pdfmake/js/URLResolver.js

Client/server side PDF printing in pure JavaScript

"use strict";

exports.__esModule = true;
exports.default = void 0;
const MAX_REDIRECTS = 30;

/**
 * @param {string} url
 * @param {object} headers
 * @param {(url: string) => boolean} urlAccessPolicy
 * @returns {Promise<Response>}
 */
async function fetchUrl(url, headers = {}, urlAccessPolicy) {
  for (let i = 0; i <= MAX_REDIRECTS; i++) {
    if (typeof urlAccessPolicy !== 'undefined' && urlAccessPolicy(url) !== true) {
      throw new Error(`Access to URL denied by resource access policy: ${url}`);
    }
    try {
      let response = await fetch(url, {
        headers,
        redirect: 'manual'
      });

      // redirect url
      if (response.status >= 300 && response.status < 400) {
        let location = response.headers.get('location');
        if (!location) {
          throw new Error('Redirect response missing Location header');
        }
        url = new URL(location, url).href;
        continue;
      }

      // browsers do not support redirect: 'manual'
      if (response.type === 'opaqueredirect') {
        response = await fetch(url, {
          headers
        });
      }
      if (!response.ok) {
        throw new Error(`Failed to fetch (status code: ${response.status})`);
      }
      return response;
    } catch (error) {
      throw new Error(`Network request failed (url: "${url}", error: ${error.message})`, {
        cause: error
      });
    }
  }
  throw new Error(`Network request failed (url: "${url}", error: Too many redirects)`);
}
class URLResolver {
  constructor(fs) {
    this.fs = fs;
    this.resolving = {};
    this.urlAccessPolicy = undefined;
  }

  /**
   * @param {(url: string) => boolean} callback
   */
  setUrlAccessPolicy(callback) {
    this.urlAccessPolicy = callback;
  }
  resolve(url, headers = {}) {
    const resolveUrlInternal = async () => {
      if (url.toLowerCase().startsWith('https://') || url.toLowerCase().startsWith('http://')) {
        if (this.fs.existsSync(url)) {
          return; // url was downloaded earlier
        }
        const response = await fetchUrl(url, headers, this.urlAccessPolicy);

        // validate access policy on redirected url (in browsers, only the final URL is validated)
        if (response.redirected) {
          if (typeof this.urlAccessPolicy !== 'undefined' && this.urlAccessPolicy(response.url) !== true) {
            throw new Error(`Access to URL denied by resource access policy: ${response.url}`);
          }
        }
        const buffer = await response.arrayBuffer();
        this.fs.writeFileSync(url, buffer);
      }
      // else cannot be resolved
    };
    if (!this.resolving[url]) {
      this.resolving[url] = resolveUrlInternal();
    }
    return this.resolving[url];
  }
  resolved() {
    return Promise.all(Object.values(this.resolving));
  }
}
var _default = exports.default = URLResolver;