Improve HTTP redirects to avoid exposing origin URL behind CDN

README.md

@@ -73,6 +73,11 @@ the `live` branch like this:
 $ make deploy
 ```
 
+As a prerequisite, this should be deployed behind a CDN (Bunny CDN) that is
+responsible for HTTPS certificate handling and forcing HTTPS redirects. This CDN
+needs to be configured to pass the `X-Forwarded-Scheme` and `X-Forwarded-Host` HTTP
+request headers to avoid exposing the origin URL in any HTTP redirects.
+
 ## Auto-Deployment
 
 The website can be automatically deployed via the GitHub Pages feature.

public/.htaccess

@@ -1,21 +1,32 @@
 RewriteEngine On
-RewriteRule ^docs/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}getting-started/ [R]
 
-RewriteRule ^docs/getting-started/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}quickstart/ [R]
-RewriteRule ^docs/best-practices/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}controllers/ [R]
-RewriteRule ^docs/api/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}app/ [R]
-RewriteRule ^docs/async/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}fibers/ [R]
-RewriteRule ^docs/integrations/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}database/ [R]
+# construct base URL for redirects from `X-Forwarded-Proto` and `X-Forwarded-Host`, otherwise empty to prefix current origin
+RewriteCond %{HTTP:X-Forwarded-Proto} ^https?$
+RewriteCond %{HTTP:X-Forwarded-Host} ^[a-zA-Z\d.-]+(:\d+)?$
+RewriteRule .* - [ENV=BASE_URL:%{HTTP:X-Forwarded-Proto}://%{HTTP:X-Forwarded-Host}]
+
+# redirect docs/ to right sub-directories
+RewriteRule ^docs/$ %{ENV:BASE_URL}%{REQUEST_URI}getting-started/ [R]
+RewriteRule ^docs/getting-started/$ %{ENV:BASE_URL}%{REQUEST_URI}quickstart/ [R]
+RewriteRule ^docs/best-practices/$ %{ENV:BASE_URL}%{REQUEST_URI}controllers/ [R]
+RewriteRule ^docs/api/$ %{ENV:BASE_URL}%{REQUEST_URI}app/ [R]
+RewriteRule ^docs/async/$ %{ENV:BASE_URL}%{REQUEST_URI}fibers/ [R]
+RewriteRule ^docs/integrations/$ %{ENV:BASE_URL}%{REQUEST_URI}database/ [R]
 
 # redirect old "more" section (2021-11-23)
-RewriteRule ^docs/more/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}../getting-started/philosophy/ [R]
-RewriteRule ^docs/more/philosophy/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}../../getting-started/philosophy/ [R]
-RewriteRule ^docs/more/architecture/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}../../getting-started/philosophy/ [R]
-RewriteRule ^docs/more/community/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}../../getting-started/community/ [R]
+RewriteRule ^docs/more/$ %{ENV:BASE_URL}%{REQUEST_URI}../getting-started/philosophy/ [R]
+RewriteRule ^docs/more/philosophy/$ %{ENV:BASE_URL}%{REQUEST_URI}../../getting-started/philosophy/ [R]
+RewriteRule ^docs/more/architecture/$ %{ENV:BASE_URL}%{REQUEST_URI}../../getting-started/philosophy/ [R]
+RewriteRule ^docs/more/community/$ %{ENV:BASE_URL}%{REQUEST_URI}../../getting-started/community/ [R]
 
 # redirect old "async" pages (2021-11-22)
-RewriteRule ^docs/async/child-processes/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}../../integrations/child-processes/ [R]
-RewriteRule ^docs/async/streaming/$ %{REQUEST_SCHEME}://%{HTTP_HOST}%{REQUEST_URI}../../integrations/streaming/ [R]
+RewriteRule ^docs/async/child-processes/$ %{ENV:BASE_URL}%{REQUEST_URI}../../integrations/child-processes/ [R]
+RewriteRule ^docs/async/streaming/$ %{ENV:BASE_URL}%{REQUEST_URI}../../integrations/streaming/ [R]
+
+# redirect requests to directories to self with trailing slash
+RewriteCond %{REQUEST_FILENAME} -d
+RewriteRule [^/]$ %{ENV:BASE_URL}%{REQUEST_URI}/ [R=301]
 
+# redirect requests to index pages to parent directory
 RewriteCond %{REQUEST_FILENAME} -f
-RewriteRule ^(.*/?)index.html$ %{REQUEST_SCHEME}://%{HTTP_HOST}/$1 [R=301]
+RewriteRule ^(.*/?)index.html$ %{ENV:BASE_URL}/$1 [R=301]

tests/acceptance.sh

@@ -8,13 +8,26 @@ match() {
     echo "$out" | grep "$@" >/dev/null && echo -n . || \
         (echo ""; echo "Error in test $n: Unable to \"grep $@\" this output:"; echo "$out"; exit 1) || exit 1
 }
+skipif() {
+    echo "$out" | grep "$@" >/dev/null && echo -n S && return 1 || return 0
+}
 
 out=$(curl -v $base/ 2>&1);         match "HTTP/.* 200" && match -iP "Content-Type: text/html[\r\n]"
 out=$(curl -v $base/invalid 2>&1);  match "HTTP/.* 404" && match -i "Content-Type: text/html"
 
 out=$(curl -v $base/docs 2>&1);                     match "HTTP/.* 301" && match -iP "Location: .*/docs/[\r\n]"
 out=$(curl -v $base/docs/ 2>&1);                    match "HTTP/.* 302" && match -iP "Location: .*/docs/getting-started/[\r\n]"
 
+out=$(curl -v $base/docs -H 'X-Forwarded-Host: example.com' -H 'X-Forwarded-Proto: https' 2>&1);
+match "HTTP/.* 301"
+skipif -iP "Location: $base/docs/[\r\n]" &&
+match -iP "Location: https://example\.com/docs/[\r\n]"
+
+out=$(curl -v $base/docs/ -H 'X-Forwarded-Host: example.com' -H 'X-Forwarded-Proto: http' 2>&1);
+match "HTTP/.* 302"
+skipif -iP "Location: $base/docs/[\r\n]" &&
+match -iP "Location: http://example\.com/docs/getting-started/[\r\n]"
+
 out=$(curl -v $base/docs/getting-started/ 2>&1);    match "HTTP/.* 302" && match -iP "Location: .*/docs/getting-started/quickstart/[\r\n]"
 out=$(curl -v $base/docs/best-practices/ 2>&1);     match "HTTP/.* 302" && match -iP "Location: .*/docs/best-practices/controllers/[\r\n]"
 out=$(curl -v $base/docs/api/ 2>&1);                match "HTTP/.* 302" && match -iP "Location: .*/docs/api/app/[\r\n]"