CuData for Tango attribute configuration and command info

The CuData received upon attribute configuration will contain the following keys:

Key	Type	Value	Description	Notes
type	string	"property"	Identifies a configuration content within CuData	Fixed value to identify the type of CuData
src	string	-	The source name as configured with setSource. Tango device / attribute	src key always present in CuData
value	CuVariant	-	The attribute value that is normally fetched during the configuration.	-
data	bool	true	A CuData with configuration data will have the "data" key always set to true	-
msg	string	-	A message bearing information about the success of the operation.	See the err key below
err	bool	-	true if an error occurred, false otherwise	See the msg key above
df	Tango::AttrDataFormat (enum)	-	Tango attribute format, Scalar,Spectrum,...	convert with toInt()
dfs	string	-	string representation of data_format	-
data_type	int	-	Tango data type	-
description	string	-	Tango attribute description from AttributeInfo	-
display_unit	string	-	Tango display unit from AttributeInfo	-
standard_unit	string	-	Tango standard unit from AttributeInfo	-
unit	string	-	Tango "unit" from AttributeInfo	-
label	string	-	Tango "label" from AttributeInfo	-
writable	Tango::AttrWriteType	-	Tango write type (enum) { READ, READ_WITH_WRITE, WRITE, READ_WRITE, WT_UNKNOWN }	convert with toInt()
writable_attr_name	string	-	writable_attr_name from AttributeInfo	-
max_alarm	string	-	Tango::AttributeAlarmInfo max_alarm	devapi.h
min_alarm	string	-	Tango::AttributeAlarmInfo min_alarm	devapi.h
max_warning	string	-	Tango::AttributeAlarmInfo max_warning	devapi.h
min_warning	string	-	Tango::AttributeAlarmInfo min_warning	devapi.h
delta_t	string	-	Tango::AttributeAlarmInfo delta_t	devapi.h
delta_val	string	-	Tango::AttributeAlarmInfo delta_val	devapi.h
archive_abs_change	string	-	Tango::AttributeEventInfo.arch_event.archive_abs_change	devapi.h
archive_rel_change	string	-	Tango::AttributeEventInfo.arch_event.archive_rel_change	devapi.h
archive_period	string	-	Tango::AttributeEventInfo.arch_event.archive_period	devapi.h
abs_change	string	-	Tango::AttributeEventInfo.ch_event.abs_change	devapi.h
rel_change	string	-	Tango::AttributeEventInfo.ch_event.rel_change	devapi.h
periodic_period	string	-	Tango::AttributeEventInfo.per_event.period	devapi.h
max	string	-	Tango AttributeConfig max_value	Named "max" for consistency with Epics
min	string	-	Tango AttributeConfig min_value	Named "min" for consistency with Epics
name	string	-	Tango name string from AttributeInfo	-
max_dim_x	int	-	Tango attribute max x dimension	-
max_dim_y	int	-	Tango attribute max y dimension	-
disp_level	Tango::DispLevel	-	Tango::DispLevel from AttributeInfoEx (lib/cpp/server/idl/tango.h: { OPERATOR, EXPERT, DL_UNKNOWN) }	convert with toInt()
root_attr_name	string	-	from AttributeInfoEx: Root attribute name (in case of forwarded attribute)	-
description	string	-	Tango attribute description from AttributeInfo	-
display_unit	string	-	Tango display unit from AttributeInfo	-
standard_unit	string	-	Tango standard unit from AttributeInfo	-
unit	string	-	Tango "unit" from AttributeInfo	-
success	string	-	A string with the name of the color provided the class CuTangoWorldConfig associated to an error/success	Can be used to decorate widgets

The CuData received upon command info configuration type will contain the following keys:

Key	Type	Value	Description	Notes
type	string	"property"	Identifies a configuration content within CuData	Fixed value to identify the type of CuData
src	string	-	The source name as configured with setSource. Tango device / attribute	src
data	bool	true	A CuData with configuration data will have the "data" key always set to true	-
msg	string	-	A message bearing information about the success of the operation.	See the err key below
err	bool	-	true if an error occurred, false otherwise	See the msg key abovekey always present in CuData
value	CuVariant	-	The attribute value that is normally fetched during the configuration.	-
cmd_name	string	-	The command name, from Tango::CommandInfo	from Tango::CommandInfo, devapi.h
in_type	long	-	Input parameter data type	from Tango::CommandInfo, devapi.h
out_type	long	-	Output parameter data type	from Tango::CommandInfo, devapi.h
dt	long	-	Output parameter type, same as "out_type", in order to be consistent with attribute configuration CuData	see CuData "data_type" from attribute configuration above
in_type_desc	string	-	Input parameter description	from Tango::CommandInfo, devapi.h
out_type_desc	string	-	Output parameter description	from Tango::CommandInfo, devapi.h
df	Tango::AttrDataFormat (enum)	-	Provided for consistency with attribute configuration CuData, determined from CommandInfo out_type	see CuData "df" from attribute configuration above
color	string	-	A string with the name of the color provided the class CuTangoWorldConfig associated to an error/success	Can be used to decorate widgets

