Web Technologies - Sharing by Divine Fung

This Blog Will Not Be Updated Anymore

2011-01-28T20:12:00.007+08:00

I have completed the course "CSIS7306 - Web Technologies" and received a grade. Since this blog was created solely as an assignment for the course, from now on I will not update the blog anymore. No new articles will be posted.

Well, I may still come back one day to post interesting things if I feel like to, but never assume that it will happen. I must say, it's nice sharing with you guys about new technologies in this blogger stuff. Thank you so much for reading my articles. Good bye!

New Ways to run Flash on Apple Devices

2010-12-09T15:18:00.001+08:00

Well, HTML5 is great - but for now Flash is still wanted. A lot of users have been trying so hard to enable Flash on their iPhone, iPod touch, iPad, etc. For Hong Kong users, their main purpose to play Facebook Flash games as well as watching videos on their Apple devices. Although these wishes are still not yet made possible, there comes a new technology called iOS Flash Video, which supports more Flash formats.

In the past, there was a technology called Frash which supports playing Flash on Apple devices, but that limits to simple Flash animations only - like the banner ads that you often encounter. And then some time ago Skyfire made Flash available on their mobile browsers, but still many video websites are not supported, like the beloved myTV for Hong Kongers.

Now, iOS Flash Video offers an option to view Flash content without jail-breaking (note: you may not have heard the term jail-breaking, but it is not the theme of this blog to introduce it here. Readers are advised to consult the wikipedia). All the users need to do is to use their Apple device to navigate to a website (via Safari) provided by the development team, bookmark the link, and then delete everything before the Javascript (intuitively some scripts will run by accessing this bookmark, and I advise users to understand the security threats behind before proceeding).

I have tried it on my iPad and it does work, but it only supports a limited number of video sites, which include Flickr Video, MegaVideo, Dailymotion, etc. Very often, these sites offer videos of alternative formats which can be viewed directly by iPad without using this hack. What's more, I usually don't watch videos on these websites, which are probably more popular among Americans. So my conclusion is that this new technology isn't very useful for me. Nevertheless, it is always exciting to see that running Flash on Apple devices are gradually becoming possible.

Welcome to Facebook

2010-12-03T22:36:00.017+08:00

A dad adds his child on Facebook. Does this mark the end of the generation gap problem? Will Web 2.0 bring harmony to family relationships?

Source: http://reface.me/humor/wtf-welcome-to-facebook/

Hong Kong to be the Web 3.0 Center

2010-11-13T20:29:00.002+08:00

I actually refer to this Yahoo! newspaper article in dated 12-November, 2010. Mr. Herman Lam, CEO of Cyberport Management Co. Ltd. (who is also the former GM of Microsoft HK Ltd.), mentions that Hong Kong may be the pioneer of Web 3.0 technology.

Supporting arguments are that Hong Kong has a well established network infrastructure, Hong Kong is an open market, ease of finding investors, etc. All these are true. In my opinion, however, Hong Kong people are quite slow in adapting to new technologies. Also, the local economy has more focus towards the financial sector, but not the other sectors. Creative sectors are often abandoned actually.

We should understand that new technologies (be it web technologies or not) can become useful only if people start to use it and realize its importance. Technology education will be the key.

The Next 5 Years of Web 2.0 Strategy

2010-11-12T18:03:00.025+08:00

Although Web 3.0 is a hot topic, we shouldn’t forget that we are still enjoying a great deal of Web 2.0 technologies. Facebook, Google Docs and Dropbox are just a few of the great examples of how Web 2.0 is changing our lives. Yesterday I attended an inspiring departmental seminar with Professor Amy Shuen as the speaker. The title of the seminar is “The Next 5 Years of Web 2.0 Strategy: What's New in Healthcare 2.0, Gov 2.0 and Smart Planet”. As the name implies, the talk explores new areas at which Web 2.0 technologies can be applied. In this article, I will briefly describe what has been shared, along with some of my personal opinions.

