JSONFlattener

Flattens JSON (JavaScript Object Notation) objects, extracting the object keys and values into FME feature attributes.

For example, consider a feature which has an attribute named json containing the following text:

   "paramName":"GeocodeResult",

   "dataType":"GPFeatureRecordSetLayer",

   "value":

      "geometryType":"esriGeometryPoint",

      "spatialReference": {"wkid":4326 }

After going through the JSONFlattener, the following attributes will have been added to the feature:

Attribute Name	Attribute Value
paramName	GeocodeResult
dataType	GPFeatureRecordSetLayer
value.geometryType	esriGeometryPoint
value.spatialReference.wkid	4326

Optional Input Port

This transformer has two modes, depending on whether a connector is attached to the Input port or not:

Input-driven: When input features are connected, the transformer runs once for each feature it receives in the Input port.
Run Once: When no input features are connected, the transformer runs one time and outputs a single new feature.

Configuration

Output Ports

Parameters

Source

Input Source

Select the type of JSON input to be provided:

JSON Document
File/URL

JSON Document

When Input Source is JSON Document, provide the document as a string expression, which may include attribute values and workspace parameters.

File/URL

When Input Source is File/URL, provide the path and filename or URL of the JSON document.

Flattening

Recursively Flatten Objects/Arrays

If this parameter is set to No, each JSON object key will become an attribute and the corresponding JSON value will become the attribute value. If this parameter is set to Yes, only object values which are simple types (integers, strings, etc) will become attribute values, while nested objects and arrays will be recursively flattened, as shown in the above example.

Prefix New Attribute Names With

This parameter may be used to provide a string with which to prefix the newly-created attributes.

Attributes to Expose

Exposes attributes so they can be used elsewhere in the workspace.

Attribute names may be entered directly or provided in the Enter Values for Attributes to Expose dialog accessed via the ellipsis button, where data type may also be specified.

For more information on exposed and unexposed attributes, see Understanding Feature Types and Attributes.

Editing Transformer Parameters

Transformer parameters can be set by directly entering values, using expressions, or referencing other elements in the workspace such as attribute values or user parameters. Various editors and context menus are available to assist. To see what is available, click beside the applicable parameter.

How to Set Parameter Values

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters.

Using the Text Editor

The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.

Text Editor

Using the Arithmetic Editor

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more.

When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.

Content Types

String Functions	These functions manipulate and format strings.
Special Characters	A set of control characters is available in the Text Editor.
Math Functions	Math functions are available in both editors.
Date/Time Functions	Date and time functions are available in the Text Editor.
Math Operators	These operators are available in the Arithmetic Editor.
FME Feature Functions	These return primarily feature-specific values.
FME Parameters	FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters	Create your own editable parameters.

Dialog Options - Tables

Table Tools

Transformers with table-style parameters have additional tools for populating and manipulating values.

Row Reordering

Enabled once you have clicked on a row item. Choices include:

Add a row
Remove a row
Move current row up one
Move current row down one
Move current row to top
Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

Cut a row - delete and copy to clipboard
Copy a row to the clipboard
Paste a row from the clipboard

Cut, copy, and paste may be used within a transformer, or between transformers.

Filter

Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output.

Import

Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.

Reset/Refresh

Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers.

Note: Not all tools are available in all transformers.

For more information, see Transformer Parameter Menu Options.

Reference

Processing Behavior	Feature-Based
Feature Holding	No
Dependencies	None
Aliases
History

FME Online Resources

The FME Community and Support Center Knowledge Base have a wealth of information, including active forums with 35,000+ members and thousands of articles.

Search for all results about the JSONFlattener on the FME Community.

Examples may contain information licensed under the Open Government Licence – Vancouver, Open Government Licence - British Columbia, and/or Open Government Licence – Canada.