233 lines
6.6 KiB
Markdown
233 lines
6.6 KiB
Markdown
# Flask
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## 介紹
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### Flask 是一個使用 Python 語言開發的輕量級 Web 應用框架。近年來因為Python簡單易學的語法以及強大的生態系統，所以在Web開發領域也逐漸受到青睞。其中Flask的哲學是保持核心簡單但擴充性強，它只提供了路由、模板、靜態檔案等最基本的功能，其他大多數功能則是通過擴展提供，這樣可以讓我們按需求選擇。
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### Flask強調概念明確、低耦合度和可擴充性。和Django等全能框架不同
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### Flask 用template 與 static 2個資料夾做區分
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#### template 用於存放HTML等網頁
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#### static 用於存放靜態文件，包刮JS、CSS、img等
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#### 若需要更進階的需求，建議去前端找Bootstrap，那邊以Flask去介紹如何套版，可以快速製作漂亮的網站頁面
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##
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## 程式碼說明
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### 首先先以Python切入
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### Python
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```python
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# 匯入會用到的庫
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from flask import Flask
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from flask import render_template
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from flask import Flask, request, jsonify
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import threading
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import requests, socket
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import pymysql
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# from flask_cors import CORS # 若有跨域需求再開，練習通常用不到
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```
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### 接著我這邊與網路上的寫法有些不同，我直接寫成物件導向的方式，實測下來沒太大問體
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#### 先設定多線呈方式，及設定好資料庫連線位置
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```python
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class Website(threading.Thread):
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def __init__(self):
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threading.Thread.__init__(self)
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self.db = pymysql.connect(host='140.125.21.65', port=3307, user='VIP125', passwd='@VIPvip125', db='VIP125', charset='utf8')
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self.app = Flask(__name__)
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# CORS(self.app)
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```
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### 路由設定
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#### 這邊統一教學，我設定成前後端分離的方式，將頁面與API做個區分，之後若是要單獨架設頁面或是API都可以直接修改
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```python
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#前端顯示
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self.app.add_url_rule('/', 'Index', self.Index)
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self.app.add_url_rule('/next/<id>', 'Next', self.Next)
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# API
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self.app.add_url_rule('/api/get_data', 'get_data', self.get_data,methods=['get'])
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self.app.add_url_rule('/api/get_one_data/<id>', 'get_one_data', self.get_one_data, methods=['get'])
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```
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### 前端頁面導向
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#### 這邊提供純頁面及需要攜帶部分參數的簡單方式
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```python
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# 前端
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def Index(self):
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return render_template('Index.html')
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def Next(self,id): # 攜帶參數
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return render_template('Next.html',id = id)
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```
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### 後端資料
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#### 建議先看過一部份的資料庫語法後再來接觸
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```python
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# 後端API
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def get_data(self):
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cursor = self.db.cursor()
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sql = "select * from teaching_sql_1"
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cursor.execute(sql)
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data = cursor.fetchall()
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print(f'ALL_data = {data}')
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return jsonify(data)
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def get_one_data(self,id):
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cursor = self.db.cursor()
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sql = f"SELECT * FROM teaching_sql_1 WHERE student_id='{id}';"
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print(sql)
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cursor.execute(sql)
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data = cursor.fetchall()
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print(f'user_id = {data}')
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return jsonify(data)
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```
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### 完整程式
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```python
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from flask import Flask
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from flask import render_template
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from flask import Flask, request, jsonify
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import threading
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import requests, socket
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import pymysql
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# from flask_cors import CORS
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class Website(threading.Thread):
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def __init__(self):
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threading.Thread.__init__(self)
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self.db = pymysql.connect(host='140.125.21.65', port=3307, user='VIP125', passwd='@VIPvip125', db='VIP125',
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charset='utf8')
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self.app = Flask(__name__)
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# CORS(self.app)
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#前端顯示
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self.app.add_url_rule('/', 'Index', self.Index)
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self.app.add_url_rule('/next/<id>', 'Next', self.Next)
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# API
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self.app.add_url_rule('/api/get_data', 'get_data', self.get_data,methods=['get'])
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self.app.add_url_rule('/api/get_one_data/<id>', 'get_one_data', self.get_one_data, methods=['get'])
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def run(self):
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#self.app.run()
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self.app.run(host="0.0.0.0", port="5500")
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# 前端
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def Index(self):
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return render_template('Index.html')
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def Next(self,id): # 攜帶參數
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return render_template('Next.html',id = id)
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# 後端API
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def get_data(self):
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cursor = self.db.cursor()
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sql = "select * from teaching_sql_1"
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cursor.execute(sql)
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data = cursor.fetchall()
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print(f'ALL_data = {data}')
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# 返回 JSON 响应
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return jsonify(data)
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def get_one_data(self,id):
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cursor = self.db.cursor()
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sql = f"SELECT * FROM teaching_sql_1 WHERE student_id='{id}';"
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print(sql)
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cursor.execute(sql)
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data = cursor.fetchall()
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print(f'user_id = {data}')
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return jsonify(data)
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if __name__ == '__main__':
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website = Website()
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website.run()
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```
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### 前端(HTML)
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#### 這邊就以基礎的HTML與JS進行
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#### 有簡單的利用AJAX去撈資料、頁面跳轉
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#### Index.html
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``` HTML
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<title>Flask HTML CSS Example</title>
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<link rel="stylesheet" href="{{ url_for('static', filename='css/style.css') }}">
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<link rel="stylesheet" href="{{ url_for('static', filename='lib/bootstrap/dist/css/bootstrap.min.css') }}"/>
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<link rel="stylesheet" href="{{ url_for('static', filename='css/site.css') }}" asp-append-version="true"/>
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<script src="{{ url_for('static', filename='js/script.js') }}"></script>
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<script src="{{ url_for('static', filename='js/site.js') }}"></script>
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<script src="{{ url_for('static', filename='lib/bootstrap/dist/js/bootstrap.bundle.min.js') }}"></script>
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<script src="{{ url_for('static', filename='lib/jquery/dist/jquery.min.js') }}" asp-append-version="true"></script>
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</head>
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<body>
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<h1>Flask</h1>
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<div class="size2">
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<div>
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Hello World!
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</div>
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<input type="text" id="value_id" />
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<button onclick="next_clicked()">下一頁</button>
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<button onclick="get_data()">獲取資料</button>
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</div>
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</body>
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</html>
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<script>
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function next_clicked(){
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var id = document.getElementById("value_id").value
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window.location = "/next/" + id;
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}
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function get_data(){
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$.ajax({
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type: "GET",
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url: "/api/get_data",
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data: {},
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contentType: "application/json",
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success: function (Model) {
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console.log(Model)
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//set_data(Model)
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}
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});
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}
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</script>
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```
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#### Next.html
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``` HTML
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<title>Title</title>
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</head>
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<body>
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<input id="value_id" value='{{ id }}' />
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<br>
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<button onclick="Index_clicked()">首頁</button>
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</body>
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</html>
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<script>
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function Index_clicked(){
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window.location = "/";
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}
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</script>
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``` |