Notes on codes, projects and everything
Trekkr is by far the largest program I have ever done as a student. Trekkr is my final year project which is co-developed with Regina. It took us about half a year in carrying out research, learning some new concepts and developing the system. The final product is still not even near to perfect but major functionalities are already done.
We carried out extensive research in determining which architecture to apply. We learned in college about 3-tier design but we wanted to find another architecture to compare with the 3-tier design as we do not really like about it. Then we heard a lot about MVC and did some research and learning about it. The reason we didn’t use popular frameworks was we wanted to learn more through developing the website.
After evaluating the two architectures and we found out that these two architectures can be combined, hence we came out with a design which is explained in this article.
*Quoted from my own final documentation.
This is one of the most important modules in the system where users are able to interact with each other the most. This is the module where user posts information to a specific location to complement the profile of the location. To start, the user would have to upload an image to the system and create the location profile as instructed, once the profile is created, other users may be able to contribute content or define tags to the profile.
However, this module doesn’t allow a piece of content to be edited directly, what the system does is create a duplicate entry for the content that is to be edited and let the user to edit from the duplicate copy. This is because each piece of content is bounded to a rating by other users, the system could not guarantee that after modification the content is still deserves the rating. Besides that, by implementing the edit system in this manner, now all users are able to edit each other’s entry without worrying about the impact to the original copy in terms of rating. As long as a piece of content is being written well and being promoted by members, then it will be promoted to the front-page.
The site administrator would not play an important role in this module as the power is distributed to the users. The users are expected to maintain the quality of the location profile, this is the reason why the users are allowed to rate a single location profile for multiple times.
Besides that, there is an internal promotion of content in each location profile. As many users may be able to contribute content, to users who just want to have a quick view to a place, this may cause them to confuse. Therefore two distinct views are created, which are the normal and the draft view. The normal view will display the most popular, or the content with the highest rating in each sub-section. However, if the user wishes to know more, he or she may go to the draft view to view all content contributed by all other users. Guests, or users without an account in the system, would be restricted to only the normal view of the location profile.
The travelogue module is a module to enable users to post their travelogues. The version submitted in this project allows the user to attach a photo. Besides posting, the system also enables the original author of a travelogue to be able to edit the content. For other users, editing others’ travelogue will result in an error screen informing that they are not allowed to edit the travelogue entry. However, if a user posted a travelogue that contains inappropriate content, then the travelogue may be deleted by the site administrator. Tags are used to describe the content of the travelogue, for example, if the user posts a story about his journey to Malacca, then he or she may tag the entry as “Malaysia, Malacca, A’Farmosa” etc.
The searching module is a module to search for a travelogue entry or a location profile using tags. A tag, as mentioned earlier, is a metadata to describe a piece of information used in web 2.0 applications. Therefore the developer finds it reasonable to search the tag in order to get to the desired information. The searching interface will be either through a web form provided by the system or just through a specific format of website address. This is to provide flexibility to user without having them to load the web form whenever they want to search for information.
The demo site can be accessed here.
Although my supervisor strongly recommend using JENA for RDF related work, but as I really don’t like Java (just personal preference), and wouldn’t want to install JRE/JVM (whatever it is called) at my shared server account, so I went to look for an alternative. After spending some time searching, I found this library called Redland and it provides binding for my current favorite language — PHP, so I decided to use this for my RDF work.
Often times one would have to write code to evaluate logical statements. For example, given statement p and q, what is p implies q? As there’s no operator for implication in PHP, one would have to rewrite the statement that consists only in NOT (!), AND (&&) and OR (||) operators. When there are a huge load of these statements, code can be difficult to read.
It is useful to have the terminal around whenever I code. However, while real screen estate is finite, having a terminal further limiting the amount of information that can be displayed at the same time. The problem with the terminal is that I don’t really need it all the time, so I usually find it buried under a group of windows.
Previously, I started practising recursions by implementing a type check on lat (list of atoms), and ismember (whether an atom is a member of a given lat). Then in the third chapter, named “Cons the Magnificent”, more list manipulation methods are being introduced.
I wanted to try using virtuoso as the storage engine for Redland but unfortunately there is no librdf-storage-virtuoso package for Ubuntu. After getting some help from @dajobe, I attempted to build the packages myself. Although it takes quite some time to build packages, but not too difficult it seems.