Language-specific client APIs as well as tools may define convenience methods that make it unnecessary to call these APIs directly.

See also:

• Master Slave APIs

• Master API

• Slave API

API Listing

deleteParam(caller_id, key)

• Delete parameter

  
  Parameters

  • caller_id (str)

    • ROS caller ID

    key (str)

    • Parameter name.

  Returns (int, str, int)

  • (code, statusMessage, ignore)

setParam(caller_id, key, value)

• Set parameter. NOTE: if value is a dictionary it will be treated as a parameter tree, where key is the parameter namespace. For example

  {'x':1,'y':2,'sub':{'z':3}}

  will set key/x=1, key/y=2, and key/sub/z=3. Furthermore, it will replace all existing parameters in the key parameter namespace with the parameters in value. You must set parameters individually if you wish to perform a union update.

  
  Parameters

  • caller_id (str)

    • ROS caller ID

    key (str)

    • Parameter name.

    value (XMLRPCLegalValue)

    • Parameter value.

  Returns (int, str, int)

  • (code, statusMessage, ignore)

getParam(caller_id, key)

• Retrieve parameter value from server.

  
  Parameters

  • caller_id (str)

    • ROS caller ID

    key (str)

    • Parameter name. If key is a namespace, getParam() will return a parameter tree.

  Returns (int, str, XMLRPCLegalValue)

  • (code, statusMessage, parameterValue)

    
    If code is not 1, parameterValue should be ignored. If key is a namespace, the return value will be a dictionary, where each key is a parameter in that namespace. Sub-namespaces are also represented as dictionaries.

searchParam(caller_id, key)

• Search for parameter key on the Parameter Server. Search starts in caller's namespace and proceeds upwards through parent namespaces until Parameter Server finds a matching key.

  searchParam()'s behavior is to search for the first partial match. For example, imagine that there are two 'robot_description' parameters

  /robot_description
   /robot_description/arm
   /robot_description/base
  /pr2/robot_description
   /pr2/robot_description/base

  If I start in the namespace /pr2/foo and search for robot_description, searchParam() will match /pr2/robot_description. If I search for robot_description/arm it will return /pr2/robot_description/arm, even though that parameter does not exist (yet).

  
  Parameters

  • caller_id (str)

    • ROS caller ID

    key (str)

    • Parameter name to search for.

  Returns (int, str, str)

  • (code, statusMessage, foundKey)

    
    If code is not 1, foundKey should be ignored.

subscribeParam(caller_id, caller_api, key)

• Retrieve parameter value from server and subscribe to updates to that param. See paramUpdate() in the Node API.

  
  Parameters

  • caller_id (str)

    • ROS caller ID.

    key (str)

    • Parameter name

    caller_api (str)

    • Node API URI of subscriber for paramUpdate callbacks.

  Returns (int, str, XMLRPCLegalValue)

  • (code, statusMessage, parameterValue)

    
    If code is not 1, parameterValue should be ignored. parameterValue is an empty dictionary if the parameter has not been set yet.

unsubscribeParam(caller_id, caller_api, key)

• Retrieve parameter value from server and subscribe to updates to that param. See paramUpdate() in the Node API.

  
  Parameters

  • caller_id (str)

    • ROS caller ID.

    key (str)

    • Parameter name.

    caller_api (str)

    • Node API URI of subscriber.

  Returns (int, str, int)

  • (code, statusMessage, numUnsubscribed)

    
    If numUnsubscribed is zero it means that the caller was not subscribed to the parameter.

hasParam(caller_id, key)

• Check if parameter is stored on server.

  
  Parameters

  • caller_id (str)

    • ROS caller ID.

    key (str)

    • Parameter name.

  Returns (int, str, bool)

  • (code, statusMessage, hasParam)

getParamNames(caller_id)

• Get list of all parameter names stored on this server.

  
  Parameters

  • caller_id (str)

    • ROS caller ID.

  Returns (int, str, [str])

  • (code, statusMessage, parameterNameList)