How to create a Proxy over Apache to Google Cloud and handle 403 failover?

Question

Summary:

I'm trying to proxy images over Apache to Google Cloud.

In case of image does not exist, I want to forward a request to a different route which will return the image and save it on Google Cloud for the next time.

Legends:

Local media domain used for proxy: media.homestead

The site where the request should be forwarded(no redirect) if the image does not exist: mainsite.homestead

Google cloud bucket: storage.googleapis.com/mymedia.appspot.com

Case 1:

http://media.homestead/dimension/150x100/sport.jpg

The image exists on google cloud, so the user will get an image response.

Case 2:

http://media.homestead/dimension/600x400/sport.jpg

The image does not exist, and the user should get a response from mainsite.homestead/dimension/150x100/sport.jpg

Why?

Because there is ErrorDocument 403 to cover that case. We get header status 403 from Google Cloud if the image does not exist.

Configuration which I'm using for Apache:

LoadModule headers_module /usr/lib/apache2/modules/mod_headers.so
LoadModule proxy_module /usr/lib/apache2/modules/mod_proxy.so
LoadModule proxy_http_module /usr/lib/apache2/modules/mod_proxy_http.so
LoadModule ssl_module /usr/lib/apache2/modules/mod_ssl.so

<VirtualHost *:80>
    ServerName media.homestead
    ServerAdmin webmaster@localhost
    ServerAlias media.homestead

    Header always append X-Frame-Options SAMEORIGIN
    Header always append X-XSS-Protection "1; mode=block"
    Header always append X-Content-Type-Options nosniff

    Header unset X-GUploader-UploadID
    Header unset alt-svc
    Header unset alternate-protocol
    Header unset x-goog-hash
    Header unset x-goog-generation
    Header unset x-goog-metageneration
    Header unset x-goog-stored-content-encoding
    Header unset x-goog-stored-content-length
    Header unset x-goog-storage-class
    Header unset Set-Cookie

    RequestHeader set X-SCHEME https
    RequestHeader set X-Forwarded-Proto https
    RequestHeader set Host "https://storage.googleapis.com/mymedia.appspot.com"

    SSLProxyEngine on
    SSLProxyVerify none
    SSLProxyCheckPeerCN off

    ProxyErrorOverride On

    <Location />
        ProxyPass http://storage.googleapis.com/mymedia.appspot.com/
        ProxyPassReverse http://storage.googleapis.com/mymedia.appspot.com/
    </Location>


    <Location /media>
        ProxyPass http://mainsite.homestead/dimension
        ProxyPassReverse http://mainsite.homestead/dimension
    </Location>

    ErrorDocument 403 /media
    ErrorDocument 404 /media
</VirtualHost>

Content of PHP script on mainsite.homestead:

<?php
echo $_SERVER['REQUEST_URI'];exit;

Problem:

Problem is that when I print the current URL on mainsite, I get "/dimension" instead of "/dimension/600x400/sport.jpg"

Answer 1

It was finally solved.

I have replaced these lines:

    <Location /media>
        ProxyPass http://mainsite.homestead/dimension
        ProxyPassReverse http://mainsite.homestead/dimension
    </Location>

    ErrorDocument 403 /media
    ErrorDocument 404 /media

With the following two:

    <Location /media>
        ProxyPass http://mainsite.homestead
        ProxyPassReverse http://mainsite.homestead
    </Location>
    ErrorDocument 403 /media/%{REQUEST_URI}
    ErrorDocument 404 /media/%{REQUEST_URI}

Now I'm getting the requested URL "/dimension/600x400/sport.jpg".