Rate limit using round tripper

go.mod

@@ -7,6 +7,7 @@ require (
 	go.uber.org/atomic v1.4.0
 	golang.org/x/crypto v0.0.0-20191227163750-53104e6ec876
 	golang.org/x/net v0.0.0-20200226121028-0de0cce0169b
+	golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e
 	k8s.io/gengo v0.0.0-20201113003025-83324d819ded
 	nhooyr.io/websocket v1.8.6
 )

go.sum

@@ -83,6 +83,8 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
+golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e h1:EHBhcS0mlXEAVwNyO2dLfjToGsyY4j24pTs2ScHnX7s=
+golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20200505023115-26f46d2f7ef8/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=

ratelimit_roundtripper.go

@@ -0,0 +1,155 @@
+package disgord
+//
+// import (
+// 	"net/http"
+// 	"net/url"
+// 	"strings"
+// 	"sync"
+//
+// 	"golang.org/x/time/rate"
+// )
+//
+// type DiscordURL url.URL
+//
+// func (d *DiscordURL) IsMajor() bool {
+// 	for _, prefix := range []string{"guilds", "channels", "webhooks"} {
+// 		if strings.HasPrefix(d.Path, prefix) {
+// 			return true
+// 		}
+// 	}
+// 	return false
+// }
+//
+// func (d *DiscordURL) Hash(method string) string {
+// 	matches := regexpURLSnowflakes.FindAllString(d.Path, -1)
+// 	isMajor := d.IsMajor()
+// 	buffer := d.Path
+// 	for i := range matches {
+// 		if i == 0 && isMajor {
+// 			continue
+// 		}
+//
+// 		buffer = strings.ReplaceAll(buffer, matches[i], "/{id}/")
+// 	}
+//
+// 	// check for reaction endpoints, convert emoji identifier to {emoji}
+// 	reactionPrefixMatch := regexpURLReactionPrefix.FindAllString(buffer, -1)
+// 	if reactionPrefixMatch != nil {
+// 		if regexpURLReactionEmoji.FindAllString(buffer, -1) != nil {
+// 			reactionEmojis := regexpURLReactionEmojiSegment.FindAllString(buffer, -1)
+// 			for i := range reactionEmojis {
+// 				buffer = strings.ReplaceAll(buffer, reactionEmojis[i], "/reactions/{emoji}")
+// 			}
+// 		} else {
+// 			// corner case for urls with emojis
+// 			suffix := buffer[len(reactionPrefixMatch[0]):]
+// 			until := len(suffix)
+// 			for i, r := range suffix {
+// 				if r == '/' {
+// 					until = i
+// 					break
+// 				}
+// 			}
+// 			newSuffix := "{emoji}" + suffix[until:]
+// 			buffer = buffer[:len(buffer)-len(suffix)] + newSuffix
+// 		}
+// 	}
+//
+// 	if strings.HasSuffix(buffer, "/") {
+// 		buffer = buffer[:len(buffer)-1]
+// 	}
+// 	return method + ":" + buffer
+// }
+//
+// type reqWaiterChan chan *rate.Limiter
+//
+// type RateLimit struct {
+// 	Next http.RoundTripper
+//
+// 	vtableMu sync.RWMutex
+// 	vtable   map[string]string
+//
+// 	waitersMu sync.RWMutex
+// 	waiters   map[string]reqWaiterChan
+//
+// 	bucketsMy sync.RWMutex
+// 	buckets   map[string]*rate.Limiter
+// }
+//
+// var _ http.RoundTripper = &RateLimit{}
+//
+// func (r *RateLimit) RoundTrip(req *http.Request) (resp *http.Response, err error) {
+// 	if !r.isDiscordAPIRequest(req) {
+// 		return r.Next.RoundTrip(req)
+// 	}
+//
+// 	durl := DiscordURL(*req.URL)
+// 	localHash := durl.Hash(req.Method)
+// 	discordHash := r.discordHash(localHash)
+// 	if discordHash == "" {
+// 		waitChan := r.waiter(localHash, func() {
+// 			resp, err := r.Next.RoundTrip(req)
+// 			if err != nil {
+// 				return nil, err
+// 			}
+// 		})
+// 	}
+//
+// 	return r.rateLimit(req, func() (*http.Response, error) {
+// 		return r.Next.RoundTrip(req)
+// 	})
+// }
+//
+// func (r *RateLimit) isDiscordAPIRequest(req *http.Request) bool {
+// 	const DiscordAPIURLPrefix = "https://discord.com/api/v"
+// 	return strings.HasPrefix(req.URL.String(), DiscordAPIURLPrefix)
+// }
+//
+// func (r *RateLimit) discordHash(localHash string) string {
+// 	r.vtableMu.RLock()
+// 	defer r.vtableMu.RUnlock()
+//
+// 	if discordHash, ok := r.vtable[localHash]; ok {
+// 		return discordHash
+// 	} else {
+// 		return ""
+// 	}
+// }
+//
+// func (r *RateLimit) waiter(localHash string) reqWaiterChan {
+// 	r.waitersMu.RLock()
+// 	defer r.waitersMu.RUnlock()
+//
+// 	if waiter, ok := r.waiters[localHash]; ok {
+// 		return waiter
+// 	} else {
+// 		return nil
+// 	}
+// }
+//
+// func (r *RateLimit) bucket(hash string, setupBucket func() (discordHash string, bucket *rate.Limiter)) string {
+// 	r.vtableMu.RLock()
+// 	if discordHash, ok := r.vtable[hash]; ok {
+// 		r.vtableMu.RUnlock()
+// 		return discordHash
+// 	}
+// 	r.vtableMu.RUnlock()
+//
+// 	r.vtableMu.Lock()
+// 	// check if another request got here faster
+// 	if discordHash, ok := r.vtable[hash]; ok {
+// 		r.vtableMu.Unlock()
+// 		return discordHash
+// 	}
+//
+// 	discordHash, bucket := setupBucket()
+// 	r.vtable[hash] = discordHash
+//
+// 	// this should be updated once bucket information is delivered by discord
+// 	r.vtable[hash] = hash
+// 	return hash
+// }
+//
+// func (r *RateLimit) bucket(hash string) *rate.Limiter {
+//
+// }