forked from andersfylling/disgord
/
ratelimit.go
339 lines (297 loc) · 8.12 KB
/
ratelimit.go
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package httd
import (
"net/http"
"strconv"
"strings"
"sync"
"time"
"encoding/json"
. "github.com/andersfylling/snowflake"
)
const (
XRateLimitLimit = "X-RateLimit-Limit"
XRateLimitRemaining = "X-RateLimit-Remaining"
XRateLimitReset = "X-RateLimit-Reset" // is converted from seconds to milliseconds!
XRateLimitGlobal = "X-RateLimit-Global"
RateLimitRetryAfter = "Retry-After"
GlobalRateLimiterKey = ""
)
// const
var majorEndpointPrefixes = []string{
"/channels/",
"/guilds/",
"/webhooks/",
}
// TODO: fix ratelimiting logic
func RatelimitChannel(id Snowflake) string {
return "c:" + id.String()
}
func RatelimitChannelPermissions(id Snowflake) string {
return RatelimitChannel(id) + ":perm"
}
func RatelimitChannelInvites(id Snowflake) string {
return RatelimitChannel(id) + ":i"
}
func RatelimitChannelTyping(id Snowflake) string {
return RatelimitChannel(id) + ":t"
}
func RatelimitChannelPins(id Snowflake) string {
return RatelimitChannel(id) + ":pins"
}
func RatelimitChannelRecipients(id Snowflake) string {
return RatelimitChannel(id) + ":r"
}
func RatelimitChannelMessages(id Snowflake) string {
return RatelimitChannel(id) + ":m"
}
func RatelimitChannelMessagesDelete(id Snowflake) string {
return RatelimitChannelMessages(id) + "_"
}
func RatelimitChannelWebhooks(id Snowflake) string {
return RatelimitChannel(id) + ":w"
}
func RatelimitGuild(id Snowflake) string {
return "g:" + id.String()
}
func RatelimitGuildAuditLogs(id Snowflake) string {
return RatelimitGuild(id) + ":a-l"
}
func RatelimitGuildEmbed(id Snowflake) string {
return RatelimitGuild(id) + ":e"
}
func RatelimitGuildVanityURL(id Snowflake) string {
return RatelimitGuild(id) + ":vurl"
}
func RatelimitGuildChannels(id Snowflake) string {
return RatelimitGuild(id) + ":c"
}
func RatelimitGuildMembers(id Snowflake) string {
return RatelimitGuild(id) + ":m"
}
func RatelimitGuildBans(id Snowflake) string {
return RatelimitGuild(id) + ":b"
}
func RatelimitGuildRoles(id Snowflake) string {
return RatelimitGuild(id) + ":r"
}
func RatelimitGuildRegions(id Snowflake) string {
return RatelimitGuild(id) + ":regions"
}
func RatelimitGuildIntegrations(id Snowflake) string {
return RatelimitGuild(id) + ":i"
}
func RatelimitGuildInvites(id Snowflake) string {
return RatelimitGuild(id) + ":inv"
}
func RatelimitGuildPrune(id Snowflake) string {
return RatelimitGuild(id) + ":p"
}
func RatelimitGuildWebhooks(id Snowflake) string {
return RatelimitGuild(id) + ":w"
}
func RatelimitWebhook(id Snowflake) string {
return "wh:" + id.String()
}
func RatelimitUsers() string {
return "u"
}
type RateLimiter interface {
Bucket(key string) *Bucket
RateLimitTimeout(key string) int64
RateLimited(key string) bool
UpdateRegisters(key string, res *http.Response, responseBody []byte)
WaitTime(req *Request) time.Duration
}
type ratelimitBody struct {
Message string `json:"message"`
RetryAfter int64 `json:"retry_after"`
Global bool `json:"global"`
Empty bool `json:"-"`
}
type RateLimitInfo struct {
Message string `json:"message"`
RetryAfter int64 `json:"retry_after"`
Global bool `json:"global"`
Limit int `json:"-"`
Remaining int `json:"-"`
Reset int64 `json:"-"`
Empty bool `json:"-"`
}
func RateLimited(resp *http.Response) bool {
return resp.StatusCode == http.StatusTooManyRequests
}
// GlobalRateLimit assumes that there will always be a header entry when a global rate limit kicks in
func GlobalRateLimit(resp *http.Response) bool {
return resp.Header.Get(XRateLimitGlobal) == "true"
}
func GlobalRateLimitSafe(resp *http.Response, body *ratelimitBody) bool {
return GlobalRateLimit(resp) && !body.Empty && body.Global
}
func ExtractRateLimitInfo(resp *http.Response, body []byte) (info *RateLimitInfo, err error) {
info = &RateLimitInfo{}
// extract header information
limitStr := resp.Header.Get(XRateLimitLimit)
remainingStr := resp.Header.Get(XRateLimitRemaining)
resetStr := resp.Header.Get(XRateLimitReset)
retryAfterStr := resp.Header.Get(RateLimitRetryAfter)
// convert types
if limitStr != "" {
info.Limit, err = strconv.Atoi(limitStr)
if err != nil {
return
}
}
if remainingStr != "" {
info.Remaining, err = strconv.Atoi(remainingStr)
if err != nil {
return
}
}
if resetStr != "" {
info.Reset, err = strconv.ParseInt(resetStr, 10, 64)
if err != nil {
return
}
info.Reset *= 1000 // second => milliseconds
}
if retryAfterStr != "" {
info.RetryAfter, err = strconv.ParseInt(retryAfterStr, 10, 64)
if err != nil {
return
}
}
// the body only contains information when a rate limit is exceeded
if RateLimited(resp) && len(body) > 0 {
err = json.Unmarshal(body, &info)
}
if !info.Global && GlobalRateLimit(resp) {
info.Global = true
}
return
}
func NewRateLimit() *RateLimit {
return &RateLimit{
buckets: make(map[string]*Bucket),
global: &Bucket{},
}
}
// RateLimit
// TODO: a bucket is created for every request. Might want to delete them after a while. seriously.
