rjweb-server
Version:
Easy and Robust Way to create a Web Server with Many Easy-to-use Features in NodeJS
88 lines (87 loc) • 3.5 kB
JavaScript
import { as } from "@rjweb/utils";
/**
* Get the best compression using a header
* @since 8.0.0
*/ export default function getCompressMethod(doCompress, header, size, proxied, global) {
if (!doCompress
|| !global.options.compression.http.enabled
|| size > global.options.compression.http.maxSize
|| size < global.options.compression.http.minSize
|| (proxied && !global.options.proxy.compress))
return null;
if (global.cache.compressionMethods.has(header))
return global.cache.compressionMethods.get(header);
let highestValue = 'none', highestPriority = -Infinity, tempValue = '', tempPriority = '';
header += ',';
let progress = 0, mode = 'value';
while (progress < header.length) {
if (!header[progress] || header[progress] === ' ') {
progress++;
continue;
}
if (header[progress] === ',') {
let prio = parseInt(tempPriority);
if (!global.options.compression.http.preferOrder.includes(tempValue === 'br' ? 'brotli' : as(tempValue)))
prio = NaN;
switch (as(tempValue)) {
case "br":
if (isNaN(prio)) {
if (global.options.compression.http.preferOrder.includes('brotli'))
prio = -(global.options.compression.http.preferOrder.indexOf('brotli') / 10);
else
prio = -Infinity;
break;
}
else
break;
case "gzip":
if (isNaN(prio)) {
if (global.options.compression.http.preferOrder.includes('gzip'))
prio = -(global.options.compression.http.preferOrder.indexOf('gzip') / 10);
else
prio = -Infinity;
break;
}
else
break;
case "deflate":
if (isNaN(prio)) {
if (global.options.compression.http.preferOrder.includes('deflate'))
prio = -(global.options.compression.http.preferOrder.indexOf('deflate') / 10);
else
prio = -Infinity;
break;
}
else
break;
default:
prio = -Infinity;
break;
}
mode = 'value';
tempValue = tempValue;
highestValue = prio > highestPriority ? tempValue : highestValue;
highestPriority = prio > highestPriority ? prio : highestPriority;
tempPriority = '';
tempValue = '';
}
else if (header[progress] === ';') {
mode = 'prio';
}
else {
if (mode === 'value') {
tempValue += header[progress];
}
else {
if (header[progress] !== 'q' && header[progress] !== '=') {
tempPriority += header[progress];
}
}
}
progress++;
}
const result = highestValue === 'none' ? null : as(highestValue === 'br' ? 'brotli' : highestValue);
if (result)
global.cache.compressionMethods.set(header, result);
return result;
}