Example

In this example, we discuss how a plot is configured using the CuData with "type" set to "property".

void QuSpectrumPlot::update(const CuData &da)
{
    if(!da["err"].toBool() && da["type"].toString() == "property")
    {
        CuVariant m, M;
        m = da["min"];  // min value
        M = da["max"];  // max value
        bool okl, oku;  // toDouble ok for lower and upper bound
        double lb, ub;  // double for lower and upper bound
        QString min = QString::fromStdString(m.toString()); // min is of type string
        QString max = QString::fromStdString(M.toString()); // max is of type string
        QString plotTitle = QString::fromStdString(da["label"].toString());
        lb = min.toDouble(&okl);  // string to double, see if ok
        ub = max.toDouble(&oku);  // string to double, see if ok
 
        if(okl && oku)
        {
            // get current default lower and upper bounds
            double current_def_lb = defaultLowerBound(QwtPlot::yLeft);
            double current_def_ub = defaultUpperBound(QwtPlot::yLeft);
            // if the minimum saved into lb is smaller than the current lower bound
            if(current_def_lb > lb)
                current_def_lb = lb;
            if(current_def_ub < ub)
                current_def_ub = ub;
            setDefaultBounds(current_def_lb, current_def_ub, QwtPlot::yLeft);
        }
    }
}

CuData contents from Tango Device attributes

When reading attributes, the key/values you should expect to find within the CuData are shown in the following table:

Key	Type	Value	Description	Notes
data	bool	true	A CuData with configuration data will have the "data" key always set to true	-
src	string	-	The source name as configured with setSource. Tango device / attribute	src
msg	string	-	A message bearing information about the success of the operation.	See the err key below
err	bool	-	true if an error occurred, false otherwise	See the msg key abovekey always present in CuData
color	string	-	A string with the name of the color provided the class CuTangoWorldConfig associated to an error/success	Can be used to decorate widgets
timestamp_ms	time_t + suseconds_t	-	Timestamp as integer: a struct timeval is used to store the timestamp. Formula: tiv.tv_sec * 1000 + tiv.tv_usec / 1000;	can convert with toLongInt()
timestamp_us	double	-	timestamp in a double: seconds.microseconds: static_cast<double>(tiv.tv_sec) + static_cast<double>(tiv.tv_usec) * 1e-6	convert with toDouble
q	const Tango::AttrQuality	-	Tango attribute quality { ATTR_VALID, ATTR_INVALID, ATTR_ALARM, ATTR_CHANGING, ATTR_WARNING }	from server/idl/tango.h. Convert with toInt
qc	string	-	A string with the name of the color provided the class CuTangoWorldConfig	can be used to decorate widgets. Use in combination with QuPalette. Convert with toString
dfs	string	-	Data format as string ("scalar", "vector", matrix", "data format unknown")	consistent naming across tango and epics
value	CuVariant	-	The attribute value. (read)	The tango read value
value	string	-	For Tango::DEV_STATE attribute types, the state is mapped into its string representation.	Convenience conversion applied only for DEV_STATE attribute data type.
w_value	CuVariant	-	The attribute write value. Available if the attribute is read/write, key missing otherwise.	Tango write value in read/write attributes
sc	string	-	state color: a string describing a color for a Tango::DEV_STATE, configuration possible through CuTangoWorldConfig.	Can be used to decorate a widget. Available only if attribute.get_type() == Tango::DEV_STATE
s	long int	-	A Tango::DEV_STATE casted to long int. Available for Tango::DEV_STATE attributes	Available only if attribute.get_type() == Tango::DEV_STATE

CuData contents from Tango commands

When getting output arguments from commands, the key/values you should expect to find within the CuData are shown in the following table:

Key	Type	Value	Description	Notes
data	bool	true	A CuData with configuration data will have the "data" key always set to true	-
src	string	-	The source name as configured with setSource. Tango device / attribute	src
msg	string	-	A message bearing information about the success of the operation.	See the err key below
err	bool	-	true if an error occurred, false otherwise	See the msg key abovekey always present in CuData
color	string	-	A string with the name of the color provided the class CuTangoWorldConfig associated to an error/success	Can be used to decorate widgets
timestamp_ms	time_t + suseconds_t	-	Timestamp as integer: a struct timeval is used to store the timestamp. Formula: tiv.tv_sec * 1000 + tiv.tv_usec / 1000;	can convert with toLongInt()
timestamp_us	double	-	timestamp in a double: seconds.microseconds: static_cast<double>(tiv.tv_sec) + static_cast<double>(tiv.tv_usec) * 1e-6	convert with toDouble
dfs	string	-	Data format as string ("scalar", "vector", matrix", "data format unknown")	consistent naming across tango and epics
dt	int	-	Tango::CmdArgType casted to an int: enum CmdArgType {DEV_VOID = 0,DEV_BOOLEAN,DEV_SHORT,DEV_LONG,... }	From /lib/cpp/server/tango_const.h
value	CuVariant	-	The attribute value. (read)	The tango read value
value	string	-	For Tango::DEV_STATE attribute types, the state is mapped into its string representation.	Convenience conversion applied only for DEV_STATE attribute data type.
sc	string	-	A string describing a color for a Tango::DEV_STATE, configuration possible through CuTangoWorldConfig.	Can be used to decorate a widget. Available only if attribute.get_type() == Tango::DEV_STATE
s	long int	-	A Tango::DEV_STATE casted to long int. Available for Tango::DEV_STATE attributes	Available only if attribute.get_type() == Tango::DEV_STATE

