Tagsummer

2018 Summer AWS Project – WordPress Hosted Through AWS

My summer of 2018 was spent interning with Cox Automotive (Atlanta) on the Enterprise Data Platform (EDP) team. Put simply, the EDP application serves as a managed data lake hosted through various AWS services. As I had previously no experience with AWS or Terraform, the language Cox uses to build infrastructure on AWS, I thought it would be fun and informative to go off on my own and play around with both subjects.

Honestly I’m surprised I waited this long to look into AWS. It’s really been blowing up in the tech world for a while now, and they continue to add new services on a regular basis. At this point they have over 50 services available to build any cloud application you could think of, from Cox’s interest in a managed data lake, to my interest in hosting a website. My original plan involved hosting the website out of an S3 bucket, but was eventually changed once I decided to stay with WordPress. I was rather surprised at how easy it was to set everything up manually – all that was required was an EC2 instance running a pre-defined image specifically used for WordPress (and a Route 53 entry pointing the domain name to the EC2 instance). Once up and running, it was simple enough to ssh into the instance and play around with the settings to get it the way I wanted (i.e. adding SSL/https support).

The original plan. It involved routing the domain using Route 53 through Cloudfront (for https) and to an S3 bucket hosting html files.

The final implementation. Instead of routing through Cloudfront and then to S3, it was routed directly to an EC2 instance running WordPress with LEGO (Let’s Encrypt) for SSL/https.

After settling on a routing strategy came building the infrastructure in terraform. For those unfamiliar with terraform, it’s used specifically for building/deploying to different cloud environments quickly and easily. It’s coded in HCL (Hashicorp Language) which is essentially a more human-friendly version of JSON. As a result of AWS’s convenient endpoint setup, its incredibly easy to link services together. After successfully deploying, all that was then required was setting up SSL/https. For this, I just used a free certificate service called LEGO.

This project was equally informative as to the kind of work I would be doing at Cox as it was fun to poke around all of the different services provided by Amazon. If you’d like to see the terraform code referenced to in this post, you can find it here.

2017 Summer App Project – The Stalk Market

As my previous post (linked here) eluded, this is the second and main project I worked on during the latter half of my summer break from Virginia Tech. Described shortly, this project is a stock market tracker of sorts for the game Animal Crossing: New Leaf (ACNL) that is able to run from any handheld Android phone. My main focus for this project was introducing myself to the world of app development, mainly following various tutorials online and playing around with the Android Studio IDE. As such, the actual logic behind this project isn’t too difficult to grasp. As I’ll get into, the stock market in ACNL is rather simple and follows a strict set of rules. Thus, I mainly focused on making the user interface as fluid as possible, to ensure ease of use and practicality while keeping the function of the app in mind.

1

What the app looks like when you open it for the first time. I put a decent amount of effort into ensuring the app looks somewhat decent and is easy to use. Note, all pictures shown here are screenshots taken on my Google Pixel.

First, onto the basics of the stock market in ACNL. Every Sunday, the player can buy Turnips from a particular NPC that visits the town. The price for that particular set of turnips can range anywhere from 90-110 bells (the currency of ACNL). Then, throughout the week, the selling price of those turnips changes depending on the particular pattern for that week. The prices change twice per day (at store-open and 12pm), with the turnips rotting at exactly 6am on Sunday. Thus, the player must guess when he or she should sell all of the turnips they purchased for that week to ensure maximum profits. This is where my app comes in. The user is to enter every price update in-game into the app. Then, when prices are optimal, the app recommends the user to sell all of their turnips.

There are 4 patterns the stalk market can have for any given week, each with its own set of rules that makes it easily distinguishable from the others. Of the patterns that produce positive returns, the player is first tempted multiple times with above average selling prices before the maximum price is observed. The biggest example of this is the big spike pattern, where there are 2 above average prices before the best price, often double that of the previous prices, is observed. My app guesses which pattern is most likely for the given week/set of values, and warns against selling your turnips until it thinks the highest value for the week has been achieved. There is only one pattern in which the player is guaranteed a loss. If you’d like to read more on the various patterns and their strategies, I would recommend visiting this page.

2    3

Though the turnip price in the first picture is much higher than the purchase price (labeled in blue), the app recommends waiting, which pays off with a week-high price 3 times that of the previously shown price, as shown in the second picture.