Web 2.5 as a Smart Use of Web 2.0

Prof. Shuen mainly described three areas at which smart use of Web 2.0 can be implemented, namely, Health care, Government and Smart Planet. She actually refers to this smart use of Web 2.0 as Web 2.5 – an intelligent way to employ Web 2.0 technologies to improve our life.

Government 2.0

The featured system is called Streetline – a digital parking system for improving city operations. In a large city, drivers may find it difficult to find a parking space. They may have to spend additional time to locate a car park, which results in traffic congestion problems. Streetline provides drivers with real-time parking information such that drivers can locate a car park more easily. The system works by storing the availability information of car parks online, and then retrieves and updates them when necessary. As this reduces the time drivers need to find a car park, roads will be less congested and everyone’s time is saved.

In Hong Kong, parking space is not as scarce. But in busy areas such as Causeway Bay and Central, it may also be difficult to find an empty parking space. Thus, Streetline may help to reduce traffic congestion problems in these areas. Such system incurs costs, however. Therefore it requires more feasibility study and cost-benefit analysis to give a conclusion.

Smart Energy

Energy can be consumed in a smarter way with Web 2.0. In the talk, I heard about the smart grid project by Google and GE. With smart grid technologies, it computes electricity usage of a household. Google then makes this information online so that a user can access its electricity usage information via a browser, a mobile phone or anything that can connect to the Internet.

In the short term, people can learn about their usage and this helps to conserve energy. For example, if one finds that a considerable portion of his electricity bill goes to the computer usage, he can choose to switch off his computer when he does not need to use it (in fact, nowadays many people don’t turn off their computers even when they don’t use it).

In the long term, more can be achieved – if privacy is not an issue, we can make use of this usage information to analyze the consumption pattern of a customer (or an aggregate of customers). Companies can make use of this information to understand their clients more. Of course, to implement this we need the consent of the users to use their information.

Health 2.0

The featured system is called PatientsLikeMe. It is a social networking site for patients. In the site, patients share about their experience, treatment, symptoms, etc. It is believed that this information will be beneficial to those patients who suffer from similar diseases. For example, patients with similar diseases can infer from others’ experience on what to expect, what kind of treatment is good and what is not, what is the chances of recovery, etc. In addition, the information shared by patients may also contribute to advances in the medical industry.

Despite the benefits discussed, the use of the system is, in fact, quite controversial. Most concerns about privacy issues. However, Prof. Shuen points out that the collective value of this information cannot be underestimated. I occasionally take a look of the website and is surprised to see that there are already 70,000 members in the database, of which 10,000 is willing to make their profile public. In my opinion, as more and more people subscribe, less and less people care about privacy. In fact, one implication of Web 2.0 is that it is making people less cautious about privacy. Think about Facebook – ten years ago, would there be so many people willing to publish their real names online? And although recently there are many privacy concerns about Facebook, we never see its number of users drops. So, web technologies are in fact changing our values and attitudes towards privacy.

The Next Generation

In the Q&A session, Prof. Shuen was asked about her opinion on Web 3.0. Her view is that we should focus more on the application aspect. After all, it is always the application that rocks. She thinks that it may be the semantic web, or some other things that surprise us. What will it be? Let’s be creative!

HTML5 to be the Flash Killer?

2010-10-08T04:27:00.000+08:00

We all know that Steve Jobs slapped Adobe Flash right in the face. This is however not a personal belief. The true fact is that since the announcement of HTML 5, people have been debating whether it would be the Flash killer. In this article, I will share something about this.

Backgrounds on Flash

For many years, Flash has been the de facto standard of creating webpages with animations, games, videos and other interactive multimedia elements. With a small browser plugin that is completely free of charge, users are able to view Flash content of the web. Although Flash player is free, Flash itself is a proprietary standard. The official authoring tool – Adobe Flash Professional – is sold at a handsome price of US$699. What this means is that while users can view Flash for free, web designers may find it costly to develop something in Flash. Although there exist freeware that can create Flash content, its functionality and performance is not comparable with the official tool, possibly due to the fact that the Flash player is also written by the same company.

