Python Quart RestAPI

Python RestAPI using Quart HTTP/3 ASGI framework.

Environment setup

• On a development host, create a virtual environment for development and test. Both must be using the same virtual environment.
• Virtual environment is optional for CI/CD do because everything runs in a docker container.
• Add the following to .env for database access credentials:

DB_USERNAME=username
DB_PASSWORD=password

Google Gemini API

• Obtain an API key from https://aistudio.google.com/apikey
• Add a .env file with the following content:

  GEMINI_API_KEY=<api key>
  

Clean up pipenv

• pipenv --rm
• pipenv --clear
• pipenv lock --clear --verbose

Setup new pipenv

$ pipenv install
$ pipenv shell

Database setup:

• This project uses PostgreSQL database with SQLAlchemy ORM with marshmallow for object SerDes.

Install python modules

$ pipenv install --python=/path/to/python
$ cd src
$ pipenv install --python=/path/to/python
$ cd test
$ pipenv install --python=/path/to/python

Create Database

• Firstly, create an empty database "library" in PostgreSQL

Database Migration

• Copy env.py to migrations/ folder.

• Set the values DB_foo in /etc/pythonrestapi_config.json

• run migrations initialization with db init command:

  $ pipenv run alembic init migrations
  $ cp env.py migrations
  $ pipenv run alembic revision --autogenerate -m "Initial migration"
  $ pipenv run alembic upgrade head
  

• There will be 3 tables, "users", "books", and "authors" created in the PostgreSQL database "library" after the upgrade.

Test using PyTest:

• There are 7 test cases
  • JWT token generation and decoding
  • HomeController
  • FibonacciController

  $ pipenv run pytest -v
  $ python -m pytest
  

Continuous Integration:

• Integrated with CircleCI

Start the application:

• ./hypercorn.sh

HTTP/3 curl:

• To build your own HTTP/3 curl: https://curl.se/docs/http3.html
• Add Host header which is defined as server_names in hypercorn.toml

curl --http3-only --insecure -v https://localhost:4433/<path> -H "Host: khteh.com"

curl --http3-only --insecure -vv https://localhost:4433/chat/invoke -F 'prompt=:"What is task decomposition?"' -F 'file=@~/data/1.jpg' -F 'receipt=true'

Chrome browser

• Close ALL chrome browser (both tabs and windows)

• Generate TLS certificate fingerprint:

$ fingerprint=`openssl x509 -pubkey -noout -in /tmp/server.crt |
        openssl rsa -pubin -outform der |
        openssl dgst -sha256 -binary | base64`

• Start Chrome browser with QUIC protocol for HTTP/3:
• $1 is URL. For example: https://localhost:4433

$  /opt/google/chrome/chrome --disable-setuid-sandbox --enable-quic --ignore-certificate-errors-spki-list=$fingerprint --origin-to-force-quic-on=${1#*//} $1

Use Cases

Google Gemini API

• Return text message from input prompt string by calling the API
• Return text message from input prompt string and an image file by calling the API
• Multimodal:
  • Upload an image, "receipt" in this case, and it wil return a structured data containing details in the receipt:

