XML Responses
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XML Responses

A response mark-up language conforming to XML will be used for all responses from the VTP service. This is intended to simplify the information parsing necessary for third party applications to interpret the data. It will take the following form.

Data elements will be identified using tags:

<element> element data </element>

There can be sub elements within elements:

<element>

<subelement> subelement data </subelement>

</element>

 Elements may also have an attribute field:

<element element_attribute= value> element data </element>

Response Element

The response element will be as follows:

<?xml version="1.0"?>

<Status Command= Command character>Status data</Status>

The status data may consist of a number of sub elements.  There will always be a State sub element if a Status request is made. If a “Query” request is made a State sub element will not be returned.

<State> State string </State>

The state string will vary depending on the command and type of response.

Authorization command response

The response to an authorization command will be as follows:

<?xml version="1.0"?><Status Command=”A”><State> Authorization state string </State></Status>

Where Authorization state string can be:

PS VTP XML Responses

VTP is an ASCII, line based protocol. This makes it simple to debug and experiment without using dedicated tools. Commands are entered as a single command letter, followed by a string of arguments relevant to the command, and a newline <LF> or carriage return <CR> to terminate and execute the command.  Commands are case-insensitive, and commands and arguments are separated by whitespace (space, TAB, etc).

All PS VTP responses are in XML to facilitate parsing by third party applications. Each XML Response has been detailed after the appropriate command within the PS VTP Commands section of this help file. A response markup language conforming to XML is used for all responses from the Aux Port Interface.  These responses take the following form.

Data elements are identified using tags:

<element>element data</element>

There can be sub elements within elements:

<element>

<subelement>subelement data</subelement>

</element>

Elements may also have an attribute field:

<element attribute=value>element data</element>

A typical response element will be as follows:

<?xml version="1.0"?><Reply Command=”Command character”>Reply data</Reply>

The response echoes the Command character.  The reply data may consist of a number of sub elements.  

There will always be a State sub element.

<State>State string</State>

The state string will be one of the following: