Why doesn’t flush_rewrite_rules() work on my plugin?

One common issue that people run into when using custom post types in their plugin is that the pretty permalink structure doesn’t seem to take hold on plugin activation.

When adding new paths into the permalink structure, like with a new custom post type, you typically need to run flush_rewrite_rules() in order for them to take hold. One common piece of advice people give is to visit the Permalinks page in the Settings menu in wp-admin. The reason for this is that page runs flush_rewrite_rules() on load.

The problem with this advice is that you do not want to have to tell your plugin users that they have to visit that page after they activate your plugin. They should be able to click “activate” and it should just work.

One would think that if you add flush_rewrite_rules() to the activation function for your plugin that that should do the trick, right?


Well, yes and no.

If you call register_activation_hook when you are supposed to, not in a hook, then it will run well before your custom post type is registered — in init.  So it never actually gets to init, and your rewrite rules are never flushed.

So you do need to call flush_rewrite_rules() in your activation function, but you need to register your custom post type there as well.

Something like this:

function my_plugin_activate() {
register_activation_hook( __FILE__, 'my_plugin_activate' );

I’ve run into this myself and lost time trying to debug what’s going on. If you are ever trying to figure out why something isn’t happening when you think it should, look at the hooks.

Subsequently, if you don’t think you can do something in WordPress, you’re probably wrong. There are hooks for everything.

I hope that it will help someone else avoid this pitfall.

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SUPER Simple React webpack Tutorial, so you can start ‘Getting Started’

I was annoyed by how many people are trying to sound smart in their tutorials, and thus not really helping anything. I wanted a simple “Here is what you need to get started” tutorial and lost a day chasing rabbits down broken holes.

So I wrote this. This is all you need.

Download this github repo for React/weback:


git clone git@github.com:jackreichert/react-webpack.git

cd react-webpack

npm install

Which will install the node dependencies for the project.

Then run: webpack

Which will compile the “Hello World” example.

Now run your favorite static server in the public/ folder.

For example, if you’re on a mac you can run:

cd public/

python -m SimpleHTTPServer

In your browser go to http://localhost:8000/.

What’s happening here?

When you ran npm install it installed the babel transpiler, React, ReactDOM, and webpack.

When you ran webpack it followed the config instructions (see comments there for more details).

That’s it. Now you can get started with React without the headache of trying to figure out how to start getting started. Of COURSE there’s a lot more you can do. But you have to start somewhere. Once you have your tools up and running you can figure out the hard stuff in your own time.