polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts - gerrit - Git at Google

 /**
  * @license
  * Copyright (C) 2019 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 import {getBaseUrl} from '../../../../utils/url-util';
 import {CancelConditionCallback} from '../../../../services/gr-rest-api/gr-rest-api';
 import {
   AuthRequestInit,
   AuthService,
 } from '../../../../services/gr-auth/gr-auth';
 import {
   AccountDetailInfo,
   EmailInfo,
   ParsedJSON,
   RequestPayload,
 } from '../../../../types/common';
 import {HttpMethod} from '../../../../constants/constants';
 import {RpcLogEventDetail} from '../../../../types/events';
 import {fireNetworkError, fireServerError} from '../../../../utils/event-util';
 import {FetchRequest} from '../../../../types/types';
 import {ErrorCallback} from '../../../../api/rest';
 import {Scheduler, Task} from '../../../../services/scheduler/scheduler';
 import {RetryError} from '../../../../services/scheduler/retry-scheduler';

 export const JSON_PREFIX = ")]}'";

 export interface ResponsePayload {
   // TODO(TS): readResponsePayload can assign null to the parsed property if
   // it can't parse input data. However polygerrit assumes in many places
   // that the parsed property can't be null. We should update
   // readResponsePayload method and reject a promise instead of assigning
   // null to the parsed property
   parsed: ParsedJSON; // Can be null!!! See comment above
   raw: string;
 }

 export function readResponsePayload(
   response: Response
 ): Promise<ResponsePayload> {
   return response.text().then(text => {
     let result;
     try {
       result = parsePrefixedJSON(text);
     } catch (_) {
       result = null;
     }
     // TODO(TS): readResponsePayload can assign null to the parsed property if
     // it can't parse input data. However polygerrit assumes in many places
     // that the parsed property can't be null. We should update
     // readResponsePayload method and reject a promise instead of assigning
     // null to the parsed property
     return {parsed: result!, raw: text};
   });
 }

 export function parsePrefixedJSON(jsonWithPrefix: string): ParsedJSON {
   return JSON.parse(jsonWithPrefix.substring(JSON_PREFIX.length)) as ParsedJSON;
 }

 /**
  * Wrapper around Map for caching server responses. Site-based so that
  * changes to CANONICAL_PATH will result in a different cache going into
  * effect.
  */
 export class SiteBasedCache {
   // TODO(TS): Type looks unusual. Fix it.
   // Container of per-canonical-path caches.
   private readonly data = new Map<
     string | undefined,
     unknown | Map<string, ParsedJSON | null>
   >();

   constructor() {
     if (window.INITIAL_DATA) {
       // Put all data shipped with index.html into the cache. This makes it
       // so that we spare more round trips to the server when the app loads
       // initially.
       Object.entries(window.INITIAL_DATA).forEach(e =>
         this._cache().set(e[0], e[1] as unknown as ParsedJSON)
       );
     }
   }

   // Returns the cache for the current canonical path.
   _cache(): Map<string, unknown> {
     if (!this.data.has(window.CANONICAL_PATH)) {
       this.data.set(
         window.CANONICAL_PATH,
         new Map<string, ParsedJSON | null>()
       );
     }
     return this.data.get(window.CANONICAL_PATH) as Map<
       string,
       ParsedJSON | null
     >;
   }

   has(key: string) {
     return this._cache().has(key);
   }

   get(key: '/accounts/self/emails'): EmailInfo[] | null;

   get(key: '/accounts/self/detail'): AccountDetailInfo[] | null;

   get(key: string): ParsedJSON | null;

   get(key: string): unknown {
     return this._cache().get(key);
   }

   set(key: '/accounts/self/emails', value: EmailInfo[]): void;

   set(key: '/accounts/self/detail', value: AccountDetailInfo[]): void;

   set(key: string, value: ParsedJSON | null): void;

   set(key: string, value: unknown) {
     this._cache().set(key, value);
   }

   delete(key: string) {
     this._cache().delete(key);
   }

   invalidatePrefix(prefix: string) {
     const newMap = new Map<string, unknown>();
     for (const [key, value] of this._cache().entries()) {
       if (!key.startsWith(prefix)) {
         newMap.set(key, value);
       }
     }
     this.data.set(window.CANONICAL_PATH, newMap);
   }
 }

