Data mapper

Copies property values from the input record into a new record of another type, field by field, as defined in the mapping editor. Use it to turn one structure into another, for example a database row into an API request or a JSON document into a flow type.

Pins

Pin	Kind	Types	Description
Input	input	any	Source records. The type on the incoming connection is the source type of a mapping.
Output	output	the types of the outgoing connections	One new record per type mapping defined for the input type. Set the type on each outgoing connection; it is the target type.

Configuration

Field	Type	Default	Description
Mappings	string (JSON, mapping editor)		The type and field mappings, see below.

Mappings format

The mapping editor stores a JSON object with one entry per (source type, target type) pair:

{
  "typeMappings": [
    {
      "inputName": "Customer",
      "outputName": "CrmContact",
      "sourceTypeName": "MyFlow.Customer",
      "targetTypeName": "MyFlow.CrmContact",
      "fieldMappings": [
        { "sourceFieldPath": "Name",            "targetFieldPath": "FullName" },
        { "sourceFieldPath": "Id",              "targetFieldPath": "ExternalId" },
        { "sourceFieldPath": "Address.City",    "targetFieldPath": "City" }
      ]
    }
  ]
}

• sourceTypeName / targetTypeName: full type names (namespace + name) as on the connections. Only these two and fieldMappings are used at runtime; inputName / outputName are the short names shown in the editor.
• sourceFieldPath / targetFieldPath: property names, nested properties separated by . (Address.City), case-sensitive, starting at the root of the type.
• When you open the editor it creates an empty type mapping for every pair of incoming and outgoing connection types. Drag a source field onto a target field to add a field mapping; "auto map" pairs fields with the most similar names. Mapping a nested field also adds the mappings of its parent properties (Address → Addr for Address.City → Addr.Town).

Behaviour

• On start every type mapping is compiled. An unknown type or property, or a pair of property types that cannot be converted, makes the flow fail to start.
• For each input record the plugin looks up the type mappings whose sourceTypeName matches the record's type. If there is none, the record fails with "Unable to find appropriate mapper for input type". For every matching type mapping a new, empty target record is created, the mapped fields are copied, and the record is sent to Output. Unmapped target fields keep their default values. Metadata is passed through unchanged.
• The output is delivered to the outgoing connections whose type equals the target type.
• Type conversion: equal types are copied (objects and lists by reference). Different simple types are converted (to string, numbers, bool, DateTime, DateTimeOffset, TimeSpan, Guid, decimal, ...). Properties of type object are converted with the standard .NET type converter.
• An orange "no mapping" indicator is shown until every type mapping has at least one field mapping (checked when the mapping is saved).

Notes

• Lists with different item types (List<A> to List<B>) and different complex types cannot be mapped; the flow fails to start. Because the editor adds parent mappings for nested fields, mapping Address.City → Addr.Town only works when Address and Addr have the same type. To map lists of different types use ForEach → Data mapper → Build array, or a script.
• Nested paths: when an object on a source path (or a parent object on a target path) is null, the remaining field mappings of that type mapping are skipped for this record, not only the one field. A dotted source path whose final value is a null string has the same effect. Target records are created empty, so nested target objects are normally null; prefer mapping to top-level target fields.
• If two outgoing connections have the same target type and the editor created two identical type mappings, each connection receives the record twice.
• Saving an empty mapping reports "The mapping definition is not set".

Example

Http listener (Customer) → Data mapper → (CrmContact) Http client