Migrating blog routes using Netlify redirects

I recently moved my blog posts from https://blog.acmiyaguchi.me to https://acmiyaguchi.me/blog/ in order to integrate the content with the rest of my website. I’m more comfortable building websites now than I was 3 years ago, and am excited to write and build more things. One of the downsides of moving everything to a route from the subdomain is that the old links have disappeared from the internet all together because I shut down the Jekyll-based blog and moved the blog subdomain to point to the main website.

Netlify provides a set of redirect and rewrite rules that are powerful for managing routes and solving this particular problem. In a _redirect file inside of the publish directory, I can write something like the following:

https://blog.acmiyaguchi.me/engineering/2020/01/24/* https://acmiyaguchi.me/blog/2021-01-24-sapper-export-and-preloaded-routes
https://blog.acmiyaguchi.me/engineering/2020/01/25/* https://acmiyaguchi.me/blog/2021-01-25-ring-wasm-tests
https://blog.acmiyaguchi.me/engineering/2020/01/26/* https://acmiyaguchi.me/blog/2021-01-26-gpuactive-backfill

These three rules show the Jekyll’s pattern versus my scheme for posts. Since I never posted more than one article a day, I could simply map all pages under a category, year, month, and day to point to the new post location. These rules go at the top of the file because the rules fall through as they go from most restrictive to least restrictive.

Finally, I define a fall through rule to map the blog subdomain to the blog route in the site. Since it is configured as an alias (i.e. it’s equivalent to my home domain), I would like to ignore serving the index.html at the root and always redirect. I append an exclamation point to shadow anything in the blog subdomain alias.

https://blog.acmiyaguchi.me/* https://acmiyaguchi.me/blog 301!

Now I can rest easy that my old blog post links won’t completely rot away.

If you’re curious, here’s the _redirects file in my repository at the time of writing.