copyResponse.js 2.4 KB
/*
  Copyright 2019 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 { canConstructResponseFromBodyStream } from './_private/canConstructResponseFromBodyStream.js';
import { WorkboxError } from './_private/WorkboxError.js';
import './_version.js';
/**
 * Allows developers to copy a response and modify its `headers`, `status`,
 * or `statusText` values (the values settable via a
 * [`ResponseInit`]{@link https://developer.mozilla.org/en-US/docs/Web/API/Response/Response#Syntax}
 * object in the constructor).
 * To modify these values, pass a function as the second argument. That
 * function will be invoked with a single object with the response properties
 * `{headers, status, statusText}`. The return value of this function will
 * be used as the `ResponseInit` for the new `Response`. To change the values
 * either modify the passed parameter(s) and return it, or return a totally
 * new object.
 *
 * This method is intentionally limited to same-origin responses, regardless of
 * whether CORS was used or not.
 *
 * @param {Response} response
 * @param {Function} modifier
 * @memberof workbox-core
 */
async function copyResponse(response, modifier) {
    let origin = null;
    // If response.url isn't set, assume it's cross-origin and keep origin null.
    if (response.url) {
        const responseURL = new URL(response.url);
        origin = responseURL.origin;
    }
    if (origin !== self.location.origin) {
        throw new WorkboxError('cross-origin-copy-response', { origin });
    }
    const clonedResponse = response.clone();
    // Create a fresh `ResponseInit` object by cloning the headers.
    const responseInit = {
        headers: new Headers(clonedResponse.headers),
        status: clonedResponse.status,
        statusText: clonedResponse.statusText,
    };
    // Apply any user modifications.
    const modifiedResponseInit = modifier ? modifier(responseInit) : responseInit;
    // Create the new response from the body stream and `ResponseInit`
    // modifications. Note: not all browsers support the Response.body stream,
    // so fall back to reading the entire body into memory as a blob.
    const body = canConstructResponseFromBodyStream()
        ? clonedResponse.body
        : await clonedResponse.blob();
    return new Response(body, modifiedResponseInit);
}
export { copyResponse };