Added error handling for specific error codes (#69)

* Added error handling for specific error codes

* added TooManyRequestsError witch have retry_after

* Added a parameters field with retry_after and handled error code 429

* added example of handling TooManyRequestsError with RetryAfter

* fix: changed description

* fix: used switch statement instead of if statement

* add MigrateError type and IsMigrateError function

* updated apiResponse struct and error handling logic

* fix: changed from %w to %s to ensure proper functionality of Sprintf

* fix: correct error message in getMe test

---------

Co-authored-by: Ehson <[email protected]>
Co-authored-by: usmonzodasomon <[email protected]>

README.md

@@ -345,14 +345,42 @@ See [documentation(https://core.telegram.org/bots/api#getfile)
 
 ## Errors
 
-The library provides error `ErrorForbidden` for error code 403. That code returns when the bot has no access to the action.
-For example, when the user blocked the bot.
+This library includes error handling. It provides the following error types:
 
+- **ErrorForbidden (403):** This error occurs when the bot has no access to the action, such as when the user has blocked the bot.
+- **ErrorBadRequest (400):** This error indicates a bad request made to the bot's API.
+- **ErrorUnauthorized (401):** This error occurs when the bot's access is unauthorized for the requested action.
+- **TooManyRequestsError: (429)** This error indicates that the bot has received too many requests within a short period. It includes a RetryAfter value indicating when to retry the request.
+- **ErrorNotFound (404):** This error indicates that the requested resource was not found.
+- **ErrorConflict (409):** This error indicates a conflict occurred during the request.
+
+Usage:
 ```go
 _, err := b.SendMessage(...)
 
-if errors.Is(err, bot.ErrorForbidden) {
-    // your code
+if errors.Is(err, mybot.ErrorForbidden) {
+    // Handle the ErrorForbidden (403) case here
+}
+
+if errors.Is(err, mybot.ErrorBadRequest) {
+    // Handle the ErrorBadRequest (400) case here
+}
+
+if errors.Is(err, mybot.ErrorUnauthorized) {
+    // Handle the ErrorUnauthorized (401) case here
+}
+
+if mybot.IsTooManyRequestsError(err) {
+    // Handle the TooManyRequestsError (429) case here
+    fmt.Println("Received TooManyRequestsError with retry_after:", err.(*mybot.TooManyRequestsError).RetryAfter)
+}
+
+if errors.Is(err, mybot.ErrorNotFound) {
+    // Handle the ErrorNotFound (404) case here
+}
+
+if errors.Is(err, mybot.ErrorConflict) {
+    // Handle the ErrorConflict (409) case here
 }
 ```
 

bot_test.go

@@ -138,7 +138,7 @@ func TestNew_error_getMe(t *testing.T) {
 	if err == nil {
 		t.Fatal("unexpected nil error")
 	}
-	if err.Error() != "error call getMe, error response from telegram for method getMe, 400 err1" {
+	if err.Error() != "error call getMe, bad request, err1" {
 		t.Fatalf("wrong error message %q", err.Error())
 	}
 }

errors.go

@@ -0,0 +1,43 @@
+package bot
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	ErrorForbidden       = errors.New("forbidden")
+	ErrorBadRequest      = errors.New("bad request")
+	ErrorUnauthorized    = errors.New("unauthorized")
+	ErrorTooManyRequests = errors.New("too many requests")
+	ErrorNotFound        = errors.New("not found")
+	ErrorConflict        = errors.New("conflict")
+)
+
+type TooManyRequestsError struct {
+	Message    string
+	RetryAfter int
+}
+
+func (e *TooManyRequestsError) Error() string {
+	return fmt.Sprintf("%s: retry_after %d", e.Message, e.RetryAfter)
+}
+
+func IsTooManyRequestsError(err error) bool {
+	_, ok := err.(*TooManyRequestsError)
+	return ok
+}
+
+type MigrateError struct {
+	Message         string
+	MigrateToChatID int
+}
+
+func (e *MigrateError) Error() string {
+	return fmt.Sprintf("%s: migrate_to_chat_id %d", e.Message, e.MigrateToChatID)
+}
+
+func IsMigrateError(err error) bool {
+	_, ok := err.(*MigrateError)
+	return ok
+}

raw_request.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io"
 	"mime/multipart"
@@ -18,10 +17,12 @@ type apiResponse struct {
 	Result      json.RawMessage `json:"result,omitempty"`
 	Description string          `json:"description,omitempty"`
 	ErrorCode   int             `json:"error_code,omitempty"`
+	Parameters  struct {
+		RetryAfter      int `json:"retry_after,omitempty"`
+		MigrateToChatID int `json:"migrate_to_chat_id,omitempty"`
+	} `json:"parameters,omitempty"`
 }
 
-var ErrorForbidden = errors.New("forbidden")
-
 func (b *Bot) rawRequest(ctx context.Context, method string, params any, dest any) error {
 	var httpBody io.Reader = http.NoBody
 	var contentType string
@@ -81,10 +82,34 @@ func (b *Bot) rawRequest(ctx context.Context, method string, params any, dest an
 	}
 
 	if !r.OK {
-		if r.ErrorCode == 403 {
+		switch r.ErrorCode {
+		case 403:
 			return fmt.Errorf("%w, %s", ErrorForbidden, r.Description)
+		case 400:
+			if r.Parameters.MigrateToChatID != 0 {
+				err := &MigrateError{
+					Message:         fmt.Sprintf("%s: %s", ErrorBadRequest, r.Description),
+					MigrateToChatID: r.Parameters.MigrateToChatID,
+				}
+
+				return err
+			}
+			return fmt.Errorf("%w, %s", ErrorBadRequest, r.Description)
+		case 401:
+			return fmt.Errorf("%w, %s", ErrorUnauthorized, r.Description)
+		case 404:
+			return fmt.Errorf("%w, %s", ErrorNotFound, r.Description)
+		case 409:
+			return fmt.Errorf("%w, %s", ErrorConflict, r.Description)
+		case 429:
+			err := &TooManyRequestsError{
+				Message:    fmt.Sprintf("%s, %s", ErrorTooManyRequests, r.Description),
+				RetryAfter: r.Parameters.RetryAfter,
+			}
+			return err
+		default:
+			return fmt.Errorf("error response from telegram for method %s, %d %s", method, r.ErrorCode, r.Description)
 		}
-		return fmt.Errorf("error response from telegram for method %s, %d %s", method, r.ErrorCode, r.Description)
 	}
 
 	if !bytes.Equal(r.Result, []byte("[]")) {