mirror of https://github.com/gabehf/massflip.git
gabe farrell
3 years ago
parent
fdbf7217e9
commit
a3e56fa753
@ -0,0 +1,80 @@
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package main
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import (
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"net"
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"net/http"
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"sync"
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"golang.org/x/time/rate"
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)
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// IP limiter code taken from
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// https://medium.com/@pliutau/rate-limiting-http-requests-in-go-based-on-ip-address-4e66d1bea4cf
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var limiter = NewIPRateLimiter(1, 10)
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// IPRateLimiter
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type IPRateLimiter struct {
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ips map[string]*rate.Limiter
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mu *sync.RWMutex
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r rate.Limit
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b int
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}
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// NewIPRateLimiter
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func NewIPRateLimiter(r rate.Limit, b int) *IPRateLimiter {
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i := &IPRateLimiter{
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ips: make(map[string]*rate.Limiter),
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mu: &sync.RWMutex{},
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r: r,
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b: b,
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}
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return i
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}
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// AddIP creates a new rate limiter and adds it to the ips map,
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// using the IP address as the key
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func (i *IPRateLimiter) AddIP(ip string) *rate.Limiter {
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i.mu.Lock()
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defer i.mu.Unlock()
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limiter := rate.NewLimiter(i.r, i.b)
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i.ips[ip] = limiter
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return limiter
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}
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// GetLimiter returns the rate limiter for the provided IP address if it exists.
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// Otherwise calls AddIP to add IP address to the map
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func (i *IPRateLimiter) GetLimiter(ip string) *rate.Limiter {
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i.mu.Lock()
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limiter, exists := i.ips[ip]
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if !exists {
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i.mu.Unlock()
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return i.AddIP(ip)
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}
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i.mu.Unlock()
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return limiter
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}
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func limitMiddleware(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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ip, _, err := net.SplitHostPort(r.RemoteAddr)
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if err != nil {
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w.WriteHeader(http.StatusBadRequest)
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return
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}
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limiter := limiter.GetLimiter(ip)
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if !limiter.Allow() {
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http.Error(w, http.StatusText(http.StatusTooManyRequests), http.StatusTooManyRequests)
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return
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}
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next.ServeHTTP(w, r)
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})
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}
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