上交易處理差异大
primary key 主键主鍵简繁相同
query 查询查詢简繁相同
record 记录記錄简繁相同
relation 联系(一对多) 關聯(一對多)
row 行列簡繁相反
save 存储;储存儲存簡繁相反
select 提取選取;撈取
SQL statement SQL语句 SQL陳述式都称SQL语法
stored procedure 存储过程預存程序差异大
table 表;数据表資料表
transaction 事务交易差异大
trigger 触发器觸發器;觸發程序简繁相同
type 类型型別
view 视图檢視表差异大

ASP.NET 相关词汇及用语
原文简中繁中补充说明
binding 綁定繫結差异大
buffer 缓冲区緩衝
button 按钮按鈕简繁相同
cache 缓存快取差异大
Code-behind 后台後端;程式碼後置
control 控件控制項
Message Queue 消息队列訊息佇列
prefix 前缀前置詞
ViewState 视图状态檢視狀態

Visual Studio 相关词汇及用语
原文简中繁中补充说明
add 添加加入
breakpoint 断点中斷點
copy 复制;拷贝複製;拷貝简繁相同
cut 剪切剪下
item 項項目
menu 菜單功能表差异大
navigate 导航巡覽
new 增加新增
paste 粘贴貼上
project 項目專案差异大
solution 解决方案方案
toolbox 工具箱工具箱简繁相同
window 窗口視窗
? 生成建置
? 引用參考差异大
? 设置設定
? 列表清單
? 选项卡索引標籤差异大
? 指针指標
? 窗体;表单表單

IT 通用词汇
原文简中繁中补充说明
bit ? 位元
Byte 字节位元組差异大
CD 光盘光碟
computer 计算机電腦
CPU 处理器處理器简繁相同
create 创建建立
default 默认預設差异大
download 下载下載简繁相同
drive 磁盘磁碟
emulator 仿真器;模拟器模擬器
file 文件檔案
flash 闪存快閃記憶體;簡短留言
folder 文件夹資料夾
HD (Hard Disk) 硬盘硬碟
hyperlink 链接超連結
Internet 互联网;因特网網際網路
LAN 局域网區域網路
Memory 内存記憶體差异大
monitor;screen 屏幕螢幕
mouse 鼠标滑鼠
network 网络網路简繁相同
on-line 在线線上
Operating System 操作系统作業系統
partition;sector 扇区磁區
path 目录目錄;路徑简繁相同
plug-in 插件;外掛外掛
performance 性能效能
print 打印列印
project 工程;项目專案差异大
project management 项目管理專案管理差异大
protocol 协议協定
read-only 只读唯讀
register 注册註冊
Registry 注册表機碼;暫存器差异大
ROM 只读存储器唯讀記憶體
save 存储;储存儲存簡繁相反
scalability 可扩展性可擴充性
scroll bar 滚动条捲軸
server 服务器伺服器
software 软件軟體
tuning 优化最佳化
upload 上载上傳
WAN 广域网廣域網路
? 短信;短讯簡訊
? 界面介面如:UI，不是指OOP编程的interface

日常用语
原文简中繁中补充说明
于於
after 后後
conflict 冲突衝突
example 示例範例
inside 里裡
lose 丢失遺失
standard 规范規範
定制制定簡繁相反
兼容性相容性

兩岸IT相關用語的對照表

2011-09-06T12:27:00.002+08:00

兩岸IT相關用語的對照表

在兩岸閱讀IT與互聯網相關內容時，會在詞彙上抓不到味，現在將繁簡中文與英文單詞列出對照表，把兩岸簡體繁體的IT常用詞彙做一個對照，希望對大家有幫助，來源三十而慄

简体中文	繁體中文	English
互联网	網路，網際網路	Internet
(簡體也稱网络)
带宽	頻寬	Bandwidth
软件硬件	軟體硬體	Software Hardware
服务器	伺服器	Server
笔记本	筆記型電腦	Notebook PC
上网本	小筆電	Netbook
台式机	桌上型電腦	Desktop PC
光驱	光碟機	CDROM
硬盘	硬碟	Hard Drive Disk
内存	記憶體	RAM, Memory
刻录光盘	燒錄光碟	Burn CD
鼠标	滑鼠	Mouse
打印机	印表機	Printer
激光	雷射	Laser
屏幕	螢幕	Monitor
(同理：看影片時，會用到全屏/全螢幕)
智能手机	智慧型手機	Smart Phone
数码相机	數位相機	Digital Camera
摄像头	網路攝影機	Webcam
U盘(优盘)	隨身碟	Flash Disk

