Add content to http caching

Author: RoyalIcing

apps/components_guide_web/assets/css/app.css

@@ -49,7 +49,7 @@ a {
   text-decoration: var(--link-decoration);
 }
 a:hover {
-  text-decoration: var(--hover\: links-decoration);
+  text-decoration: var(--hover\:links-decoration);
 }
 
 h1,

apps/components_guide_web/lib/components_guide_web/controllers/research_controller.ex

@@ -137,6 +137,7 @@ defmodule ComponentsGuideWeb.ResearchController do
            }
          ) do
       Section.card([
+        # inspect(item),
         content_tag(:h3, title, class: "text-2xl"),
         content_tag(
           :dl,

apps/components_guide_web/lib/components_guide_web/templates/web/http-caching.html.md

@@ -1,11 +1,122 @@
 # HTTP Caching
 
-## Initial response
+## Resource that does not want to be cached
 
-## When server has same etag
+```http
+GET /about HTTP/1.1
+HOST: example.org
+```
 
-## When server has not been modified since
+```http
+HTTP/1.1 200 OK
+Cache-Control: max-age=0, private, must-revalidate
+Date: Fri, 02 Oct 2020 09:28:50 GMT
+Content-Type: text/html; charset=utf-8
+Content-Length: 4321
+```
 
-## When server has different etag
+## Resource that wants to be cached
 
-## When server has been modified since
+```http
+GET /assets/logo.png HTTP/1.1
+Host: example.org
+```
+
+```http
+HTTP/1.1 200 OK
+ETag: "ABC"
+Last-Modified: Wed, 21 Oct 2015 07:28:00 GMT 
+Cache-Control: public, max-age=31536000
+Date: Fri, 02 Oct 2020 09:28:50 GMT
+Content-Type: image/png
+Content-Length: 2348
+Vary: Accept-Encoding
+
+… data …
+```
+
+### When server has same etag
+
+```http
+GET /assets/logo.png HTTP/1.1
+Host: example.org
+If-None-Match: "ABC"
+```
+
+```http
+HTTP/1.1 304 Not Modified
+ETag: "ABC"
+Date: Fri, 02 Oct 2020 09:28:50 GMT
+Content-Type: image/png
+Content-Length: 2348
+Cache-Control: public, max-age=31536000
+Last-Modified: Wed, 21 Oct 2015 07:28:00 GMT 
+Vary: Accept-Encoding
+
+```
+
+### When server has not been modified since
+
+```http
+GET /assets/logo.png HTTP/1.1
+Host: example.org
+If-Modified-Since: Wed, 21 Oct 2015 07:28:00 GMT 
+```
+
+```http
+HTTP/1.1 304 Not Modified
+Date: Fri, 02 Oct 2020 09:28:50 GMT
+Content-Type: image/png
+Content-Length: 2348
+Cache-Control: public, max-age=31536000
+ETag: "ABC"
+Last-Modified: Wed, 21 Oct 2015 07:28:00 GMT 
+Vary: Accept-Encoding
+
+```
+
+### When server does not have that etag
+
+```http
+GET /assets/logo.png HTTP/1.1
+Host: example.org
+If-None-Match: "ABC"
+```
+
+```http
+HTTP/1.1 200 OK
+ETag: "XYZ"
+Date: Fri, 02 Oct 2020 09:28:50 GMT
+Content-Type: image/png
+Content-Length: 2348
+Cache-Control: public, max-age=31536000
+Last-Modified: Wed, 21 Oct 2015 07:28:00 GMT 
+Vary: Accept-Encoding
+
+```
+
+### When server has been modified since
+
+```http
+GET /assets/logo.png HTTP/1.1
+Host: example.org
+If-Modified-Since: Wed, 21 Oct 2015 07:28:00 GMT 
+```
+
+```http
+HTTP/1.1 200 OK
+ETag: "XYZ"
+Date: Fri, 02 Oct 2020 09:28:50 GMT
+Content-Type: image/png
+Content-Length: 2348
+Cache-Control: public, max-age=31536000
+Last-Modified: Thu, 22 Oct 2015 07:28:00 GMT 
+Vary: Accept-Encoding
+
+```
+
+## See more
+
+- [MDN: HTTP caching](https://developer.mozilla.org/en-US/docs/Web/HTTP/Caching)
+- [MDN: If-None-Match](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/If-None-Match)
+- [MDN: 412 Precondition Failed](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/412)

apps/components_guide_web/lib/components_guide_web/templates/web/index.html.eex

@@ -2,7 +2,7 @@
 
 <article>
   <div class="text-white bg-gray-900">
-    <div class="content max-w-4xl mx-auto py-8 text-xl">
+    <div class="content max-w-4xl mx-auto py-8 text-xl" style="--link-decoration: underline;">
       <%= render(@view_module, @article <> ".html", conn: @conn) %>
     </div>
   </div>