47 lines
1.7 KiB
TypeScript
47 lines
1.7 KiB
TypeScript
|
export type RangeParseResult =
|
||
|
|
| { type: 'none' }
|
||
|
|
| { type: 'valid'; start: number; end: number }
|
||
|
|
| { type: 'invalid' };
|
||
|
|
|
||
|
|
const DECIMAL = /^\d+$/;
|
||
|
|
|
||
|
|
export const parseRangeHeader = (rangeHeader: string | null, size: number): RangeParseResult => {
|
||
|
|
if (!rangeHeader) return { type: 'none' };
|
||
|
|
if (!Number.isSafeInteger(size) || size < 0) return { type: 'invalid' };
|
||
|
|
if (!rangeHeader.startsWith('bytes=')) return { type: 'invalid' };
|
||
|
|
|
||
|
|
const spec = rangeHeader.slice('bytes='.length).trim();
|
||
|
|
if (spec.includes(',')) return { type: 'invalid' };
|
||
|
|
|
||
|
|
const dash = spec.indexOf('-');
|
||
|
|
if (dash === -1) return { type: 'invalid' };
|
||
|
|
|
||
|
|
const startText = spec.slice(0, dash).trim();
|
||
|
|
const endText = spec.slice(dash + 1).trim();
|
||
|
|
if (!startText && !endText) return { type: 'invalid' };
|
||
|
|
if (size === 0) return { type: 'invalid' };
|
||
|
|
|
||
|
|
if (!startText) {
|
||
|
|
if (!DECIMAL.test(endText)) return { type: 'invalid' };
|
||
|
|
const suffixLength = Number.parseInt(endText, 10);
|
||
|
|
if (suffixLength <= 0) return { type: 'invalid' };
|
||
|
|
return { type: 'valid', start: Math.max(size - suffixLength, 0), end: size - 1 };
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!DECIMAL.test(startText)) return { type: 'invalid' };
|
||
|
|
const start = Number.parseInt(startText, 10);
|
||
|
|
if (start >= size) return { type: 'invalid' };
|
||
|
|
|
||
|
|
if (!endText) return { type: 'valid', start, end: size - 1 };
|
||
|
|
if (!DECIMAL.test(endText)) return { type: 'invalid' };
|
||
|
|
|
||
|
|
const requestedEnd = Number.parseInt(endText, 10);
|
||
|
|
if (requestedEnd < start) return { type: 'invalid' };
|
||
|
|
return { type: 'valid', start, end: Math.min(requestedEnd, size - 1) };
|
||
|
|
};
|
||
|
|
|
||
|
|
export const contentRange = (start: number, end: number, size: number): string =>
|
||
|
|
`bytes ${start}-${end}/${size}`;
|
||
|
|
|
||
|
|
export const unsatisfiedContentRange = (size: number): string => `bytes */${size}`;
|