Merge pull request express-rate-limit#8 from Mindtraveller/master

Added support for decrement method (see https://github.com/nfriedly/e…
mganga0109 · Jan 13, 2018 · cf156be · cf156be
2 parents 4f5779b + 8ce18b1
commit cf156be
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Showing 3 changed files with 76 additions and 16 deletions.
diff --git a/.gitignore b/.gitignore
@@ -1 +1,2 @@
 node_modules
+.idea
diff --git a/lib/redis-store.js b/lib/redis-store.js
@@ -13,6 +13,27 @@ var RedisStore = function(options) {
   // create the client if one isn't provided
   options.client = options.client || redis.createClient();
 
+  var setExpire = function(replies, rdskey) {
+    // if this is new or has no expiry
+    if (replies[0] === 1 || replies[1] === -1) {
+      // then expire it after the timeout
+      options.client.pexpire(rdskey, expiryMs);
+    }
+  };
+
+  var processReplies = function(replies) {
+    // in ioredis, every reply consists of an array [err, value].
+    // We don't need the error here, and if we aren't dealing with an array,
+    // nothing is changed.
+    return replies.map(function(val) {
+      if (Array.isArray(val) && val.length >= 2) {
+        return val[1];
+      }
+
+      return val;
+    });
+  };
+
   this.incr = function(key, cb) {
     var rdskey = options.prefix + key;
 
@@ -24,27 +45,29 @@ var RedisStore = function(options) {
           return cb(err);
         }
 
-        // in ioredis, every reply consists of an array [err, value].
-        // We don't need the error here, and if we aren't dealing with an array,
-        // nothing is changed.
-        replies = replies.map(function(val) {
-          if (Array.isArray(val) && val.length >= 2) {
-            return val[1];
-          }
-
-          return val;
-        });
-
-        // if this is new or has no expiry
-        if (replies[0] === 1 || replies[1] === -1) {
-          // then expire it after the timeout
-          options.client.pexpire(rdskey, expiryMs);
-        }
+        replies = processReplies(replies);
+        setExpire(replies, rdskey);
 
         cb(null, replies[0]);
       });
   };
 
+  this.decrement = function(key) {
+    var rdskey = options.prefix + key;
+
+    options.client.multi()
+      .decr(rdskey)
+      .pttl(rdskey)
+      .exec(function(err, replies) {
+        if (err) {
+          return;
+        }
+
+        replies = processReplies(replies);
+        setExpire(replies, rdskey);
+      });
+  };
+
   this.resetKey = function(key) {
     var rdskey = options.prefix + key;
 

diff --git a/test/test.js b/test/test.js
@@ -23,6 +23,20 @@ describe("rate-limit-redis node module", function() {
         return this;
       };
 
+      this.decr = function(key) {
+        opts.push(function() {
+          if (keys[key]) {
+            keys[key].value--;
+          } else {
+            keys[key] = { value: 0 };
+          }
+
+          return keys[key].value;
+        });
+
+        return this;
+      };
+
       this.pttl = function(key) {
         opts.push(function() {
           if (keys[key] && keys[key].ttl) {
@@ -115,6 +129,28 @@ describe("rate-limit-redis node module", function() {
     });
   });
 
+  it("decrements the key for the store each decrement", function(done) {
+    var store = new RedisStore({
+      client: new MockRedisClient()
+    });
+    var key = "test-store-decrement";
+
+    store.incr(key, function() {
+      store.decrement(key);
+      store.incr(key, function(err, value) {
+        if (err) {
+          done(err);
+        } else {
+          if (value === 1) {
+            done();
+          } else {
+            done(new Error("decrement did not decrement the store"));
+          }
+        }
+      });
+    });
+  });
+
   it("resets the key for the store when used with resetKey", function(done) {
     var store = new RedisStore({
       client: new MockRedisClient()