 type FetchPromisesCacheData = {
   [url: string]: Promise<ParsedJSON | undefined> | undefined;
 };

 export class FetchPromisesCache {
   private data: FetchPromisesCacheData;

   constructor() {
     this.data = {};
   }

   public testOnlyGetData() {
     return this.data;
   }

   /**
    * @return true only if a value for a key sets and it is not undefined
    */
   has(key: string): boolean {
     return !!this.data[key];
   }

   get(key: string) {
     return this.data[key];
   }

   /**
    * @param value a Promise to store in the cache. Pass undefined value to
    *     mark key as deleted.
    */
   set(key: string, value: Promise<ParsedJSON | undefined> | undefined) {
     this.data[key] = value;
   }

   invalidatePrefix(prefix: string) {
     const newData: FetchPromisesCacheData = {};
     Object.entries(this.data).forEach(([key, value]) => {
       if (!key.startsWith(prefix)) {
         newData[key] = value;
       }
     });
     this.data = newData;
   }
 }
 export type FetchParams = {
   [name: string]: string[] | string | number | boolean | undefined | null;
 };

 interface SendRequestBase {
   method: HttpMethod | undefined;
   body?: RequestPayload;
   contentType?: string;
   headers?: Record<string, string>;
   url: string;
   reportUrlAsIs?: boolean;
   anonymizedUrl?: string;
   errFn?: ErrorCallback;
 }

 export interface SendRawRequest extends SendRequestBase {
   parseResponse?: false | null;
 }

 export interface SendJSONRequest extends SendRequestBase {
   parseResponse: true;
 }

 export type SendRequest = SendRawRequest | SendJSONRequest;

 export interface FetchJSONRequest extends FetchRequest {
   reportUrlAsIs?: boolean;
   params?: FetchParams;
   cancelCondition?: CancelConditionCallback;
   errFn?: ErrorCallback;
 }

 // export function isRequestWithCancel<T extends FetchJSONRequest>(
 //   x: T
 // ): x is T & RequestWithCancel {
 //   return !!(x as RequestWithCancel).cancelCondition;
 // }
 //
 // export function isRequestWithErrFn<T extends FetchJSONRequest>(
 //   x: T
 // ): x is T & RequestWithErrFn {
 //   return !!(x as RequestWithErrFn).errFn;
 // }

 export class GrRestApiHelper {
   constructor(
     private readonly _cache: SiteBasedCache,
     private readonly _auth: AuthService,
     private readonly _fetchPromisesCache: FetchPromisesCache,
     private readonly readScheduler: Scheduler<Response>,
     private readonly writeScheduler: Scheduler<Response>
   ) {}

   private schedule(method: string, task: Task<Response>) {
     if (method === 'PUT' || method === 'POST' || method === 'DELETE') {
       return this.writeScheduler.schedule(task);
     } else {
       return this.readScheduler.schedule(task);
     }
   }

   /**
    * Wraps calls to the underlying authenticated fetch function (_auth.fetch)
    * with timing and logging.
 s   */
   fetch(req: FetchRequest): Promise<Response> {
     const method =
       req.fetchOptions && req.fetchOptions.method
         ? req.fetchOptions.method
         : 'GET';
     const start = Date.now();
     const task = async () => {
       const res = await this._auth.fetch(req.url, req.fetchOptions);
       if (!res.ok && res.status === 429) throw new RetryError<Response>(res);
       return res;
     };

     const xhr = this.schedule(method, task).catch((err: unknown) => {
       if (err instanceof RetryError) {
         return err.payload;
       } else {
         throw err;
       }
     });

     // Log the call after it completes.
     xhr.then(res => this._logCall(req, start, res ? res.status : null));
     // Return the XHR directly (without the log).
     return xhr;
   }

