apps.apple.com/node_modules/@apple-media-services/media-api/src/network.ts

/**
 * Created by ls on 9/7/2018.
 *
 * This `network.ts` is the NON-MEDIA API arm of network fetch requests.
 * It is built on `Network` object and provides standard functionality, such as:
 *     1. Parsing the body into specific format.
 *     2. Adding timing metrics onto blob.
 *
 * This should *only* be used for objects that should have timing metrics, i.e. requests to Non-MediaAPI endpoints
 * that will ultimately render some whole page. Otherwise, use `objectGraph.network.fetch` directly.
 *
 * @see `src/media/network.ts` for fetching from Media API endpoints
 */

import { FetchRequest, FetchResponse, HTTPTimingMetrics } from "@jet/environment/types/globals/net";
import { FetchTimingMetrics, MetricsFields } from "@jet/environment/types/metrics";
import { FetchTimingMetricsBuilder } from "@jet/environment/metrics";
import { isSome, Opt } from "@jet/environment/types/optional";
import * as serverData from "./models/server-data";
import { ParsedNetworkResponse } from "./models/data-structure";
import { Request } from "./models/request";
import * as urls from "./models/urls";
import * as urlBuilder from "./url-builder";
import { MediaConfigurationType, MediaTokenService } from "./models/mediapi-configuration";
import { HTTPMethod, HTTPCachePolicy, HTTPSigningStyle, HTTPHeaders } from "@jet/environment";

/** @public */
// eslint-disable-next-line @typescript-eslint/no-namespace
export namespace ResponseMetadata {
    export const requestedUrl = "_jet-internal:metricsHelpers_requestedUrl";

    /**
     * Symbol used to place timing metrics values onto fetch responses
     * without interfering with the data returned by the server.
     */
    export const timingValues = "_jet-internal:metricsHelpers_timingValues";

    /**
     * Key used to access the page information gathered from a response's headers
     */
    export const pageInformation = "_jet-internal:metricsHelpers_pageInformation";

    /**
     * Key used to access the content max-age gathered from a response's headers.
     */
    export const contentMaxAge = "_jet-internal:responseMetadata_contentMaxAge";
}

/**
 * Module's private fetch implementation built off `net` global.
 *
 * @param {FetchRequest} request describes fetch request.
 * @param {(value: string) => Type} parser Some function parsing response body `string` into specific type.
 * @returns {Promise<Type>} Promise resolving to specific object.
 * @throws {Error} Throws error if status code of request is not 200.
 *
 * @note Similar to `fetchWithToken` in `media` module, but excludes media token specific functionality.
 * Top level data fetches to endpoints that don't do redirects, and can benefit from metrics should
 * call methods that build off of this instead of calling `objectGraph.network.fetch(...)` directly.
 */
export async function fetch<Type>(
    configuration: MediaConfigurationType,
    request: FetchRequest,
    parser: (value: Opt<string>) => Type,
): Promise<Type & ParsedNetworkResponse> {
    const response = await configuration.network.fetch(request);
    if (!response.ok) {
        throw Error(`Bad Status code ${response.status} for ${request.url}`);
    }
    const parseStartTime = Date.now();
    const result = parser(response.body) as Type & ParsedNetworkResponse;
    const parseEndTime = Date.now();

    // Build full network timing metrics.
    const completeTimingMetrics = networkTimingMetricsWithParseTime(response.metrics, parseStartTime, parseEndTime);
    if (serverData.isDefinedNonNull(completeTimingMetrics)) {
        result[ResponseMetadata.timingValues] = completeTimingMetrics;
    }
    result[ResponseMetadata.requestedUrl] = request.url.toString();
    return result;
}

/**
 * Fetch from an endpoint with JSON response body.
 *
 * @param {FetchRequest} request to fetch from endpoint with JSON response..
 * @returns {Promise<Type>} Promise resolving to body of response parsed as `Type`.
 * @throws {Error} Throws error if status code of request is not 200.
 */
export async function fetchJSON<Type>(configuration: MediaConfigurationType, request: FetchRequest): Promise<Type> {
    return await fetch(configuration, request, (body) => {
        if (isSome(body)) {
            return JSON.parse(body) as Type;
        } else {
            // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
            return {} as Type;
        }
    });
}

