後端學習紀錄 Backend with FastAPI - Setting Enviroment

tags: `backend`

Copyright 2021, 月下麒麟

Target

該筆記主要目標為使用Web之Python框架FastAPI，
並結合資料庫框架Flask-SQLAlchemy與資料庫SQLite，
會著墨在探討FastAPI實作與前端分離應用。

Advantage

FastAPI is a Web framework for developing RESTful APIs in Python
support asynchronous programming FastAPI Wiki
FastAPI為排行第三的Python網頁框架，僅次於Django、Flask stackoverflow 2021 Developer Survey
前後端工具選用也須注意，盡量以前後的特性都一致(如:都支援異步)

Installation

Python(for Windows)

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

務必勾選add Python..PATH(等同設定環境變數)

Check

開啟終端機(cmd)，確認Python、Pip安裝成功與否，成功即出現版本資訊

Image Not Showing Possible Reasons
The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported
Learn More →

Reference: Pip是什麼? pip (軟體包管理系統)

Pip Install Module

安裝虛擬環境

pip install virtualenv

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

Reference:詳細請參考這篇IT邦幫忙 DAY03-搞懂Python的virtualenv

Create Vitual Enviroment

創建虛擬環境

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

虛擬環境資料夾被創建出來

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

Run Vitual Enviroment

進入資料夾

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

啟用虛擬環境，路徑前面會有被雙小括號的虛擬環境名稱，表示啟用成功

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

Different from Reality and Virtual

虛擬環境的好處就是作業環境可以隔離
舉個例子:
我在虛擬環境安裝了netmiko網路應用套件後

pip install netmiko

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

當你pip list 查看套件清單內容時會發現netmiko套件

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

(虛擬環境)

但是，當你離開虛擬環境再次查看，並不會發現有它

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

(實際環境)

Exit Virtual Enviroment

離開虛擬環境，路徑前的小括號不見了

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

Package your List

假設我這個專案安裝了很多套件，
移植到別處執行程式時，總不可能一個一個確認吧~~(會瘋掉…~~
所以阿~

pip 有個指令可以將該環境下的套件打包起來

pip freeze > requirement.txt

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

Unpckage your List

有打包，一定也有解包囉
解包時可以同時安裝requirements.txt裡的套件

Image Not Showing Possible Reasons

The image file may be corrupted
The server hosting the image is unavailable
The image path is incorrect
The image format is not supported

這樣就會進行自動安裝了~ 是不是超方便的!

Summary

所以應該要好好區隔每個專案的作業環境，
將來你把程式打包給別人使用時，環境才會一致且具移植性