export class RateLimiter {
constructor(env) {
this.env = env;
this.windowMs = 60000; // 1 minute window
this.maxRequests = parseInt(env.MAX_REQUESTS_PER_MINUTE || '100');
}
/**
* Checks if a user has exceeded their rate limit
*/
async checkLimit(userId, action = 'default') {
const key = `rate:${userId}:${action}`;
const now = Date.now();
// Get current rate limit entry
const data = await this.env.RATE_LIMITS.get(key);
let entry;
if (data) {
entry = JSON.parse(data);
// Check if window has expired
if (now >= entry.reset_at) {
// Reset the window
entry = {
count: 1,
window_start: now,
reset_at: now + this.windowMs
};
}
else {
// Within current window
if (entry.count >= this.maxRequests) {
return false; // Rate limit exceeded
}
entry.count++;
}
}
else {
// First request in this window
entry = {
count: 1,
window_start: now,
reset_at: now + this.windowMs
};
}
// Store updated entry with TTL
await this.env.RATE_LIMITS.put(key, JSON.stringify(entry), {
expirationTtl: Math.ceil(this.windowMs / 1000) + 60 // Extra 60 seconds buffer
});
return true;
}
/**
* Gets remaining requests for a user
*/
async getRemainingRequests(userId, action = 'default') {
const key = `rate:${userId}:${action}`;
const now = Date.now();
const data = await this.env.RATE_LIMITS.get(key);
if (!data) {
return {
remaining: this.maxRequests,
reset_at: now + this.windowMs
};
}
const entry = JSON.parse(data);
if (now >= entry.reset_at) {
return {
remaining: this.maxRequests,
reset_at: now + this.windowMs
};
}
return {
remaining: Math.max(0, this.maxRequests - entry.count),
reset_at: entry.reset_at
};
}
/**
* Resets rate limit for a user
*/
async resetLimit(userId, action = 'default') {
const key = `rate:${userId}:${action}`;
await this.env.RATE_LIMITS.delete(key);
}
/**
* Gets custom rate limits for premium users
*/
async getPremiumLimits(userId) {
// Premium users get 5x the rate limit
return this.maxRequests * 5;
}
/**
* Checks rate limit with tier-based limits
*/
async checkLimitWithTier(userId, action, isPremium) {
const limit = isPremium
? await this.getPremiumLimits(userId)
: this.maxRequests;
const key = `rate:${userId}:${action}`;
const now = Date.now();
const data = await this.env.RATE_LIMITS.get(key);
let entry;
if (data) {
entry = JSON.parse(data);
if (now >= entry.reset_at) {
entry = {
count: 1,
window_start: now,
reset_at: now + this.windowMs
};
}
else {
if (entry.count >= limit) {
return false;
}
entry.count++;
}
}
else {
entry = {
count: 1,
window_start: now,
reset_at: now + this.windowMs
};
}
await this.env.RATE_LIMITS.put(key, JSON.stringify(entry), {
expirationTtl: Math.ceil(this.windowMs / 1000) + 60
});
return true;
}
}
