limiter - npm Package Compare versions

Comparing version 1.0.1 to 1.0.2

lib/rateLimiter.js

@@ -6,4 +6,4 @@ var TokenBucket = require('./tokenBucket');
  * an additional check to limit how many tokens we can remove each interval.
- * @author John Hurliman <[e-mail]>
- * 
+ * @author John Hurliman <[e-mail]>
+ *
  * @param {Number} tokensPerInterval Maximum number of tokens that can be
@@ -13,4 +13,6 @@ *  removed at any given moment and over the course of one interval.
  *  one of the following strings: 'second', 'minute', 'hour', day'.
+ * @param {Boolean} fireImmediately Optional. Whether or not the callback
+ *  will fire immediately when rate limiting is in effect (default is false).
  */
-var RateLimiter = function(tokensPerInterval, interval) {
+var RateLimiter = function(tokensPerInterval, interval, fireImmediately) {
   this.tokenBucket = new TokenBucket(tokensPerInterval, tokensPerInterval,
@@ -24,2 +26,3 @@ interval, null);
   this.tokensThisInterval = 0;
+  this.fireImmediately = fireImmediately;
 };
@@ -31,2 +34,3 @@
   tokensThisInterval: 0,
+  fireImmediately: false,
   
@@ -65,9 +69,12 @@ /**
     if (count > this.tokenBucket.tokensPerInterval - this.tokensThisInterval) {
-      var waitInterval = Math.ceil(
-        this.curIntervalStart + this.tokenBucket.interval - now);
-      
-      setTimeout(function() {
-        self.tokenBucket.removeTokens(count, afterTokensRemoved);
-      }, waitInterval);
-      
+      if (this.fireImmediately) {
+        callback(null, -1);
+      } else {
+        var waitInterval = Math.ceil(
+          this.curIntervalStart + this.tokenBucket.interval - now);
+
+        setTimeout(function() {
+          self.tokenBucket.removeTokens(count, afterTokensRemoved);
+        }, waitInterval);
+      }
       return false;
@@ -74,0 +81,0 @@ }

package.json

 {
   "name": "limiter",
   "description": "A generic rate limiter for node.js. Useful for API clients, web crawling, or other tasks that need to be throttled",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "author": "John Hurliman <[e-mail]>",
@@ -6,0 +6,0 @@ "dependencies": { },

README.md

@@ -22,40 +22,66 @@
 
-    var RateLimiter = require('limiter').RateLimiter;
-    // Allow 150 requests per hour (the Twitter search limit). Also understands
-    // 'second', 'minute', 'day', or a number of milliseconds
-    var limiter = new RateLimiter(150, 'hour');
-    
-    // Throttle requests
-    limiter.removeTokens(1, function(err, remainingRequests) {
-      // err will only be set if we request more than the maximum number of
-      // requests we set in the constructor
-      
-      // remainingRequests tells us how many additional requests could be sent
-      // right this moment
-      
-      callMyRequestSendingFunction(...);
-    });
+```javascript
+var RateLimiter = require('limiter').RateLimiter;
+// Allow 150 requests per hour (the Twitter search limit). Also understands
+// 'second', 'minute', 'day', or a number of milliseconds
+var limiter = new RateLimiter(150, 'hour');
 
+// Throttle requests
+limiter.removeTokens(1, function(err, remainingRequests) {
+  // err will only be set if we request more than the maximum number of
+  // requests we set in the constructor
+  
+  // remainingRequests tells us how many additional requests could be sent
+  // right this moment
+  
+  callMyRequestSendingFunction(...);
+});
+```
+
 Another example allowing one message to be sent every 250ms:
 
-    var RateLimiter = require('limiter').RateLimiter;
-    var limiter = new RateLimiter(1, 250);
-    
-    limiter.removeTokens(1, function() {
-      callMyMessageSendingFunction(...);
-    });
+```javascript
+var RateLimiter = require('limiter').RateLimiter;
+var limiter = new RateLimiter(1, 250);
 
+limiter.removeTokens(1, function() {
+  callMyMessageSendingFunction(...);
+});
+```
+
+The default behaviour is to wait for the duration of the rate limiting
+that’s currently in effect before the callback is fired, but if you 
+pass in ```true``` as the third parameter, the callback will be fired 
+immediately with remainingRequests set to -1:
+
+```javascript
+var RateLimiter = require('limiter').RateLimiter;
+var limiter = new RateLimiter(150, 'hour', true);  // fire CB immediately
+
+// Immediately send 429 header to client when rate limiting is in effect
+limiter.removeTokens(1, function(err, remainingRequests) {
+  if (remainingRequests < 0) {
+    response.writeHead(429, {'Content-Type': 'text/plain;charset=UTF-8'});
+    response.end('429 Too Many Requests - your IP is being rate limited');
+  } else {
+    callMyMessageSendingFunction(...);
+  }
+});
+```
+
 Uses the token bucket directly to throttle at the byte level:
 
-    var BURST_RATE = 1024 * 1024 * 150; // 150KB/sec burst rate
-    var FILL_RATE = 1024 * 1024 * 50; // 50KB/sec sustained rate
-    var TokenBucket = require('limiter').TokenBucket;
-    // We could also pass a parent token bucket in as the last parameter to
-    // create a hierarchical token bucket
-    var bucket = new TokenBucket(BURST_RATE, FILL_RATE, 'second', null);
-    
-    bucket.removeTokens(myData.byteLength, function() {
-      sendMyData(myData);
-    });
+```javascript
+var BURST_RATE = 1024 * 1024 * 150; // 150KB/sec burst rate
+var FILL_RATE = 1024 * 1024 * 50; // 50KB/sec sustained rate
+var TokenBucket = require('limiter').TokenBucket;
+// We could also pass a parent token bucket in as the last parameter to
+// create a hierarchical token bucket
+var bucket = new TokenBucket(BURST_RATE, FILL_RATE, 'second', null);
 
+bucket.removeTokens(myData.byteLength, function() {
+  sendMyData(myData);
+});
+```
+
 ## Additional Notes ##
@@ -62,0 +88,0 @@

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Improved metrics

Total package byte prevSize

15909

increased by6.92%

Lines of code

258

increased by3.2%

Number of lines in readme file

122

increased by27.08%

No dependency changes