122 lines
2.8 KiB
Go
122 lines
2.8 KiB
Go
package main
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import (
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"crypto/sha256"
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"io"
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"log"
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"net/http"
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"os"
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"strconv"
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"strings"
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"time"
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"github.com/joho/godotenv"
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"gopkg.in/gomail.v2"
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)
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/* Get a website HTML. */
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func getWebsite(url string) []byte {
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response, err := http.Get(url)
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if err != nil {
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log.Fatal("Error: ", err)
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}
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defer response.Body.Close()
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body, err := io.ReadAll(response.Body)
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if err != nil {
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log.Fatal("Error reading response body: ", err)
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}
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return body
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}
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/* Convert data to sha256 hash. */
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func stringToHash(data []byte) string {
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hash := sha256.Sum256(data)
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return string(hash[:])
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}
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/* Send an email. */
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func sendEmail(identity string, username string, password string, host string, recipient []string, port int) {
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message := gomail.NewMessage()
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message.SetHeader("From", identity)
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message.SetHeader("To", strings.Join(recipient, ", "))
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message.SetHeader("Subject", "Changes on website")
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message.SetBody("text/plain", "A changed has been found on the website.")
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dialer := gomail.NewDialer(host, port, username, password)
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if err := dialer.DialAndSend(message); err != nil {
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log.Fatal(err)
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}
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}
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/* Environnement variable checker */
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func checkEnvVariables(keys []string) {
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for _, key := range keys {
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_, i := os.LookupEnv(key)
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if !i {
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log.Fatal(key, " doesn't exist.")
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}
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}
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}
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/* Take a map of string * string and returns a list of its values */
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func valuesOfMapStringToListString(from map[string]string) []string {
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res := make([]string, 0, len(from))
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for _, value := range from {
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res = append(res, value)
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}
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return res
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}
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func main() {
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// Loading environment variables
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godotenv.Load()
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keys := map[string]string{
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"url": "WEBSITE",
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"smtp_host": "SMTP_HOST",
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"smtp_from": "SMTP_FROM",
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"smtp_user": "SMTP_USERNAME",
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"smtp_pass": "SMTP_PASSWORD",
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"smtp_port": "SMTP_PORT",
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"recipient_adress": "RECIPIENT_ADRESS",
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}
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checkEnvVariables(valuesOfMapStringToListString(keys))
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url := os.Getenv(keys["url"])
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smtp_from := os.Getenv(keys["smtp_from"])
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smtp_user := os.Getenv(keys["smtp_user"])
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smtp_pass := os.Getenv(keys["smtp_pass"])
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smtp_host := os.Getenv(keys["smtp_host"])
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recipient_adress := os.Getenv(keys["recipient_adress"])
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smtp_port, err := strconv.Atoi(os.Getenv(keys["smtp_port"]))
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if err != nil {
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log.Fatal("SMTP port is invalid.")
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}
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last_hash := ""
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sleepDuration := 24
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log.Default().Print("Checking: ", url)
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log.Default().Print("Running each ", sleepDuration, "h, starting now.")
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for {
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body := getWebsite(url)
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hash := stringToHash(body)
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if last_hash != hash && len(last_hash) > 0 {
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sendEmail(
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smtp_from,
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smtp_user,
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smtp_pass,
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smtp_host,
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strings.Split(recipient_adress, ","),
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smtp_port,
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)
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}
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last_hash = hash
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/* log.Default().Print("Next loop in ", sleepDuration, "h.") */
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time.Sleep(time.Duration(sleepDuration) * time.Hour)
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}
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}
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