A simple logging class. More...

#include <Wt/WLogger>

Classes
class	Field
	Class that holds the configuration for a single field. More...

struct	Sep
	Class that indicates a field separator. More...

struct	TimeStamp
	Class that indicates a time stamp. More...

Public Member Functions
	WLogger ()
	Creates a new logger. More...

	~WLogger ()
	Destructor.

void	setStream (std::ostream &o)
	Sets the output stream. More...

void	setFile (const std::string &path)
	Sets the output file. More...

void	configure (const std::string &config)
	Configures what things are logged. More...

void	addField (const std::string &name, bool isString)
	Adds a field. More...

const std::vector< Field > &	fields () const
	Returns the field list.

WLogEntry	entry (const std::string &type) const
	Starts a new log entry. More...

bool	logging (const std::string &type) const
	Returns whether messages of a given type are logged. More...

bool	logging (const char *type) const
	Returns whether messages of a given type are logged. More...

bool	logging (const std::string &type, const std::string &scope) const
	Returns whether messages of a given type and scope are logged. More...

Static Public Attributes
static const Sep	sep = WLogger::Sep()
	Field separator constant. More...

static const TimeStamp	timestamp = WLogger::TimeStamp()
	Timestamp field constant. More...

Related Functions
(Note that these are not member functions.)
WLogEntry	log (const std::string &type)
	Logging function. More...

Detailed Description

A simple logging class.

This class logs events to a stream in a flexible way. It allows to create log files using the commonly used Common Log Format or Combined Log Format, but provides a general way for logging entries that consists of a fixed number of fields.

It is used by Wt to create the application log (WApplication::log()), and built-in httpd access log.

To use this class for custom logging, you should instantiate a logger, add one or more field definitions using addField(), and set an output stream using setStream() or setFile(). To stream data to the logger, use entry() to start formatting a new entry.

Usage example:

// Setup the logger
Wt::WLogger logger;
logger.addField("datetime", false);
logger.addField("session", false);
logger.addField("type", false);
logger.addField("message", true);
logger.setFile("/tmp/mylog.txt");
// Add an entry
Wt::WLogEntry entry = logger.entry();
entry << Wt::WLogger::timestamp << Wt::WLogger::sep
      << '[' << wApp->sessionId() << ']' << Wt::WLogger::sep
      << '[' << "notice" << ']' << Wt::WLogger::sep
      << "Succesfully started.";

See also: WApplication::log()

Constructor & Destructor Documentation

Wt::WLogger::WLogger ( )

Creates a new logger.

This creates a new logger, which defaults to logging to stderr.

Member Function Documentation

void Wt::WLogger::addField	(	const std::string &	name,
		bool	isString
	)

Adds a field.

Add a field to the logger. When isString is true, values will be quoted.

void Wt::WLogger::configure ( const std::string & config )

Configures what things are logged.

The configuration is a string that defines rules for enabling or disabling certain logging. It is a white-space delimited list of rules, and each rule is of the form:

[-]level : enables (or disables) logging of messages of the given level; '*' is a wild-card that matches all levels
[-]level:scope : enables (or disables) logging of messages of the given level and scope; '*' is a wild-card that matches all levels or scopes.

The default configuration is "* -debug", i.e. by default everything is logged, except for "debug" messages.

Some other examples:

"* -debug debug:wthttp": logs everything, including debugging messages of scope "wthttp", but no other debugging messages.
"* -info -debug": disables logging of info messages in addition to debugging messages.