/**
 * Fetch from an endpoint with XML response body.
 *
 * @param {FetchRequest} request to fetch from endpoint with XML response.
 * @returns {Promise<Type>} Promise resolving to body of response parsed as `Type`.
 * @throws {Error} Throws error if status code of request is not 200.
 */
export async function fetchPlist<Type>(configuration: MediaConfigurationType, request: FetchRequest): Promise<Type> {
    return await fetch(configuration, request, (body) => {
        if (isSome(body)) {
            return configuration.plist.parse(body) as Type;
        } else {
            throw new Error(`Could not fetch Plist, response body was not defined for ${request.url}`);
        }
    });
}

/**
 * With network requests now being created and parsed in JS, different timing metrics are measured in both Native and JS.
 * This function populates the missing values from `HTTPTimingMetrics`'s native counterpart, `JSNetworkPerformanceMetrics`.
 *
 * @param {HTTPTimingMetrics[] | null} responseMetrics Array of response metrics provided by native.
 * @param {number} parseStartTime Time at which response body string parse began in JS.
 * @param {number} parseEndTime Time at which response body string parse ended in JS.
 * @returns {HTTPTimingMetrics | null} Fully populated timing metrics, or `null` if native response provided no metrics events to build off of.
 */
function networkTimingMetricsWithParseTime(
    responseMetrics: HTTPTimingMetrics[] | null,
    parseStartTime: number,
    parseEndTime: number,
): FetchTimingMetrics | null {
    // No metrics events to build from.
    if (serverData.isNull(responseMetrics) || responseMetrics.length === 0) {
        return null;
    }

    // Append parse times to first partial timing metrics from native.
    const firstPartialTimingMetrics: FetchTimingMetrics = {
        ...responseMetrics[0],
        parseStartTime: parseStartTime,
        parseEndTime: parseEndTime,
    };
    // Timing metrics with all properties populated.
    return firstPartialTimingMetrics;
}

export type FetchOptions = {
    headers?: { [key: string]: string };
    method?: "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH";
    requestBodyString?: string;
    timeout?: number; // in seconds. Check for feature 'supportsRequestTimeoutOption'.
    /// When true the fetch wont throw if we dont get any data back for given request.
    allowEmptyDataResponse?: boolean;
    excludeIdentifierHeadersForAccount?: boolean; // Defaults to false
    alwaysIncludeAuthKitHeaders?: boolean; // Defaults to true
    alwaysIncludeMMeClientInfoAndDeviceHeaders?: boolean; // Defaults to true
};

/**
 * Implements the MAPI fetch, building URL from MAPI Request and opaquely managing initial token request and refreshes.
 *
 * @param {MediaConfigurationType} configuration Base media API configuration.
 * @param {Request} request MAPI Request to fetch with.
 * @param {FetchOptions} [options] FetchOptions for the MAPI request.
 * @returns {Promise<Type>} Promise resolving to some type for given MAPI request.
 */
export async function fetchData<Type>(
    configuration: MediaConfigurationType,
    mediaToken: MediaTokenService,
    request: Request,
    options?: FetchOptions,
): Promise<Type & ParsedNetworkResponse> {
    const url = urlBuilder.buildURLFromRequest(configuration, request).toString();
    const startTime = Date.now();
    const token = await mediaToken.refreshToken();
    const response = await fetchWithToken<Type>(
        configuration,
        mediaToken,
        url,
        token,
        options,
        false,
        configuration.fetchTimingMetricsBuilder,
    );
    const endTime = Date.now();
    if (request.canonicalUrl) {
        response[ResponseMetadata.requestedUrl] = request.canonicalUrl;
    }
    const roundTripTimeIncludingWaiting = endTime - startTime;
    if (roundTripTimeIncludingWaiting > 500) {
        console.warn("Fetch took too long (" + roundTripTimeIncludingWaiting.toString() + "ms) " + url);
    }
    return response;
}

