Insert Example

Overview

This document demonstrates the complete Insert flow using the AddToShipping feature from the EBusiness application. The flow starts with a POST request to the controller and ends with event publishing and subscriber processing.

Complete Flow Architecture

POST Request → Controller → Service → PreBus Plugins → Command Handler → RESTClient → External System
                                                                                    ↓
Response ← Controller ← Service ← Command Handler ← RESTClient ← External System

Detailed Flow Breakdown

1. POST Request
   ↓
2. Controller (API Entry Point)
   ↓
3. Service Layer (Business Orchestration)
   ↓
4. PreBus Processing (Validation Pipeline)
   ├── AddToShippingSequence (Plugin Registration)
   ├── AddToShippingDataPacket (Validation Context)
   └── ValidateShipping Plugin (Business Rules)
   ↓
5. Command Handler (RESTClient Integration)
   ├── Internal DTO → Request DTO Mapping
   ├── RESTClient Call to External System
   └── Response DTO Processing
   ↓
6. Event Publishing (Asynchronous Processing)
   ↓
7. Subscribers (Side Effects)

Step-by-Step Implementation

1. API Controller - The Entry Point

File: ShippingController_AddToShipping.cs

[HttpPost]
[Route("AddToShipping")]
[ProducesResponseType(typeof(BadRequestResult), 400)]
[ProducesResponseType(typeof(string), 201)]
public async Task<IActionResult> AddToShipping([FromBody]AddToShippingDto dto)
{
    return await RunService(201, dto, _processShippingService.AddToShipping);
}

What Happens:

• HTTP Method: POST /api/Shipping/AddToShipping

• Input: AddToShippingDto from request body

• Action: Calls the service layer to process the shipping

• Response: HTTP 201 Created with shipping ID

2. Service Layer - Business Orchestration

File: ProcessShippingService_AddToShipping.cs

public async Task<CommandResult> AddToShipping(AddToShippingDto dto)
{
    var packet = await ProcessBusinessRuleSequence<AddToShippingDataPacket, AddToShippingSequence, AddToShippingDto, FlexAppContextBridge>(dto);

    if (packet.HasError)
    {
        return new CommandResult(Status.Failed, packet.Errors());
    }
    else
    {
        dto.SetGeneratedId(_pkGenerator.GenerateKey());
        AddToShippingCommand cmd = new AddToShippingCommand
        {
             Dto = dto,
        };

        await ProcessCommand(cmd);

        CommandResult cmdResult = new CommandResult(Status.Success);

        AddToShippingResultModel outputResult = new AddToShippingResultModel();
        outputResult.Id = dto.GetGeneratedId();
        cmdResult.result = outputResult;

        return cmdResult;
    }
}

What Happens:

• PreBus Processing: Executes business rule sequences (plugins)

• Validation: Processes business rule sequences

• ID Generation: Generates unique shipping ID

• Command Creation: Creates AddToShippingCommand with DTO

• Command Processing: Calls the command handler

• Result: Returns success with generated shipping ID

2.1. PreBus Business Rule Sequence - Validation Pipeline

File: AddToShippingSequence.cs

public class AddToShippingSequence : FlexiBusinessRuleSequenceBase<AddToShippingDataPacket>
{
    public AddToShippingSequence()
    {
        this.Add<ValidateShipping>(); 
    }
}

What Happens:

• Plugin Registration: Registers validation plugins in execution order

• Sequential Processing: Executes plugins one by one

• Error Collection: Collects validation errors from all plugins

• Early Exit: Stops processing if any plugin fails

2.2. PreBus Data Packet - Validation Context

File: AddToShippingDataPacket.cs

public partial class AddToShippingDataPacket : FlexiFlowDataPacketWithDtoBridge<AddToShippingDto, FlexAppContextBridge>
{
    protected readonly ILogger<AddToShippingDataPacket> _logger;

    public AddToShippingDataPacket(ILogger<AddToShippingDataPacket> logger)
    {
        _logger = logger;
    }

    #region "Properties
    //Models and other properties goes here
    #endregion
}

What Happens:

• Context Container: Holds DTO and application context

• Error Collection: Collects validation errors from plugins

• Data Sharing: Allows plugins to share data during validation

• Logging: Provides logging capabilities for plugins

2.3. PreBus Validation Plugin - Business Rules

File: ValidateShipping.cs

public partial class ValidateShipping : FlexiBusinessRuleBase, IFlexiBusinessRule<AddToShippingDataPacket>
{
    public override string Id { get; set; } = "3a1cd0401f931dd4a01587e229b720dc";
    public override string FriendlyName { get; set; } = "ValidateShipping";

    protected readonly ILogger<ValidateShipping> _logger;
    protected readonly RepoFactory _repoFactory;

    public ValidateShipping(ILogger<ValidateShipping> logger, RepoFactory repoFactory)
    {
        _logger = logger;
        _repoFactory = repoFactory;
    }

    public virtual async Task Validate(AddToShippingDataPacket packet)
    {
        //Uncomment the below line if validating against a db data using your repo
        //_repoFactory.Init(packet.Dto);

        //If any validation fails, uncomment and use the below line of code to add error to the packet
        //packet.AddError("key", "ErrorMessage");

        await Task.CompletedTask; //If you have any await in the validation, remove this line
    }
}

What Happens:

• Business Rule Validation: Implements specific validation logic

• Database Access: Can access repository for data validation

• Error Reporting: Adds errors to the data packet if validation fails

• Async Support: Supports asynchronous validation operations

• Dependency Injection: Receives logger and repository factory

2.4. PreBus Plugin Benefits

• Modular Validation: Each plugin handles one validation concern

• Reusable Rules: Plugins can be reused across different features

• Testable: Each plugin can be unit tested independently

• Configurable: Plugins can be enabled/disabled per feature

• Extensible: Easy to add new validation rules

• Ordered Execution: Plugins execute in defined sequence

3. Command Handler - RESTClient Integration

File: AddToShippingHandler.cs

public partial class AddToShippingHandler : IAddToShippingHandler
{
    protected string EventCondition = "";
    protected readonly ILogger<AddToShippingHandler> _logger;
    protected readonly IFlexHost _flexHost;
    protected ShippingRESTClient _restClient;
    protected FlexAppContextBridge? _flexAppContext;

    public AddToShippingHandler(ILogger<AddToShippingHandler> logger, IFlexHost flexHost, ShippingRESTClient restClient)
    {
        _logger = logger;
        _flexHost = flexHost;
        _restClient = restClient;
    }

    public virtual async Task Execute(AddToShippingCommand cmd, IFlexServiceBusContext serviceBusContext)
    {
        // Convert internal DTO to Request DTO
        AddToShippingRequestDto requestParams = new AddToShippingRequestDto
        {
            OrderId = cmd.Dto.OrderId,
            ShippingAddress = cmd.Dto.ShippingAddress,
            TrackingNumber = cmd.Dto.TrackingNumber,
            TotalWeight = cmd.Dto.ShippingItems?.Sum(x => x.Weight) ?? 0,
            ShippingItems = cmd.Dto.ShippingItems?.Select(x => new ShippingItemRequestDto
            {
                ProductId = x.ProductId,
                Quantity = x.Qty,
                Weight = x.Weight,
                Volume = x.Volume
            }).ToList()
        };

        // Call external REST service
        var response = await _restClient.AddToShipping(requestParams);

        // Process response
        if (response.IsSuccessStatusCode)
        {
            var responseContent = await response.Content.ReadAsStringAsync();
            var responseDto = JsonConvert.DeserializeObject<AddToShippingResponseDto>(responseContent);
            
            _logger.LogDebug("Shipping created successfully with external ID: {ExternalId}", responseDto?.Id);
            
            // Set success condition for event firing
            EventCondition = "CONDITION_ONSUCCESS";
        }
        else
        {
            _logger.LogError("Failed to create shipping. Status: {StatusCode}", response.StatusCode);
            EventCondition = "CONDITION_ONFAILED";
        }

        await this.Fire(EventCondition, serviceBusContext);
    }
}

What Happens:

• DTO Mapping: Converts internal DTO to Request DTO for external system

• RESTClient Call: Calls external shipping service via RESTClient

• Response Processing: Handles success/failure responses from external system

• Logging: Logs success/failure of external service call

• Event Publishing: Fires events based on external service result

4. NServiceBus Handler - Message Processing

File: AddToShippingNsbHandler.cs

public class AddToShippingNsbHandler : NsbCommandHandler<AddToShippingCommand>
{
    readonly ILogger<AddToShippingNsbHandler> _logger;
    readonly IFlexHost _flexHost;
    readonly IAddToShippingHandler _handler;

    public AddToShippingNsbHandler(ILogger<AddToShippingNsbHandler> logger, IFlexHost flexHost, IAddToShippingHandler handler)
    {
        _logger = logger;
        _flexHost = flexHost;
        _handler = handler;
    }

    public override async Task Handle(AddToShippingCommand message, IMessageHandlerContext context)
    {
        _logger.LogTrace($"Executing {nameof(AddToShippingNsbHandler)}");

        await _handler.Execute(message, new NsbHandlerContextBridge(context));
    }
}

What Happens:

• Message Reception: Receives AddToShippingCommand from message bus

• Logging: Logs handler execution

• Delegation: Calls the actual command handler

• Context Bridge: Converts NServiceBus context to FlexBase context

6. Event Publishing - Asynchronous Processing

Event: ShippingAddedEvent

public class ShippingAddedEvent : FlexEventBridge<FlexAppContextBridge>
{
    // Event data is automatically populated by FlexBase
}

What Happens:

• Event Creation: FlexBase creates event with shipping data

• Message Bus: Event is published to message bus

• Subscriber Notification: All subscribers are notified

7. RESTClient Integration - External Communication

File: ShippingRESTClient_AddToShipping.cs

public async Task<HttpResponseMessage> AddToShipping(AddToShippingRequestDto model)
{
    var httpClient = _httpClientFactory.CreateClient(ShippingServicesRESTClientMaster.Name);

    var serializedModel = JsonConvert.SerializeObject(model);

    var request = new HttpRequestMessage(
           HttpMethod.Post,
           $"yourUri");
    request.Content = new StringContent(serializedModel, Encoding.UTF8, "application/json");
    request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var response = await httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead);

    return await response.HandleHttpResponse();
}

What Happens:

• HTTP Client: Creates HTTP client for external communication

• Serialization: Converts Request DTO to JSON

• HTTP Request: Sends POST to external shipping system

• Response Handling: Processes HTTP response from external system

7.1. Request DTO - External Contract

File: AddToShippingRequestDto.cs

public partial class AddToShippingRequestDto
{
    public string OrderId { get; set; }
    public string ShippingAddress { get; set; }
    public string TrackingNumber { get; set; }
    public decimal TotalWeight { get; set; }
    public ICollection<ShippingItemRequestDto> ShippingItems { get; set; }
}

What Happens:

• External Contract: Designed for external system consumption

• Serialization: Optimized for JSON serialization

• Validation: May include external system specific validation

7.2. Response DTO - External Contract

File: AddToShippingResponseDto.cs

public partial class AddToShippingResponseDto
{
    public string Id { get; set; }
    public string Status { get; set; }
    public string Message { get; set; }
    public DateTime ProcessedDate { get; set; }
    public string ExternalReferenceId { get; set; }
}

What Happens:

• External Contract: Designed for external system responses

• Deserialization: Optimized for JSON deserialization

• External Fields: May include external system specific fields

7.3. Mapping Configuration - DTO Transformation

File: ShippingRESTClientMapperProfile.cs

public class ShippingRESTClientMapperProfile : Profile
{
    public ShippingRESTClientMapperProfile()
    {
        // Internal DTO → Request DTO Mapping
        CreateMap<AddToShippingDto, AddToShippingRequestDto>()
            .ForMember(d => d.TotalWeight, opt => opt.MapFrom(s => s.ShippingItems.Sum(x => x.Weight)))
            .ForMember(d => d.ShippingItems, opt => opt.MapFrom(s => s.ShippingItems));
            
        // Response DTO → Internal DTO Mapping
        CreateMap<AddToShippingResponseDto, AddToShippingDto>()
            .ForMember(d => d.Status, opt => opt.MapFrom(s => ParseStatus(s.Status)))
            .ForMember(d => d.ExternalReferenceId, opt => opt.MapFrom(s => s.ExternalReferenceId));
    }
    
    private ShippingStatus ParseStatus(string status)
    {
        return status?.ToLower() switch
        {
            "created" => ShippingStatus.Created,
            "in_transit" => ShippingStatus.InTransit,
            "delivered" => ShippingStatus.Delivered,
            "cancelled" => ShippingStatus.Cancelled,
            _ => ShippingStatus.Unknown
        };
    }
}

