Environment Setup

This chapter introduces how to prepare a development environment for Flask projects.

Prerequisites: Python 3.9+ already installed; recommended to use VS Code + Python extension.

Steps:

1. Create project folder and enter it
2. Create and activate virtual environment
3. Install Flask
4. Verify installation

Windows (PowerShell):

mkdir flask-demo; cd flask-demo
python -m venv .venv
.venv\Scripts\Activate.ps1
pip install --upgrade pip
pip install "flask>=2.3"
python -c "import flask, sys; print('Flask', flask.__version__, sys.executable)"

macOS/Linux (bash/zsh):

mkdir flask-demo && cd flask-demo
python3 -m venv .venv
source .venv/bin/activate
pip install --upgrade pip
pip install "flask>=2.3"
python -c "import flask, sys; print('Flask', flask.__version__, sys.executable)"

Optional Tools:

• pip-tools/poetry/pdm: Dependency management
• ruff/black/isort: Code quality
• pre-commit: Commit hooks

Common Issues:

• Windows activation script error: Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned as administrator and retry
• Multiple Python versions: Use py -3.11 -m venv .venv or explicitly use the Python path