export function redirectParametersInUrl(configuration: MediaConfigurationType, url: urls.URL): string[] {
    const redirectURLParams = configuration.redirectUrlWhitelistedQueryParams;
    return redirectURLParams.filter((param) => serverData.isDefinedNonNull(url.query?.[param]));
}

export type MediaAPIFetchRequest = {
    url: string;
    excludeIdentifierHeadersForAccount?: boolean;
    alwaysIncludeAuthKitHeaders?: boolean;
    alwaysIncludeMMeClientInfoAndDeviceHeaders?: boolean;
    method?: Opt<HTTPMethod>;
    cache?: Opt<HTTPCachePolicy>;
    signingStyle?: Opt<HTTPSigningStyle>;
    headers?: Opt<HTTPHeaders>;
    timeout?: Opt<number>;
    body?: Opt<string>;
};

/**
 * Given a built URL, token, and options, calls into native networking APIs to fetch content.
 *
 * @param {string} url URL to fetch data from.
 * @param {string} token MAPI token key.
 * @param {FetchOptions} options Fetch options for MAPI requests.
 * @param {boolean} isRetry flag indicating whether this is a fetch retry following a 401 request, and media token was refreshed.
 * @returns {Promise<Type>} Promise resolving to some type for given MAPI request.
 */
async function fetchWithToken<Type>(
    configuration: MediaConfigurationType,
    mediaToken: MediaTokenService,
    url: string,
    token: string,
    options: FetchOptions = {},
    isRetry = false,
    fetchTimingMetricsBuilder: Opt<FetchTimingMetricsBuilder>,
): Promise<Type & ParsedNetworkResponse> {
    // Removes all affiliate/redirect params for caching (https://connectme.apple.com/docs/DOC-577671)
    const filteredURL = new urls.URL(url);
    const redirectParameters = redirectParametersInUrl(configuration, filteredURL);
    for (const param of redirectParameters) {
        filteredURL.removeParam(param);
    }
    const filteredUrlString = filteredURL.toString();

    let headers = options.headers;
    if (headers == null) {
        headers = {};
    }
    headers["Authorization"] = "Bearer " + token;

    const fetchRequest: MediaAPIFetchRequest = {
        url: filteredUrlString,
        excludeIdentifierHeadersForAccount: options.excludeIdentifierHeadersForAccount ?? false,
        alwaysIncludeAuthKitHeaders: options.alwaysIncludeAuthKitHeaders ?? true,
        alwaysIncludeMMeClientInfoAndDeviceHeaders: options.alwaysIncludeMMeClientInfoAndDeviceHeaders ?? true,
        headers: headers,
        method: options.method,
        body: options.requestBodyString,
        timeout: options.timeout,
    };

    const response = await configuration.network.fetch(fetchRequest);

    try {
        if (response.status === 401 || response.status === 403) {
            if (isRetry) {
                throw Error("We refreshed the token but we still get 401 from the API");
            }
            mediaToken.resetToken();
            return await mediaToken.refreshToken().then(async (newToken) => {
                // Explicitly re-fetch with the original request so logging and metrics are correct
                return await fetchWithToken<Type>(
                    configuration,
                    mediaToken,
                    url,
                    newToken,
                    options,
                    true,
                    fetchTimingMetricsBuilder,
                );
            });
        } else if (response.status === 404) {
            // item is not available in this storefront or perhaps not at all
            throw noContentError();
        } else if (!response.ok) {
            const correlationKey = response.headers["x-apple-jingle-correlation-key"] ?? "N/A";
            const error = new NetworkError(
                `Bad Status code ${response.status} (correlationKey: ${correlationKey}) for ${filteredUrlString}, original ${url}`,
            );
            error.statusCode = response.status;
            throw error;
        }

