Working on assets README

Author: davegaeddert

plain/plain/assets/README.md

@@ -2,11 +2,10 @@
 
 Serve static assets (CSS, JS, images, etc.) directly from your app.
 
-The default behavior is for Plain to serve its own assets through a view. This behaves in a way similar to [Whitenoise](https://whitenoise.readthedocs.io/en/latest/).
 
 ## Usage
 
-To include assests in your app, put them either in `app/assets` or `app/<package>/assets`.
+To serve assets, put them in `app/assets` or `app/{package}/assets`.
 
 Then include the `plain.assets.urls` in your `urls.py`:
 
@@ -22,16 +21,74 @@ urlpatterns = [
 ]
 ```
 
-Then in your template you can use the `asset()` function to get the URL.
+Now in your template you can use the `asset()` function to get the URL:
 
 ```html
 <link rel="stylesheet" href="{{ asset('css/style.css') }}">
 ```
 
-If you ever need to reference an asset directly in Python code, you can use the `get_asset_url()` function.
+
+## Local development
+
+When you're working with `settings.DEBUG = True`, the assets will be served directly from their original location. You don't need to run `plain compile` or configure anything else.
+
+
+## Production deployment
+
+In production, one of your deployment steps should be to compile the assets.
+
+```bash
+plain compile
+```
+
+By default, this generates "fingerprinted" and compressed versions of the assets, which are then served by your app. This means that a file like `main.css` will result in two new files, like `main.d0db67b.css` and `main.d0db67b.css.gz`.
+
+The purpose of fingerprinting the assets is to allow the browser to cache them indefinitely. When the content of the file changes, the fingerprint will change, and the browser will use the newer file. This cuts down on the number of requests that your app has to handle related to assets.
+
+
+## FAQs
+
+### How do you reference assets in Python code?
 
 ```python
 from plain.assets.urls import get_asset_url
 
-print(get_asset_url("css/style.css"))
+url = get_asset_url("css/style.css")
+```
+
+### What if I need the files in a different location?
+
+The generated/copied files are stored in `{repo}/.plain/assets/compiled`. If you need them to be somewhere else, try simply moving them after compilation.
+
+```bash
+plain compile
+mv .plain/assets/compiled /path/to/your/static
 ```
+
+### How do I upload the assets to a CDN?
+
+The steps for this will vary, but the general idea is to compile them, and then upload the compiled assets.
+
+```bash
+plain compile
+./example-upload-to-cdn-script
+```
+
+Use the `ASSETS_BASE_URL` setting to tell the `{{ asset() }}` template function where to point.
+
+```python
+# app/settings.py
+ASSETS_BASE_URL = "https://cdn.example.com/"
+```
+
+
+### Why aren't the originals copied to the compiled directory?
+
+The default behavior is to fingerprint assets, which is an exact copy of the original file but with a different filename. The originals aren't copied over because you should generally always use this fingerprinted path (that automatically uses longer-lived caching).
+
+If you need the originals for any reason, you can use `plain compile --keep-original`, though this will typically be combined with `--no-fingerprint` otherwise the fingerprinted files will still get priority in `{{ asset() }}` template calls.
+
+
+### What about source maps or imported css files?
+
+TODO