New TIL on Axum Fallback route

til/2024-02-27T10:40:08Z.md

@@ -0,0 +1,43 @@
+---
+title: Fallback Routing with Axum
+date: 2024-02-27
+slug: fallback-routing-with-axum
+---
+
+Yesterday I ran into a small problem with my Axum routing for my blog.
+So today I wanted to take 10 minutes and do quick write up about it!
+
+My blog uses `Axum` as its Web Framework of choice. I was looking through some old emails and found one where a reader reached out about a post I made! (It was [this one about FZF Spell Checking in VIM](https://coreyja.com/posts/vim-spelling-suggestions-fzf/))
+
+But I realized that it was linking to an older URL format, The link was to 
+`https://coreyja.com/https://coreyja.com/blog/2018/11/10/vim-spelling-suggestions-fzf.html`!
+
+And you can see I was using a different URL structure then, and my current blog didn't have a redirect setup!
+
+And that was our goal! I wanted `https://coreyja.com/blog/2018/11/10/vim-spelling-suggestions-fzf.html` to redirect to `/posts/vim-spelling-suggestions-fzf`.
+And I also decided that I wanted `blog/anything-else-here` to redirect to `/posts`
+
+Simple enough!
+
+I added these two routes to my Axum Router function:
+
+```rust
+.route("/blog/:year/:month/:date/:slug", get(redirect_to_new_post_url))
+.route("/blog/*catchall", get(redirect_to_posts_index))
+```
+
+And I expected this to work out of the box! But it didn't :sadnerd:
+
+Instead I got an error about conflicting routes. Luckily the answer is relatively easy, at least in my case!
+I just needed to use `nest` to target all the `/blog` urls and then use a `fallback`. Here is what I ended up with!
+
+```rust
+.nest(
+  "/blog",
+  Router::new()
+    .route("/:year/:month/:date/:slug", get(redirect_to_new_post_url))
+    .fallback(redirect_to_posts_index)
+)
+```
+
+And now I was able to get all the redirects working as I wanted! Go check out that 'old' URL above now and with any luck you should be redirected to the right post!