@fedify/fedify
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An ActivityPub server framework
114 lines (113 loc) • 3.98 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 SIMPLE_LANGUAGE_REGEXP = /^\s*([^\s\-;]+)(?:-([^\s;]+))?\s*(?:;(.*))?$/;
function parseLanguage(str, i) {
const match = SIMPLE_LANGUAGE_REGEXP.exec(str);
if (!match) {
return undefined;
}
const [, prefix, suffix] = match;
if (!prefix) {
return undefined;
}
const full = suffix !== undefined ? `${prefix}-${suffix}` : prefix;
let q = 1;
if (match[3]) {
const params = match[3].split(";");
for (const param of params) {
const [key, value] = param.trim().split("=");
if (key === "q" && value) {
q = parseFloat(value);
break;
}
}
}
return { prefix, suffix, full, i, o: undefined, q, s: undefined };
}
function parseAcceptLanguage(accept) {
const accepts = accept.split(",");
const result = [];
for (const [i, accept] of accepts.entries()) {
const language = parseLanguage(accept.trim(), i);
if (language) {
result.push(language);
}
}
return result;
}
function specify(language, spec, i) {
const p = parseLanguage(language, i);
if (!p) {
return undefined;
}
let s = 0;
if (spec.full.toLowerCase() === p.full.toLowerCase()) {
s |= 4;
}
else if (spec.prefix.toLowerCase() === p.prefix.toLowerCase()) {
s |= 2;
}
else if (spec.full.toLowerCase() === p.prefix.toLowerCase()) {
s |= 1;
}
else if (spec.full !== "*") {
return;
}
return { i, o: spec.i, q: spec.q, s };
}
function getLanguagePriority(language, accepted, index) {
let priority = { i: -1, o: -1, q: 0, s: 0 };
for (const accepts of accepted) {
const spec = specify(language, accepts, index);
if (spec &&
((priority.s ?? 0) - (spec.s ?? 0) || priority.q - spec.q ||
(priority.o ?? 0) - (spec.o ?? 0)) < 0) {
priority = spec;
}
}
return priority;
}
export function preferredLanguages(accept = "*", provided) {
const accepts = parseAcceptLanguage(accept);
if (!provided) {
return accepts
.filter(isQuality)
.sort(compareSpecs)
.map((spec) => spec.full);
}
const priorities = provided
.map((type, index) => getLanguagePriority(type, accepts, index));
return priorities
.filter(isQuality)
.sort(compareSpecs)
.map((priority) => provided[priorities.indexOf(priority)]);
}