The Rise of HTML5 and its Threats

The proprietary nature of Flash has called for the development of HTML 5 – which allows web designers and developers to create advanced graphics, animations, videos and effects that are not supported in previous versions of HTML.

There are many reasons why HTML 5 is a threat to Adobe Flash. First, it introduces the ‘video’ tag. For the first time, a Flash player will no longer be a prerequisite for consuming video contents on the web. Since most videos currently on the web are encoded in Flash, the newly introduced HTML 5 standard has the potential to drive out all these Flash videos.

Second, other than videos, the HTML 5 also supports other functionalities that are threats to Flash. The CSS animation, WebSocket and SVG are some examples. In addition, we have been talking about the semantic web. Programs parse web documents to retrieve meaning of a website. On the other hand, there are no efficient programs that can parse a Flash content. This violates the concept of semantic web and people will eventually find it more beneficial to use alternative formats, which is very likely to be HTML 5.

Third, Flash is proprietary by nature. “They are only available from Adobe, and Adobe has sole authority as to their future enhancement, pricing, etc.” (Steve Jobs, 2010). When compared with open standards like the HTML 5, which is always free, carefully planned and controlled by a group of committees, Flash does not appear to be a promising investment for many web designers and developers, relatively speaking.

Fourth, Flash on mobile devices is banned by Apple. This reason may sound too straightforward, lacking deductive logic. But in fact it is not. We all know that the iPhone, iPod and the iPad were a big hit. In particular, the iPhone enjoys the leading market share (beside BlackBerry) in the U.S. smartphone market. What’s interesting is that all these Apple mobile devices use the Mobile Safari as the browser, which cannot play Flash. What this means is that a large portion of mobile users aren’t able to play Flash on their mobile devices. If I were a web developer and I were to develop a mobile version of my website, will I choose Flash or HTML? The answer is obvious – HTML. I won’t want a large portion of potential customers being not able to read my website. What’s more, nowadays more and more people access the Internet via devices other than their desktop computers, so Apple’s decision to ban Flash on their devices has a great impact.

Will Flash be killed?

Having mentioned so many threats to Adobe Flash, one might think that Flash will be killed by HTML 5. My personal opinion is no. I will explain in two perspectives why I think so, namely, the short run and the long run.

Flash is well established. It also has a very strong installed user base. To these users, it is indifferent to them whether the content is in Flash or not. So an average user will continue to consume Flash content as he always does. On the other hand, the HTML 5 is still pending. It still needs to go through stages in W3C standardization. Currently, not all major browsers are supporting all capabilities of HTML 5. Furthermore, currently there are many existing contents – videos in particular – that are only available in Flash but not in other formats. In other words, users must install Flash player to watch these videos. A good local example is the myTV which I always fail to watch with my iPad. Another more international example is the Restaurant City on Facebook which I cannot play on my iPhone. In the short run, HTML 5 is not going to kill Flash.

In the long run, though, it is expected that more contents will be available in HTML 5 – at least a HTML 5 version will be an option to choose. However, Flash still has its benefits – it is a great tool for creating interactive multimedia elements in an efficient manner. It is also expected that many games will continue to be developed in Flash, as game companies rely much on existing libraries and codes. On the other hand, although it is still unlikely that Apple will allow Flash in the long run, more and more tweaks and hacks are expected to be released such that they can bring a Flash world to Apple devices. By all these, Flash is still likely to survive in the long run.

Associated Blog Topic: Why is HTML 5 a threat to Adobe Flash? Will HTML 5 kill Flash? What is your view?

Yet Another Markup Language

2010-09-17T21:05:00.001+08:00

We mentioned several times that we have to make our online resources to be readable to machines. XML is a format created to accomplish this. There comes another similar language - YAML, which stands for 'YAML Ain't Markup Language'. In this article, I am going to briefly talk about this language.

Introduction

YAML is a human readable data serialization standard. It was designed so that its syntax could be easily mapped to/from data types used by high-level languages like C or Java. For example, we can represent lists and arrays easily using YAML. There are a number of parsing libraries available in the official page of YAML - I could see that most common languages like C#, Javascript and PHP - have all been included.

