Initial commit

.gitignore

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+node_modules

.npmignore

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+test

Makefile

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+
+test:
+	@./node_modules/.bin/mocha \
+		--reporter spec \
+		--require should
+
+.PHONY: test

index.js

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+
+/**
+ * Expose `fresh()`.
+ */
+
+module.exports = fresh;
+
+/**
+ * Check freshness of `req` and `res` headers.
+ *
+ * When the cache is "fresh" __true__ is returned,
+ * otherwise __false__ is returned to indicate that
+ * the cache is now stale.
+ *
+ * @param {Object} req
+ * @param {Object} res
+ * @return {Boolean}
+ * @api public
+ */
+
+function fresh(req, res) {
+  // defaults
+  var etagMatches = true;
+  var notModified = true;
+
+  // fields
+  var modifiedSince = req['if-modified-since'];
+  var noneMatch = req['if-none-match'];
+  var lastModified = res['last-modified'];
+  var etag = res['etag'];
+
+  // unconditional request
+  if (!modifiedSince && !noneMatch) return false;
+
+  // parse if-none-match
+  if (noneMatch) noneMatch = noneMatch.split(/ *, */);
+
+  // if-none-match
+  if (noneMatch) etagMatches = ~noneMatch.indexOf(etag);
+
+  // if-modified-since
+  if (modifiedSince) {
+    modifiedSince = new Date(modifiedSince);
+    lastModified = new Date(lastModified);
+    notModified = lastModified <= modifiedSince;
+  }
+
+  return !! (etagMatches && notModified);
+}

package.json

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+{
+  "name": "fresh",
+  "author": "TJ Holowaychuk <tj@vision-media.ca> (http://tjholowaychuk.com)",
+  "description": "HTTP response freshness testing",
+  "version": "0.0.1",
+  "main": "index.js",
+  "dependencies": {},
+  "devDependencies": {
+    "mocha": "*",
+    "should": "*"
+  }
+}

test/fresh.js

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+
+var fresh = require('..');
+
+describe('fresh(reqHeader, resHeader)', function(){
+  describe('when a non-conditional GET is performed', function(){
+    it('should be stale', function(){
+      var req = {};
+      var res = {};
+      fresh(req, res).should.be.false;
+    })
+  })
+
+  describe('when requested with If-None-Match', function(){
+    describe('when ETags match', function(){
+      it('should be fresh', function(){
+        var req = { 'if-none-match': 'tobi' };
+        var res = { 'etag': 'tobi' };
+        fresh(req, res).should.be.true;
+      })
+    })
+
+    describe('when ETags mismatch', function(){
+      it('should be stale', function(){
+        var req = { 'if-none-match': 'tobi' };
+        var res = { 'etag': 'luna' };
+        fresh(req, res).should.be.false;
+      })
+    })
+
+    xdescribe('when etag is missing');
+  })
+
+  describe('when requested with If-Modified-Since', function(){
+    describe('when modified since the date', function(){
+      it('should be stale', function(){
+        var now = new Date;
+        var req = { 'if-modified-since': new Date(now - 4000).toUTCString() };
+        var res = { 'last-modified': new Date(now - 2000).toUTCString() };
+        fresh(req, res).should.be.false;
+      })
+    })
+
+    describe('when unmodified since the date', function(){
+      it('should be fresh', function(){
+        var now = new Date;
+        var req = { 'if-modified-since': new Date(now - 2000).toUTCString() };
+        var res = { 'last-modified': new Date(now - 4000).toUTCString() };
+        fresh(req, res).should.be.true;
+      })
+    })
+
+    xdescribe('with invalid if-modified-since date');
+    xdescribe('with invalid modified-since date');
+    xdescribe('when last-modified is missing');
+  })
+})