HeaderExists VI

Owning Palette: Headers VIs

Requires: Base Development System

Determines if the header is associated with the client handle. Headers define attributes of the data exchanged between the client and server. Client handles save header values across multiple Web requests. Use the Open Handle VI to create a client handle. Refer to the World Wide Web Consortium website at www.w3.org for more information about header field definitions including example headers, descriptions, and syntax.

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	client handle specifies the client handle to associate with the Web request. Use client handles to wire together multiple HTTP Client VIs while preserving authentication credentials, HTTP headers, and cookies. Client handles are not required when making independent Web requests without persistent data such as headers or credentials.
	header specifies a header field included in the Web requests of the client handle. The header control provides a pull-down menu with some available header fields.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	client handle out returns the client handle associated with the Web request. Use client handles to wire together multiple HTTP Client VIs while preserving authentication credentials, HTTP headers, and cookies. Client handles are not required when making independent Web requests without persistent data such as headers or credentials.
	header exists? returns TRUE if the specified header is associated with the client handle.
	value returns the value assigned to the header. If header exists? returns FALSE, this output returns an empty string.
	error out contains error information. This output provides standard error out functionality.