Receives WebSocket messages from the specified WebSocket server.
Produces a feature each time a message is received, and places the contents of the message into the specified attribute. Each incoming feature will cause the WebSocketReceiver to initialize a connection to the specified WebSocket server. The transformer will block while it waits to receive WebSocket messages until the remote host closes the connection.
The performance of this transformer is dependent on the amount of memory allocated to the Java Virtual Machine (JVM). The following environment variables allow you to specify memory available to Java Plugins:
- FME_JVM_MIN_HEAP_SIZE: Initial heap size for initializing the JVM. If unset, the default value is 1024K.
These variables must be set in multiples of 1024 and greater than 1 MB. To indicate kilobytes, megabytes, or gigabytes, append k or K, m or M, or g or G respectively. For example, any of these values is acceptable:
- FME_JVM_MAX_HEAP_SIZE: Maximum heap size for initializing the JVM. If unset, the default value is 16384K.
These variables must be set in multiples of 1024 and greater than 2 MB. To indicate kilobytes, megabytes, or gigabytes, append k or K, m or M, or g or G respectively. For example, any of these values is acceptable:
Note: To pass additional parameters used by FME to the Java Virtual Machine, use the JAVA_TOOL_OPTIONS environment variable.
This transformer accepts any feature.
Features containing the data that has been received from the specified WebSocket server.
|WebSocket Server URL||
The URL of the remote WebSocket server that the WebSocketReceiver will connect to in order to receive WebSocket messages. The default value is ws://localhost:7078. To initiate a secure connection to a WebSocket server using TLS, specify wss://<hostname>:<port>.
|Verify SSL Certificates||
If Yes is specified, either explicitly or through a parameter, the WebSocketReceiver verifies the certificate (or chain of certificates) of the WebSocket server before establishing a connection.
If this optional parameter has a value, then the WebSocketReceiver will transmit the contents of this parameter to the remote WebSocket server before processing any incoming data.
To connect to the FME Server WebSocket server, use the following preamble:
"ws_op" : "open",
"ws_stream_ids" : ["<STREAMID>", "<STREAMID>", "<STREAMID>", ...]
To specify this preamble, click the ellipsis (...) to open the Connection Preamble dialog. Under FME Server WebSocket Preambles, select the Open Public Stream template. Then, specify a ws_stream_ids value.
ws_stream_ids identifies one or more message streams in order for the WebSocket server to associate them with the correct requesting application.
Name the attribute to contain the received WebSocket message data.
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.
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. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.
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.
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.
Set values depending on one or more test conditions that either pass or fail.
Parameter Condition Definition Dialog
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.
|These functions manipulate and format strings.|
|A set of control characters is available in the Text Editor.|
|Math functions are available in both editors.|
|Date/Time Functions||Date and time functions are available in the Text Editor.|
|These operators are available in the Arithmetic Editor.|
|These return primarily feature-specific values.|
|FME and workspace-specific parameters may be used.|
|Creating and Modifying User Parameters||Create your own editable parameters.|
Dialog Options - Tables
Transformers with table-style parameters have additional tools for populating and manipulating values.
Enabled once you have clicked on a row item. Choices include:
Cut, Copy, and Paste
Enabled once you have clicked on a row item. Choices include:
Cut, copy, and paste may be used within a transformer, or between transformers.
|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 populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.|
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.
The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.
Search for samples and information about this transformer on the FME Community.