A Google Cloud Function (Go 1.16) that changes a streamer's lights based on chat events

TwitchSubsToLights.go

// Package p contains an HTTP Cloud Function.
package p

import (
        "encoding/json"
        "fmt"
        "io/ioutil"
        "net/http"
        "strings"
        "net/url"
)

// TwitchWebhookTarget is our default entry point
func TwitchWebhookTarget(w http.ResponseWriter, r *http.Request) {
        body, err := ioutil.ReadAll(r.Body)
        if err != nil {
                panic(err)
        }
  
        jsonMap := make(map[string]interface{})
        err = json.Unmarshal(body, &jsonMap)
        if err != nil {
                panic(err)
        }
        dumpMap("", jsonMap)

        // for twitch to verify the webhook
        challenge, exists := jsonMap["challenge"]
        if exists == true {
                w.Write([]byte(rawurlEncode(challenge.(string))))
                return
        }

        // time to find this data
        eventData, exists2 := jsonMap["event"]
        if !exists2 {
                panic("n event data from twitch")
        }

        evData := eventData.(map[string]interface{})
        userInput, exists3 := evData["user_input"]
        if !exists3 {
                panic("event data found, but no user_input field")
        }

        input := userInput.(string)

        // input is the user input with data type string
        sendLightChange(input)
        return
}

func rawurlEncode(str string) string {
        return strings.Replace(url.QueryEscape(str), "+", "%20", -1)
}

func dumpMap(space string, m map[string]interface{}) {
        for k, v := range m {
                if mv, ok := v.(map[string]interface{}); ok {
                        fmt.Printf("{ %v: \n", k)
                        dumpMap(space+"\t", mv)
                        fmt.Printf("} \n")
                } else {
                        fmt.Printf("%v %v : %v \n", space, k, v)
                }
        }
}

func sendLightChange(userInput string) {
        params := url.Values{}
        params.Add("color", userInput)
        body := strings.NewReader(params.Encode())

        req, err := http.NewRequest("PUT", "https://api.lifx.com/v1/lights/all/state", body)
        if err != nil {
                panic(err)
        }
        req.Header.Set("Authorization", "Bearer <Your TiFX Lights API Token>")
        req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

        resp, err := http.DefaultClient.Do(req)
        if err != nil {
                panic(err)
        }
        defer resp.Body.Close()
}