Dabi

Databases Group Project (Namtrak)

Install flask by running:

pip install flask

Install pip if you haven't since it's pretty useful anyway.

Go into the dabi_app directory, run:

python2 run.py

Go to http://localhost:5000/ (or http://127.0.0.1:5000/) in your web browser and you'll get the index page. Alternatively, add a page e.g. http://localhost:5000/search_results.html to go directly to it.

Remember your browser has a cache, so any changes you make while the server is up and running might not be immediately visible. For best results, refresh using CTRL-<F5> so the cache is ignored.

The directories are organized as such:

• the root directory contains this file, the requirements.txt file which outlines the packages required to run flask, as well as the required versions, and the new_schema.sql file, which was used to initialize our database with the correct tables and some sample data. Within the root directory we also have the following directories:

  • report directory: Contains TEX file and resulting PDF file for the report submitted earlier in the semester.

  • dabi_app contains our code. In it, we have:

    • The database.db file contains our SQLite database. We are currently in the process of shifting away from SQLite and towards MySQL.

    • The __init__.py file defines the location of files containing code necessary for flask to properly display pages and respond to requests.

    • The create_seats_free.py file is used to generate the create_seats_free.sql file, which in turn was used to populate the free_seats table of our database. We elected to automate this process due to the sheer number of entries that free_seats would require. For reference, the python script is only 253 bytes in size, while the SQL file generated is over 700 kilobytes. Even the new_schema.sql file, used to initialize the database, is less than a tenth of that size, at 51.2 kilobytes.

    • The app directory contains the following:

      • __init__.py is required for flask to run properly.

      • models.py contains various utility functions called on to interface with the database as well as to resolve variables used to render templates.

      • views.py is where the functions used to render templates are defined. Defining a new page is done by first creating a template for it in the templates directory, and adding a route in views.py to have the desired page requested render the template we created. For example, accessing the check_schedule page on the website will run the check_schedule function in views.py, which runs the get_all_stations function from models.py and assigns the return value to a variable, which is then passed into the render_template function to render the template defined, which will be looked for inside the templates directory. Instances of all_stations in the specified template will be replaced with the value passed into the return_template function.

      • The static directory contains the CSS and JavaScript files used to control how the pages look.

      • The templates directory contains all the templates used. Most of them extend layout.html, since that is the page which contains everything we'd like to include in the majority of pages on our website, such as script and style declarations, as well as the navigation bar at the top of the pages. The other template should be quite self-explanatory, as they consist of mostly unspectacular HTML. The text in between curly braces is used by the template rendering engine to determine how the templates are to be rendered. For example, in confirmation.html, we have the text "Thank you! Ticket number for Passender {{ passenger_id }} is {{ticket_num}}". On calling render_template, we must also pass in the variables we would like to use for passenger_id and ticket_num. These are obtained by calling functions from models.py. The template rendering engine will then replace {{ passenger_id }} and {{ticket_num}} with the values provided when returning a complete HTML page to be displayed in a browser.