  2025-05-21 13:15:34 DEBUG    ProcessReceipt response: {
  "date_str": "28-07-2017",
  "vendor": "Walmart",
  "currency": "USD",
  "items": [
    {
      "name": "PET TOY",
      "amount": 1.97
    },
    {
      "name": "FLOPPY PUPPY",
      "amount": 1.97
    },
    {
      "name": "SSSUPREME S",
      "amount": 4.97
    },
    {
      "name": "2.5 SQUEAK",
      "amount": 5.92
    },
    {
      "name": "MUNCHY DMBEL",
      "amount": 3.77
    },
    {
      "name": "DOG TREAT",
      "amount": 2.92
    },
    {
      "name": "PED PCH 1",
      "amount": 0.50
    },
    {
      "name": "PED PCH 1",
      "amount": 0.50
    },
    {
      "name": "COUPON 23100",
      "amount": 1.00
    },
    {
      "name": "HNYMD SMORES",
      "amount": 3.98
    },
    {
      "name": "FRENCH DRSNG",
      "amount": 1.98
    },
    {
      "name": "3 ORANGES",
      "amount": 5.47
    },
    {
      "name": "BABY CARROTS",
      "amount": 1.48
    },
    {
      "name": "COLLARDS",
      "amount": 1.24
    },
    {
      "name": "CALZONE",
      "amount": 2.50
    },
    {
      "name": "MM RVW MNT",
      "amount": 19.77
    },
    {
      "name": "STKOBRLPLABL",
      "amount": 1.97
    },
    {
      "name": "STKOBRLPLABL",
      "amount": 1.97
    },
    {
      "name": "STKO SUNFLWR",
      "amount": 0.97
    },
    {
      "name": "STKO SUNFLWR",
      "amount": 0.97
    },
    {
      "name": "STKO SUNFLWR",
      "amount": 0.97
    },
    {
      "name": "STKO SUNFLWR",
      "amount": 0.97
    },
    {
      "name": "BLING BEADS",
      "amount": 0.97
    },
    {
      "name": "GREAT VALUE",
      "amount": 9.97
    },
    {
      "name": "LIPTON",
      "amount": 4.48
    },
    {
      "name": "DRY DOG",
      "amount": 12.44
    }
  ],
  "tax": 4.59,
  "total": 98.21
  }, receipt: vendor='Walmart' currency='USD' items=[ReceiptItem(name='PET TOY', amount=1.97), ReceiptItem(name='FLOPPY PUPPY', amount=1.97), ReceiptItem(name='SSSUPREME S', amount=4.97), ReceiptItem(name='2.5 SQUEAK', amount=5.92), ReceiptItem(name='MUNCHY DMBEL', amount=3.77), ReceiptItem(name='DOG TREAT', amount=2.92), ReceiptItem(name='PED PCH 1', amount=0.5), ReceiptItem(name='PED PCH 1', amount=0.5), ReceiptItem(name='COUPON 23100', amount=1.0), ReceiptItem(name='HNYMD SMORES', amount=3.98), ReceiptItem(name='FRENCH DRSNG', amount=1.98), ReceiptItem(name='3 ORANGES', amount=5.47), ReceiptItem(name='BABY CARROTS', amount=1.48), ReceiptItem(name='COLLARDS', amount=1.24), ReceiptItem(name='CALZONE', amount=2.5), ReceiptItem(name='MM RVW MNT', amount=19.77), ReceiptItem(name='STKOBRLPLABL', amount=1.97), ReceiptItem(name='STKOBRLPLABL', amount=1.97), ReceiptItem(name='STKO SUNFLWR', amount=0.97), ReceiptItem(name='STKO SUNFLWR', amount=0.97), ReceiptItem(name='STKO SUNFLWR', amount=0.97), ReceiptItem(name='STKO SUNFLWR', amount=0.97), ReceiptItem(name='BLING BEADS', amount=0.97), ReceiptItem(name='GREAT VALUE', amount=9.97), ReceiptItem(name='LIPTON', amount=4.48), ReceiptItem(name='DRY DOG', amount=12.44)] tax=4.59 total=98.21 date_of_receipt=datetime.date(2017, 7, 28)
  

  • On the UI:

Create User:

• POST https://localhost:4433/users/create with the following JSON data:

  {
      "firstname": "First Name",
      "lastname": "LastName",
      "email": "[email protected]",
      "password": "P@$$w0rd"
  }
  

Login:

• POST https://localhost:4433/users/login with the following JSON data:

  {
      "email": "[email protected]",
      "password": "P@$$w0rd"
  }
  

• Sample response:

  {
      "jwt_token": "token string"
  }
  

Subsequent request header:

Key: api-key
Vaue: jwt_token from the login response

Create Author:

• POST https://localhost:4433/authors/create with the following JSON data:

  {
      "email": "[email protected]",
      "firstname": "JK",
      "lastname": "Rowing"
  }
  

Create Book:

• POST https://localhost:4433/books/create with the following JSON data:

  {
      "author_id": 1,
      "isbn": "123456",
      "page_count": "123",
      "title": "My First Book"
  }
  

Delete an author:

• Books table has a foreign key id to Authors.id and this is defined as required in BookSchema.
• Therefore, when a DELETE RESTful operation is sent to the application to delete an author which has associated book:

mysql.connector.errors.IntegrityError: 1048 (23000): Column 'author_id' cannot be null

Get Requests:

• Headers:

  Key: api-key
  Vaue: jwt_token from the login response
  

• visit https://localhost:4433

• visit https://localhost:4433/fibonacci/

• visit https://localhost:4433/users/all

• visit https://localhost:4433/authors/all

• visit https://localhost:4433/books/all