shaka-player/third_party/cml-cmcd/cml_utils.js

DASH/EME video player library

/*! @license
 * Copyright 2024 Streaming Video Technology Alliance
 * SPDX-License-Identifier: Apache-2.0
 */

goog.provide('cml.cmcd.getBaseUrl');
goog.provide('cml.cmcd.urlToRelativePath');
goog.provide('cml.cmcd.uuid');


/**
 * UUID shim for the vendored @svta/cml-cmcd port.
 *
 * Upstream CML's `CmcdReporter` imports `uuid()` from `@svta/cml-utils`
 * and uses it as the default for `sid` in `createCmcdReporterConfig`.
 * The shaka adapter always sets `sid` explicitly, so this codepath is
 * dead at runtime — Closure ADVANCED will strip it. Kept for verbatim
 * parity with upstream CmcdReporter source so per-bump diffs stay
 * trivial.
 *
 * `crypto.randomUUID()` is polyfilled in browsers without native
 * support by `lib/polyfill/random_uuid.js`.
 *
 * @return {string}
 */
cml.cmcd.uuid = () => crypto.randomUUID();

/**
 * Constructs a relative path from a URL.
 *
 * Vendored verbatim from `@svta/cml-utils`'s `urlToRelativePath`. Used
 * by `cml.cmcd.CMCD_FORMATTER_MAP`'s `nor` formatter to produce
 * sibling-relative URLs when a `baseUrl` is supplied via
 * `CmcdEncodeOptions.baseUrl`.
 *
 * If `url` is already a relative path (parses as invalid URL), or its
 * origin differs from `base`, it is returned unchanged.
 *
 * @param {string} url The destination URL.
 * @param {string} base The base URL.
 * @return {string} The relative path.
 */
cml.cmcd.urlToRelativePath = (url, base) => {
  let to;
  try {
    to = new URL(url);
  } catch (e) {
    return url;
  }

  const from = new URL(base);

  if (to.origin !== from.origin) {
    return url;
  }

  const toPath = to.pathname.split('/').slice(1);
  const fromPath = from.pathname.split('/').slice(1, -1);

  // remove common parents
  const length = Math.min(toPath.length, fromPath.length);

  for (let i = 0; i < length; i++) {
    if (toPath[i] !== fromPath[i]) {
      break;
    }

    toPath.shift();
    fromPath.shift();
  }

  // add back paths
  while (fromPath.length) {
    fromPath.shift();
    toPath.unshift('..');
  }

  const relativePath = toPath.join('/');

  // preserve query parameters and hash of the destination url
  return relativePath + to.search + to.hash;
};

/**
 * Get the base URL (origin + directory) from a full URL.
 *
 * Vendored verbatim from `@svta/cml-utils`'s `getBaseUrl`. Used by
 * `cml.cmcd.CmcdReporter` to derive a sibling-relative base for `nor`
 * conversion from the current request URL. Upstream signature accepts
 * `string | URL`; the vendored shim restricts to `string` because
 * shaka's only caller passes a string.
 *
 * @param {string} fullUrl The full URL.
 * @return {string} The base URL.
 */
cml.cmcd.getBaseUrl = (fullUrl) => {
  const url = new URL(fullUrl);
  return url.origin +
      url.pathname.substring(0, url.pathname.lastIndexOf('/') + 1);
};