add json error code & message to rest.Error

rest/rest_error.go

@@ -3,43 +3,59 @@ package rest
 import (
 	"fmt"
 	"net/http"
+
+	"github.com/disgoorg/json"
 )
 
+// JSONErrorCode is the error code returned by the Discord API.
+// See https://discord.com/developers/docs/topics/opcodes-and-status-codes#json-json-error-codes
+type JSONErrorCode int
+
 var _ error = (*Error)(nil)
 
 // Error holds the http.Response & an error related to a REST request
 type Error struct {
-	Request  *http.Request
-	RqBody   []byte
-	Response *http.Response
-	RsBody   []byte
+	Request  *http.Request  `json:"-"`
+	RqBody   []byte         `json:"-"`
+	Response *http.Response `json:"-"`
+	RsBody   []byte         `json:"-"`
+
+	Code    JSONErrorCode   `json:"code"`
+	Errors  json.RawMessage `json:"errors"`
+	Message string          `json:"message"`
 }
 
 // NewError returns a new Error with the given http.Request, http.Response
 func NewError(rq *http.Request, rqBody []byte, rs *http.Response, rsBody []byte) error {
-	return &Error{
-		Request:  rq,
-		RqBody:   rqBody,
-		Response: rs,
-		RsBody:   rsBody,
-	}
+	var err Error
+	_ = json.Unmarshal(rsBody, &err)
+
+	err.Request = rq
+	err.RqBody = rqBody
+	err.Response = rs
+	err.RsBody = rsBody
+
+	return err
 }
 
-// Is returns true if the error is a discord.APIError 6 has the same StatusCode
+// Is returns true if the error is a *Error with the same status code as the target error
 func (e Error) Is(target error) bool {
 	err, ok := target.(*Error)
 	if !ok {
 		return false
 	}
+	if e.Code != 0 && err.Code != 0 {
+		return e.Code == err.Code
+	}
 	return err.Response != nil && e.Response != nil && err.Response.StatusCode == e.Response.StatusCode
 }
 
 // Error returns the error formatted as string
 func (e Error) Error() string {
-	if e.Response != nil {
-		return fmt.Sprintf("Status: %s, Body: %s", e.Response.Status, string(e.RsBody))
+	if e.Code != 0 {
+		return fmt.Sprintf("%d: %s", e.Code, e.Message)
 	}
-	return "unknown error"
+	return fmt.Sprintf("Status: %s, Body: %s", e.Response.Status, string(e.RsBody))
 }
 
 // Error returns the error formatted as string