Set base URL for TubeArchivist with Nginx

reverse-proxy.conf

js_path "/etc/nginx/conf.d/";
js_import main from ta_filter.js;
js_set $body_hash main.get_hash;

server {
    location /multimedia/tubearchivist/ {
        rewrite ^/multimedia/tubearchivist(.*)$ $1 break;
        proxy_pass http://{{subnets.multimedia}}.0.14:8000;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $http_host;
        proxy_set_header Accept-Encoding identity;
        proxy_redirect ~^(.*)$ /multimedia/tubearchivist$1;
        js_body_filter main.apply_base_url;
        add_trailer Body-Hash $body_hash;
    }
}

ta_filter.js

var hash = "";
var res = "";
var buf = 0;

// Modify the response body using regular expressions
function apply_base_url(r, data, flags) {
    let requestUrl = r.uri;

    let fileExtension = getFileExtension(requestUrl)
    if (fileExtension === "" || fileExtension === "css" || fileExtension === "js") {
        // Replace URLs in API responses
        if (requestUrl.includes("/api/")) {
            data = data.replace(/("[^"\n\r\f\v]*"(?=\s*:):")(\/.*?")/g, '$1/multimedia/tubearchivist$2');
        } else {
            // Fix some hardcoded /api in JS scripts
            if (fileExtension === "js") {
                data = data.replace(/`(\/api.*)/g, '`/multimedia/tubearchivist$1');
            }
            data = data.replace(/(src|href|action)=["'](\/.*?)["']/g, '$1="/multimedia/tubearchivist$2"');
            data = data.replace(/'(\/.*)'/g, '\'/multimedia/tubearchivist$1\'');
        }
    }
    if (data.length) buf++;
    res += data; // Collect the entire response,
    if (flags.last) { //  until we get the last byte.
        try {
            hash = require('crypto').createHash('sha1').update(res).digest('base64');
            r.sendBuffer(res, flags);
            ngx.log(ngx.INFO, `FILTERED ${res.length} bytes in ${buf} buffers`);
        } catch (e) {
            ngx.log(ngx.ERR, `ERROR ${e}`);
            r.sendBuffer("", flags);
        }
    }

}

// Extract the file extension from the URL
function getFileExtension(url) {
    let match = url.match(/\.([a-z0-9]+)(?:[\?#]|$)/i);
    return match ? match[1].toLowerCase() : '';
}

function get_hash() {
    return hash;
}

export default {
    apply_base_url,
    get_hash
}