limiter - npm Package Compare versions

Comparing version 1.0.4 to 1.0.5

lib/rateLimiter.js

@@ -53,3 +53,3 @@ var TokenBucket = require('./tokenBucket');
     var self = this;
-    var now = +new Date();
+    var now = Date.now();
     
@@ -91,2 +91,33 @@ // Advance the current interval and reset the current interval token count
   /**
+   * Attempt to remove the requested number of tokens and return immediately.
+   * If the bucket (and any parent buckets) contains enough tokens and we
+   * haven't spent too many tokens in this interval already, this will return
+   * true. Otherwise, false is returned.
+   * @param {Number} count The number of tokens to remove.
+   * @param {Boolean} True if the tokens were successfully removed, otherwise
+   *  false.
+   */
+  tryRemoveTokens: function(count) {
+    // Make sure the request isn't for more than we can handle
+    if (count > this.tokenBucket.bucketSize)
+      return false;
+
+    var now = Date.now();
+
+    // Advance the current interval and reset the current interval token count
+    // if needed
+    if (now - this.curIntervalStart >= this.tokenBucket.interval) {
+      this.curIntervalStart = now;
+      this.tokensThisInterval = 0;
+    }
+
+    // If we don't have enough tokens left in this interval, return false
+    if (count > this.tokenBucket.tokensPerInterval - this.tokensThisInterval)
+      return false;
+
+    // Try to remove the requested number of tokens from the token bucket
+    return this.tokenBucket.tryRemoveTokens(count);
+  },
+
+  /**
    * Returns the number of tokens remaining in the TokenBucket.
@@ -93,0 +124,0 @@ * @returns {Number} The number of tokens remaining.

lib/tokenBucket.js

@@ -60,3 +60,3 @@
     var self = this;
-
+    
     // Is this an infinite size bucket?
@@ -79,9 +79,4 @@ if (!this.bucketSize) {
     // If we don't have enough tokens in this bucket, come back later
-    if (count > this.content) {
-      // How long do we need to wait to make up the difference in tokens?
-      var waitInterval = Math.ceil(
-        (count - this.content) * (this.interval / this.tokensPerInterval));
-      setTimeout(function() { self.removeTokens(count, callback); }, waitInterval);
-      return false;
-    }
+    if (count > this.content)
+      return comeBackLater();
     
@@ -91,7 +86,8 @@ if (this.parentBucket) {
       return this.parentBucket.removeTokens(count, function(err, remainingTokens) {
-        if (err) {
-          callback(err, null);
-          return;
-        }
+        if (err) return callback(err, null);
         
+        // Check that we still have enough tokens in this bucket
+        if (count > self.content)
+          return comeBackLater();
+        
         // Tokens were removed from the parent bucket, now remove them from
@@ -103,3 +99,3 @@ // this bucket and fire the callback. Note that we look at the current
         callback(null, Math.min(remainingTokens, self.content));
-      })
+      });
     } else {
@@ -111,5 +107,46 @@ // Remove the requested tokens from this bucket and fire the callback
     }
+    
+    function comeBackLater() {
+      // How long do we need to wait to make up the difference in tokens?
+      var waitInterval = Math.ceil(
+        (count - self.content) * (self.interval / self.tokensPerInterval));
+      setTimeout(function() { self.removeTokens(count, callback); }, waitInterval);
+      return false;
+    }
   },
-  
+
   /**
+   * Attempt to remove the requested number of tokens and return immediately.
+   * If the bucket (and any parent buckets) contains enough tokens this will
+   * return true, otherwise false is returned.
+   * @param {Number} count The number of tokens to remove.
+   * @param {Boolean} True if the tokens were successfully removed, otherwise
+   *  false.
+   */
+  tryRemoveTokens: function(count) {
+    // Is this an infinite size bucket?
+    if (!this.bucketSize)
+      return true;
+    
+    // Make sure the bucket can hold the requested number of tokens
+    if (count > this.bucketSize)
+      return false;
+    
+    // Drip new tokens into this bucket
+    this.drip();
+
+    // If we don't have enough tokens in this bucket, return false
+    if (count > this.content)
+      return false;
+
+    // Try to remove the requested tokens from the parent bucket
+    if (this.parentBucket && !this.parent.tryRemoveTokens(count))
+      return false;
+
+    // Remove the requested tokens from this bucket and return
+    this.content -= count;
+    return true;
+  },
+
+  /**
    * Add any new tokens to the bucket since the last drip.
@@ -116,0 +153,0 @@ * @returns {Boolean} True if new tokens were added, otherwise false.

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": "1.0.4",
+  "version": "1.0.5",
   "author": "John Hurliman <[e-mail]>",
@@ -6,0 +6,0 @@ "dependencies": { },

README.md

@@ -71,2 +71,13 @@
 
+A synchronous method, tryRemoveTokens(), is available in both RateLimiter and TokenBucket. This will return immediately with a boolean value indicating if the token removal was successful.
+```javascript
+var RateLimiter = require('limiter').RateLimiter;
+var limiter = new RateLimiter(10, 'second');
+
+if (limiter.tryRemoveTokens(5))
+  console.log('Tokens removed');
+else
+  console.log('No tokens removed');
+```
+
 To get the number of remaining tokens **outside** the `removeTokens`-callback
@@ -82,3 +93,3 @@ simply use the `getTokensRemaining`-method.
 
-Uses the token bucket directly to throttle at the byte level:
+Using the token bucket directly to throttle at the byte level:
 
@@ -106,6 +117,2 @@ ```javascript
 
-## Sponsors ##
-
-* [cull.tv](http://cull.tv/) - New music television
-
 ## License ##
@@ -115,3 +122,3 @@
 
-Copyright (c) 2011 Cull TV, Inc. <[e-mail]>
+Copyright (c) 2013 John Hurliman. <[e-mail]>
 
@@ -118,0 +125,0 @@ Permission is hereby granted, free of charge, to any person obtaining

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Improved metrics

Total package byte prevSize

19251

increased by16.69%

Lines of code

321

increased by20.68%

Number of lines in readme file

139

increased by5.3%

No dependency changes