Global

Methods

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Session#fetch

This function can take any number of arguments. Each argument can be a string or a TopicSelector. Alternatively, an array of strings and TopicSelectors can be passed as a single argument.(selector)

Fetch the current state of one or more topics.

Fetching a topic will provide its current value without subscribing this client to that topic. The returned FetchStream will emit value events for each topic that is matched for which a fetch request can be satisfied. Once complete, the FetchStream will be closed.

Parameters:

Name	Type	Description
selector	String | TopicSelector | Array.<String>	The topic selector to fetch

Returns:

A FetchStream that will emit the fetched values.

Type

FetchStream

Examples

// Fetch a topic's value
session.fetch("foo").on('value', function(value, path) {
    console.log("Value for topic '" + path + "' is: " + value);
});

// Fetch multiple topics, handling possible errors
session.fetch("?foo/bar.*").on({
    value : function(value, path) { ... },
    error : function(error) { ... },
    close : function() { ... }
});

Type Definitions

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CloseReason

Type:

• Object

Properties:

Name	Type	Description
id	Number	unique id
message	String	message with further details

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Field

Properties:

Name	Type	Description
scale	Number	the scale of a decimal field

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Node

Properties:

Name	Type	Description
Node.name	String	the node name
Node.min	Number	the minimum number of occurences of the node within its parent
Node.max	Number	the maximum number of occurences of the node within its parent
Node.isVariable	Boolean	if the node has variable multiplicity, or has fixed multiplicity, i.e min != max

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Record

Properties:

Name	Type	Description
Record.fields	Array.<Field>	a list of the field definitions. There will be at least one