Swift Journal

I have been thinking about MVC design pattern, and I was very confused. 

I have ran into a problem while developing a social media app as a side project. I have custom UITableViewCell, and it sits in a UIViewController, from now on I will call it “controller class”. Problem was all the outlets of the cell are connected to the UITableViewCell’s particular class, from now on I will call it “view class”, in order to preserve MVC. And I want to perform segue while an image in a cell is tapped. 

First, I have tried to do it in the “view class”. Although it violates MVC principals, I found it the easiest way to do.  Usually, things may not go as planned :) After some thinking, googling and trying, I realized that it looked impossible and unnecessary to do. Then I started over everything.

I have attended many iOS Meetups in New York since October 2015, and I am in a Slack group of one of the best Meetup around. I asked my question there, and they answered me very fast. According to a friend, solution is the delegation. I have heard about protocols and delegations before, however I couldn’t think the solution was there. I was a huge enlightenment to me. I googled “reywenderlich protocols delegates”, and there was the solution :) http://www.raywenderlich.com/115300/swift-2-tutorial-part-3-tuples-protocols-delegates-and-table-views I wrote a protocol in my view class, and create a delegate variable, then I made my controller class conform the protocol. That was all, and it was very satisfying to solve the problem which made me uncomfortable for a time.

Thanks for the friend, reywenderlich, stackoverflow and surely google!

Web request is composed of just four(yeah, it is true, just 4(for Romans it is IV)) operations. These are POST, GET, UPDATE, and DELETE.

When you write a text, or take a picture from your device and submit it to your favourite app, under the hood, the app talks with a cloud server, then cloud server save the data to its database. This is the high level picture of the how client server architect works.

Most of the application we use everyday on smart phones, are just capable of the GET request. It means they asks for the server for the data, and server give them the data they requested. It is just that. For the code snippets below, I will show how this kind of web request works.

Applications

Web request can be challenging and sometimes difficult to debug, because you have to differentiate problem source is whether your code or your request. To eliminate the possibilities of having a bad request, it is nice to check to request before put it into the code. For this aim, I use postman. You can click the link at the end of the page. You can read the comments in order to have better idea about the process.

//It is better to call this function in your view controller func webRequest(){

//It is our request. I check it with the postman app before I put the code        let urlString = "http://jsonplaceholder.typicode.com/comments/5"        //I create shared session in order to start request let session = NSURLSession.sharedSession() //This is for our session need NSURL kind of url, it looks like just parsing        let url = NSURL(string: urlString)!

       session.dataTaskWithURL(url) { (let data: NSData?, let response: NSURLResponse?, let error: NSError?) -> Void in            if let responseData = data {                do {                    let json = try NSJSONSerialization.JSONObjectWithData(responseData, options: NSJSONReadingOptions.AllowFragments)                    print(json)                }                catch {                    print("There is an error")                }            }

       }.resume()        } }

The apps & technologies used for web requests

Postman JSON HTTP NSURL

Yesterday, I have had a problem to download a data(picture) from a web source. Despite, I was pretty sure that each line of code I wrote was correct, I cannot prevent myself to see the default image all my tableview on the application that I developed. App doesn’t load picture from URLs, it just show the picture in its assets folder. The code just have some warning, and that's all. After many times I checked whether the URLs that I borrowed pictures are active, and built the application for couple of times, I realised that on Xcode, "Application Transport Security has blocked a cleartext HTTP (http://) resource load since it is insecure. Temporary exceptions can be configured via your app's Info.plist file." warning appears.

Apparently, apple doesn't want your app to talk with the insecure HTTP instead of secure HTTPS. For that reason, it sets default not to talk with HTTP, but you have the power to change it!

And after some search, I found the solution.

Adding the following to your Info.plist will disable Application Transport Security and let the application to talk with the HTTP.

<key>NSAppTransportSecurity</key>       <dict>            <key>NSAllowsArbitraryLoads</key><true/>       </dict>  

Currently, I joined MIT’s famous “6.00.1x Introduction to the Computer Science and Programming Using Python” course.

Although I write many lines of code during my first year in CS, the course is really helpful to me. Thanks to its solid structured design, I am able to learn deeper than ever in the subject of CS.

It is not a course for just coding, one can infer from its name, it is a really fast and solid introduction to the CS.

Professor Eric Grimson is also fantastic teacher. He is straight and all examples he gives are crisp and sticky to my mind. He is not a funny person, he is a science guy with the solid teaching skills. 

As far as my time, this is the most serious and beneficial MOOC I have ever seen. I would like to the friends who took this class before and have taken right now.

Network Science

Network science is an interdisciplinary academic field which studies complex networks such as telecommunication networks, computer networks, biological networks, cognitive and semantic networks, and social networks. The field draws on theories and methods including graph theory from mathematics, statistical mechanics from physics, data mining and information visualization from computer science, inferential modeling from statistics, and social structurefrom sociology. The United States National Research Council defines network science as "the study of network representations of physical, biological, and social phenomena leading to predictive models of these phenomena.

Computer Network

A computer network or data network is a telecommunications network which allows computers to exchange data. In computer networks, networked computing devices pass data to each other along network links (data connections). Data is transferred in the form of packets. The connections between nodes are established using either cable mediaor wireless media. The best-known computer network is the Internet.

ARP

The Address Resolution Protocol (ARP) is a telecommunication protocol used for resolution of network layeraddresses into link layer addresses, a critical function in multiple-access networks. ARP was defined by RFC 826 in 1982.[1] It is Internet Standard STD 37. It is also the name of the program for manipulating these addresses in most operating systems.

Wireless Netwok

A wireless network is any type of computer network that uses wireless data connections for connecting network nodes.

Wireless networking is a method by which homes, telecommunications networks and enterprise (business) installations avoid the costly process of introducing cables into a building, or as a connection between various equipment locations.[1] Wirelesstelecommunications networks are generally implemented and administered using radio communication. This implementation takes place at the physical level (layer) of the OSI model network structure.[2]

Examples of wireless networks include cell phone networks, Wi-Fi local networks and terrestrial microwave networks.

Frequency-shift keying

Frequency-shift keying (FSK) is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier wave.[1] The simplest FSK is binary FSK (BFSK). BFSK uses a pair of discrete frequencies to transmit binary (0s and 1s) information.[2] With this scheme, the "1" is called the mark frequency and the "0" is called the space frequency. The time domain of an FSK modulated carrier is illustrated in the figures to the right.

Twisted Pair

Twisted pair cabling is a type of wiring in which two conductors of a single circuit are twisted together for the purposes of canceling out electromagnetic interference (EMI) from external sources; for instance, electromagnetic radiation from unshielded twisted pair (UTP) cables, and crosstalk between neighboring pairs.

Coax

DDoS

Unicast

Cocktail Party Effect

https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing

Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL Internet access, wireless networks, powerline networks, and 4G mobile communications.

CSMA

MAC

Modülasyon

Tutorial for General Networking

https://en.wikipedia.org/wiki/International_Telecommunication_Union

https://en.wikipedia.org/wiki/Media_access_control

I think all around the world, people learn with comparison. We all compare something that we know with the others we have not know to understand it better. Especially in geography courses that I took during elementary and high school years, I implemented this method intuitively to understand how the biggest lake is bigger than the biggest lake I have ever seen.

Most of the people travel around, and they do not have enough time to get the gist of the destination. In this point, I think a software which will help both students and travellers help to get the big picture of the world and the destinations that they will go in future. 

What would if we have an application which compare a known country/region/city/lake etc. that we have seen/known before with the others we have not any idea yet.