@fedify/fedify
Version:
An ActivityPub server framework
124 lines (123 loc) • 4.21 kB
JavaScript
// Copyright 2018-2025 the Deno authors. MIT license.
/*!
* Adapted directly from negotiator at https://github.com/jshttp/negotiator/
* which is licensed as follows:
*
* (The MIT License)
*
* Copyright (c) 2012-2014 Federico Romero
* Copyright (c) 2012-2014 Isaac Z. Schlueter
* Copyright (c) 2014-2015 Douglas Christopher Wilson
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* 'Software'), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
import { compareSpecs, isQuality } from "./common.js";
const simpleEncodingRegExp = /^\s*([^\s;]+)\s*(?:;(.*))?$/;
function parseEncoding(str, i) {
const match = simpleEncodingRegExp.exec(str);
if (!match) {
return undefined;
}
const encoding = match[1];
let q = 1;
if (match[2]) {
const params = match[2].split(";");
for (const param of params) {
const p = param.trim().split("=");
if (p[0] === "q" && p[1]) {
q = parseFloat(p[1]);
break;
}
}
}
return { encoding, o: undefined, q, i, s: undefined };
}
function specify(encoding, spec, i = -1) {
if (!spec.encoding) {
return;
}
let s = 0;
if (spec.encoding.toLowerCase() === encoding.toLowerCase()) {
s = 1;
}
else if (spec.encoding !== "*") {
return;
}
return {
i,
o: spec.i,
q: spec.q,
s,
};
}
function parseAcceptEncoding(accept) {
const accepts = accept.split(",");
const parsedAccepts = [];
let hasIdentity = false;
let minQuality = 1;
for (const [i, accept] of accepts.entries()) {
const encoding = parseEncoding(accept.trim(), i);
if (encoding) {
parsedAccepts.push(encoding);
hasIdentity = hasIdentity || !!specify("identity", encoding);
minQuality = Math.min(minQuality, encoding.q || 1);
}
}
if (!hasIdentity) {
parsedAccepts.push({
encoding: "identity",
o: undefined,
q: minQuality,
i: accepts.length - 1,
s: undefined,
});
}
return parsedAccepts;
}
function getEncodingPriority(encoding, accepted, index) {
let priority = { o: -1, q: 0, s: 0, i: 0 };
for (const s of accepted) {
const spec = specify(encoding, s, index);
if (spec &&
(priority.s - spec.s || priority.q - spec.q ||
priority.o - spec.o) <
0) {
priority = spec;
}
}
return priority;
}
/** Given an `Accept-Encoding` string, parse out the encoding returning a
* negotiated encoding based on the `provided` encodings otherwise just a
* prioritized array of encodings. */
export function preferredEncodings(accept, provided) {
const accepts = parseAcceptEncoding(accept);
if (!provided) {
return accepts
.filter(isQuality)
.sort(compareSpecs)
.map((spec) => spec.encoding);
}
const priorities = provided.map((type, index) => getEncodingPriority(type, accepts, index));
return priorities
.filter(isQuality)
.sort(compareSpecs)
.map((priority) => provided[priorities.indexOf(priority)]);
}