sample.js

/*eslint-env node*/

/*

    This class is for:

     1. Creating Authentication HTTP headers
     2. Creating Accept-Language headers
     3. Sending a HTTP request

*/

const LDServiceClient = require( "./LDServiceClient" );

function getHeaders( options ) {

    const { localisation, defaultHeaders, identifier } = options;
    const headers = {};

    // do we have an authorization header to pass through?
    const authorizationHeader = defaultHeaders.authorization || defaultHeaders.Authorization;
    if ( authorizationHeader ) { headers.authorization = authorizationHeader; }
    // do we have an accept language header to pass through as preferred??
    const acceptLanguage = "Accept-Language";
    const preferredLanguages = [ localisation.language, "en;q=0.5", "*;q=0.1" ];
    headers[ acceptLanguage ] = preferredLanguages.join( ", " );
    // headers for sprint sleuth traceability
    // stupid Spring Could Sleuth requires (hex) numbers
    const spanId = identifier.slice( identifier.indexOf( "-" ) + 1 );
    const traceId = process.hrtime()[ 1 ];
    Object.assign( headers, {

        "X-B3-TraceId": traceId,
        "X-B3-SpanId": spanId,
        "X-B3-ParentSpanId": 0

    } );
    return headers;

}

class KMServiceClient extends LDServiceClient {

    request( uri, method, options ) {

        options.headers = getHeaders( options );
        options.traceId = options.headers[ "X-B3-TraceId" ];
        return super.request( uri, method, options )
            .then( response => response.body )
            .catch( e => {

                const err = Error( `Error calling ${uri}: ${e.stack}` );
                err.body = e.body;
                throw err;

            } );

    }

}

module.exports = KMServiceClient;