   /**
    * Log information about a REST call. Because the elapsed time is determined
    * by this method, it should be called immediately after the request
    * finishes.
    *
    * @param startTime the time that the request was started.
    * @param status the HTTP status of the response. The status value
    *     is used here rather than the response object so there is no way this
    *     method can read the body stream.
    */
   private _logCall(
     req: FetchRequest,
     startTime: number,
     status: number | null
   ) {
     const method =
       req.fetchOptions && req.fetchOptions.method
         ? req.fetchOptions.method
         : 'GET';
     const endTime = Date.now();
     const elapsed = endTime - startTime;
     const startAt = new Date(startTime);
     const endAt = new Date(endTime);
     console.debug(
       [
         'HTTP',
         status,
         method,
         `${elapsed}ms`,
         req.anonymizedUrl || req.url,
         `(${startAt.toISOString()}, ${endAt.toISOString()})`,
       ].join(' ')
     );
     if (req.anonymizedUrl) {
       const detail: RpcLogEventDetail = {
         status,
         method,
         elapsed,
         anonymizedUrl: req.anonymizedUrl,
       };
       document.dispatchEvent(
         new CustomEvent('gr-rpc-log', {
           detail,
           composed: true,
           bubbles: true,
         })
       );
     }
   }

   /**
    * Fetch JSON from url provided.
    * Returns a Promise that resolves to a native Response.
    * Doesn't do error checking. Supports cancel condition. Performs auth.
    * Validates auth expiry errors.
    *
    * @return Promise which resolves to undefined if cancelCondition returns true
    *     and resolves to Response otherwise
    */
   fetchRawJSON(req: FetchJSONRequest): Promise<Response | undefined> {
     const urlWithParams = this.urlWithParams(req.url, req.params);
     const fetchReq: FetchRequest = {
       url: urlWithParams,
       fetchOptions: req.fetchOptions,
       anonymizedUrl: req.reportUrlAsIs ? urlWithParams : req.anonymizedUrl,
     };
     return this.fetch(fetchReq)
       .then((res: Response) => {
         if (req.cancelCondition && req.cancelCondition()) {
           if (res.body) {
             res.body.cancel();
           }
           return;
         }
         return res;
       })
       .catch(err => {
         if (req.errFn) {
           req.errFn.call(undefined, null, err);
         } else {
           fireNetworkError(err);
         }
         throw err;
       });
   }

   /**
    * Fetch JSON from url provided.
    * Returns a Promise that resolves to a parsed response.
    * Same as {@link fetchRawJSON}, plus error handling.
    *
    * @param noAcceptHeader - don't add default accept json header
    */
   fetchJSON(
     req: FetchJSONRequest,
     noAcceptHeader?: boolean
   ): Promise<ParsedJSON | undefined> {
     if (!noAcceptHeader) {
       req = this.addAcceptJsonHeader(req);
     }
     return this.fetchRawJSON(req).then(response => {
       if (!response) {
         return;
       }
       if (!response.ok) {
         if (req.errFn) {
           req.errFn.call(null, response);
           return;
         }
         fireServerError(response, req);
         return;
       }
       return this.getResponseObject(response);
     });
   }

   urlWithParams(url: string, fetchParams?: FetchParams): string {
     if (!fetchParams) {
       return getBaseUrl() + url;
     }

     const params: Array<string | number | boolean> = [];
     for (const [p, paramValue] of Object.entries(fetchParams)) {
       // TODO(TS): Replace == null with === and check for null and undefined
       // eslint-disable-next-line eqeqeq
       if (paramValue == null) {
         params.push(this.encodeRFC5987(p));
         continue;
       }
       // TODO(TS): Unclear, why do we need the following code.
       // If paramValue can be array - we should either fix FetchParams type
       // or convert the array to a string before calling urlWithParams method.
       const paramValueAsArray = ([] as Array<string | number | boolean>).concat(
         paramValue
       );
       for (const value of paramValueAsArray) {
         params.push(`${this.encodeRFC5987(p)}=${this.encodeRFC5987(value)}`);
       }
     }
     return getBaseUrl() + url + '?' + params.join('&');
   }