Comparison with XML

In contrast to XML, YAML is pretty strong at representing relational data. XML can do this too, but the results may be less readable to human. XML is strong in representing hierarchical data (due to its inherited hierarchical syntax). There are some studies that try to compare the two languages - but I will decline to comment whether YAML or XML is a better data representation language - it all depends on what type of data you would like to represent, and the amount of which.

Associated Blog Topic: What is YAML? What are its advantages over XML? Give examples on how an XML document can be represented by a YAML document.

Introduction to Session Hijacking

2010-09-14T03:14:00.000+08:00

With the emergence of Web 2.0, people increasingly share their information online. Very often, this information is not intended to be shared with everyone. Hence, it becomes important for websites to restrict access to certain resources.

Maintain States with Sessions

One intuitive way of achieving this is to build an authentication system that requires login and logout. Once the user has logged in to a system, the user can access to resources that are otherwise locked. However, the bad news is that HTTP is a stateless protocol. What this means is that when the client machine sends a HTTP request to the server requesting for resources, without using other technologies, the server has no idea whether the client has previously logged in or not. To overcome this limitation, we introduce sessions. A session is set up or established when a user logs in, and torn down when the user logs out or the session expires. With sessions, server can maintain states of a particular user so that it can know whether a user has logged in or not.

HTTP Cookies

Quite often, session data is stored in the client’s computer rather than the server’s. This reduces the storage requirement on the server side. To implement this, the server sends state data to the client, who stores it in the form of magic cookie in its computer. When the client wishes to initiate new HTTP request, it sends its request together with information contained in the cookie. With this information, the server knows which state the client is in; hence it can generate the appropriate response.

What is Session Hijacking?

Session hijacking is a technique that exploits the vulnerabilities of a session in order to gain unauthorized access to systems. As previously mentioned, clients can prove themselves as having logged in by presenting valid session data (known as session key). In other words, anyone who can present such session key will be identified as valid clients. Thus, if hackers can generate or steal session key, they can gain unauthorized access.

Session Sidejacking and How to Avoid

There are many ways in which hackers can obtain the session data. One direct way is to intercept the messages passed between the client and server. This is called packet sniffing. As the client has to use the session data to communicate with the server, the hacker can steal this piece of information via the network traffic. (In fact, this is not difficult at all by using some freely available packet sniffing software like Wireshark). Once the session data is known to the hacker, the hacker can produce the session key to impersonate the user in order to gain unauthorized access.

To combat with this kind of behavior, messages passed between servers and clients are often encrypted – this means that even if the hacker can observe the network, the session data will be unreadable. Although encryption can eliminate stealing of session data via packet sniffing, it is important to know that not all content are encrypted before communicating with the other side. Since encryption and decryption takes time, the website developer may choose not to encrypt all kinds of information that is communicated. This information will hence not be protected.

Pattern Guessing and How to Avoid

Hackers can also try to guess a valid session key. This sounds impossible at first glance, but hackers can first register an account themselves and then analyze the session data that they have, with the hope of finding some patterns. If the website is poorly designed such that the pattern is fixed and easily found, the hackers may derive the session key of other users.

To deal with this technique, modern websites often use long random numbers or strings as session key, which will be changed upon each successive client activity. As a result, it will be almost impossible for hackers to guess the session key.

Most Important Factor – User as the Owner of Credentials

So far, we have mentioned two ways that a hacker can get the session key, and the corresponding combating measure that a web developer can do. However, since the session key is stored in the client’s computer, if the hackers can have access to the client’s computer, then everything will be easy. Hackers can for example trick users into running some malicious scripts that reveal session keys to the hackers. Hence, users are recommended to scan their computers regularly for computer viruses. Do not open suspicious attachments from emails and do not download suspicious software from the Internet.

Associated Blog Topic: What is “session hijacking”? What are its security threats? How can web developers avoid it?

