Caddyfile

{
        order cache before rewrite
        cache ttl 24h
}

(try) { 
        reverse_proxy @parts {args[0]} {

                # Remove all headers to upstream - particularly the original host
                header_up -*
                # Remove all return headers from upstream - particulraly content-type
                header_down -*

                header_up Host {upstream_hostport}

                rewrite {args[1]}

                # Return content if found
                @ok status 200
                handle_response @ok {
                        copy_response
                }

                # Ignore not found
                @error status 4xx
                handle_response @error 

                # Follow redirect
                @redirect status 3xx
                handle_response @redirect {
                        rewrite {rp.header.Location}
                        reverse_proxy {args[0]} {
                                header_up -*
                                header_down -*
                        }
                }
        }
}

:80 {   
        log stdout 

        # Gitea host:port with public repositories with raw files
        vars upstream "{$GITEA_HOST:git:3000}"
        
        # Gitea raw urls return everything as text/plain 
        # Set content-type based on the extension
        @extension path_regexp extension (.*)\.(\w+)
        
        # got the list from somewhere on the internet - should reference here if I can find it back
        map @extension {re.extension.2} {content_type} {
            ~^(?:appcache|manifest)$    text/cache-manifest;charset=utf-8
            ~^atom$                     application/atom+xml;charset=utf-8
            ~^bat$                      application/x-msdownload;
            ~^coffee$                   text/coffeescript;charset=utf-8
            ~^css$                      text/css;charset=utf-8
            ~^csv$                      text/csv;charset=utf-8
            ~^eot$                      application/vnd.ms-fontobject;
            ~^geojson$                  application/vnd.geo+json;charset=utf-8
            ~^(?:hbs|handlebars)$       text/x-handlebars-template;
            ~^htc$                      text/x-component;
            ~^html?$                    text/html;charset=utf-8
            ~^ics$                      text/calendar;charset=utf-8
            ~^jscad$                    application/javascript;charset=utf-8
            ~^json$                     application/json;charset=utf-8
            ~^jsonld$                   application/ld+json;charset=utf-8
            ~^kml$                      application/vnd.google-earth.kml+xml;charset=utf-8
            ~^(?:md|markdown)$          text/markdown;charset=utf-8
            ~^m?js$                     application/javascript;charset=utf-8
            ~^mhtml$                    multipart/related;charset=utf-8
            ~^n3$                       text/n3;charset=utf-8
            ~^nt$                       application/n-triples;
            ~^otf$                      font/otf;
            ~^(?:owl|rdf)$              application/rdf+xml;charset=utf-8
            ~^pdf$                      application/pdf;
            ~^rss$                      application/rss+xml;charset=utf-8
            ~^shexc?$                   text/shex;
            ~^svg$                      image/svg+xml;
            ~^swf$                      application/x-shockwave-flash;
            ~^stl$                      model/stl;
            ~^tt(?:c|f)$                application/x-font-ttf;
            ~^ttl$                      text/turtle;
            ~^vcard$                    text/vcard;charset=utf-8
            ~^vcf$                      text/x-vcard;charset=utf-8
            ~^vtt$                      text/vtt;
            ~^woff$                     application/font-woff;
            ~^woff2$                    application/font-woff2;
            ~^xht(?:ml)?$               application/xhtml+xml;charset=utf-8
            ~^xml$                      text/xml;charset=utf-8
            ~^txt$                      text/plain;charset=utf-8
            ~^(?:xsl|xsd)$              application/xml;charset=utf-8
            ~^xslt$                     application/xslt+xml;charset=utf-8
            ~^ya?ml$                    text/yaml;charset=utf-8
            ~^wasm$                     application/wasm;
            ~^(?:d|s)?rpm$              application/x-redhat-package-manager;
            default                     text/html;charset=utf-8
        } 

        header @extension Content-Type {content_type}

        # get subdomain of the requested url
        @parts header_regexp host Host ^(\w+)\..*$

        # Look for the first file that we can find

        # Example  http://org.example.com/app/
        # try http://gitea:3000/org/org.example.com/raw/branch/pages/app
        import try {vars.upstream} /{re.host.1}/{host}/raw/branch/pages{path}

        # try http://gitea:3000/org/org.example.com/raw/branch/pages/app/index.html
        import try {vars.upstream} /{re.host.1}/{host}/raw/branch/pages{path}/index.html

        # try http://gitea:3000/org/org.example.com/raw/branch/[defult branch: e.g. master or main]/app
        import try {vars.upstream} /{re.host.1}/{host}/raw{path}

        import try {vars.upstream} /{re.host.1}/{host}/raw{path}/index.html
        #import try {vars.upstream} /{re.host.1}/{re.host.1}/raw/branch/pages{path}
        #import try {vars.upstream} /{re.host.1}/{re.host.1}/raw/branch/pages{path}/index.html
        #import try {vars.upstream} /{re.host.1}/{re.host.1}/raw{path}
        #import try {vars.upstream} /{re.host.1}/{re.host.1}/raw{path}/index.html

        # Default back to the full url - not using subdomain or host
        # This is useful as it doesn't need subdomain or branch or
        # any other defaults but it fixes the content type
        @raw path_regexp raw ^\/[^\/]+\/[^\/]+\/raw\/\.*
        reverse_proxy @raw {vars.upstream} {
                header_up -*
                header_down -*
        }       
}