   // Backend encode url in RFC5987 and frontend needs to do same to match
   // queries for preloading queries
   encodeRFC5987(uri: string | number | boolean) {
     return encodeURIComponent(uri).replace(
       /['()*]/g,
       c => '%' + c.charCodeAt(0).toString(16)
     );
   }

   getResponseObject(response: Response): Promise<ParsedJSON> {
     return readResponsePayload(response).then(payload => payload.parsed);
   }

   addAcceptJsonHeader(req: FetchJSONRequest) {
     if (!req.fetchOptions) req.fetchOptions = {};
     if (!req.fetchOptions.headers) req.fetchOptions.headers = new Headers();
     if (!req.fetchOptions.headers.has('Accept')) {
       req.fetchOptions.headers.append('Accept', 'application/json');
     }
     return req;
   }

   fetchCacheURL(req: FetchJSONRequest): Promise<ParsedJSON | undefined> {
     if (this._fetchPromisesCache.has(req.url)) {
       return this._fetchPromisesCache.get(req.url)!;
     }
     // TODO(andybons): Periodic cache invalidation.
     if (this._cache.has(req.url)) {
       return Promise.resolve(this._cache.get(req.url)!);
     }
     this._fetchPromisesCache.set(
       req.url,
       this.fetchJSON(req)
         .then(response => {
           if (response !== undefined) {
             this._cache.set(req.url, response);
           }
           this._fetchPromisesCache.set(req.url, undefined);
           return response;
         })
         .catch(err => {
           this._fetchPromisesCache.set(req.url, undefined);
           throw err;
         })
     );
     return this._fetchPromisesCache.get(req.url)!;
   }

   // if errFn is not set, then only Response possible
   send(req: SendRawRequest & {errFn?: undefined}): Promise<Response>;

   send(req: SendRawRequest): Promise<Response | undefined>;

   send(req: SendJSONRequest): Promise<ParsedJSON>;

   send(req: SendRequest): Promise<Response | ParsedJSON | undefined>;

   /**
    * Send an XHR.
    *
    * @return Promise resolves to Response/ParsedJSON only if the request is successful
    *     (i.e. no exception and response.ok is true). If response fails then
    *     promise resolves either to void if errFn is set or rejects if errFn
    *     is not set   */
   send(req: SendRequest): Promise<Response | ParsedJSON | undefined> {
     const options: AuthRequestInit = {method: req.method};
     if (req.body) {
       options.headers = new Headers();
       options.headers.set(
         'Content-Type',
         req.contentType || 'application/json'
       );
       options.body =
         typeof req.body === 'string' ? req.body : JSON.stringify(req.body);
     }
     if (req.headers) {
       if (!options.headers) {
         options.headers = new Headers();
       }
       for (const [name, value] of Object.entries(req.headers)) {
         options.headers.set(name, value);
       }
     }
     const url = req.url.startsWith('http') ? req.url : getBaseUrl() + req.url;
     const fetchReq: FetchRequest = {
       url,
       fetchOptions: options,
       anonymizedUrl: req.reportUrlAsIs ? url : req.anonymizedUrl,
     };
     const xhr = this.fetch(fetchReq)
       .catch(err => {
         fireNetworkError(err);
         if (req.errFn) {
           req.errFn.call(undefined, null, err);
           return;
         } else {
           throw err;
         }
       })
       .then(response => {
         if (response && !response.ok) {
           if (req.errFn) {
             req.errFn.call(undefined, response);
             return;
           }
           fireServerError(response, fetchReq);
         }
         return response;
       });

     if (req.parseResponse) {
       // TODO(TS): remove as Response and fix error.
       // Javascript code allows returning of a Response object from errFn.
       // This can be a mistake and we should add check here or it can be used
       // somewhere - in this case we should fix it carefully (define
       // different type of callback if parseResponse is true, etc...).
       return xhr.then(res => this.getResponseObject(res as Response));
     }
     // The actual xhr type is Promise<Response|undefined|void> because of the
     // catch callback
     return xhr as Promise<Response | undefined>;
   }

