I Designed a Custom Protocol for My App

Summary

Introduction Rast (in Kurdish: “ڕاست” [raːst]) is a new experimental project of mine for detecting orthographical errors in texts written in the Central Kurdish language, also known as Sorani. I designed it in a way that works very efficiently with long texts over a duplex network connection. To do this, I first created K8, a 8-bit coding standard for Kurdish. K8 This was designed because Kurdish characters are non-ASCII, and take two bytes each when encoded using UTF-8, making them very unefficient for binary protocols. It also supports backward-compatibility for non-covered UTF-8 characters when needed by encoding an optional footer. Below is an example of that. 00 -- version 97 -- س A1 -- ڵ 8A -- ا A6 -- و AB -- ، 20 -- space 00 00 00 21 -- ! 01 -- footer start D0 BC -- м D0 B8 -- и D1 80 -- рThe above is a representation of the literal سڵاو، мир!. This footer-based compatibility is used K8 is used in Rast's URL state, and the version without it is used in the transport protocol as described below. The Transport Protocol The goal of the project is straightforward: receive a stream of text, stream back a list of errors. Errors are made up of their details, which are two strings of text: a generic title and a specific description. Each component of an error’s detail is transported once only. Afterwards, their references will be kept by both the server and the client throughout the WebSocket connection. Below is a brief representation of it. +-------------------------------------------------------------------+ header | uin16 - error count | header +-------------------------------------------------------------------+ header | uin16 - detail count | header +-----------------------+-------------------------------------------+ errors | uint16 - error offset | uint8 error length | errors +-----------------------+-------------------------------------------+ errors | ..................... | .................. | errors +-----------------------+------------------------------...