From 092ed4b585669191c7919e4bb5244fc812268b7a Mon Sep 17 00:00:00 2001
From: jonas747 <jonasr747@gmail.com>
Date: Mon, 11 Jul 2016 22:30:11 +0200
Subject: [PATCH] Retry on 502's

---
 restapi.go | 26 +++++++++++++++++++-------
 structs.go |  3 +++
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/restapi.go b/restapi.go
index 85a4858..c5a4462 100644
--- a/restapi.go
+++ b/restapi.go
@@ -45,11 +45,13 @@ func (s *Session) Request(method, urlStr string, data interface{}) (response []b
 		}
 	}
 
-	return s.request(method, urlStr, "application/json", body)
+	return s.request(method, urlStr, "application/json", body, 0)
 }
 
 // request makes a (GET/POST/...) Requests to Discord REST API.
-func (s *Session) request(method, urlStr, contentType string, b []byte) (response []byte, err error) {
+// Sequence is the sequence number, if it fails with a 502 it will
+// retry with sequence+1 until it either succeeds or sequence >= session.MaxRestRetries
+func (s *Session) request(method, urlStr, contentType string, b []byte, sequence int) (response []byte, err error) {
 
 	// rate limit mutex for this url
 	// TODO: review for performance improvements
@@ -135,6 +137,16 @@ func (s *Session) request(method, urlStr, contentType string, b []byte) (respons
 
 		// TODO check for 401 response, invalidate token if we get one.
 
+	case http.StatusBadGateway:
+		// Retry sending request if possible
+		if sequence < s.MaxRestRetries {
+
+			s.log(LogInformational, "%s Failed (%s), Retrying...", urlStr, resp.Status)
+			response, err = s.request(method, urlStr, contentType, b, sequence+1)
+		} else {
+			err = fmt.Errorf("Exceeded Max retries HTTP %s, %s", resp.Status, response)
+		}
+
 	case 429: // TOO MANY REQUESTS - Rate limiting
 
 		mu.Lock() // lock URL ratelimit mutex
@@ -151,10 +163,10 @@ func (s *Session) request(method, urlStr, contentType string, b []byte) (respons
 
 		time.Sleep(rl.RetryAfter)
 		// we can make the above smarter
-		// this method can cause longer delays then required
+		// this method can cause longer delays than required
 
 		mu.Unlock() // we have to unlock here
-		response, err = s.request(method, urlStr, contentType, b)
+		response, err = s.request(method, urlStr, contentType, b, sequence)
 
 	default: // Error condition
 		err = fmt.Errorf("HTTP %s, %s", resp.Status, response)
@@ -708,7 +720,7 @@ func (s *Session) GuildMemberNickname(guildID, userID, nickname string) (err err
 // guildID   : The ID of a Guild.
 func (s *Session) GuildChannels(guildID string) (st []*Channel, err error) {
 
-	body, err := s.request("GET", EndpointGuildChannels(guildID), "", nil)
+	body, err := s.request("GET", EndpointGuildChannels(guildID), "", nil, 0)
 	if err != nil {
 		return
 	}
@@ -1084,7 +1096,7 @@ func (s *Session) ChannelMessage(channelID, messageID string) (st *Message, err
 // messageID : the ID of a Message
 func (s *Session) ChannelMessageAck(channelID, messageID string) (err error) {
 
-	_, err = s.request("POST", EndpointChannelMessageAck(channelID, messageID), "", nil)
+	_, err = s.request("POST", EndpointChannelMessageAck(channelID, messageID), "", nil, 0)
 	return
 }
 
@@ -1236,7 +1248,7 @@ func (s *Session) ChannelFileSend(channelID, name string, r io.Reader) (st *Mess
 		return
 	}
 
-	response, err := s.request("POST", EndpointChannelMessages(channelID), bodywriter.FormDataContentType(), body.Bytes())
+	response, err := s.request("POST", EndpointChannelMessages(channelID), bodywriter.FormDataContentType(), body.Bytes(), 0)
 	if err != nil {
 		return
 	}
diff --git a/structs.go b/structs.go
index 19a291f..168895a 100644
--- a/structs.go
+++ b/structs.go
@@ -53,6 +53,9 @@ type Session struct {
 	// Whether the Data Websocket is ready
 	DataReady bool // NOTE: Maye be deprecated soon
 
+	// Max number of REST API retries
+	MaxRestRetries int
+
 	// Status stores the currect status of the websocket connection
 	// this is being tested, may stay, may go away.
 	status int32