   invalidateFetchPromisesPrefix(prefix: string) {
     this._fetchPromisesCache.invalidatePrefix(prefix);
     this._cache.invalidatePrefix(prefix);
   }
 }
	/**
	* @license
	* Copyright (C) 2019 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	import {getBaseUrl} from '../../../../utils/url-util';
	import {CancelConditionCallback} from '../../../../services/gr-rest-api/gr-rest-api';
	import {
	AuthRequestInit,
	AuthService,
	} from '../../../../services/gr-auth/gr-auth';
	import {
	AccountDetailInfo,
	EmailInfo,
	ParsedJSON,
	RequestPayload,
	} from '../../../../types/common';
	import {HttpMethod} from '../../../../constants/constants';
	import {RpcLogEventDetail} from '../../../../types/events';
	import {fireNetworkError, fireServerError} from '../../../../utils/event-util';
	import {FetchRequest} from '../../../../types/types';
	import {ErrorCallback} from '../../../../api/rest';
	import {Scheduler, Task} from '../../../../services/scheduler/scheduler';
	import {RetryError} from '../../../../services/scheduler/retry-scheduler';

	export const JSON_PREFIX = ")]}'";

	export interface ResponsePayload {
	// TODO(TS): readResponsePayload can assign null to the parsed property if
	// it can't parse input data. However polygerrit assumes in many places
	// that the parsed property can't be null. We should update
	// readResponsePayload method and reject a promise instead of assigning
	// null to the parsed property
	parsed: ParsedJSON; // Can be null!!! See comment above
	raw: string;
	}

	export function readResponsePayload(
	response: Response
	): Promise<ResponsePayload> {
	return response.text().then(text => {
	let result;
	try {
	result = parsePrefixedJSON(text);
	} catch (_) {
	result = null;
	}
	// TODO(TS): readResponsePayload can assign null to the parsed property if
	// it can't parse input data. However polygerrit assumes in many places
	// that the parsed property can't be null. We should update
	// readResponsePayload method and reject a promise instead of assigning
	// null to the parsed property
	return {parsed: result!, raw: text};
	});
	}

	export function parsePrefixedJSON(jsonWithPrefix: string): ParsedJSON {
	return JSON.parse(jsonWithPrefix.substring(JSON_PREFIX.length)) as ParsedJSON;
	}

	/**
	* Wrapper around Map for caching server responses. Site-based so that
	* changes to CANONICAL_PATH will result in a different cache going into
	* effect.
	*/
	export class SiteBasedCache {
	// TODO(TS): Type looks unusual. Fix it.
	// Container of per-canonical-path caches.
	private readonly data = new Map<
	string \| undefined,
	unknown \| Map<string, ParsedJSON \| null>
	>();

	constructor() {
	if (window.INITIAL_DATA) {
	// Put all data shipped with index.html into the cache. This makes it
	// so that we spare more round trips to the server when the app loads
	// initially.
	Object.entries(window.INITIAL_DATA).forEach(e =>
	this._cache().set(e[0], e[1] as unknown as ParsedJSON)
	);
	}
	}

	// Returns the cache for the current canonical path.
	_cache(): Map<string, unknown> {
	if (!this.data.has(window.CANONICAL_PATH)) {
	this.data.set(
	window.CANONICAL_PATH,
	new Map<string, ParsedJSON \| null>()
	);
	}
	return this.data.get(window.CANONICAL_PATH) as Map<
	string,
	ParsedJSON \| null
	>;
	}

	has(key: string) {
	return this._cache().has(key);
	}

	get(key: '/accounts/self/emails'): EmailInfo[] \| null;

	get(key: '/accounts/self/detail'): AccountDetailInfo[] \| null;

	get(key: string): ParsedJSON \| null;

	get(key: string): unknown {
	return this._cache().get(key);
	}

	set(key: '/accounts/self/emails', value: EmailInfo[]): void;

	set(key: '/accounts/self/detail', value: AccountDetailInfo[]): void;

	set(key: string, value: ParsedJSON \| null): void;

	set(key: string, value: unknown) {
	this._cache().set(key, value);
	}

	delete(key: string) {
	this._cache().delete(key);
	}

	invalidatePrefix(prefix: string) {
	const newMap = new Map<string, unknown>();
	for (const [key, value] of this._cache().entries()) {
	if (!key.startsWith(prefix)) {
	newMap.set(key, value);
	}
	}
	this.data.set(window.CANONICAL_PATH, newMap);
	}
	}

