Introduction of Flask

Flask is a lightweight “microkernel” Web application framework written in Python.

How to understand microkernels?

the “micro” in microframework means Flask aims to keep the core simple but extensible.

Contrast Django with the following:

Flask development environment setup

Python package management tool

  • eazy_install
  • PIP (Recommended)

⚠️ Note: Python can only be installed globally

  • Advantages: Only need to install once, can be used in other projects, avoid repeated installation.
  • Disadvantages: Some projects use different Python versions.

PIP command

  • pip install
  • pip uninstall
  • pip list

Build MAC development environment

Install Flask using PIP:pip install flask

Flask development tool

As the saying goes, “To do a good job, you must sharpen your tools.”

Common plain text development tools

  • Notepad++
  • Sublime
  • Emacs
  • Vim (recommended)

Configure the Python development environment based on Vim

  • Vundle: Vim management plug-in
  • YouCompleteMe: Powerful autocomplete plugin
  • NERDTree: jump between files
  • Vim-Jinja2-Syntax: Syntax enhancement plug-in

Vundle

Installation source: git clone https://github.com/VundleVim/Vundle.vim.git ~ / vim/bundle/Vundle vim configuration: $vim. ~ / vimrc

set nocompatible              " be iMproved, required filetype off " required

" set the runtime path to include Vundle and initialize
set rtp+=~/.vim/bundle/Vundle.vim
call vundle#begin()
" alternatively, pass a path where Vundle should install plugins
"call vundle#begin('~/some/path/here') " let Vundle manage Vundle, required
Plugin 'VundleVim/Vundle.vim'

" The following are examples of different formats supported.
" Keep Plugin commands between vundle#begin/end.
" plugin on GitHub repo
Plugin 'tpope/vim-fugitive'
" plugin from http://vim-scripts.org/vim/scripts.html
" Plugin 'L9'
" Git plugin not hosted on GitHub
Plugin 'git://git.wincent.com/command-t.git'
" git repos on your local machine (i.e. when working on your own plugin)
Plugin 'file:///home/gmarik/path/to/plugin'
" The sparkup vim script is in a subdirectory of this repo called vim.
" Pass the path to set the runtimepath properly.
Plugin 'rstacruz/sparkup', {'rtp': 'vim/'}
" Install L9 and avoid a Naming conflict if you've already installed a
" different version somewhere else.
" Plugin 'ascenator/L9', {'name': 'newL9'}

" All of your Plugins must be added before the following line call vundle#end() " required
filetype plugin indent on    " required
" To ignore plugin indent changes, instead use:
"filetype plugin on
"
" Brief help
" :PluginList       - lists configured plugins
" :PluginInstall - installs plugins; append `! ` to update or just :PluginUpdate " :PluginSearch foo - searches forfoo; append `! ` to refresh local cache" :PluginClean - confirms removal of unused plugins; append `! ` to auto-approve removal "
" see :h vundle for more details or wiki for FAQ
" Put your non-Plugin stuff after this line
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Start plug-in installation:

Write your first Flask application

$ vim app.py

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello_world() :
    return 'Hello World! '

if __name__ == '__main__':
    app.run()
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$python hello.py runs

Common integrated development environments

  • Microsoft Visual Studio
  • Eclipse + pydev
  • Pycharm (Recommended)

Create a Flask project2, implement “Hello world”

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello_world() :
    return 'Hello World! '

if __name__ == '__main__':
    app.run()
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