The Semantic Web as a component of Web 3.0

2010-09-10T00:45:00.000+08:00

It has been more than five years since the term ‘Web 2.0’ was discussed in the O’Reilly Media conference in 2004. And now people are speculating what Web 3.0 will be like. In this article, I intend to share about my views on Web 3.0. I will first talk about some backgrounds, followed by a discussion on semantic web – a popular belief of Web 3.0.

Backgrounds

It makes sense to cover a bit history of Web 2.0. The term is commonly referred to as the use of web technologies to collaborate, share information and contribute knowledge. It is a two-way communication in which user retrieves information from the Internet, while at the same time gives something back. During the process, the Internet is enriched, generating more information to be available for everyone. Examples of Web 2.0 include social networking websites like Facebook and MySpace, content sharing websites like Youtube and Scribd, blogs such as Blogger and Xanga, and more. We can classify any websites as an example of Web 2.0 as long as user-generated content plays a role in the website.

Semantic Web

Web 2.0 has been very successful – users find it appealing to interact with others via the web; companies also make use of it to formulate innovative business models that generate trillions of profit. Despite the success of Web 2.0, the term ‘Web 3.0’ on the other hand still does not have a commonly agreed definition. Some people believe that it refers to the semantic web. Others refer to it as the use of artificial intelligence in web technologies. Some believe that it will be a three dimensional web, visualizing a virtual world. In this article, I will talk about the semantic web.

Computer-Friendly Webpages

Traditional web pages are designed to be read by human beings, who process the content so that they can do something useful. However, with the rapid growth of websites, information overloading is just so common. An average person is only capable of handling a small portion in the Internet. Whilst search engines can help us to search for resources more easily, it has its limitations.

To better help search engines to locate the desired information, people begin to describe information in a way that computers can better understand. For example, people label their articles with relevant tags. This is exactly the key concept of semantic web – a collection of technologies that permit computers to understand the meaning of information on the web. In addition to tags, some languages like RDF and XML are specially designed to allow computers to understand web content more easily. It is believed that as computers can understand the web content, they can assist human beings in deriving more value from the information.

Technical Requirements

Current technology can only support semantic web to a limited extent. For example, words with similar meanings (synonym) may not be interpreted as the same thing. Multimedia elements like images, videos and graphics may not be interpreted by machines. There will be a need to develop advanced analysis techniques in text, images and other multimedia elements. The techniques have to be efficient, such that they can analyze the vast amount of information on the web.

Another technical challenge is that the technology also has to deal with inconsistency in the data representation on the web. Different people write XML documents of different styles. Very often these XML documents are not readable to people other than the owner. Although there exist initiatives like the Interoperability Framework of the government, it remains a challenge as to whether developers will comply with the standards.

In addition, it is inevitable that the technology also has to deal with fraudulent data. It is not news that people often write codes to trick machines. For example, web developers may overload their websites with irrelevant tags to increase their possibly of being visited. Other might use similar techniques to trick search engines into giving them a higher ranking. There has to be a really sophisticated technology that can analyze the given information in breadth and in depth such that it can distinguish good information from bad information.

Most Important Factor – We as the Creator of Information

Although people are more willing to share information since Web 2.0, there still exists the belief of data protectionism. Users concern about privacy. Websites want to protect their own services from being taken over by those of their competitors. Companies want to prevent their ideas or business models from being imitated. As a result, people may be reluctant to express data in a way that can easily be processed by outsiders. Perhaps this is the most important barrier to overcome before we can see the use of semantic web becoming popular.

Associated Blog Topic: What is your vision on Web 3.0? What are the key technologies that will make it happen?

Introduction

2010-09-07T01:32:00.000+08:00

This blog is created as a homework assignment for the course CSIS7306 - Web Technologies offered by the Department of Computer Science, the University of Hong Kong in Fall 2010. The instructor of this course is Dr. Thomas Lee.

All published articles and comments are intended for academic discussion only. While the author strikes to ensure accuracy in all publications, correctness is not guaranteed. You are welcome and encouraged to point out any errors.