	type FetchPromisesCacheData = {
	[url: string]: Promise<ParsedJSON \| undefined> \| undefined;
	};

	export class FetchPromisesCache {
	private data: FetchPromisesCacheData;

	constructor() {
	this.data = {};
	}

	public testOnlyGetData() {
	return this.data;
	}

	/**
	* @return true only if a value for a key sets and it is not undefined
	*/
	has(key: string): boolean {
	return !!this.data[key];
	}

	get(key: string) {
	return this.data[key];
	}

	/**
	* @param value a Promise to store in the cache. Pass undefined value to
	* mark key as deleted.
	*/
	set(key: string, value: Promise<ParsedJSON \| undefined> \| undefined) {
	this.data[key] = value;
	}

	invalidatePrefix(prefix: string) {
	const newData: FetchPromisesCacheData = {};
	Object.entries(this.data).forEach(([key, value]) => {
	if (!key.startsWith(prefix)) {
	newData[key] = value;
	}
	});
	this.data = newData;
	}
	}
	export type FetchParams = {
	[name: string]: string[] \| string \| number \| boolean \| undefined \| null;
	};

	interface SendRequestBase {
	method: HttpMethod \| undefined;
	body?: RequestPayload;
	contentType?: string;
	headers?: Record<string, string>;
	url: string;
	reportUrlAsIs?: boolean;
	anonymizedUrl?: string;
	errFn?: ErrorCallback;
	}

	export interface SendRawRequest extends SendRequestBase {
	parseResponse?: false \| null;
	}

	export interface SendJSONRequest extends SendRequestBase {
	parseResponse: true;
	}

	export type SendRequest = SendRawRequest \| SendJSONRequest;

	export interface FetchJSONRequest extends FetchRequest {
	reportUrlAsIs?: boolean;
	params?: FetchParams;
	cancelCondition?: CancelConditionCallback;
	errFn?: ErrorCallback;
	}

	// export function isRequestWithCancel<T extends FetchJSONRequest>(
	// x: T
	// ): x is T & RequestWithCancel {
	// return !!(x as RequestWithCancel).cancelCondition;
	// }
	//
	// export function isRequestWithErrFn<T extends FetchJSONRequest>(
	// x: T
	// ): x is T & RequestWithErrFn {
	// return !!(x as RequestWithErrFn).errFn;
	// }

	export class GrRestApiHelper {
	constructor(
	private readonly _cache: SiteBasedCache,
	private readonly _auth: AuthService,
	private readonly _fetchPromisesCache: FetchPromisesCache,
	private readonly readScheduler: Scheduler<Response>,
	private readonly writeScheduler: Scheduler<Response>
	) {}

	private schedule(method: string, task: Task<Response>) {
	if (method === 'PUT' \|\| method === 'POST' \|\| method === 'DELETE') {
	return this.writeScheduler.schedule(task);
	} else {
	return this.readScheduler.schedule(task);
	}
	}

	/**
	* Wraps calls to the underlying authenticated fetch function (_auth.fetch)
	* with timing and logging.
	s */
	fetch(req: FetchRequest): Promise<Response> {
	const method =
	req.fetchOptions && req.fetchOptions.method
	? req.fetchOptions.method
	: 'GET';
	const start = Date.now();
	const task = async () => {
	const res = await this._auth.fetch(req.url, req.fetchOptions);
	if (!res.ok && res.status === 429) throw new RetryError<Response>(res);
	return res;
	};

	const xhr = this.schedule(method, task).catch((err: unknown) => {
	if (err instanceof RetryError) {
	return err.payload;
	} else {
	throw err;
	}
	});

	// Log the call after it completes.
	xhr.then(res => this._logCall(req, start, res ? res.status : null));
	// Return the XHR directly (without the log).
	return xhr;
	}

