This is a Web-based text editor with auto-save capabilities. As a user edits text in the text editor, that text is automatically saved every time user types in. Typing also contains characters like Backspace, Delete, Ctrl-V or Ctrl-X. To reduce network traffic, you can increase the parameter SAVE_AFTER_X_TIMES at file public/javascripts/saveScript.js, which indicates how many times user must change to text to autosave. Text is automatically saved in a PostgreSQL database. If the web page is reloaded or the service is restarted, the text is recovered so that the user can continue editing. Also, files can be opened only in one tab. If the file is open, it can not be opened by another user, neither the same browser nor any other browser. With this, we avoid simultaneous processing and achieve file consistency.
The user has the following capabilities:
- view all the files of the web text editor (that exist in database).
- open a file and edit it.
- autosave of changes every time he/she edits the file.
- informed if file is saved, while it is saved, if something went wrong with saving, or how many more times does he/she have to type to autosave the file.
- create a new file.
- delete a file after he/she opens it.
- notify him/her if something went wrong with the creation, the deletion or the saving process of a file with the appropriate error pages.
Some assumptions of this project are:
- A file can be opened only in one tab. An error message occurs if someone tries to open it in another tab or browser.
- After X times the user edits the file, it is automatically saved. In this implementation parameter X equals to 1, but you can easily change it.
To store files we use PostgreSQL relational database.
To install it follow the instructions:
sudo apt update
sudo apt install postgresql postgresql-contrib
To set up the database you have to follow the instructions of file sql/setup.sql. Create a user, then create a database with owner the user you just created and then alter the role of user to superuser, to have the appropriate permissions.
CREATE USER texteditormanager WITH PASSWORD 'root';
CREATE DATABASE texteditordb WITH OWNER=texteditormanager;
ALTER ROLE texteditormanager WITH SUPERUSER;
After that you have to create a table into the database to store the files. You can also find the instructions in the file sql/createTables.sql.
CREATE TABLE files (
file_id serial PRIMARY KEY,
title varchar(200) NOT NULL,
text TEXT NOT NULL
);
If you want to insert rows into the database (from the terminal) you have to type:
INSERT INTO files (title,text)
VALUES ('new_file_name','Your new text...');
After the setup of the database you have to run the code of file models/CodeGen.scala to autogenerate the data model of database to Scala code, by using Slick library. To run it open a sbt shell and run the command:
runMain models.CodeGen
It will create a new model named Tables.scala with autogenerated code.
The following frameworks and tools were used for the implementation of the project:
Scala 2.13 to build backend of the assignment.
Sbt 1.7.0 version to build Scala project.
Play framework 2.8.18 version (running Java 11.0.17). Play Framework is an open-source web application framework which follows the model–view–controller architectural pattern. It is written in Scala and usable from other programming languages that are compiled to JVM bytecode.
Slick 5.1.0 version. Slick is a database access library for Scala.
IntelliJ IDEA was used for the development of the project.
There are several ideas for future work and improvements on this project. Some automated tests could be added, security could be checked and protect the application against malicious users. Also, some kind user authentication or user-account creation could be added and the cookie policy could be changed.