@sap/odata-v4/lib/format/RequestContentNegotiator.js

OData V4.0 server library

'use strict';

const RepresentationKind = require('./RepresentationKind');
const RepresentationKinds = RepresentationKind.Kinds;
const HttpHeader = require('../http/HttpHeader');
const HeaderNames = HttpHeader.HeaderNames;
const DeserializationError = require('../errors/DeserializationError');

/**
 * Negotiates the request payload type for the provided request.
 */
class RequestContentNegotiator {

    /**
     * Negotiates the deserializer function in dependency of the request type and sets the result
     * to the request contract.
     *
     * @param {FormatManager} bodyParserManager The format manager holding the deserializing function
     * @param {OdataRequest} request The current odata request
     * @returns {RequestContract} Returns the contract with attached deserializer facade
     */
    negotiate(bodyParserManager, request) {
        const representationKind = RepresentationKind.getRequestRepresentationKind(
            request.getUriInfo(),
            request.getMethod());
        let contract = request.getContract();
        contract.setRepresentationKind(representationKind);

        if (representationKind !== RepresentationKinds.NO_CONTENT) {
            try {
                contract.setContentTypeInfo(HttpHeader.parseContentTypeHeader(
                    request.getHeader(HeaderNames.CONTENT_TYPE.toLowerCase())));
            } catch (error) {
                throw new DeserializationError(
                    'Invalid value "' + request.getHeader(HeaderNames.CONTENT_TYPE.toLowerCase()) +
                    '" in ' + HeaderNames.CONTENT_TYPE.toLowerCase() + ' header', error);
            }
        }

        if (contract.getContentTypeInfo()) {
            const mimeType = contract.getContentTypeInfo().getMimeType();
            let formatDescriptions = bodyParserManager.getFormatDescriptions(representationKind, mimeType);
            // If a binary is sent and no specific deserializer is found,
            // use the deserializer registered for the empty-string content type.
            if (!formatDescriptions.length && representationKind === RepresentationKinds.BINARY) {
                formatDescriptions = bodyParserManager.getFormatDescriptions(representationKind, '');
            }
            contract.setDeserializerFunction(
                formatDescriptions.length ? formatDescriptions[0].getSerializerFunction() : null);
        }

        return contract;
    }
}

module.exports = RequestContentNegotiator;