	/**
	* Log information about a REST call. Because the elapsed time is determined
	* by this method, it should be called immediately after the request
	* finishes.
	*
	* @param startTime the time that the request was started.
	* @param status the HTTP status of the response. The status value
	* is used here rather than the response object so there is no way this
	* method can read the body stream.
	*/
	private _logCall(
	req: FetchRequest,
	startTime: number,
	status: number \| null
	) {
	const method =
	req.fetchOptions && req.fetchOptions.method
	? req.fetchOptions.method
	: 'GET';
	const endTime = Date.now();
	const elapsed = endTime - startTime;
	const startAt = new Date(startTime);
	const endAt = new Date(endTime);
	console.debug(
	[
	'HTTP',
	status,
	method,
	`${elapsed}ms`,
	req.anonymizedUrl \|\| req.url,
	`(${startAt.toISOString()}, ${endAt.toISOString()})`,
	].join(' ')
	);
	if (req.anonymizedUrl) {
	const detail: RpcLogEventDetail = {
	status,
	method,
	elapsed,
	anonymizedUrl: req.anonymizedUrl,
	};
	document.dispatchEvent(
	new CustomEvent('gr-rpc-log', {
	detail,
	composed: true,
	bubbles: true,
	})
	);
	}
	}

	/**
	* Fetch JSON from url provided.
	* Returns a Promise that resolves to a native Response.
	* Doesn't do error checking. Supports cancel condition. Performs auth.
	* Validates auth expiry errors.
	*
	* @return Promise which resolves to undefined if cancelCondition returns true
	* and resolves to Response otherwise
	*/
	fetchRawJSON(req: FetchJSONRequest): Promise<Response \| undefined> {
	const urlWithParams = this.urlWithParams(req.url, req.params);
	const fetchReq: FetchRequest = {
	url: urlWithParams,
	fetchOptions: req.fetchOptions,
	anonymizedUrl: req.reportUrlAsIs ? urlWithParams : req.anonymizedUrl,
	};
	return this.fetch(fetchReq)
	.then((res: Response) => {
	if (req.cancelCondition && req.cancelCondition()) {
	if (res.body) {
	res.body.cancel();
	}
	return;
	}
	return res;
	})
	.catch(err => {
	if (req.errFn) {
	req.errFn.call(undefined, null, err);
	} else {
	fireNetworkError(err);
	}
	throw err;
	});
	}

	/**
	* Fetch JSON from url provided.
	* Returns a Promise that resolves to a parsed response.
	* Same as {@link fetchRawJSON}, plus error handling.
	*
	* @param noAcceptHeader - don't add default accept json header
	*/
	fetchJSON(
	req: FetchJSONRequest,
	noAcceptHeader?: boolean
	): Promise<ParsedJSON \| undefined> {
	if (!noAcceptHeader) {
	req = this.addAcceptJsonHeader(req);
	}
	return this.fetchRawJSON(req).then(response => {
	if (!response) {
	return;
	}
	if (!response.ok) {
	if (req.errFn) {
	req.errFn.call(null, response);
	return;
	}
	fireServerError(response, req);
	return;
	}
	return this.getResponseObject(response);
	});
	}

	urlWithParams(url: string, fetchParams?: FetchParams): string {
	if (!fetchParams) {
	return getBaseUrl() + url;
	}

	const params: Array<string \| number \| boolean> = [];
	for (const [p, paramValue] of Object.entries(fetchParams)) {
	// TODO(TS): Replace == null with === and check for null and undefined
	// eslint-disable-next-line eqeqeq
	if (paramValue == null) {
	params.push(this.encodeRFC5987(p));
	continue;
	}
	// TODO(TS): Unclear, why do we need the following code.
	// If paramValue can be array - we should either fix FetchParams type
	// or convert the array to a string before calling urlWithParams method.
	const paramValueAsArray = ([] as Array<string \| number \| boolean>).concat(
	paramValue
	);
	for (const value of paramValueAsArray) {
	params.push(`${this.encodeRFC5987(p)}=${this.encodeRFC5987(value)}`);
	}
	}
	return getBaseUrl() + url + '?' + params.join('&');
	}

