Create S3 301 redirect objects for URLs without trailing slashes

By default, S3 redirects a request for a directory (e.g.,
https://somesite.com/somepath) to the folder to serve its index.html
file by default (e.g., https://somesite.com/somepath/).

Its redirects are served with a 302 status code [1].

Best practice states that we want links to URLs without trailing slashes
to redirect to the correct URL with a 301 [2].

This change generates the appropriate redirect objects on every publish
configured with the correct redirect URL and redirect code [3].

1: https://docs.aws.amazon.com/AmazonS3/latest/dev/IndexDocumentSupport.html
2: https://moz.com/learn/seo/redirection
3: https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectPUT.html

Author: TheDahv

Diff for: gulpfile.js

@@ -1,6 +1,7 @@
 const _            = require('underscore');
 const awspublish   = require('gulp-awspublish');
 const del          = require('del');
+const es           = require('event-stream');
 const gulp         = require('gulp');
 const mkdirp       = require('mkdirp');
 const path         = require('path');
@@ -114,6 +115,20 @@ gulp.task('create-sitemap', () => {
   return transblogify.sitemap({ siteRoot: SITE_ROOT });
 });
 
+gulp.task('redirects', () => {
+  const {client} = awspublish.create(require('./awscredentials.json'));
+  return transblogify.redirects()
+    .pipe(es.map((Key, callback) => {
+      console.log(Key);
+      client.putObject({
+        ACL: 'public-read',
+        Key,
+        WebsiteRedirectLocation: `https://www.thedahv.com/${Key}/`
+      }, callback);
+    }))
+  .pipe(awspublish.reporter());
+});
+
 gulp.task('build', () => {
   runSequence(
     'clean',

Diff for: lib/transblogify/index.js

@@ -8,22 +8,24 @@ const mkdirp      = require('mkdirp');
 const pages       = require('./pages');
 const path        = require('path');
 const posts       = require('./posts');
+const redirects   = require('./redirects');
 const reduce      = require('stream-reduce');
 const sitemap     = require('./sitemap');
 const w           = require('when');
 
 const transblogify = {};
 
 const defaults = {
+  'categories': true,
+  'dataDir': 'data',
+  'defaultPostTemplate': 'post',
+  'outputDir': 'build',
+  'pagesDir': 'pages',
   'postsDir': 'posts',
   'postsPattern': '*.md',
-  'pagesDir': 'pages',
-  'outputDir': 'build',
-  'categories': true,
+  'redirectsDir': 'redirects',
+  'siteRoot': '',
   'templatesDir': 'templates',
-  'defaultPostTemplate': 'post',
-  'dataDir': 'data',
-  'siteRoot': ''
 };
 
 function getTemplates(options) {
@@ -184,6 +186,10 @@ transblogify.pages = options => {
 transblogify.sitemap = options => {
   options = _.extend(defaults, options);
   return sitemap(options);
-}
+};
+
+transblogify.redirects = options => {
+  return redirects(_.extend(defaults, options));
+};
 
 module.exports = transblogify;

Diff for: lib/transblogify/redirects.js

@@ -0,0 +1,41 @@
+const es   = require('event-stream');
+const fs = require('fs');
+const frontMatter = require('gulp-front-matter');
+const gulp = require('gulp');
+const mkdirp = require('mkdirp');
+const path = require('path');
+const posts = require('./posts');
+const reduce      = require('stream-reduce');
+
+module.exports = options => {
+  const { redirectsDir } = options || {};
+  const generateSlug = posts.generateSlug();
+
+  return gulp
+    .src([ 'pages/**/*', 'posts/**/*' ], { read: true, } )
+    .pipe(es.map((file, callback) => {
+      callback(null, file.isDirectory() ? undefined : file);
+    }))
+    .pipe(frontMatter({ property: 'frontMatter', remove: true }))
+    .pipe(posts.generateSlug())
+    .pipe(es.map((file, callback) => {
+      const { cwd, base, path, slug } = file;
+      const type = base.replace(/\/$/, '').split('/').pop();
+      const page = slug
+        ? slug
+        : path
+            .replace(cwd, '')
+            .split('/')
+            .slice(2)
+            .join('/')
+            .replace(/(\.html|\.md)$/, '');
+
+      const entry = type === 'posts' ?
+        [ 'blog', page ].join('/')
+          : page === 'index' ?
+            undefined
+            : page
+
+      callback(null, entry);
+    }))
+};

Diff for: package.json

@@ -30,7 +30,7 @@
     "build": "gulp",
     "clean": "gulp clean",
     "dev": "gulp autoserve",
-    "publish": "gulp publish"
+    "publish": "gulp publish && gulp redirects"
   },
   "author": "",
   "license": "BSD-2-Clause"