Tweeter

This is a project for the SQL-course at Ludu.co.

Setup

The application uses python 3, and 4 external libraries:

• flask - For setting up the server.
• wtforms - For easily creating forms.
• psycopg2 - For inteacting with our database.
• passlib - To hash and salt passwords.

You'll also need four tables in your database:

• Users(userID, username, email, age)
• Tweets(tweetID, posterID, content, time_posted)
• Followers(userID, followerID)
• Passwords(userID, password)

You can download the libraries and create the tables manually, or by running setup.py. The file will download the libraries and create an create.sql file with all tables. It'll also create 4 CSV-files with compatible data for each table.

Running the application

To run the application, simply run app/tweeter.py. By default, all functionality will be limited, as it is expected you provide the functionality yourself by filling in the functions in the file database_exercise.py.

If you want to run the full-featured application, change the import in app/tweeter.py from from database_exercise ... to from database ....

Common errors

• The application throws the error "Couldn't connect to server. Potential problems might be: ..."

If you want to run the full-featured version, you'll have to start the server. Launch psql and connecting to the database.

Another problem might be the arguments you pass (or don't pass). Make sure the arguments match the values from psql:

The only differences should be that the Database is "tweeter" (rather than "postgres") and Username is "tweeter_admin".

• Another error pops up

The application is written and tested with Python 3 in mind. If you're using Python 2 it won't work. Check your version by running python --version, or py --version if you're on Windows, in the command line.

Notice

• The flask server is supplied by Werkzeug, which loads your application twice in debug mode. This is to enable it to reload your server when the code changes without having to completely restart the server. However, this means that any code you have in the top-level will be run twice. Shouldn't cause any problem however, but is something to be aware about.
• Some code in this application doesn't follow best practices. This is to keep things less complicated. One of the biggest concerns is the lack of an ORM, which was omitted as the course is about learning SQL and not about developing a website. This causes some synchronization issues and thus some hardcoding has to take place. So be cautious about taking things in this project as sign of good practice!

Known errors/bugs

• The paragraph tag doesn't wrap text by default. This means that posting a tweet with just a single long word or reducing your browser width will overflow the edge. Solution to this is to implement some check for long words and manually break them, or to include a CSS property word-break.
• An email doesn't have to be valid. This could be fixed by adding a trigger to the User table and make sure the application handles those exceptions.
• The settings page is not displaying good error messages when the data is invalid or the password is wrong. This could be fixed by raising an error from validate_and_perform_user_changes which could get caught in the application and displayed with a flash message.
• Searching for a tweet containing an URL (for example 'http://127.0.0.1:5000'), will yield 'Not Found'.

Author

The project is written by Ted Klein Bergman, a KTH student in Media Technology / Computer Science. He's a T.A. in Database and Software Development and passionated about programming. He's also not afraid of constructive criticism, so don't be afraid to point out errors in the Ludu course.