Rewrite URL via htaccess when request header has a specific value

Question

I'm using Cloudflare, which has a request header named CF-IPCountry that holds the value of the country the user is visiting from. Example: DE for Germany.

I need to serve a different image in certain cases. For example, for all users, the France flag will be loaded with this request: https://example.com/static/img/lang/fr.png

But, if the CF-IPCountry request header value is CA (Canada), then all requests for https://example.com/static/img/lang/fr.png should actually load this other file https://example.com/static/img/lang/fr-ca.png

I've detected those cases for these visitors:

• CA: canadians should load fr-ca instead of the french flag fr
• BR: brazilians should load pt-br instead of the portuguese flag pt

How can this logic be implemented on my .htaccess file?

Update

Based on @CBroe's recommendation, I've come up with 2 approaches.

1. Redirecting:

RewriteEngine On
RewriteCond %{HTTP:CF-IPCountry} ^CA$
RewriteRule ^static/img/lang/fr\.png$ https://example.com/static/img/lang/fr-ca.png [L,R=301]

2. Serving alternate file:

SetEnvIf CF-IPCountry ^CA$ ServeAlternativeFile=true

<FilesMatch "^static/img/lang/fr\.png$">
    Header set Location "/static/img/lang/fr-ca.png" env=ServeAlternativeFile
    Header set Content-Disposition "attachment; filename=fr-ca.png" env=ServeAlternativeFile
</FilesMatch>

Answer 1

Solution

Based on @CBroe's recommendation, I came up with 2 approaches.

1. Redirecting:

RewriteEngine On
RewriteCond %{HTTP:CF-IPCountry} ^CA$
RewriteRule ^static/img/lang/fr\.png$ https://example.com/static/img/lang/fr-ca.png [L,R=301]

2. Serving alternate file:

SetEnvIf CF-IPCountry ^CA$ ServeAlternativeFile=true

<FilesMatch "^static/img/lang/fr\.png$">
    Header set Location "/static/img/lang/fr-ca.png" env=ServeAlternativeFile
    Header set Content-Disposition "attachment; filename=fr-ca.png" env=ServeAlternativeFile
</FilesMatch>