CuData contents for attribute properties.

The contents of CuData when used to fetch properties from the database are more dynamic and depend on the type of property fetched: attribute, class or device. Please refer to the Writing an activity to read Tango device, attribute and class properties for more information and for an example of application reading from the tango database.

To fetch properties from the Tango database, a list of input CuData must be provided.

To get attribute properties, each CuData element must be compiled as follows:

Key	Type	Description	Example
device	string	The tango device name	"test/device/1"
name	string	The attribute property name	"description"

To get device properties, each CuData element must be compiled as follows:

Key	Type	Description	Example
device	string	The tango device name	"test/device/1"
name	string	The device property name	"description"

To get class properties, each CuData bundle must be compiled as follows:

Key	Type	Description	Example
class	string	The class name of the device	"TangoTest"
name	string	The property name	"description"

Example of code to get properties from the Tango database

The following code shows how to set up a list of CuData where every element describes the type and name of the property to be fetched. The PropertyReader class implements CuDataListener, so that when properties are available, the onUpdate method is invoked.

// Suppose each element of "props" is a std::string formed as follows:
// - test/device/1:description device property: two '/' and ':'
// - test/device/1/double_scalar:values attribute properties: three '/' and one ':'
// - TangoTest:Description class property: one '/'
void PropertyReader::get(const char *id, const std::vector<std::string> &props)
{
    /* start the event loop in a separate thread, where data from activities will be posted */
    std::list<CuData> in_data;
    for(size_t i = 0; i < props.size(); i++) {
        size_t cnt = count(props[i].begin(), props[i].end(), '/');
        size_t cpos = props[i].find(':');
        if(cnt == 2 && cpos < std::string::npos)
        {
            CuData devpd("device", props[i].substr(0, cpos));
            devpd["name"] = props[i].substr(cpos + 1, std::string::npos);
            in_data.push_back(devpd);
        }
        else if(cnt == 3) {
            CuData devpd("device", props[i].substr(0, props[i].rfind('/')));
            if(cpos < std::string::npos) {
                devpd["attribute"] = props[i].substr(props[i].rfind('/') + 1, cpos - props[i].rfind('/') -1);
                devpd["name"] = props[i].substr(cpos + 1, std::string::npos);
            }
            else
                devpd["attribute"] = props[i].substr(props[i].rfind('/') + 1, cpos); // cpos == npos
 
            in_data.push_back(devpd);
        }
        else if(cnt == 0 && cpos < std::string::npos) { // class
            CuData cld("class", props[i].substr(0, cpos));
            cld["name"] = props[i].substr(cpos + 1);
            in_data.push_back(cld);
        }
    }
    
    // now fetch the properties
    CuTDbPropertyReader *pr = new CuTDbPropertyReader(id, m_ct);
    // PropertyReader in this example implements the CuDataListener interface
    pr->addListener(this);
    // get the properties listed within in_data
    pr->get(in_data);

The result is again a CuData compiled as follows:

Key	Type	Description	Example	Notes
err	bool	true if an error occurred, false otherwise	if(data["err"].toBool() { ... error ... }	See the msg key below
msg	string	A message bearing information about the success of the operation.	-	See the err key above
list	vector of strings	The list of the properties contained in the result	"test/device/1/long_scalar:abs_change", "TangoTest:Description", "test/device/1:helperApplication"	use this to get the list of fetched properties
property1	CuVariant	The property value corresponding to the "property1" property	double abs_ch = std::stod(data["test/device/1/long_scalar:abs_change"].toString());	always use toString, properties are fetched as strings
property2	CuVariant	The property value corresponding to the "property2" property	std::string helperApp = data["test/device/1:helperApplication"].toString();	always use toString, properties are fetched as strings
...	CuVariant	The i-th property value...	-	always use toString, properties are fetched as strings
propertyN	CuVariant	The N-th property value corresponding to the "propertyN" property	std::string nthpropval = data["propertyN"].toString();	always use toString, properties are fetched as strings

and is delivered as argument of the onUpdate method.