80 lines
2.9 KiB
JavaScript
80 lines
2.9 KiB
JavaScript
/**
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* Analyzes HTTP caching headers
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*
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* @see https://developers.google.com/speed/docs/best-practices/caching
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*/
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exports.version = '0.2.a';
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exports.module = function(phantomas) {
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'use strict';
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var cacheControlRegExp = /max-age=(\d+)/;
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function getCachingTime(url, headers) {
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// false means "no caching"
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var ttl = false,
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headerName,
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now = new Date(),
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headerDate;
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for (headerName in headers) {
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var value = headers[headerName];
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switch (headerName.toLowerCase()) {
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// parse max-age=...
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//
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// max-age=2592000
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// public, max-age=300, must-revalidate
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case 'cache-control':
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var matches = value.match(cacheControlRegExp);
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if (matches) {
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ttl = parseInt(matches[1], 10);
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}
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break;
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// catch Expires and Pragma headers
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case 'expires':
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case 'pragma':
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// and Varnish specific headers
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case 'x-pass-expires':
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case 'x-pass-cache-control':
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phantomas.incrMetric('oldCachingHeaders'); // @desc number of responses with old, HTTP 1.0 caching headers (Expires and Pragma)
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phantomas.addOffender('oldCachingHeaders', url + ' - ' + headerName + ': ' + value);
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headerDate = Date.parse(value);
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if (headerDate) ttl = Math.round((headerDate - now) / 1000);
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break;
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}
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}
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//console.log(JSON.stringify(headers)); console.log("TTL: " + ttl + ' s');
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return ttl;
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}
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phantomas.setMetric('cachingNotSpecified'); // @desc number of responses with no caching header sent (no Cache-Control header)
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phantomas.setMetric('cachingTooShort'); // @desc number of responses with too short (less than a week) caching time
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phantomas.setMetric('cachingDisabled'); // @desc number of responses with caching disabled (max-age=0)
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phantomas.setMetric('oldCachingHeaders');
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phantomas.on('recv', function(entry, res) {
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var ttl = getCachingTime(entry.url, entry.headers);
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// static assets
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if (entry.isImage || entry.isJS || entry.isCSS) {
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if (ttl === false) {
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phantomas.incrMetric('cachingNotSpecified');
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phantomas.addOffender('cachingNotSpecified', entry.url);
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} else if (ttl <= 0) {
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phantomas.incrMetric('cachingDisabled');
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phantomas.addOffender('cachingDisabled', entry.url);
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} else if (ttl < 7 * 86400) {
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phantomas.incrMetric('cachingTooShort');
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phantomas.addOffender('cachingTooShort', entry.url + ' cached for ' + ttl + ' s');
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}
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}
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});
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};
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