Once the logic was finished and patted down, I moved onto the user interface portion of the app. The only non-native library I used was GraphView for the plot of prices seen on the upper-half of the screen. The main challenge when coming up with the UI for this project was where to place the buttons and text box in relation to each other and the graph. I ended up with the current design, as I think it looks and feels simple and easy to use. One of the previous designs had all of the buttons underneath the graph in a 2×2 grid pattern, which failed due to the strangeness of fingers as a cursor. Sometimes, I found myself pressing the bottom right button when I meant to press the upper left button, among other similar problems. I’ve found that the current vertical design is a clear and easy solution that wasn’t difficult to implement. Other than button placement, I used in-game and fan art (the background, turnip, and animal figure) for decorating the app. If I were to publish this on the Play Store, I would first want to draw myself or enlist the help of a friend to redraw all of these assets to ensure I didn’t steal content from their creators. As such, you will not be able to find this on the Play Store as of yet. However, if you email me saying you want to put this app to use, feel free to and I will post an app that falls within these guidelines.

This project was fun to explore. I learned a whole lot about Android app development, and created something I can put to use in my future ACNL endeavors. If you’d like to look at the source code, you can see it here.

 

2017 Summer Cryptography Project – Caesar Ciphers and ASCII Tables

Admittedly, the time before my summer semester in Japan was ill-spent in regards to furthering my understanding in the Computer Science world. However, there were still a couple of projects that I did for fun before I left. This first project, a rather simple caesar cipher, was the first of two projects I did. I did this project in particular as a way to brush up on some of the knowledge of the C language I gained during my spring semester CS 2505 class at Virginia Tech. For those unfamiliar with the concept of a caesar cipher, it’s a crude way to encode a chunk of information — simply taking every letter and shifting it up or down a predetermined number of spaces in the alphabet. For instance, the string “abcd” would be encrypted to “bcde” with a caesar key of positive one. Of course, traditionally, wrapping occurs at the ends of the alphabet; meaning z -> a with a key of +1, and a -> z with a key of -1.

There are a couple key parts when it comes to translating this into code. First and foremost, I made it runnable via. the command line. The program expects the file path to the text file the user wants scrambled or unscrambled, along with either ‘e’ or ‘d’ for ‘encode’ and ‘decode’ respectively. Next, instead of letting the letters wrap once at the end/beginning of the alphabet, I allowed the characters to go above/below this limit, possible thanks to the format of the ASCII table.

asciifull

ASCII table

In C, along with the vast majority of programming languages used today, ‘char’ (character) variables are actually stored as integers. Each character is 1 byte, allowing for up to 256 different characters to exist. This not only includes your standard upper/lower case alphabet and numbers, but also special characters, along with some special, machine only characters, like ‘\n’ (new line). So, instead of wrapping at the ends of the alphabet, I wrapped at the ends of the ASCII table (see methods encode and decode in the block below to see how). In regards to my program, this is relevant because it allows for characters to spill over into generally weird or unexpected characters, making it easier on us to program because we don’t need to look for specific ASCII values to wrap around, as well as adding a bit more effectiveness to the final product. Of course, this method won’t fool someone who knows what they’re doing when it comes to decryption, but it should generally prevent friends or co-workers from snooping into information you don’t want shared.

There are still plenty of improvements that can be made to this system to improve it even further and lessen the chance of someone cracking a particular files key. As you can see in this iteration of the program below, the key is static between all files, meaning a correct guess on one file means access to your entire library of secret text files. This could be improved by simply making the key random between files and stored somewhere inconspicuous. For instance, the key could be between 0 and 255, and simply written as the first character of the encoded file. While again, this method would fail almost instantly in the case of a professional crack, it should stump the average Joe for a couple of hours. Or, perhaps this method is repeated for every character in any one file; the key for any given character placed just before or after it. I’m sure you can see how this method can become increasingly complex, and increasingly difficult to break, the longer you think about it.

FILE *f;

int caesar = 5;

int main(int argc, char **argv) {
	if (argc != 3)
		badInput();
	FILE* f = getFile(argv[1]);
	if (strcmp(argv[2], "e") == 0)
		encode(f);
	else if (strcmp(argv[2], "d") == 0)
		decode(f);
	else
		badInput();
	fclose(f);
	return 0;
}

void badInput() {
	printf("Format is '.../caeser <.../fileToEdit.txt> <e/d>'\n");
	exit(1);
}

FILE* getFile(char *url) {
	FILE *f = fopen(url, "r+");
	if (f == NULL) {
		printf("Can't locate file '%s'", url);
		badInput();
	}
	return f;
}

void encode(FILE *f) {
	int c;
	while((c = fgetc(f)) != EOF) {
		fseek(f, -1, SEEK_CUR);
		fputc((c + caesar) % 255, f);
		fseek(f, 0, SEEK_CUR);
	}
}

void decode(FILE *f) {
	int c;
	while((c = fgetc(f)) != EOF) {
		fseek(f, -1, SEEK_CUR);
		fputc((c - caesar) % 255, f);
		fseek(f, 0, SEEK_CUR);
	}
}

The C code behind the Caesar Cipher. If you have any questions about the code feel free to email me: [email protected]

This project was an easy, quick, and fun way to stay familiar with the ins and outs of ASCII values and C I/O alike. Feel free to take this idea further and create ciphers of your own!

