Top 10 Features of RemObjects SDK for Delphi

Migrating Delphi Apps to RemObjects SDK — Step-by-StepMigrating an existing Delphi application to use RemObjects SDK can unlock robust, cross-platform communication, modern protocol support, and easier maintenance of distributed systems. This guide walks you through a practical, step-by-step migration process, with concrete examples, best practices, and troubleshooting tips to help you move safely and efficiently.

Why migrate to RemObjects SDK?

Interoperability: RemObjects SDK supports multiple platforms and languages, enabling Delphi servers and clients to interoperate with .NET, Java, Node.js, and others.
Flexible transport and protocols: TCP, HTTP/S, WebSockets, and more, plus support for binary and textual protocols.
Performance and scalability: Lightweight binary protocols, connection pooling, and efficient marshaling.
Security: Built-in support for TLS, authentication hooks, and pluggable security mechanisms.
Tooling: Visual designers, code generation, and well-documented APIs that fit Delphi’s component model.

Prerequisites

Delphi IDE (recommended recent version compatible with RemObjects SDK).
Existing Delphi application with clearly separated business logic and data access layers (if not, expect some refactoring).
RemObjects SDK for Delphi installed and licensed.
Backup of your project and source control (git, SVN).
Test environment for iterative verification (unit tests and integration tests preferred).

Overview of the migration process

Analyze current architecture and identify service boundaries.
Decide on transport and protocol (e.g., TCP + Binary, HTTP + RO/JSON).
Refactor application to separate service interface and implementation.
Define service contracts (interfaces, data structures).
Implement server-side RemObjects service components.
Implement client-side proxies or use generated stubs.
Secure and configure transports, authentication, and error handling.
Test incrementally (unit, integration, performance).
Deploy and monitor; roll back strategy if needed.

Step 1 — Analyze your current application

Inventory the parts of the app that need to communicate remotely:

Identify modules that act as logical services (e.g., OrderProcessing, Inventory, Auth).
List public methods that should be remote procedures.
Identify data models and transfer objects used by those methods.
Note dependencies that cannot be easily serialized (file handles, complex pointers).

Tip: Start with a small, non-critical service to gain experience before migrating core systems.

Step 2 — Choose transport and protocol

Choose based on requirements:

TCP + Binary: high-performance, low overhead — suitable for internal networks.
HTTP(S) + RO/JSON or SOAP: easier to traverse firewalls and integrate with web clients.
WebSockets: for real-time bidirectional communication to browsers.

Factors:

Firewall/NAT traversal needs
Cross-platform clients
Human-readable payloads vs compact binary
Authentication and TLS requirements

Step 3 — Refactor to separate interface from implementation

Create clear service interfaces that expose only the operations you want remotely available.

Example pattern (pseudo-Delphi interface):

type   IOrderService = interface     ['{8B3A5C2D-4E7F-4A1A-9F2B-1234567890AB}']     function CreateOrder(const CustomerID: Integer; const Items: TOrderItems): Integer;     function GetOrder(const OrderID: Integer): TOrder;   end;

Move business logic into classes that implement these interfaces. Keep heavy UI or local-only logic out of service classes.

Step 4 — Define service contracts and DTOs

Define data transfer objects (DTOs) that are simple, version-tolerant, and serializable. Avoid including behavior (methods) in DTOs — keep them as plain records or classes with properties.

Example DTO:

type   TOrderItemDTO = class   private     FProductID: Integer;     FQuantity: Integer;   public     property ProductID: Integer read FProductID write FProductID;     property Quantity: Integer read FQuantity write FQuantity;   end;

Versioning tips:

Use optional fields where possible.
Avoid breaking changes to existing fields; add new fields with defaults.
Consider explicit version numbers in service endpoints if necessary.

Step 5 — Implement server-side RemObjects services

Add RemObjects SDK components to your Delphi project (server channel, message handlers, service modules).
Create a service component class that wraps your business logic.