        const parser = (resp: FetchResponse) => {
            const parseStartTime = Date.now();
            let result: Type & ParsedNetworkResponse;
            if (serverData.isNull(resp.body) || resp.body === "") {
                if (resp.status === 204) {
                    // 204 indicates a success, but the response will typically be empty
                    // Create a fake result so that we don't throw an error when JSON parsing
                    const emptyData: ParsedNetworkResponse = {};
                    result = emptyData as Type & ParsedNetworkResponse;
                } else {
                    throw noContentError();
                }
            } else {
                result = JSON.parse(resp.body) as Type & ParsedNetworkResponse;
            }
            const parseEndTime = Date.now();

            result[ResponseMetadata.pageInformation] = serverData.asJSONData(
                getPageInformationFromResponse(configuration, resp),
            );
            if (resp.metrics.length > 0) {
                const metrics: FetchTimingMetrics = {
                    ...resp.metrics[0],
                    parseStartTime: parseStartTime,
                    parseEndTime: parseEndTime,
                };
                result[ResponseMetadata.timingValues] = metrics;
            } else {
                const fallbackMetrics: FetchTimingMetrics = {
                    pageURL: resp.url,
                    parseStartTime,
                    parseEndTime,
                };
                result[ResponseMetadata.timingValues] = fallbackMetrics;
            }
            result[ResponseMetadata.contentMaxAge] = getContentTimeToLiveFromResponse(resp);

            // If we have an empty data object, throw a 204 (No Content).
            if (
                Array.isArray(result.data) &&
                serverData.isArrayDefinedNonNullAndEmpty(result.data) &&
                !serverData.asBooleanOrFalse(options.allowEmptyDataResponse)
            ) {
                throw noContentError();
            }

            result[ResponseMetadata.requestedUrl] = url;
            return result;
        };
        if (isSome(fetchTimingMetricsBuilder)) {
            return fetchTimingMetricsBuilder.measureParsing(response, parser);
        } else {
            return parser(response);
        }
    } catch (e) {
        if (e instanceof NetworkError) {
            throw e;
        }
        throw new Error(`Error Fetching - filtered: ${filteredUrlString}, original: ${url}, ${e.name}, ${e.message}`);
    }
}

export class NetworkError extends Error {
    statusCode?: number;
}

function noContentError(): NetworkError {
    const error = new NetworkError(`No content`);
    error.statusCode = 204;
    return error;
}

const serverInstanceHeader = "x-apple-application-instance";

const environmentDataCenterHeader = "x-apple-application-site";

function getPageInformationFromResponse(
    configuration: MediaConfigurationType,
    response: FetchResponse,
): MetricsFields | null {
    const storeFrontHeader: string = configuration.storefrontIdentifier;

    let storeFront: Opt<string> = null;
    if (serverData.isDefinedNonNullNonEmpty(storeFrontHeader)) {
        const storeFrontHeaderComponents: string[] = storeFrontHeader.split("-");
        if (serverData.isDefinedNonNullNonEmpty(storeFrontHeaderComponents)) {
            storeFront = storeFrontHeaderComponents[0];
        }
    }

    return {
        serverInstance: response.headers[serverInstanceHeader],
        storeFrontHeader: storeFrontHeader,
        language: configuration.bagLanguage,
        storeFront: storeFront,
        environmentDataCenter: response.headers[environmentDataCenterHeader],
    };
}

function getContentTimeToLiveFromResponse(response: FetchResponse): Opt<number> {
    const cacheControlHeaderKey = Object.keys(response.headers).find((key) => key.toLowerCase() === "cache-control");
    if (serverData.isNull(cacheControlHeaderKey) || cacheControlHeaderKey === "") {
        return null;
    }

    const headerValue = response.headers[cacheControlHeaderKey];
    if (serverData.isNullOrEmpty(headerValue)) {
        return null;
    }
    const matches = headerValue.match(/max-age=(\d+)/);
    if (serverData.isNull(matches) || matches.length < 2) {
        return null;
    }
    return serverData.asNumber(matches[1]);
}