知识产权	智慧財產權	Intellectual Property
数字娱乐	數位娛樂	Digital Entertainment
(同理：数字版权/數位出版等)
社交网站	社群網站	Social Network
(如：Facebook)
社会媒体	社群媒體	Social Media
博客	部落格	Blog
论坛	討論區	Forum
在线游戏	線上遊戲	Online Game
讯息产业	資訊產業	IT Industry
(同理：讯息工程/資訊工程，讯息管理/資訊管理等)
网站运营	網站營運	Website Operation
网络营销	網路行銷	Internet Marketing
关键词	關鍵字	Keyword
搜索引擎	搜尋引擎	Search Engine
文件管理	檔案管理	File Management
(簡體也稱文档)
数据库	資料庫	Database
优化	最佳化	Optimization
文本	純文字檔	Text File

程序	程式	Program
程序报错	系統出錯	System Error
系统设置	系統設定	Setting
连接超时	伺服器沒有響應	Timeout
查找	查詢	Searching
卸载	移除	Uninstall
拷贝	複製	Copy
视频	視訊	Video
音频	語音	Voice
短信	簡訊	Message
(同理：彩信/多媒體簡訊/SMS)
在线离线	上線下線	Online Offline
(用於MSN，QQ等即時通訊)
掉线	斷線	Drop
(非人為的)
重启电脑	重開機	Restart, Reboot
个人形象	個人造型	Photo, Avatar
(用於MSN、QQ或者論壇、SNS，簡體也用個人頭像)
联系人	聯絡人	Contacts

首席执行官	執行長	CEO
首席运营官	營運長	COO

Stay hungry, stay foolish

2011-08-27T00:25:00.000+08:00

i hv been rejected but i still in love.
connecting dots.
awful tasted med. do what u believe

Playing with youtube

2011-08-26T10:43:00.001+08:00

http://code.google.com/apis/youtube/youtube_player_demo.html

LOVE

2011-08-14T22:42:00.000+08:00

HK Java Usergroup

2011-08-11T23:51:00.002+08:00

Went PolyU for Java usergroup meeting.

Promotion from Oracle
ADF, JDevelop
http://www.oracle.com/technetwork/developer-tools/adf/overview/index.html

Java with more fancy UI

Aug update

2011-08-10T19:50:00.000+08:00

Lunch + Book

Book Times

Read another chicken soup book passed from Dad. Reading these kind of book is like unwrapping onion. Layer by layer unveiling myself.

- I once think the best of life or the environment everyone should strike for is harmony, loving.

But then I realized there are goods in conflict, where debat can start throughoutly, things are in check-and-balance. Conflicts do play its role in motivating the improvement of life and change of world (given it dun break the relationship).

So I should learn to embrace conflict also

- Also life is full of problems. Yet another source of improvement and innovation and an actualization of one's value (thru solving them).

I see a onion of problems here, while some are more superficial, more everyday, like how to manage things and resolve adhoc issue. Some are deeper inside, like core value, future, path to take, happiness.

I do need time to condense, to think through layers and reach to the core. (Sadly, now I dun have the time and not quite ready for that). But it is a path to better know myself and to inline my goal and path.

- Talking about problems, there must be success and failure. While what I have learnt is even though I fail, I have to forget that and move on and be more careful on other task and dun ruin other things.

- Think thru, be mindful, to love but also to embrace conflict :)

- Dun waste time on worrying, try my best all the time and leave more time for rest.

What I want

- PM skills

- Programming & Tech skills

- Jogging

- Piano

- Squash

Jogging in TST

Completed City Runner, a short 3.3km track in 17mins. Can run faster. Need to train and maintenance. Dun get problem ruin other part of my life.

看書

2011-07-20T23:41:00.000+08:00

偶然得到的一本書，挺有意義。
如果大家也心善，行善，社會也會不一樣。

按中國人的傳統還是由自身做起：P

書沒有不值得看，人沒有不值得交

Converting Flash to HTML animation

2011-07-19T10:08:00.006+08:00

There is a website with flash needing to convert some of the component to iOS compatible.
There are couple ways
1) Rewrite the animation using jQuery
example

2) Convert Flash to HTML animation
* fla source is needed
* the function is currently limited, but ok for animation
download
release note

Reading for work..

