utils/flask_rest_api/README.md

# Flask REST API
[REST](https://en.wikipedia.org/wiki/Representational_state_transfer) [API](https://en.wikipedia.org/wiki/API)s are commonly used to expose Machine Learning (ML)  models to other services. This folder contains an example REST API created using Flask to expose the `yolov5s` model from [PyTorch Hub](https://pytorch.org/hub/ultralytics_yolov5/).

## Requirements

[Flask](https://palletsprojects.com/p/flask/) is required. Install with:
```shell
$ pip install Flask
```

## Run

After Flask installation run:

```shell
$ python3 restapi.py --port 5000
```

Then use [curl](https://curl.se/) to perform a request:

```shell
$ curl -X POST -F [email protected] 'http://localhost:5000/v1/object-detection/yolov5s'`
```

The model inference results are returned:

```shell
[{'class': 0,
  'confidence': 0.8197850585,
  'name': 'person',
  'xmax': 1159.1403808594,
  'xmin': 750.912902832,
  'ymax': 711.2583007812,
  'ymin': 44.0350036621},
 {'class': 0,
  'confidence': 0.5667674541,
  'name': 'person',
  'xmax': 1065.5523681641,
  'xmin': 116.0448303223,
  'ymax': 713.8904418945,
  'ymin': 198.4603881836},
 {'class': 27,
  'confidence': 0.5661227107,
  'name': 'tie',
  'xmax': 516.7975463867,
  'xmin': 416.6880187988,
  'ymax': 717.0524902344,
  'ymin': 429.2020568848}]
```

An example python script to perform inference using [requests](https://docs.python-requests.org/en/master/) is given in `example_request.py`