Added netlify header auto generation

docs/_headers

@@ -0,0 +1,9 @@
+/*
+  X-Frame-Options: DENY
+  X-XSS-Protection: 1; mode=block
+  X-Content-Type-Options: nosniff
+  Strict-Transport-Security: max-age=31536000, includeSubDomains
+
+## Far future expires for hashed file names
+/static/*
+  Cache-Control: max-age=31536000

package.json

@@ -305,7 +305,7 @@
     "coveralls": "nyc report --reporter=text-lcov | coveralls",
     "prebuildDocs": "rm -rf docs/_dist && node scripts/docs-update-toc.js",
     "buildDocs": "bundle exec jekyll build --source ./docs --destination ./docs/_site --config ./docs/_config.yml --safe --drafts",
-    "postbuildDocs": "buildProduction docs/_site/index.html --outroot docs/_dist --canonicalroot https://mochajs.org/ --optimizeimages --inlinehtmlimage 10000 --asyncscripts ",
+    "postbuildDocs": "cp docs/_headers docs/_site/_headers && buildProduction docs/_site/index.html docs/_site/_headers --outroot docs/_dist --canonicalroot https://mochajs.org/ --optimizeimages --inlinehtmlimage 10000 --asyncscripts && cp docs/_headers docs/_dist/_headers && node scripts/netlify-headers.js >> docs/_dist/_headers",
     "prewatchDocs": "node scripts/docs-update-toc.js",
     "watchDocs": "bundle exec jekyll serve --source ./docs --destination ./docs/_site --config ./docs/_config.yml --safe --drafts --watch"
   },

scripts/netlify-headers.js

@@ -0,0 +1,103 @@
+var AssetGraph = require('assetgraph');
+
+var headers = [
+    'Content-Security-Policy'
+];
+
+var resourceHintTypeMap = {
+    HtmlPreloadLink: 'preload',
+    HtmlPrefetchLink: 'prefetch',
+    HtmlPreconnectLink: 'preconnect',
+    HtmlDnsPrefetchLink: 'dns-prefetch'
+};
+
+function getHeaderForRelation (rel) {
+    let header = `Link: <${rel.href}>; rel=${resourceHintTypeMap[rel.type]}; as=${rel.as}; type=${rel.to.contentType}`;
+
+    if (rel.crossorigin || rel.as === 'font') {
+        header = `${header}; crossorigin=anonymous`;
+    }
+
+    return header;
+}
+
+new AssetGraph({ root: 'docs/_dist' })
+    .loadAssets('*.html')
+    .populate({
+        followRelations: { type: 'HtmlAnchor', crossorigin: false }
+    })
+    .queue(function (assetGraph) {
+        var assets = assetGraph.findAssets({ type: 'Html', isInline: false });
+
+        var headerMap = {};
+
+        assets.forEach(function (asset) {
+            var url = '/' + asset.url.replace(assetGraph.root, '').replace(/#.*/, '').replace('index.html', '');
+            if (!headerMap[url]) {
+                headerMap[url] = [];
+            }
+
+            headers.forEach(function (header) {
+                var node = asset.parseTree.querySelector('meta[http-equiv=' + header + ']');
+
+                if (node) {
+                    headerMap[url].push(`${header}: ${node.getAttribute('content')}`)
+
+                    node.parentNode.removeChild(node);
+                    asset.markDirty();
+                }
+            });
+
+            var firstCssRel = asset.outgoingRelations.filter(r => {
+                return r.type === 'HtmlStyle'
+                    && r.crossorigin === false
+                    && r.href !== undefined;
+            })[0];
+
+            if (firstCssRel) {
+                const header = `Link: <${firstCssRel.href}>; rel=preload; as=style`;
+
+
+                headerMap[url].push(header);
+            }
+
+            var resourceHintRelations = asset.outgoingRelations.filter(r => ['HtmlPreloadLink', 'HtmlPrefetchLink'].includes(r.type));
+
+            resourceHintRelations.forEach(rel => {
+                headerMap[url].push(getHeaderForRelation(rel));
+
+                rel.detach();
+            });
+
+            var resourceHintRelations = asset.outgoingRelations.filter(r => ['HtmlPreconnectLink'].includes(r.type));
+
+            resourceHintRelations.forEach(rel => {
+                let header = `Link: <${rel.href}>; rel=preconnect`;
+
+                if (rel.crossorigin) {
+                    header = `${header}; crossorigin=anonymous`;
+                }
+
+                headerMap[url].push(header);
+
+                rel.detach();
+            });
+        });
+
+        console.log('\n## Autogenerated headers:\n')
+
+        Object.keys(headerMap).forEach(function (url) {
+            console.log(url);
+
+            var httpHeaders = headerMap[url];
+
+            httpHeaders.forEach(function (header) {
+                console.log(`  ${header}`)
+            });
+
+            console.log('');
+        });
+
+    })
+    .writeAssetsToDisc({ isLoaded: true })
+    .run();