Serialize object to JSON

JsonFlow uses RTTI to inspect published and public properties and convert them to a JSON object. The primary entry points are TJsonFlow (static facade) and TJSONSerializer (configurable instance).

Using the TJsonFlow facade

uses
  JsonFlow;

// Single object
LJson := TJsonFlow.ObjectToJsonString(LUser);

// Object list (non-generic)
LJson := TJsonFlow.ObjectListToJsonString(LObjectList);

// Object list (generic)
LJson := TJsonFlow.ObjectListToJsonString<TUser>(LUserList);

The optional AStoreClassName flag adds a "$ClassName" field to the output — useful for polymorphic round-trips.

Using TJSONSerializer directly

TJSONSerializer (unit JsonFlow.Serializer) exposes a configurable API:

uses
  JsonFlow.Serializer,
  JsonFlow.Interfaces;

var
  LSerializer: TJSONSerializer;
  LElement: IJSONElement;
begin
  LSerializer := TJSONSerializer.Create;
  try
    // Object → IJSONElement (interface, not string)
    LElement := LSerializer.FromObject(LUser);

    // Back to object
    LSerializer.ToObject(LElement, LUserCopy);
  finally
    LSerializer.Free;
  end;
end;

Constructor overloads

Constructor	Description
Create	Default format settings (en-US decimal separator)
Create(AFormatSettings, AUseISO8601)	Custom format settings; ISO 8601 datetime flag
Create(AOptions)	Full TJSONSerializerOptions record

TJSONSerializerOptions

type
  TJSONSerializerOptions = record
    UsePool: Boolean;                          // Use internal object pool
    DetectCircularReferences: Boolean;         // Detect and handle circular refs
    CircularReferenceStrategy: TCircularReferenceStrategy;
    ProcessAttributes: Boolean;                // Honor [JSONIgnore], [JSONName], etc.
    IgnoreNullValues: Boolean;                 // Skip null properties in output
    DateTimeFormat: string;                    // Custom DateTime format string
    FloatFormat: string;                       // Custom float format string
    MaxDepth: Integer;                         // Max object graph depth
  end;

Call TJSONSerializerOptions.Default for sensible defaults.

Middleware on serialization

Attach middleware to intercept and transform property values during serialization:

LSerializer.Middlewares.Add(LMyMiddleware);

Middleware must implement IGetValueMiddleware or ISetValueMiddleware (see JsonFlow.Interfaces).

Logging

LSerializer.OnLog(
  procedure(const AMsg: string) begin WriteLn(AMsg); end
);

Object lists

Both ObjectListToJsonString overloads return a JSON array string. The generic variant (ObjectListToJsonString<T>) works with TObjectList<T>; the non-generic variant works with TObjectList<TObject>.