// `/users/1` has the same ratelimiter as `/users/2`
// but any major endpoint prefix does not: `/channels/1` != `/channels/2`
type RateLimit struct {
buckets map[string]*Bucket
global *Bucket
mu sync.RWMutex
}
func (r *RateLimit) Bucket(key string) *Bucket {
var bucket *Bucket
var exists bool
// check for major endpoints
// TODO: this feels frail
var endpoint string
for _, major := range majorEndpointPrefixes {
if !strings.HasPrefix(key, major) {
continue
}
pathAfterMajor := strings.TrimPrefix(key, major)
endpoint = major
for _, r := range pathAfterMajor {
if r == '/' {
break
}
endpoint += string(r)
}
}
if endpoint == "" {
endpoint = key
}
r.mu.Lock()
if bucket, exists = r.buckets[key]; !exists {
r.buckets[key] = &Bucket{
endpoint: key,
reset: time.Now().UnixNano() / 1000,
}
bucket = r.buckets[key]
}
r.mu.Unlock()
return bucket
}
func (r *RateLimit) RateLimitTimeout(key string) int64 {
if r.global.limited() {
return r.global.timeout()
}
bucket := r.Bucket(key)
return bucket.timeout()
}
func (r *RateLimit) RateLimited(key string) bool {
if r.global.limited() {
return true
}
bucket := r.Bucket(key)
return bucket.limited()
}
// WaitTime check both the global and route specific rate limiter bucket before sending any REST requests
func (r *RateLimit) WaitTime(req *Request) time.Duration {
timeout := int64(0)
if r.global.remaining == 0 {
timeout = r.global.timeout()
} else if req.Ratelimiter != "" {
timeout = r.RateLimitTimeout(req.Ratelimiter)
}
// discord specifies this in seconds, however it is converted to milliseconds before stored in memory.
return time.Millisecond * time.Duration(timeout)
}
// TODO: rewrite
func (r *RateLimit) UpdateRegisters(key string, resp *http.Response, content []byte) {
info, err := ExtractRateLimitInfo(resp, content)
if err != nil {
return // TODO: logging
}
// select bucket
// TODO: what if "key" is an endpoint with a global rate limiter only?
var bucket *Bucket
if info.Global {
bucket = r.global
} else {
bucket = r.Bucket(key)
}
// update
bucket.mu.Lock()
bucket.update(info)
bucket.mu.Unlock()
}
// ---------------------
type Bucket struct {
endpoint string // endpoint where rate limit is applied. endpoint = key
limit uint64 // total allowed requests before rate limit
remaining uint64 // remaining requests
reset int64 // unix milliseconds, even tho discord prefers seconds. global uses milliseconds however.
mu sync.RWMutex
}
func (b *Bucket) update(info *RateLimitInfo) {
b.limit = uint64(info.Limit)
b.remaining = uint64(info.Remaining)
b.reset = info.Reset
// assumption: Retry-After and X-RateLimit-Reset points to the same time.
// info.Reset is converted to milliseconds when the type is converted from
// string to int64.
if info.Reset == 0 && info.RetryAfter > 0 {
b.reset = (time.Now().UnixNano() / 1000) + info.RetryAfter
}
}
func (b *Bucket) limited() bool {
b.mu.RLock()
defer b.mu.RUnlock()
now := time.Now().UnixNano() / 1000
return b.reset > now
}
func (b *Bucket) timeout() int64 {
b.mu.RLock()
defer b.mu.RUnlock()
now := time.Now().UnixNano() / 1000
if b.reset > now {
return b.reset - now
}
return 0
}