	// Backend encode url in RFC5987 and frontend needs to do same to match
	// queries for preloading queries
	encodeRFC5987(uri: string \| number \| boolean) {
	return encodeURIComponent(uri).replace(
	/['()*]/g,
	c => '%' + c.charCodeAt(0).toString(16)
	);
	}

	getResponseObject(response: Response): Promise<ParsedJSON> {
	return readResponsePayload(response).then(payload => payload.parsed);
	}

	addAcceptJsonHeader(req: FetchJSONRequest) {
	if (!req.fetchOptions) req.fetchOptions = {};
	if (!req.fetchOptions.headers) req.fetchOptions.headers = new Headers();
	if (!req.fetchOptions.headers.has('Accept')) {
	req.fetchOptions.headers.append('Accept', 'application/json');
	}
	return req;
	}

	fetchCacheURL(req: FetchJSONRequest): Promise<ParsedJSON \| undefined> {
	if (this._fetchPromisesCache.has(req.url)) {
	return this._fetchPromisesCache.get(req.url)!;
	}
	// TODO(andybons): Periodic cache invalidation.
	if (this._cache.has(req.url)) {
	return Promise.resolve(this._cache.get(req.url)!);
	}
	this._fetchPromisesCache.set(
	req.url,
	this.fetchJSON(req)
	.then(response => {
	if (response !== undefined) {
	this._cache.set(req.url, response);
	}
	this._fetchPromisesCache.set(req.url, undefined);
	return response;
	})
	.catch(err => {
	this._fetchPromisesCache.set(req.url, undefined);
	throw err;
	})
	);
	return this._fetchPromisesCache.get(req.url)!;
	}

	// if errFn is not set, then only Response possible
	send(req: SendRawRequest & {errFn?: undefined}): Promise<Response>;

	send(req: SendRawRequest): Promise<Response \| undefined>;

	send(req: SendJSONRequest): Promise<ParsedJSON>;

	send(req: SendRequest): Promise<Response \| ParsedJSON \| undefined>;

	/**
	* Send an XHR.
	*
	* @return Promise resolves to Response/ParsedJSON only if the request is successful
	* (i.e. no exception and response.ok is true). If response fails then
	* promise resolves either to void if errFn is set or rejects if errFn
	* is not set */
	send(req: SendRequest): Promise<Response \| ParsedJSON \| undefined> {
	const options: AuthRequestInit = {method: req.method};
	if (req.body) {
	options.headers = new Headers();
	options.headers.set(
	'Content-Type',
	req.contentType \|\| 'application/json'
	);
	options.body =
	typeof req.body === 'string' ? req.body : JSON.stringify(req.body);
	}
	if (req.headers) {
	if (!options.headers) {
	options.headers = new Headers();
	}
	for (const [name, value] of Object.entries(req.headers)) {
	options.headers.set(name, value);
	}
	}
	const url = req.url.startsWith('http') ? req.url : getBaseUrl() + req.url;
	const fetchReq: FetchRequest = {
	url,
	fetchOptions: options,
	anonymizedUrl: req.reportUrlAsIs ? url : req.anonymizedUrl,
	};
	const xhr = this.fetch(fetchReq)
	.catch(err => {
	fireNetworkError(err);
	if (req.errFn) {
	req.errFn.call(undefined, null, err);
	return;
	} else {
	throw err;
	}
	})
	.then(response => {
	if (response && !response.ok) {
	if (req.errFn) {
	req.errFn.call(undefined, response);
	return;
	}
	fireServerError(response, fetchReq);
	}
	return response;
	});

	if (req.parseResponse) {
	// TODO(TS): remove as Response and fix error.
	// Javascript code allows returning of a Response object from errFn.
	// This can be a mistake and we should add check here or it can be used
	// somewhere - in this case we should fix it carefully (define
	// different type of callback if parseResponse is true, etc...).
	return xhr.then(res => this.getResponseObject(res as Response));
	}
	// The actual xhr type is Promise<Response\|undefined\|void> because of the
	// catch callback
	return xhr as Promise<Response \| undefined>;
	}

	invalidateFetchPromisesPrefix(prefix: string) {
	this._fetchPromisesCache.invalidatePrefix(prefix);
	this._cache.invalidatePrefix(prefix);
	}
	}