export function getWebApi(serviceUri: string, accessToken: string): vsts.WebApi{
    const credentialHandler = vsts.getBasicHandler("vsts", accessToken);
    const options: IRequestOptions = {
        proxy: tl.getHttpProxyConfiguration(serviceUri),
    };
    return new vsts.WebApi(serviceUri, credentialHandler, options);
}

    constructor() {
        const serverUrl: string = tl.getVariable('System.TeamFoundationCollectionUri');
        const serverCreds: string = tl.getEndpointAuthorizationParameter('SYSTEMVSSCONNECTION', 'ACCESSTOKEN', false);
        const authHandler = vsts.getPersonalAccessTokenHandler(serverCreds);

        const proxy = tl.getHttpProxyConfiguration();
        const options = proxy ? { proxy, ignoreSslError: true } : undefined;

        this.serverConnection = new vsts.WebApi(serverUrl, authHandler, options);
    }

export function getWebApiWithProxy(serviceUri: string, accessToken?: string): vsts.WebApi {
    if (!accessToken) {
        accessToken = getSystemAccessToken();
    }

    const credentialHandler = vsts.getBasicHandler('vsts', accessToken);
    const options: IRequestOptions = {
        proxy: tl.getHttpProxyConfiguration(serviceUri)
    };
    return new vsts.WebApi(serviceUri, credentialHandler, options);
}

    // make a request to the endpoint uri, and take a look at the response header to
    // determine whether this is our service, or an external service.
    private static async isEndpointInternal(endpointUri: string): Promise<boolean> {
        let requestOptions: IRequestOptions;
        try {
            const proxy = tl.getHttpProxyConfiguration();
            requestOptions = proxy ? { proxy } : {};
        } catch (error) {
            tl.debug('unable to determine proxy configuration: ' + error);
            requestOptions = {};
        }

        const headers: IHeaders = {};
        headers['X-TFS-FedAuthRedirect'] = 'Suppress';

        const endpointClient = new HttpClient(tl.getVariable('AZURE_HTTP_USER_AGENT'), null, requestOptions);
        try {
            const resp = await endpointClient.get(endpointUri, headers);
            return resp.message.rawHeaders !== null && resp.message.rawHeaders.some( t => t.toLowerCase().indexOf('x-tfs') >= 0 || t.toLowerCase().indexOf('x-vss') >= 0 );
        } catch (error) {
            tl.debug(error);
            return false;
        }
    }

 .then(url => {
     const options: IRequestOptions = {
         proxy: tl.getHttpProxyConfiguration(url)
     };
     return new WebApi(url, new BearerHandlerForPresignedUrls(accessToken), options);
 })