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html, body, .ui-content {
background-color: #333;
color: #ddd;
}

body > .ui-infobar {
display: none;
}

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display: block;
}

.markdown-body h1,
.markdown-body h2,
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color: #ddd;
}

.markdown-body h1,
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border-bottom-color: #ffffff69;
}

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color: #fff;
}

.markdown-body img {
background-color: transparent;
}

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color: white;
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color: white;
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background-color: #333;
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background-color: #191919;
color: white;
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color: white;
border-left: 1px solid white;
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color: #bcbcbc;
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background-color: #5f5f5f;
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.markdown-body table tr:nth-child(2n) {
background-color: #4f4f4f;
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.markdown-body code,
.markdown-body tt {
color: #eee;
background-color: rgba(230, 230, 230, 0.36);
}

a,
.open-files-container li.selected a {
color: #5EB7E0;
}

</style>}
# Python + Flask 虛擬美國股票交易網站 Part1 （配置＋工廠函數）
###### tags: `CS50` `Python` `Flask`
### 前言
四月開始上哈佛的CS50後，最後一個Project是要用Python + Flask 製作一個虛擬股票交易網站，做了蠻久一段時間的，還去買了[李辉 - Flask Web开发实战 helloflask](http://helloflask.com/book/1/) 來讀，最後總算做出來一個雛形，雖然有點陽春，不過該有的基本功能都有。

用[XMind](http://helloflask.com/book/1/) 畫了一下架構圖


#

### 使用套件
Flask
Bootstrap-Flask
Sqlalchemy
DebugToolbarExtension
LoginManager
Moment
CSRFProtect

## 配置 vfinance/setting.py

import os

prefix = 'sqlite:////'
basedir = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))

class BaseConfig(object):
    SECRET_KEY = os.getenv("SECRET_KEY", "dev key")

    
    DEBUG_TB_INTERCEPT_REDIRECTS = False

    SQLALCHEMY_TRACK_MODIFICATIONS = False
    SQLALCHEMY_RECORD_QUERIES = True

    # Flag used to enable CSRF protection for image uploading
    CKEDITOR_ENABLE_CSRF = True
    # The URL or endpoint that handles file browser.
    CKEDITOR_FILE_UPLOADER = 'admin.upload_image'
    TEMPLATES_AUTO_RELOAD = True
    

class DevelopmentConfig(BaseConfig):
    SQLALCHEMY_DATABASE_URI = prefix + os.path.join(basedir, 'vfinance.db')
    
config = {
    "development" :DevelopmentConfig
}

`DEBUG_TB_INTERCEPT_REDIRECTS = False` ：

FlaskDebugToolbar會攔截重新導向的請求，將DEBUG_TB_INTERCEPT_REDIRECTS配置設定為False可以關閉這個特性。

`DEBUG_TB_INTERCEPT_REDIRECTS = False` ：

安裝並初始化FlaskSQLAlchemy後，啓動程序時會看到命令行下有一行警告信息。這是因為FlaskSQLAlchemy建議你設置SQLALCHEMY_TRACK_MODIFICATIONS配置變量，這個配置變量決定是否追蹤對象的修改，這用於FlaskSQLAlchemy的事件通知系統。這個配置鍵的默認值為None，如果沒有特殊需要，我們可以把它設為False來關閉

`SQLALCHEMY_RECORD_QUERIES = True`
Can be used to explicitly disable or enable query recording. Query recording automatically happens in debug or testing mode. 自動記錄query的紀錄

#

在Setting.py文件的最後，建立了一個用來儲存配置名稱及對應配置的dictionary，之後便可以在建立程式實例後使用app.config.from_object()方法來加載配置。

## 在工廠函數載入設置、註冊藍本 vfinance/__init__.py

def create_app(config_name = None):
    if config_name == None:
        config_name = os.getenv("FLASK_CONFIG", "development")
    
    app = Flask('vfinance')
    app.config.from_object(config[config_name])
    
    app.register_blueprint(home_bp)
    app.register_blueprint(admin_bp, url_prefix = "/admin")
    app.register_blueprint(auth_bp, url_prefix = "/auth")

    return app

## 擴充外掛 vfinance/extensions.py

from flask_bootstrap import Bootstrap
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager
from flask_debugtoolbar import DebugToolbarExtension
from flask_moment import Moment
from flask_wtf import CSRFProtect



bootstrap = Bootstrap()
db = SQLAlchemy()
login_manager = LoginManager()
toolbar = DebugToolbarExtension()
moment = Moment()
csrf = CSRFProtect()

之後便可在工廠函數中導入以上的擴充對象，並使用init_app()函數傳入程式實例完成初始化

## vfinance/__init__.py

from vfinance.extensions import bootstrap, db, login_manager, toolbar, moment, csrf

def create_app(config_name = None):
    ...
    app = Flask('vfinance')
    ...
    
    bootstrap.init_app(app)
    db.init_app(app)
    login_manager.init_app(app)
    toolbar.init_app(app)
    moment.init_app(app)
    csrf.init_app(app)

    return app

除了外掛擴充外，還有很多函數要註冊到程序上，例如錯誤處理函數、上下文處理函數等。為了避免太複雜，可以根據類別把這些程式碼分類成多個函數，如下：

## vfinance/__init__.py：組織工廠函數

basedir = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
config_name = os.getenv("FLASK_CONFIG", "develpement")

if not os.environ.get("API_KEY"):
    raise RuntimeError("API_KEY not set")

def create_app(config_name = None):

    if config_name == None:
        config_name = os.getenv("FLASK_CONFIG", "development")
    
    app = Flask('vfinance')
    app.config.from_object(config[config_name])
    app.jinja_env.filters["usd"] = usd
    app.jinja_env.globals["lookup"] = lookup
    app.jinja_env.auto_reload = True


    register_blueprints(app) # 註冊藍本
    register_commands(app) # 註冊自定義shell命令
    register_extensions(app) # 註冊擴充功能
    register_template_context(app) # 註冊模板上下文處理函數
    return app


def register_blueprints(app):

    app.register_blueprint(home_bp)
    app.register_blueprint(admin_bp, url_prefix = "/admin")
    app.register_blueprint(auth_bp, url_prefix = "/auth")

def register_extensions(app):

    bootstrap.init_app(app)
    db.init_app(app)
    login_manager.init_app(app)
    toolbar.init_app(app)
    moment.init_app(app)
    csrf.init_app(app)

def register_shell_context(app):
    @app.shell_context_processor
    def make_shell_context():
        pass

def register_template_context(app):
    pass


def register_commands(app):
    ...

接著執行flask run來啟動程序

$flask run