2015 Summer Game Project – Fast Paced Rogue-Like

In an attempt to gain familiarity with different approaches and methods towards game design and implementing images/text files into projects, I created several short games over the summer that were fast, fun, and a learning experience.

After spending a while playing games like FTL, the Binding of Isaac, and even watching twitch.tv streams like FourBitFriday’s Catacomb Kids really interested me in the realm of rogue like games. This time, I wanted to make a game that was as organized as I could make it while also advancing my skills in animation and level generation.

In my previous games, animating had been a real challenge because I had never implemented something solely for the purpose of animation. With this game, however, I decided to simplify it so that it wouldn’t be such a pain to implement every time I wanted a new entity. This determination propelled me to learn as much as I could about the animation process and sprite sheets as a whole, and in the end I found a pretty simple way of handling animation.

Screen Shot 2015-12-09 at 4.24.22 PM

Final product

I also spent a long time figuring out how to add smooth camera controls. After playing the game with a rigid camera, i knew it was time to make it smoother in order to encourage a faster pace throughout the game. So I learned a lot about how cameras and perspectives can interact with the current view point, knowledge that would become invaluable to me in future projects.

Screen Shot 2015-12-09 at 4.25.54 PM

Close-up of an enemy mob in the game

Lastly, I learned a lot about level creation. I had never made something that could load levels before, but I wanted to try and make a system for that specifically for this game. I decided to use a simple program like MSPaint to draw out the levels using colors to represent the various blocks, load them in, and connect them room by room. This proved more of a challenge than I had originally thought, as I did not anticipate the difficulty that came with reading RGB values of individual pixels. However, I pushed through by learning not only how to look at each individual pixel, but also the notation for RGB as well.

Screen Shot 2015-12-09 at 4.28.45 PM

An example of what a level looks like in MSPaint. Gray/Black = walls, Blue = enemy spawn points, etc.

This project was a fun one. I feel it really enhanced my organization skills when it comes to code as a whole, as well as strengthened my knowledge on how each individual part of a project comes together in the end to make one single product.

You can find the source code here (Java, 742kb): https://drive.google.com/file/d/0Bz_0wgRmDpKqTXNCSjFEU0V3X2M/view?usp=sharing

2015 Summer Game Project – Creation Sandbox

In an attempt to gain familiarity with different approaches and methods towards game design and implementing images/text files into projects, I created several short games over the summer that were fast, fun, and a learning experience.

This game is a side scrolling-open world-randomly generated creation sandbox similar to games like Minecraft or Terraria. In fact, the inspiration from this game came from spending several weeks replaying Terraria. Anyway, I wanted to explore concepts like world generation, mob behavior, inventory systems, animation, and more.

Screen Shot 2015-12-09 at 3.43.15 PM

Final product.

After creating a basic world, I decided to first take on mob interaction. Having not done anything like this before, I found it challenging at first to figure out how to not only spawn mobs in strategic places around the player, but how they could be unique from each other and their interaction with the player. I added 2 mobs: a snake, and a slime. They differ in behavior in that the snakes are faster while the slimes jump higher.

Screen Shot 2015-12-09 at 3.55.14 PM

Some slimes jumping above the player.

Another one of the most challenging yet most interesting parts of making this game was the world generation. I spent about 3 days wondering how I would add interesting caves, or even things like ore into the game. My final solution was to add something of a ‘miner’, a randomly placed dirt destroyer that cleared out the underground area it started in and moved around randomly until it decided to stop.

Screen Shot 2015-12-09 at 3.49.39 PM

Example of a very small fraction of the world, but in tile IDs. -1 = empty space underground, 0 = sky, 1 = dirt, 2 = grass, 4 = tree, etc.

All in all I learned a lot about this project, whether intentional or unintentional. One of the more important lessons it taught me is that organization, especially between objects, is crucial for keeping the entire project as a whole neat and orderly.

You can find the source code here (Java, 311kb): https://drive.google.com/file/d/0Bz_0wgRmDpKqZFpfMHlEUlNvdU0/view?usp=sharing

 

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