Class ImpitHttpClient

packages/impit-client/src/index.ts:25–255

 * A HTTP client implementation based on the `impit library.
 */
export class ImpitHttpClient implements BaseHttpClient {
    private impitOptions: ImpitOptions;
    private maxRedirects: number;
    private followRedirects: boolean;

    /**
     * Enables reuse of `impit` clients for the same set of options.
     * This is useful for performance reasons, as creating
     * a new client for each request breaks TCP connection
     * (and other resources) reuse.
     */
    private clientCache: LruCache<{ client: Impit; cookieJar: ToughCookieJar }> = new LruCache({ maxLength: 10 });

    private getClient(options: ImpitOptions) {
        const { cookieJar, ...rest } = options;

        const cacheKey = JSON.stringify(rest);
        const existingClient = this.clientCache.get(cacheKey);

        if (existingClient && (!cookieJar || existingClient.cookieJar === cookieJar)) {
            return existingClient.client;
        }

        const client = new Impit(options);
        this.clientCache.add(cacheKey, { client, cookieJar: cookieJar as ToughCookieJar });

        return client;
    }

    constructor(options?: Omit<ImpitOptions, 'proxyUrl'> & { maxRedirects?: number }) {
        this.impitOptions = options ?? {};

        this.maxRedirects = options?.maxRedirects ?? 10;
        this.followRedirects = options?.followRedirects ?? true;
    }

    /**
     * Flattens the headers of a `HttpRequest` to a format that can be passed to `impit`.
     * @param headers `SimpleHeaders` object
     * @returns `Record<string, string>` object
     */
    private intoHeaders<TResponseType extends keyof ResponseTypes>(
        headers?: Exclude<HttpRequest<TResponseType>['headers'], undefined>,
    ): Headers | undefined {
        if (!headers) {
            return undefined;
        }

        const result = new Headers();

        for (const headerName of Object.keys(headers)) {
            const headerValue = headers[headerName];

            for (const value of Array.isArray(headerValue) ? headerValue : [headerValue]) {
                if (value === undefined) continue;

                result.append(headerName, value);
            }