Package roslib :: Module message

Module message

Support library for Python autogenerated message files. This defines the Message base class used by genmsg_py as well as support libraries for type checking and retrieving message classes by type name.

Classes
	long int(x[, base]) -> integer
	ROSMessageException Exception type for errors in roslib.message routines
	Message Base class of Message data classes auto-generated from msg files.
	ServiceDefinition Base class of Service classes auto-generated from srv files
	DeserializationError Message deserialization error
	SerializationError Message serialization error

Functions

isstring(s)
Small helper version to check an object is a string in a way that works for both Python 2 and 3

source code

Message class

get_message_class(message_type, reload_on_error=False)
Get the message class.

source code

Service class

get_service_class(service_type, reload_on_error=False)
Get the service class.

source code

str

strify_message(val, indent='', time_offset=None, current_time=None, field_filter=None)
Convert value to string representation source code

check_type(field_name, field_type, field_val)
Dynamic type checker that maps ROS .msg types to python types and verifies the python value.

source code

str

get_printable_message_args(msg, buff=None, prefix='')
Get string representation of msg arguments source code

fill_message_args(msg, msg_args, keys={})
Populate message with specified args. source code

Variables
	struct_I = `struct.Struct('<I')`
	__package__ = `'roslib'`

Function Details

get_message_class(message_type, reload_on_error=False)

source code

Get the message class. NOTE: this function maintains a local cache of results to improve performance.

Parameters:

message_type (str) - type name of message
reload_on_error - (optional). Attempt to reload the Python module if unable to load message the first time. Defaults to False. This is necessary if messages are built after the first load.

Returns: Message class

Message class for message/service type

Raises:

ValueError - if message_type is invalidly specified

get_service_class(service_type, reload_on_error=False)

source code

Get the service class. NOTE: this function maintains a local cache of results to improve performance.

Parameters:

service_type (str) - type name of service
reload_on_error - (optional). Attempt to reload the Python module if unable to load message the first time. Defaults to False. This is necessary if messages are built after the first load.

Returns: Service class

Service class for service type

Raises:

Exception - if service_type is invalidly specified

strify_message(val, indent=`''`, time_offset=None, current_time=None, field_filter=None)

source code

Convert value to string representation

Parameters:

val (Value) - to convert to string representation. Most likely a Message.
indent (str) - indentation. If indent is set, then the return value will have a leading
time_offset (Time) - if not None, time fields will be displayed as deltas from time_offset
current_time (Time) - currently not used. Only provided for API compatibility. current_time passes in the current time with respect to the message.
field_filter (fn(Message)->iter(str)) - filter the fields that are strified for Messages.

Returns: str

string (YAML) representation of message

check_type(field_name, field_type, field_val)

source code

Dynamic type checker that maps ROS .msg types to python types and verifies the python value. check_type() is not designed to be fast and is targeted at error diagnosis. This type checker is not designed to run fast and is meant only for error diagnosis.

Parameters:

field_name (str) - ROS .msg field name
field_type (str) - ROS .msg field type
field_val (Any) - field value

Raises:

SerializationError - if typecheck fails

get_printable_message_args(msg, buff=None, prefix=`''`)

source code

Get string representation of msg arguments

Parameters:

msg (Message) - msg message to fill
prefix (str) - field name prefix (for verbose printing)

Returns: str

printable representation of msg args

fill_message_args(msg, msg_args, keys=`{}`)

source code

Populate message with specified args. Args are assumed to be a list of arguments from a command-line YAML parser. See http://www.ros.org/wiki/ROS/YAMLCommandLine for specification on how messages are filled.

fill_message_args also takes in an optional 'keys' dictionary which contain substitute values for message and time types. These values must be of the correct instance type, i.e. a Message, Time, or Duration. In a string key is encountered with these types, the value from the keys dictionary will be used instead. This is mainly used to provide values for the 'now' timestamp.

Parameters:

msg (Message) - message to fill
msg_args ([args]) - list of arguments to set fields to, or If None, msg_args will be made an empty list.
keys (dict) - keys to use as substitute values for messages and timestamps.

Raises:

ROSMessageException - if not enough/too many message arguments to fill message

Module message

get_message_class(message_type, reload_on_error=False)

get_service_class(service_type, reload_on_error=False)

strify_message(val, indent='', time_offset=None, current_time=None, field_filter=None)

check_type(field_name, field_type, field_val)

get_printable_message_args(msg, buff=None, prefix='')

fill_message_args(msg, msg_args, keys={})

strify_message(val, indent=`''`, time_offset=None, current_time=None, field_filter=None)

get_printable_message_args(msg, buff=None, prefix=`''`)

fill_message_args(msg, msg_args, keys=`{}`)