What Happens:

• Request Mapping: Converts internal DTO to external request format

• Response Mapping: Converts external response to internal DTO format

• Field Transformation: Handles different field names and types

• Business Logic: Applies business rules during mapping

8. Event Subscribers - Side Effects

File: NotifyLogisticsOnShippingAdded.cs

public partial class NotifyLogisticsOnShippingAdded : INotifyLogisticsOnShippingAdded
{
    protected readonly ILogger<NotifyLogisticsOnShippingAdded> _logger;
    protected string EventCondition = "";

    public NotifyLogisticsOnShippingAdded(ILogger<NotifyLogisticsOnShippingAdded> logger)
    {
        _logger = logger;
    }

    public virtual async Task Execute(ShippingAddedEvent @event, IFlexServiceBusContext serviceBusContext)
    {
        _flexAppContext = @event.AppContext;

        //TODO: Write your business logic here:
        // - Send shipping confirmation email
        // - Update inventory levels
        // - Notify logistics system
        // - Update tracking information

        await this.Fire<NotifyLogisticsOnShippingAdded>(EventCondition, serviceBusContext);
    }
}

What Happens:

• Event Reception: Receives ShippingAddedEvent from message bus

• Side Effects: Executes business logic (emails, notifications, etc.)

• Additional Events: Can fire more events if needed

Data Transfer Objects (DTOs)

Internal DTOs - Application Contracts

Input DTO: AddToShippingDto

public partial class AddToShippingDto : DtoBridge 
{
    [StringLength(100)]
    public string OrderId { get; set; }

    [StringLength(200)]
    public string ShippingAddress { get; set; }

    public ICollection<AddToShippingDto_ShippingItem> ShippingItems { get; set; }
}

Command: AddToShippingCommand

public class AddToShippingCommand : FlexCommandBridge<AddToShippingDto, FlexAppContextBridge>
{
    // Command data is automatically populated by FlexBase
}

External DTOs - External System Contracts

Request DTO: AddToShippingRequestDto

public partial class AddToShippingRequestDto
{
    public string OrderId { get; set; }
    public string ShippingAddress { get; set; }
    public string TrackingNumber { get; set; }
    public decimal TotalWeight { get; set; }
    public ICollection<ShippingItemRequestDto> ShippingItems { get; set; }
}

Response DTO: AddToShippingResponseDto

public partial class AddToShippingResponseDto
{
    public string Id { get; set; }
    public string Status { get; set; }
    public string Message { get; set; }
    public DateTime ProcessedDate { get; set; }
    public string ExternalReferenceId { get; set; }
}

DTO Mapping Relationships

Internal DTO (AddToShippingDto) ←→ Request DTO (AddToShippingRequestDto)
     ↑                                    ↓
     │                              External System
     │                                    ↓
     └── Response DTO (AddToShippingResponseDto) ←┘

Flow Summary

Synchronous Flow (Immediate Response)

1. POST Request → Controller receives request

2. Service Processing → Business orchestration and PreBus validation

3. PreBus Plugins → Sequential validation of business rules

4. Command Handler → RESTClient integration

   • Internal DTO → Request DTO mapping

   • External system API call

   • Response DTO processing

5. Response → HTTP 201 with shipping ID

Asynchronous Flow (Event Processing)

1. Event Publishing → ShippingAddedEvent published to message bus

2. Subscriber Processing → NotifyLogisticsOnShippingAdded executes

3. Side Effects → Emails, notifications, inventory updates

4. Additional Events → Can trigger more business processes

External Communication Flow

1. Internal DTO → Request DTO mapping

2. RESTClient Call → HTTP request to external system

3. External Response → Response DTO from external system

4. Response Mapping → Response DTO to Internal DTO

5. Data Integration → External data integrated with internal data

Key Benefits

• Separation of Concerns: Each layer has a single responsibility

• Testability: Each component can be tested independently

• Scalability: Asynchronous processing handles high loads

• Maintainability: Clear, readable code structure

• Event-Driven: Loose coupling between components

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This AddToShipping example demonstrates how FlexBase enables clean, maintainable, and scalable insert operations with proper separation of concerns and event-driven architecture! 🚀