function postProcessResponse()

in core/nodejsActionBase/platform/knative.js [274:367]
61 lines of code
17 McCabe index (conditional complexity)

function postProcessResponse(req, result, res) {

    var content_types = {
        json: 'application/json',
        html: 'text/html',
        png: 'image/png',
        svg: 'image/svg+xml',
    };

    // After getting the result back from an action, update the HTTP headers,
    // status code, and body based on its result if it includes one or more of the
    // following as top level JSON properties: headers, statusCode, body
    let statusCode = result.code;
    let headers = {};
    let body = result.response;
    let contentTypeInHeader = false;

    // statusCode: default is 200 OK if body is not empty otherwise 204 No Content
    if (result.response.statusCode !== undefined) {
        statusCode = result.response.statusCode;
        delete body['statusCode'];
    }

    // the default content-type for an HTTP response is application/json
    // this default are overwritten with the action specified headers
    if (result.response.headers !== undefined) {
        headers = result.response.headers;
        delete body['headers'];
    }

    // addressing content-type v/s Content-Type
    // marking 'Content-Type' as standard inside header
    if (headers.hasOwnProperty(CONTENT_TYPE.toLowerCase())) {
        headers[CONTENT_TYPE] = headers[CONTENT_TYPE.toLowerCase()];
        delete headers[CONTENT_TYPE.toLowerCase()];
    }

    //  If a content-type header is not declared in the action result’s headers,
    //  the body is interpreted as application/json for non-string values,
    //  and text/html otherwise.
    if (!headers.hasOwnProperty(CONTENT_TYPE)) {
        if (result.response.body !== undefined && typeof result.response.body == "string") {
            headers[CONTENT_TYPE] = content_types.html;
        } else {
            headers[CONTENT_TYPE] = content_types.json;
        }
    } else {
        contentTypeInHeader = true;
    }


    // body: a string which is either a plain text, JSON object, or a base64 encoded string for binary data (default is "")
    // body is considered empty if it is null, "", or undefined
    if (result.response.body !== undefined) {
        body = result.response.body;
        delete body['main'];
        delete body['code'];
        delete body['binary'];
    }

    // When the content-type is defined, check if the response is binary data or
    // plain text and decode the plain text using a base64 decoder whenever needed.
    // Should the body fail to decoded correctly, return an error to the caller.
    if (contentTypeInHeader && headers[CONTENT_TYPE].lastIndexOf("image", 0) === 0) {
        if (typeof body === "string") {
            body = Buffer.from(body, 'base64')
            headers["Content-Transfer-Encoding"] = "binary";
        }
        // TODO: throw an error if body can not be decoded
    }


    // statusCode: set it to 204 No Content if body is empty
    if (statusCode === 200 && body === "") {
        statusCode = 204;
    }

    if (!headers.hasOwnProperty('Access-Control-Allow-Origin')) {
        headers['Access-Control-Allow-Origin'] = '*';
    }
    if (!headers.hasOwnProperty('Access-Control-Allow-Methods')) {
        headers['Access-Control-Allow-Methods'] = 'OPTIONS, GET, DELETE, POST, PUT, HEAD, PATCH';
    }
    // the header Access-Control-Request-Headers is echoed back as the header Access-Control-Allow-Headers if it is present in the HTTP request.
    // Otherwise, a default value is generated.
    if (!headers.hasOwnProperty['Access-Control-Allow-Headers']) {
        headers['Access-Control-Allow-Headers'] = 'Authorization, Origin, X - Requested - With, Content - Type, Accept, User - Agent';
        if (typeof req.headers['Access-Control-Request-Headers'] !== "undefined") {
            headers['Access-Control-Allow-Headers'] = req.headers['Access-Control-Request-Headers'];
        }
    }

    res.header(headers).status(statusCode).send(body);
}