How to create a web service that accepts a json with an array?

Question

I already know that the "official" way is sending all the entire JSON in a string with unbound actions, but per project specification I need the API to be able to read json arrays in json format.

To be clear with an example, this is the data to be sent to the API:

{
    "Batch": "IC0001",
    "Colors": [
        {
            "Color": "GENERAL",
            "Code": "112",
            "Description": "BERMELLON",
            "RGB": "255,0,0",
            "GroupWeb": "40"
        },
        {
            "Color": "GENERAL",
            "Code": "111",
            "Description": "ROJERAS",
            "RGB": "255,0,0",
            "GroupWeb": "40"
        }
    ]
}

I'm trying to read the JSON with the codeunit "JSON Management":

codeunit 60201 IntegracionPLM
{ 
    procedure ReadColorJSON(data: Text)
    var
        JSONManagement: Codeunit "JSON Management";
        ArrayJSONManagement: Codeunit "JSON Management";
        ObjectJSONManagement: Codeunit "JSON Management";
        i: Integer;
        JsonArrayText: Text;
        ColorJsonObject: Text;
        GrupoColoresText: Text;
        CodigoText: Text;
        DescripcionText: Text;
        ValorRGBText: Text;
        AgrupacionWebText: Text;
    begin
        JSONManagement.InitializeObject(Data);

        if JSONManagement.GetArrayPropertyValueAsStringByName('data', JsonArrayText) then begin
            ArrayJSONManagement.InitializeCollection(JsonArrayText);

            for i := 0 to ArrayJSONManagement.GetCollectionCount() - 1 do begin
                ArrayJSONManagement.GetObjectFromCollectionByIndex(ColorJsonObject, i);
                ObjectJSONManagement.InitializeObject(ColorJsonObject);

                ObjectJSONManagement.GetStringPropertyValueByName('GrupoColores', GrupoColoresText);
                ObjectJSONManagement.GetStringPropertyValueByName('Codigo', CodigoText);
                ObjectJSONManagement.GetStringPropertyValueByName('Descripcion', DescripcionText);
                ObjectJSONManagement.GetStringPropertyValueByName('ValorRGB', ValorRGBText);
                ObjectJSONManagement.GetStringPropertyValueByName('AgrupacionWeb', AgrupacionWebText);

                Message('GrupoColores: %1, Codigo: %2, Descripcion: %3, ValorRGB: %4, AgrupacionWeb: %5', 
                         GrupoColoresText, CodigoText, DescripcionText, ValorRGBText, AgrupacionWebText);
            end;
        end;
    end;
}

But I'm getting this error:

{
    "error": {
        "code": "BadRequest",
        "message": "One or more errors occurred. (One or more errors occurred. (An unexpected 'StartArray' node was found when reading from the JSON reader. A 'StartObject' node was expected.))  CorrelationId:  829669bb-ea16-4703-9ef1-e9431d47928e."
    }
}

The request is not going through. Not even reaching my code.

How can I read a json array from my Business Central web service?

Answer 1

Solved by following this guide: https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-develop-custom-api

Step 3 did the trick, creating a page with a part:

page 50100 "API Car Brand"
{
    PageType = API;

    APIVersion = 'v1.0';
    APIPublisher = 'bctech';
    APIGroup = 'demo';

    EntityCaption = 'Car Brand';
    EntitySetCaption = 'Car Brands';
    EntityName = 'carBrand';
    EntitySetName = 'carBrands';

    ODataKeyFields = SystemId;
    SourceTable = "Car Brand";

    Extensible = false;
    DelayedInsert = true;

    layout
    {
        area(content)
        {
            repeater(Group)
            {
                field(id; Rec.SystemId)
                {
                    Caption = 'Id';
                    Editable = false;
                }

                field(name; Rec.Name)
                {
                    Caption = 'Name';
                }
                field(description; Rec.Description)
                {
                    Caption = 'Description';
                }
                field(country; Rec.Country)
                {
                    Caption = 'Country';
                }
            }

            part(carModels; "API Car Model")
            {
                Caption = 'Car Models';
                EntityName = 'carModel';
                EntitySetName = 'carModels';
                SubPageLink = "Brand Id" = Field(SystemId);
            }
        }
    }
}

And it's part:

page 50101 "API Car Model"
{
    PageType = API;

    APIVersion = 'v1.0';
    APIPublisher = 'bctech';
    APIGroup = 'demo';

    EntityCaption = 'Car Model';
    EntitySetCaption = 'Car Models';
    EntityName = 'carModel';
    EntitySetName = 'carModels';

    ODataKeyFields = SystemId;
    SourceTable = "Car Model";

    Extensible = false;
    DelayedInsert = true;

    layout
    {
        area(content)
        {
            repeater(Group)
            {
                field(id; Rec.SystemId)
                {
                    Caption = 'Id';
                    Editable = false;
                }
                field(name; Rec.Name)
                {
                    Caption = 'Name';
                }
                field(description; Rec.Description)
                {
                    Caption = 'Description';
                }
                field(brandId; Rec."Brand Id")
                {
                    Caption = 'Brand Id';
                }
                field(power; Rec.Power)
                {
                    Caption = 'Power';
                }
                field(fuelType; Rec."Fuel Type")
                {
                    Caption = 'Fuel Type';
                }
            }
        }
    }
}

Then go to Postman or your tool of preference and test this:

POST https://api.businesscentral.dynamics.com/v2.0/<environmentName>/api/bctech/demo/v1.0/companies(<company id>))/carBrands
{
    "name": "CARBRAND2",
    "description": "Car Brand 2",
    "country": "Germany",
    "carModels": [{
                    "name": "MODELA",
                    "description": "Model A",
                    "power": 0,
                    "fuelType": "Electric"
                },
                {
                    "name": "MODELB",
                    "description": "Model B",
                    "power": 0,
                    "fuelType": "Electric"
                }]
}