GoScrobble/web/node_modules/workbox-range-requests/utils/parseRangeHeader.js

48 lines
1.9 KiB
JavaScript

/*
Copyright 2018 Google LLC
Use of this source code is governed by an MIT-style
license that can be found in the LICENSE file or at
https://opensource.org/licenses/MIT.
*/
import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
import { assert } from 'workbox-core/_private/assert.js';
import '../_version.js';
/**
* @param {string} rangeHeader A Range: header value.
* @return {Object} An object with `start` and `end` properties, reflecting
* the parsed value of the Range: header. If either the `start` or `end` are
* omitted, then `null` will be returned.
*
* @private
*/
function parseRangeHeader(rangeHeader) {
if (process.env.NODE_ENV !== 'production') {
assert.isType(rangeHeader, 'string', {
moduleName: 'workbox-range-requests',
funcName: 'parseRangeHeader',
paramName: 'rangeHeader',
});
}
const normalizedRangeHeader = rangeHeader.trim().toLowerCase();
if (!normalizedRangeHeader.startsWith('bytes=')) {
throw new WorkboxError('unit-must-be-bytes', { normalizedRangeHeader });
}
// Specifying multiple ranges separate by commas is valid syntax, but this
// library only attempts to handle a single, contiguous sequence of bytes.
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Range#Syntax
if (normalizedRangeHeader.includes(',')) {
throw new WorkboxError('single-range-only', { normalizedRangeHeader });
}
const rangeParts = /(\d*)-(\d*)/.exec(normalizedRangeHeader);
// We need either at least one of the start or end values.
if (!rangeParts || !(rangeParts[1] || rangeParts[2])) {
throw new WorkboxError('invalid-range-values', { normalizedRangeHeader });
}
return {
start: rangeParts[1] === '' ? undefined : Number(rangeParts[1]),
end: rangeParts[2] === '' ? undefined : Number(rangeParts[2]),
};
}
export { parseRangeHeader };