# Line Bot Lesson 3 - 專題實作-旅遊購物外幣換算 fastapi+firebase版
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###### tags: `python` `Line` `Bot` `api`
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試試看這個 line-bot吧! <a href="https://lin.ee/VbbJPCq"><img src="https://scdn.line-apps.com/n/line_add_friends/btn/zh-Hant.png" alt="加入好友" height="36" border="0"></a>


在程式中，
我們使用到 fastapi 取代 flask, uvicorn 取代 gunicorn,
資料庫使用firebase 的 nosql 資料庫，有興趣的可以看看詳細使用方法請參閱

[FastAPI與Python內建wsgi]https://hackmd.io/@CSL/Hyzuh83Oo

[Python 連結NoSQL資料庫(Firebase)的 CRUD] https://hackmd.io/@CSL/BJVz8SFl3

因此 你必須先
pip install fastapi,uvicorn,twder,re,linebot-sdk,firebase_admin

這是這個程式的原始碼

# 使用fastapi
LINE_CHANNEL_ACCESS_TOKEN='xxxxx'
LINE_CHANNEL_SECRET='xxx'

AUTHOR='林奇賢'
curd={"..":{"美金":"..USD","日圓":"..JPY","韓元":"..KRW","歐元":"..EUR","人民幣":"..CNY","更多":"..,"},
"..,":{"港幣":"..HKD","英鎊":"..GPB","澳幣":"..AUD","泰幣":"..THB","馬來幣":"..MYR","更多":"..,,"},
"..,,":{"菲比索":"..PHP","印尼幣":"..IDR","越南盾":"..VND","加幣":"..CAD","紐元":"..NZD","更多":"..,,,"},
"..,,,":{"瑞士法郎":"..CHF","南非幣":"..ZAR","瑞典幣":"..SEK","新加坡幣":"..SGD","更多":".."},
}

import re
import twder

from fastapi import FastAPI, Request
from linebot import LineBotApi, WebhookHandler
from linebot.exceptions import InvalidSignatureError
from linebot.models import MessageEvent, TextMessage, TextSendMessage, QuickReply, QuickReplyButton, MessageAction
import firebase_admin
from firebase_admin import credentials
from firebase_admin import db

app= FastAPI(docs_url=None, redoc_url=None, openapi_url = None)
myDB='https://myfirstfirebase-601001.firebaseio.com/'
cred = credentials.Certificate("apikey.json")
firebase_admin.initialize_app(cred, {'databaseURL': myDB})
curr_users = db.reference('/bot3')

line_bot_api = LineBotApi(LINE_CHANNEL_ACCESS_TOKEN)
handler = WebhookHandler(LINE_CHANNEL_SECRET)

# a POST route for our webhook events
@app.post("/")
async def webhook_handler(request: Request):
    # verify signature if needed
    # add logic to handle the request
    signature = request.headers['X-Line-Signature']
    body = await request.body()
    try:
        handler.handle(body.decode(),signature)
    except InvalidSignatureError:
        raise HTTPException(status_code=400, detail="SignatureError")

    return "ok"

@handler.add(MessageEvent, message=TextMessage)
def handling_message(event):
    mtext=event.message.text
    user_id=event.source.user_id #get userID in Line
    query_id=curr_users.child(userid)
    currency=query_id.get() # get data-line userID in firebase

    if currency is 'None': # if there is no data in firebase
       curr_users.update({user_id:"JPY"})
       currency='JPY'

    try:
       regex = r'[^0-9.+-/()*]'
       prog = re.compile(regex)
       if not prog.search(mtext):
              money=eval(mtext)
       else:
              money=-1
       curr=float(twder.now(currency)[2] if twder.now(currency)[4]=='-' else twder.now(currency)[4])
       #2:現鈔賣出 4:即期賣出 ，若無即期報價則回傳現鈔報價
    except:
       curr=0
       money=-1

    if mtext.upper()=="AUTHOR":
        message=TextSendMessage("作者:"+AUTHOR)
    elif mtext in curd:    # mtext='..' or '...' or '....' and so on
        items=[]
        for item in curd[mtext]:
            items.append(QuickReplyButton(action=MessageAction(item,curd[mtext][item])))
        try:
            message=TextSendMessage(
                '選擇要查詢的外幣',
                quick_reply=QuickReply(items)
            )
        except:
            message=TextSendMessage("Error at QuickReply")
    elif (mtext[:2]=='..')and(len(mtext)>2):
        changecurrency=mtext[2:5].upper()
        if changecurrency in twder.currencies():
           curr_users.update({user_id:changecurrency})
           message=TextSendMessage(f'設定成{twder.currency_name_dict()[changecurrency]}換台幣\n請直接輸入數值或運算式')
    elif (money>=0):
        message=TextSendMessage(f'''{money} {twder.currency_name_dict()[currency]}\n台幣約為 {str(round(money*curr))}元\n輸入 .. 變換幣別''')
    else:
        message=TextSendMessage(f'現在查詢的是{twder.currency_name_dict()[currency]}\n輸入..變換幣別\n或是輸入數值或運算式\n例如:\n1500\n50+45*0.7')           

    line_bot_api.reply_message(event.reply_token,message)