feat: add a control for rate limiting

discordwebhook.go

@@ -3,11 +3,97 @@ package discordwebhook
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"io"
 	"io/ioutil"
+	"log"
+	"math"
 	"net/http"
+	"time"
 )
 
+/*
+SendMessageRateLimitAware is designed for scenarios where there is a need to dispatch numerous webhooks in rapid succession.
+Its purpose is to prevent potential bans from Discord by ensuring that the requests are rate-limited,
+thus maintaining a responsible and compliant approach to webhook communication.
+*/
+func SendMessageRateLimitAware(url string, message Message) error {
+	// Validate parameters
+	if url == "" {
+		return errors.New("empty URL")
+	}
+
+	for {
+		payload := new(bytes.Buffer)
+
+		err := json.NewEncoder(payload).Encode(message)
+		if err != nil {
+			return err
+		}
+
+		// Make the HTTP request
+		resp, err := http.Post(url, "application/json", payload)
+
+		if err != nil {
+			log.Printf("HTTP request failed: %v", err)
+			return err
+		}
+
+		switch resp.StatusCode {
+		case http.StatusOK, http.StatusNoContent:
+			// Success
+			err := resp.Body.Close()
+			if err != nil {
+				return err
+			}
+			return nil
+		case http.StatusTooManyRequests:
+			// Rate limit exceeded, retry after backoff duration
+			var response DiscordResponse
+			body, err := io.ReadAll(resp.Body)
+			if err != nil {
+				return err
+			}
+			err = json.Unmarshal(body, &response)
+			if err != nil {
+				return err
+			}
+
+			/*
+				Calculate the time until reset and add it to the current local time.
+				Some extra time of 750ms is added because without it I still encountered 429s.
+			*/
+
+			if response.RetryAfter != 0 {
+
+				whole, frac := math.Modf(response.RetryAfter)
+				resetAt := time.Now().Add(time.Duration(whole) * time.Second).Add(time.Duration(frac*1000) * time.Millisecond).Add(750 * time.Millisecond)
+				time.Sleep(time.Until(resetAt))
+			} else {
+				time.Sleep(5 * time.Second)
+			}
+
+			err = resp.Body.Close()
+			if err != nil {
+				return err
+			}
+		default:
+			// Handle other HTTP status codes
+			err := resp.Body.Close()
+			if err != nil {
+				return err
+			}
+			responseBody, err := ioutil.ReadAll(resp.Body)
+			if err != nil {
+				return err
+			}
+
+			return fmt.Errorf("HTTP request failed with status %d, body: \n %s", resp.StatusCode, responseBody)
+		}
+	}
+}
+
 func SendMessage(url string, message Message) error {
 	payload := new(bytes.Buffer)
 
@@ -22,7 +108,12 @@ func SendMessage(url string, message Message) error {
 	}
 
 	if resp.StatusCode != 200 && resp.StatusCode != 204 {
-		defer resp.Body.Close()
+		defer func(Body io.ReadCloser) {
+			err := Body.Close()
+			if err != nil {
+
+			}
+		}(resp.Body)
 
 		responseBody, err := ioutil.ReadAll(resp.Body)
 		if err != nil {

examples/basic_example/basic_example.go

@@ -9,16 +9,17 @@ import (
 func main() {
 	var username = "BotUser"
 	var content = "This is a test message"
-	var url = "https://discord.com/api/webhooks/..."
+	var url = ""
 
 	message := discordwebhook.Message{
 		Username: &username,
 		Content:  &content,
 	}
+	for {
+		err := discordwebhook.SendMessageRateLimitAware(url, message)
+		if err != nil {
+			log.Fatal(err)
+		}
 
-	err := discordwebhook.SendMessage(url, message)
-	if err != nil {
-		log.Fatal(err)
 	}
 }
-

types.go

@@ -1,5 +1,7 @@
 package discordwebhook
 
+import "time"
+
 type Message struct {
 	Username        *string          `json:"username,omitempty"`
 	AvatarUrl       *string          `json:"avatar_url,omitempty"`
@@ -18,6 +20,7 @@ type Embed struct {
 	Thumbnail   *Thumbnail `json:"thumbnail,omitempty"`
 	Image       *Image     `json:"image,omitempty"`
 	Footer      *Footer    `json:"footer,omitempty"`
+	Timestamp   *time.Time `json:"timestamp,omitempty"`
 }
 
 type Author struct {
@@ -50,3 +53,9 @@ type AllowedMentions struct {
 	Users *[]string `json:"users,omitempty"`
 	Roles *[]string `json:"roles,omitempty"`
 }
+
+type DiscordResponse struct {
+	Message    string  `json:"message"`
+	RetryAfter float64 `json:"retry_after"`
+	Global     bool    `json:"global"`
+}