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fix: do spec-compliant date parsing
Signed-off-by: flakey5 <[email protected]>
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‎src/utils/http-date.ts‎

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/**
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* Valid months that are allowed to be in an IMF date
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*/
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const IMF_DAYS = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'];
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/**
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* Specific locations that are expected to be spaces in an IMF date
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*/
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const IMF_SPACES = [4, 7, 11, 16, 25];
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/**
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* Valid months that are allowed to be in an IMF date
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*/
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const IMF_MONTHS = [
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'jan',
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'feb',
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'mar',
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'apr',
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'may',
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'jun',
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'jul',
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'aug',
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'sep',
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'oct',
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'nov',
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'dec',
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];
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/**
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* Specific locations that are expected to be colons in an IMF date
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*/
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const IMF_COLONS = [19, 22];
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/**
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* Specific locations that are expected to be spaces in an asctime() date
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*/
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const ASCTIME_SPACES = [3, 7, 10, 19];
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/**
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* Valid days allowed in an RF850 date
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*/
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const RFC850_DAYS = [
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'monday',
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'tuesday',
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'wednesday',
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'thursday',
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'friday',
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'saturday',
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'sunday',
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];
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/**
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* @see https://www.rfc-editor.org/rfc/rfc9110.html#name-date-time-formats
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*/
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export function parseHttpDate(
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date: string | null,
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now = new Date()
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): Date | undefined {
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// Sun, 06 Nov 1994 08:49:37 GMT ; IMF-fixdate
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// Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format
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// Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
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if (date === null) {
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return undefined;
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}
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date = date.toLowerCase();
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switch (date[3]) {
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case ',':
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return parseImfDate(date);
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case ' ':
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return parseAscTimeDate(date);
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default:
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return parseRfc850Date(date, now);
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}
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}
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/**
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* @see https://httpwg.org/specs/rfc9110.html#preferred.date.format
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*/
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function parseImfDate(date: string): Date | undefined {
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if (date.length !== 29) {
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return undefined;
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}
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if (!date.endsWith('gmt')) {
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// Unsupported timezone
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return undefined;
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}
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// Ensure there are spaces in the expected locations
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for (const spaceInx of IMF_SPACES) {
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if (date[spaceInx] !== ' ') {
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return undefined;
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}
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}
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// Ensure there are colons in the expected locations
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for (const colonIdx of IMF_COLONS) {
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if (date[colonIdx] !== ':') {
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return undefined;
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}
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}
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const dayName = date.substring(0, 3);
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if (!IMF_DAYS.includes(dayName)) {
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return undefined;
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}
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const dayString = date.substring(5, 7);
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const day = Number.parseInt(dayString);
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if (isNaN(day) || (day < 10 && dayString[0] !== '0')) {
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// Not a number, 0, or it's less than 10 and didn't start with a 0
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return undefined;
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}
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const month = date.substring(8, 11);
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const monthIdx = IMF_MONTHS.indexOf(month);
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if (monthIdx === -1) {
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return undefined;
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}
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const year = Number.parseInt(date.substring(12, 16));
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if (isNaN(year)) {
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return undefined;
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}
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const hourString = date.substring(17, 19);
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const hour = Number.parseInt(hourString);
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if (isNaN(hour) || (hour < 10 && hourString[0] !== '0')) {
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return undefined;
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}
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const minuteString = date.substring(20, 22);
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const minute = Number.parseInt(minuteString);
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if (isNaN(minute) || (minute < 10 && minuteString[0] !== '0')) {
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return undefined;
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}
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const secondString = date.substring(23, 25);
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const second = Number.parseInt(secondString);
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if (isNaN(second) || (second < 10 && secondString[0] !== '0')) {
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return undefined;
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}
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return new Date(Date.UTC(year, monthIdx, day, hour, minute, second));
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}
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/**
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* @see https://httpwg.org/specs/rfc9110.html#obsolete.date.formats
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*/
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function parseAscTimeDate(date: string): Date | undefined {
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// This is assumed to be in UTC
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if (date.length !== 24) {
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return undefined;
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}
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// Ensure there are spaces in the expected locations
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for (const spaceIdx of ASCTIME_SPACES) {
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if (date[spaceIdx] !== ' ') {
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return undefined;
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}
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}
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const dayName = date.substring(0, 3);
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if (!IMF_DAYS.includes(dayName)) {
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return undefined;
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}
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const month = date.substring(4, 7);
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const monthIdx = IMF_MONTHS.indexOf(month);
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if (monthIdx === -1) {
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return undefined;
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}
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const dayString = date.substring(8, 10);
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const day = Number.parseInt(dayString);
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if (isNaN(day) || (day < 10 && dayString[0] !== ' ')) {
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return undefined;
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}
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const hourString = date.substring(11, 13);
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const hour = Number.parseInt(hourString);
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if (isNaN(hour) || (hour < 10 && hourString[0] !== '0')) {
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return undefined;
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}
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const minuteString = date.substring(14, 16);
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const minute = Number.parseInt(minuteString);
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if (isNaN(minute) || (minute < 10 && minuteString[0] !== '0')) {
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return undefined;
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}
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const secondString = date.substring(17, 19);
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const second = Number.parseInt(secondString);
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if (isNaN(second) || (second < 10 && secondString[0] !== '0')) {
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return undefined;
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}
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const year = Number.parseInt(date.substring(20, 24));
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if (isNaN(year)) {
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return undefined;
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}
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return new Date(Date.UTC(year, monthIdx, day, hour, minute, second));
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}
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/**
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* @see https://httpwg.org/specs/rfc9110.html#obsolete.date.formats
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*/
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function parseRfc850Date(date: string, now = new Date()): Date | undefined {
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if (!date.endsWith('gmt')) {
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// Unsupported timezone
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return undefined;
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}
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const commaIndex = date.indexOf(',');
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if (commaIndex === -1) {
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return undefined;
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}
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if (date.length - commaIndex - 1 !== 23) {
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return undefined;
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}
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const dayName = date.substring(0, commaIndex);
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if (!RFC850_DAYS.includes(dayName)) {
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return undefined;
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}
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// Ensure there are spaces, dashes, and colons in the expected locations
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if (
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date[commaIndex + 1] !== ' ' ||
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date[commaIndex + 4] !== '-' ||
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date[commaIndex + 8] !== '-' ||
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date[commaIndex + 11] !== ' ' ||
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date[commaIndex + 14] !== ':' ||
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date[commaIndex + 17] !== ':' ||
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date[commaIndex + 20] !== ' '
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) {
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return undefined;
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}
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const dayString = date.substring(commaIndex + 2, commaIndex + 4);
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const day = Number.parseInt(dayString);
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if (isNaN(day) || (day < 10 && dayString[0] !== '0')) {
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// Not a number, or it's less than 10 and didn't start with a 0
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return undefined;
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}
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const month = date.substring(commaIndex + 5, commaIndex + 8);
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const monthIdx = IMF_MONTHS.indexOf(month);
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if (monthIdx === -1) {
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return undefined;
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}
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// As of this point year is just the decade (i.e. 94)
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let year = Number.parseInt(date.substring(commaIndex + 9, commaIndex + 11));
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if (isNaN(year)) {
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return undefined;
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}
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const currentYear = now.getUTCFullYear();
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const currentDecade = currentYear % 100;
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const currentCentury = Math.floor(currentYear / 100);
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if (year > currentDecade && year - currentDecade >= 50) {
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// Over 50 years in future, go to previous century
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year += (currentCentury - 1) * 100;
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} else {
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year += currentCentury * 100;
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}
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const hourString = date.substring(commaIndex + 12, commaIndex + 14);
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const hour = Number.parseInt(hourString);
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if (isNaN(hour) || (hour < 10 && hourString[0] !== '0')) {
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return undefined;
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}
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const minuteString = date.substring(commaIndex + 15, commaIndex + 17);
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const minute = Number.parseInt(minuteString);
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if (isNaN(minute) || (minute < 10 && minuteString[0] !== '0')) {
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return undefined;
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}
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const secondString = date.substring(commaIndex + 18, commaIndex + 20);
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const second = Number.parseInt(secondString);
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if (isNaN(second) || (second < 10 && secondString[0] !== '0')) {
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return undefined;
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}
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return new Date(Date.UTC(year, monthIdx, day, hour, minute, second));
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}

