判斷從Redis Cache 或 公開資料集拿資料

這幾日我們已經知道如何在Azure上建立Redis Cache，並學會如何操作，現在只需修改Workflow.ts程式，請求口罩公開資料集前，先判斷Redis Cache中是否已有資料，如果Cache中資料的存入時間相差不到30秒則由Azure Cache for Redis取得資料，如果超過30秒則重新搜尋公開資料並存入Redis Cache中

Worflow.ts:

import * as lineService from "./lineService"
import * as RedisCache from "./RedisCache"
import axios from "axios"

export const findMaskStore = async (GPS: any, userId: string) => {

    let maskSnapshot
    let nearMaskStore = []
    const timestamp = new Date().getTime()
    maskSnapshot = await RedisCache.getMask('mask')

    if (maskSnapshot == 'null' || (timestamp - maskSnapshot.updateTime) >= 30000) {
        maskSnapshot = await getMaskFromOpenSource()
    } 
    console.log(maskSnapshot)
    
    for (let element of maskSnapshot.content.features) {
        const storeGPS = element.geometry.coordinates

        let R = 6371 // Radius of the earth in km
        let dLon = (storeGPS[0] - GPS.lon) * (Math.PI / 180)
        let dLat = (storeGPS[1] - GPS.lat) * (Math.PI / 180)  // deg2rad below

        let a =
            Math.sin(dLat / 2) * Math.sin(dLat / 2) +
            Math.cos((GPS.lat) * (Math.PI / 180)) * Math.cos((GPS.lat) * (Math.PI / 180)) *
            Math.sin(dLon / 2) * Math.sin(dLon / 2)

        let c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a))
        let d = R * c // Distance in km
        if (d < 0.4) {
            nearMaskStore.push(element)
        }
    }

    for (const store of nearMaskStore) {
        const maskMessage = lineService.toMaskMessage(store)
        lineService.pushMessage(maskMessage, userId)
    }
}

const getMaskFromOpenSource = async () => {
    const mastData = await axios.get('https://raw.githubusercontent.com/kiang/pharmacies/master/json/points.json')
    const maskSnapshot = {
        updateTime: new Date().getTime(),
        content: mastData.data
    }
    await RedisCache.setMask('mask', maskSnapshot)
    return maskSnapshot
}

由於昨天我們將Line官方帳號的cannelSecret, channelAccessToken與Redis Cache的REDISCACHEHOSTNAME,REDISCACHEKEY重要參數寫入新增config.ts檔案，因此需修改一下先前的lineService.ts程式

修改後lineService.ts如下：

import { LINE } from "../config"
import { Client, TextMessage } from "@line/bot-sdk"

export function replyMessage(text: string, replyToken: string) {
    const textMessage = {
        type: "text",
        text: text
    } as TextMessage

    const client = new Client(LINE)
    return client.replyMessage(replyToken, textMessage)
}

export function pushMessage(text: string, userId: string) {
    const textMessage = {
        type: "text",
        text: text
    } as TextMessage

    const client = new Client(LINE)
    return client.pushMessage(userId, textMessage)
}

export function toMaskMessage(nearMaskStore: any) {
    const maskMessage = 
           `${nearMaskStore.properties.name}\n` +
            `${nearMaskStore.properties.phone}\n` +
            `${nearMaskStore.properties.address}\n` +
            `成人口罩:${nearMaskStore.properties.mask_adult}\n` +
            `兒童口罩:${nearMaskStore.properties.mask_child}`
    return maskMessage
}

Workflow.ts 與 lineService.ts原本程式可參考-Day [10] Azure Functions-Line Chatbot實作(二)

最後祝大家中秋節快樂
連假還是要記得發文歐！