Example (simplified):

type   TOrderService = class(TROService) // TROService is a RemObjects base   public     function CreateOrder(const CustomerID: Integer; const Items: TROArray): Integer;     function GetOrder(const OrderID: Integer): TROObject;   end;

Register service class and its methods.
Map incoming messages to method handlers.

Configure transport channel (e.g., TROIndyHTTPServerChannel or TROInetTcpServerChannel) and start listening.

Practical tips:

Use dependency injection to provide real business classes to the service component, making unit testing easier.
Keep service methods thin: validate inputs, call business logic, return DTOs.

Step 6 — Implement client-side access

Option 1 — Use generated stubs:

RemObjects SDK can generate Delphi client proxies for your service interfaces. Generate proxies to simplify client calls.

Option 2 — Manual proxy:

Create client classes that use TRORemoteService or TROClientChannel to call server methods.

Example using generated proxy pattern (pseudo):

var   OrderClient: TOrderServiceClient; begin   OrderClient := TOrderServiceClient.Create(nil);   try     OrderClient.ServerChannel := MyHttpChannel;     NewID := OrderClient.CreateOrder(123, ItemArray);   finally     OrderClient.Free;   end; end;

Handle serialization errors, network timeouts, and retries gracefully in client code.

Step 7 — Secure, configure, and tune

Security:

Enable TLS for HTTP or TCP channels.
Require authentication tokens or certificates for sensitive services.
Sanitize inputs and validate all parameters server-side.

Configuration:

Expose channel endpoints via configuration files or environment variables.
Support multiple channels if you need both internal fast TCP and external HTTP.

Performance tuning:

Use binary protocol for high-throughput services.
Cache connection/channel objects instead of creating per-call if appropriate.
Profile serialization/deserialization and reduce DTO size where possible.

Step 8 — Testing strategy

Unit tests: Test business logic independently from RemObjects components.
Integration tests: Exercise full client-server calls (mock channels where useful).
Load tests: Simulate production traffic patterns; test connection pooling and max-connections.
Compatibility tests: If you have mixed clients (Delphi + .NET), verify cross-platform behavior.

Include rollback verification — ensure you can route clients to the old implementation while validating the new RemObjects-based service.

Step 9 — Deployment and migration plan

Staged rollout: Start with a canary environment or small subset of users.
Feature flags: Switch traffic gradually from legacy endpoints to the new services.
Monitoring: Instrument latency, error rates, resource usage. Log serialization or protocol errors separately.
Backout plan: Keep legacy endpoints available and route traffic back if critical issues are discovered.

Common pitfalls and troubleshooting

Serialization mismatches: Ensure DTOs match exactly (field names/types) or use versioning strategies.
Tight coupling: If UI or other modules depend on implementation details, refactor before migrating.
Blocking calls: Avoid long-running synchronous methods in service handlers; consider asynchronous/task-based patterns.
Firewall and network: Opening new ports may require ops coordination — prefer HTTP(S) when simpler.

Example migration: Orders service (concise walkthrough)

Identify CreateOrder and GetOrder as remote operations.
Extract IOrderService and DTOs (TOrderDTO, TOrderItemDTO).
Implement TOrderService (RemObjects service) that delegates to existing OrderManager class.
Configure TROHttpServerChannel with TLS, register TOrderService.
Generate TOrderServiceClient proxy and replace local calls in client app with proxy calls.
Run integration tests, tune performance, then deploy behind a load balancer.

Additional resources and learning path

RemObjects SDK official docs and examples.
RemObjects community forums and sample projects.
Delphi unit testing frameworks (DUnitX) for business logic testing.
Network and security best practices for production deployments.

Final notes

Migrating to RemObjects SDK generally improves interoperability and maintainability of Delphi-based distributed systems, but it pays to refactor for clear service boundaries and to follow incremental rollout practices. Start small, automate tests, and iterate quickly to minimize disruption.