‎src/utils/request.ts‎

Lines changed: 4 additions & 13 deletions
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@@ -1,3 +1,5 @@
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import { parseHttpDate } from './http-date';
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/**
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* Etags will have quotes removed from them
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* R2 supports every conditional header except `If-Range`
@@ -30,7 +32,7 @@ export function parseUrl(request: Request): URL | undefined {
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}
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3234
export function parseConditionalHeaders(headers: Headers): ConditionalHeaders {
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const ifModifiedSince = getDateFromHeader(headers.get('if-modified-since'));
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const ifModifiedSince = parseHttpDate(headers.get('if-modified-since'));
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3537
const ifMatch = headers.has('if-match')
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? headers.get('if-match')!.replaceAll('"', '')
@@ -40,9 +42,7 @@ export function parseConditionalHeaders(headers: Headers): ConditionalHeaders {
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? headers.get('if-none-match')!.replaceAll('"', '')
4143
: undefined;
4244

43-
const ifUnmodifiedSince = getDateFromHeader(
44-
headers.get('if-unmodified-since')
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);
45+
const ifUnmodifiedSince = parseHttpDate(headers.get('if-unmodified-since'));
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4747
const range = headers.has('range')
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? parseRangeHeader(headers.get('range')!)
@@ -57,15 +57,6 @@ export function parseConditionalHeaders(headers: Headers): ConditionalHeaders {
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};
5858
}
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60-
function getDateFromHeader(dateString: string | null): Date | undefined {
61-
if (dateString === null) {
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return undefined;
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}
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const date = new Date(dateString);
66-
return !isNaN(date.getTime()) ? date : undefined;
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}
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/**
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* @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Range
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* @returns undefined if header is invalid

‎tests/unit/index.test.ts‎

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@@ -2,5 +2,6 @@ import './utils/object.test';
22
import './utils/path.test';
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import './utils/request.test';
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import './utils/memo.test';
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import './utils/http-date.test';
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import './router/router.test';
67
import './middleware/substituteMiddleware.test';

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