2011-07-19T01:24:00.000+08:00

Weekend reading

2011-07-08T00:29:00.000+08:00

The Power of Nice
- A book on negotiation

- Find sth I am not doing enough
-> Prepare (ok but can be better)
-> Probe (normally I dun... miss a lot of needed info)
-> Purpose
- Find some funny negotiation game
-> The $10 game
-> The low bidder must sell in high bidder price
- Deal with diff characteristic
-> Extrovert
-> Progmatic
-> Analytic
-> Amiable
- and know more who am I and possible weakness
- how to aware of emotion
- In general, nice for leisure reading

Weekend Reading

2011-07-01T00:42:00.000+08:00

A nice PM book
- Discuss general PM framework
- Discuss the key reason behind a framework
- Good discussion on Earn value analysis

PMP PDU

2011-06-19T00:32:00.000+08:00

PDU Hunt - IT Auditing for Project Manager
- Learn what audit want to identify
-> Risk
-> Key Control

Weekend Reading

2011-05-28T14:03:00.000+08:00

Too many examples

Simple Model viewer using OpenTK and C# .net

2010-09-17T12:36:00.000+08:00

For a long while, I want to try programming editor with a nice interface.
This is a good start. Enjoy

Daily Digest

2010-01-12T12:59:00.000+08:00

20 C++ tips
The "Empty Member" C++ Optimization
Exception
Syntax Explicit
Sth fun
US education system?

Assignment 4 - Spring mass vs constraint

2009-12-07T10:45:00.000+08:00

From http://cg.alexandra.dk/, they got a tutorial on cloth simulation using Verlet integration, and iterative constraint satisfaction. Video as below:

In class we use spring mass + Euler integration, lets see what is the different

Few Observation
* Euler integration is nicer with smaller time step
* System is not very stable and very subjective to forces and constants
* Spring mass constant has to be set carefully below some threshold (got to test it) to maintain stability
* Spring mass fail to spread out the position offset from collision detection.
This lead to i) over extend of few vertex
ii) CD obj pass thru cloth as vertex are sequeezed out to the side of CD obj
So these may be the reasons why Euler + Spring mass is not used

On the hand, iterative constraint satisfaction, to me, is like a moving average that spread out the old peak while maintaining new constraint like collision detection.

Anyway, here is my Source code for Euler Integration + Spring mass

Quick Revision on C/C++

2009-11-30T17:03:00.001+08:00

Some Reference:

Tutorial
http://www.learncpp.com/

On storage
http://ee.hawaii.edu/~tep/EE160/Book/

dll
http://www.codeguru.com/cpp/cpp/cpp_mfc/tutorials/article.php/c9855/

A year in NUS

2009-11-28T19:23:00.000+08:00

Wow, it is an amazing year studying in NUS. I reckon that today is my last exam but everything just flashing in my mind just like they just happened yesterday. From class to summer intern to lab TA, so many nice memory (oh I forget to mention leisure time, but do I really have that?)

Class are nice, from the challenging foundation class from Prof Yap and Prof Sim (at least I am more fluent in Maths and technique used in OS and Multimedia), nice graphic class from Prof Low, simulation and distribution class from Prof Yu and Gary, Weitsang for his excellent explanation on computer network, to the PM class from Irene... Thanks all for enrichment and knowledge passed.

Then to summer intern in India. Same, short time but long story

Then to lab TA, I feel grateful to have a chance working with Michael and Pasha and meeting extra-ordinary students (in all sense, not just the dancing man). Michael is inspiring and he will just do whatever it takes to let ppl understand the concept (impressive) and Pasha is really a nice glue helping and cheering ppl.

Thanks all friends, your encouragement and advice. Without that, I cant believe I can finish 10 courses in a year.

So, a new chapter will soon start!

CS3241 Lab 10

2009-11-02T01:42:00.000+08:00

Time flies and we are in lab 10. As assignment 4 requires us to do particle and physics simulation, we will look into collision detection and response a bit. Hopefully, it will help your assignment 4.

Pls get the source code in forum (lab 10)

Nice video from TED

2009-10-28T00:54:00.000+08:00

Randomly watching video from TED and find some cool stuff.

Research on digital face
Project site: http://projects.ict.usc.edu/graphics/

David Perry on videogames,
The later part of the talk featuring a gamer's video is very nice.

CS3241 Memories~

2009-10-27T00:26:00.000+08:00

After all the sweat n pain.... Thx Pasha putting everything up.

NOC India presentation

2009-10-21T04:23:00.000+08:00

CS3241 - Lab9 Implementing Bézier curve

2009-10-19T01:20:00.000+08:00

Thx Michael for saving my day and providing us a nice toy to play.
This week, we will follow Michael's example on implmenting Bézier curve in OpenGL.
Todo Solution