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/*** @file metadata.ts* @author tngan* @desc An abstraction for metadata of identity provider and service provider*/import * as fs from 'fs';import { namespace } from './urn';import { extract } from './extractor';import { isString } from './utility';
export interface MetadataInterface {  xmlString: string;  getMetadata: () => string;  exportMetadata: (exportFile: string) => void;  getEntityID: () => string;  getX509Certificate: (certType: string) => string | string[];  getNameIDFormat: () => any[];  getSingleLogoutService: (binding: string | undefined) => string | object;  getSupportBindings: (services: string[]) => string[];}
export default class Metadata implements MetadataInterface {
  xmlString: string;  meta: any;
  /**  * @param  {string | Buffer} metadata xml  * @param  {object} extraParse for custom metadata extractor  */  constructor(xml: string | Buffer, extraParse: any = []) {    this.xmlString = xml.toString();    this.meta = extract(this.xmlString, extraParse.concat([      {        key: 'entityDescriptor',        localPath: ['EntityDescriptor'],        attributes: [],        context: true      },      {        key: 'entityID',        localPath: ['EntityDescriptor'],        attributes: ['entityID']      },      {        // shared certificate for both encryption and signing        key: 'sharedCertificate',        localPath: ['EntityDescriptor', '~SSODescriptor', 'KeyDescriptor', 'KeyInfo', 'X509Data', 'X509Certificate'],        attributes: []      },      {        // explicit certificate declaration for encryption and signing        key: 'certificate',        localPath: ['EntityDescriptor', '~SSODescriptor', 'KeyDescriptor'],        index: ['use'],        attributePath: ['KeyInfo', 'X509Data', 'X509Certificate'],        attributes: []      },      {        key: 'singleLogoutService',        localPath: ['EntityDescriptor', '~SSODescriptor', 'SingleLogoutService'],        attributes: ['Binding', 'Location']      },      {        key: 'nameIDFormat',        localPath: ['EntityDescriptor', '~SSODescriptor', 'NameIDFormat'],        attributes: [],      }    ]));
    // get shared certificate    const sharedCertificate = this.meta.sharedCertificate;    if (typeof sharedCertificate === 'string') {      this.meta.certificate = {        signing: sharedCertificate,        encryption: sharedCertificate      };      delete this.meta.sharedCertificate;    }
    if (      Array.isArray(this.meta.entityDescriptor) &&      this.meta.entityDescriptor.length > 1    ) {      throw new Error('ERR_MULTIPLE_METADATA_ENTITYDESCRIPTOR');    }
  }
  /**  * @desc Get the metadata in xml format  * @return {string} metadata in xml format  */  public getMetadata(): string {    return this.xmlString;  }
  /**  * @desc Export the metadata to specific file  * @param {string} exportFile is the output file path  */  public exportMetadata(exportFile: string): void {    fs.writeFileSync(exportFile, this.xmlString);  }
  /**  * @desc Get the entityID in metadata  * @return {string} entityID  */  public getEntityID(): string {    return this.meta.entityID;  }
  /**  * @desc Get the x509 certificate declared in entity metadata  * @param  {string} use declares the type of certificate  * @return {string} certificate in string format  */  public getX509Certificate(use: string): string | string[] {    return this.meta.certificate[use] || null;  }
  /**  * @desc Get the support NameID format declared in entity metadata  * @return {array} support NameID format  */  public getNameIDFormat(): any {    return this.meta.nameIDFormat;  }
  /**  * @desc Get the entity endpoint for single logout service  * @param  {string} binding e.g. redirect, post  * @return {string/object} location  */  public getSingleLogoutService(binding: string | undefined): string | object {    if (binding && isString(binding)) {      const bindType = namespace.binding[binding];      let singleLogoutService = this.meta.singleLogoutService;      if (!(singleLogoutService instanceof Array)) {        singleLogoutService = [singleLogoutService];       }      const service = singleLogoutService.find(obj => obj.binding === bindType);            if (service) {        return service.location;      }    }    return this.meta.singleLogoutService;  }
  /**  * @desc Get the support bindings  * @param  {[string]} services  * @return {[string]} support bindings  */  public getSupportBindings(services: string[]): string[] {    let supportBindings = [];    if (services) {      supportBindings = services.reduce((acc: any, service) => {        const supportBinding = Object.keys(service)[0];        return acc.push(supportBinding);      }, []);    }    return supportBindings;  }}