This project is a library management system to help library users and librarian with the proccess of borrowing book. There are 5 main models in this project: Book, Comment, Contract, User, ContractUpdater. it is similar to an e-commerce site but instead of buying products, user can create a contract to reserve a book. the contract model has 4 main statuses: waiting, means the contract is waiting for user to take the book and accepted by staff, expired mean the waiting time has expired and the contract become not eligible, active mean the staff has accepted the contract, the book is in the user hand and need to be returned before the due date, late mean the book has not been returned after the due date have passed.

ContractUpdater is a daily updater that whenever saved, it checks the date on waiting, and active contracts and change its status based on its expiration date and current date. It is not exactly a daily update, it will be created whenever a staff authenticate/visit the website and no ContractUpdater already present in the current date.

The app is mobile responsive, it is styled using plain css.

```
construe
│
├── books               # rest APIs
│     ├── models.py 
│     ├── views.py
│     ├── serializers.py
│     ├── permissions.py
│     ├── utils.py
│     ├── urls.py
│     └── ...
│ 
├── construe
│     ├── settings.py
│     └── ...
│
├── construe_frontend   #react frontend
│     ├── src
│     │    └── Components
│     │            ├── App.js
│     │            ├── Auth.js
│     │            ├── BookPage.js
│     │            ├── Comments.js
│     │            ├── Header.js
│     │            └── ...
│     │
│     ├── static
│     ├── templates
|     └── ...
|
├── users     
│     ├── models.py 
│     ├── views.py
│     ├── serializers.py
│     └── ...
│
├── manage.py
└── reuirements.txt
```

• Book model contain common field such as title, description, author, slug and category. The quantity field will determine if the book currently available and can be reserved.
• Contract model have a UniqueConstraint Meta class where a user can't have 2 contracts with the same book. the save() method will extend the expiry if the status changed to active.
• Comment model contain common field such as book(which book page this comment is in), user, body, timestamp, reply(which comment is this comment/reply is in). The reply comment will have a None book field and a relation to a book comment and Book comment will have None reply field and a book object.
• ContractUpdater have a contracts ManyToManyField where it stores all the contracts that has been automatically updated at the current date.
• ContactUS model is similar to Comment, just different table.

Most of the ModelSerializer use a default django-rest-framework settings. in BookSerializer, get_quantity method will substract the actual book quantity with the book active + waiting contracts

these files provide some helper function for the views.py like custom permissions and validators.

Most of the views in this file are created using django rest framework generic views. The get_queryset() method in book_list class optionally take an argument 'pattern' to filter the books before its get returned as a response. The get_queryset() method in CommentsView takes 2 arguments 'group' and 'pk'. if the group is 'replies' then the pk is a comment_id thus will return comment objects that has reply relation to the comment with the given id, if the group is 'comments' then the pk will be a book_id thus will return comment objects with a relation to the book. The same thing is also applied to the perform_create() method.

this is the frontend part of the apps, the index() view in views.py will render html with an empty div templates/construe_frontend/index.html with a script that link to static/construe_frontend/main.js. inside main.js is a bundling of react components from src/components.js folder.

In App.js the user state is being passed as a global state userContext with help of createContext() and contextProvider. Auth.js provides LoginPage and RegisterPage component

BookPage have a reserve book button for authenticated user that will triger a rentBook function and render ContractBox component. in ContractBox there is a function toggle that will check the class name of the clicked div, if its not a 'box-layout'(in this case outside of the contract box) it will unmount the ContractBox component.

The ContractPage will render a list of authenticated user contracts (all users contracts if its a staff user), The pagination of the list is created using django-rest-framework pagination and useEffect hook. the api will return a JSON contain { results: ..., next: *url, previous: *url}. a next or previous button will change the url state thus will trigger the useEffect hooks and fetch the next/previous url. and if there are no next/previous url the button should be disabled. this method also used for the book list in Sidebar.js.

The Home components will render a list of recently added books and a random quote about books from a list of quote in quotes.

install requirements

-pip install -r requirements.txt

migrate

-python manage.py makemigrations books
-python manage.py migrate

create superuser for admin page

-python manage.py createsuperuser
-python manage.py runserver

login with superuser account, there should be an administrator button to go to the admin page. then create some book samples(only book title is required to save a book object). back to the main page to try its features.

• Cookie must be enabled to be able to authenticate a user (CSRF token is acquired from cookie),
• to edit the react components, refer to Construe_frontend to start react development mode