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PatternThe Canonical Data Model is a common message format used by different applications for communication.
How Ballerina helps

Ballerina provides powerful data modelling capabilities through its Type System. You can define data types like JSON and xml, and structures like records to represent your canonical data model. This ensures interoperability when integrating different components in your system, making it easier to exchange data seamlessly.

Canonical Data ModelMessage RouterMessage TranslatorFormat Indicator
import ballerina/http;

const DATASET_ID = "f57074a0-a8b6-403e-9df1-e9fc46";

final http:Client gMapClient = check new ("");
final http:Client microsoftClient = check new ("");

type Gpx xml;

type Kml xml;

type Csv record {|
    float X;
    float Y;
    string Name;
    string Description;

type GeoJson record {
    string 'type = "FeatureCollection";
    string name = "PlaceMarks";
    Feature[] features;

type Feature record {|
    string 'type = "Feature";
    record {|
        string X;
        string Y;
        string Name;
        string description;
    |} properties;
    record {|
        string 'type = "Point";
        string[] coordinates;
    |} geometry;

type GMapResponse record {
    string name;
    string displayName;
    string createTime;

type MicrosoftMapResponse record {
    string formatVersion;
    record {
        record {
            string latitude;
            string longitude;
        }[] points;
    }[] routes;

service /map on new http:Listener(8080) {
    resource function post uploadPlaceMarks(http:Request request) returns GMapResponse|error? {
        Csv|Gpx data = check getPayload(request);
        GeoJson geoJson = convertToCanonical(data);
        Kml kmlData = convertFromCanonicalToKml(geoJson);
        GMapResponse gMapResponse = check gMapClient->post(
            string `/v1/projects/${PROJECT_ID}/datasets/${DATASET_ID}:import`, kmlData);
        return gMapResponse;

    resource function post getRouteDirection(http:Request request, string query) returns MicrosoftMapResponse|error {
        Csv|Gpx data = check getPayload(request);
        GeoJson geoJson = convertToCanonical(data);
        MicrosoftMapResponse microsoftMapResponse = check microsoftClient->/route/directions/'
            {"supportingPoints": geoJson.toJson()}, {query: string `${query}`}
        return microsoftMapResponse;

isolated function convertToCanonical(Csv|Gpx data) returns GeoJson {
    if data is Csv {
        return convertFromCsvToCanonical(data);
    } else {
        return convertFromGpxToCanonical(data);

isolated function getPayload(http:Request request) returns Csv|Gpx|error {
    if request.getContentType().includes("xml") {
        return request.getXmlPayload();
    json data = check request.getJsonPayload();
    return data.cloneWithType(Csv);

isolated function convertFromCsvToCanonical(Csv data) returns GeoJson {
    return {
        features: from var member in data
                  let string X = member.X.toString(), string Y = member.Y.toString()
                  select {
                      properties: {X, Y, Name: member.Name, description: member.Description},
                      geometry: {coordinates: [X, Y]}

isolated function convertFromGpxToCanonical(Gpx gpxData) returns GeoJson {
    return {
        features: from var extension in gpxData/**/<extensions>
            select {
                properties: {
                    X: (extension/**/<X>).data(),
                    Y: (extension/**/<X>).data(),
                    Name: (extension/**/<Name>).data(),
                    description: (extension/**/<description>).data()
                geometry: {coordinates: [(extension/**/<X>).data(), (extension/**/<Y>).data()]}

isolated function convertFromCanonicalToKml(GeoJson geoJson) returns Kml {
    xml kmlData = xml `<kml>
            <Schema id="temp">
                <SimpleField name="X" type="double"/>
                <SimpleField name="Y" type="double"/>
                <SimpleField name="Name" type="string"/>
            ${from Feature feature in geoJson.features
              select xml `<Placemark>
    return kmlData;