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fftJSONFile

fftJSONFile = 4

Example​

procedure ConfigureJSON(FileDef: TvxFileDef);
begin
  FileDef.FileType := fftJSONFile;
end;

Usage​

fftJSONFile selects the Velox JSON file-definition engine, JSON data-module type and application/json media default.

Additional Technical Info​

fftJSONFile is ordinal 4 of TvxFileType. It selects TvxJSONFileEngine, module class TvxFileDefJSON, data type fdtJSONFile, and MIME default application/json.

The constant chooses the engine family; it does not define the JSON document shape. Root object/array expectations, repeated records, nested paths, missing/null properties, number/date interpretation and output property names belong to the File Definition/data-view/schema mapping.

Data-contract boundaries​

  • JSON names and String values are case/Unicode-sensitive according to the consumer contract. Do not normalize them merely because Velox field names are configured differently.
  • Distinguish an absent property, explicit JSON null, empty String, zero, false and empty array/object. Mapping them to one Variant state loses information.
  • JSON numbers do not carry an integer/decimal schema by themselves. Define precision, range and decimal expectations for business identifiers and amounts.
  • application/json is a media label, not validation. The engine can still reject malformed structure or a mapping-incompatible valid document.
  • File extension is independent of FileType. Validate payload and size before processing untrusted data.
  • Read/Write event logging can occur before all parsing/serialization finishes; determine outcome from Flow/module status.

The example only selects configuration and was source-reviewed; no JSON parse/write, schema, file, runtime or image-function test was executed.

External references

Created 2026-07-15