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					320 lines
				
				9.0 KiB
			| 
											2 years ago
										 | /** | ||
|  |  * Cross-browser support for logging in a web application. | ||
|  |  * | ||
|  |  * @author David I. Lehn <dlehn@digitalbazaar.com> | ||
|  |  * | ||
|  |  * Copyright (c) 2008-2013 Digital Bazaar, Inc. | ||
|  |  */ | ||
|  | var forge = require('./forge'); | ||
|  | require('./util'); | ||
|  | 
 | ||
|  | /* LOG API */ | ||
|  | module.exports = forge.log = forge.log || {}; | ||
|  | 
 | ||
|  | /** | ||
|  |  * Application logging system. | ||
|  |  * | ||
|  |  * Each logger level available as it's own function of the form: | ||
|  |  *   forge.log.level(category, args...) | ||
|  |  * The category is an arbitrary string, and the args are the same as | ||
|  |  * Firebug's console.log API. By default the call will be output as: | ||
|  |  *   'LEVEL [category] <args[0]>, args[1], ...' | ||
|  |  * This enables proper % formatting via the first argument. | ||
|  |  * Each category is enabled by default but can be enabled or disabled with | ||
|  |  * the setCategoryEnabled() function. | ||
|  |  */ | ||
|  | // list of known levels
 | ||
|  | forge.log.levels = [ | ||
|  |   'none', 'error', 'warning', 'info', 'debug', 'verbose', 'max']; | ||
|  | // info on the levels indexed by name:
 | ||
|  | //   index: level index
 | ||
|  | //   name: uppercased display name
 | ||
|  | var sLevelInfo = {}; | ||
|  | // list of loggers
 | ||
|  | var sLoggers = []; | ||
|  | /** | ||
|  |  * Standard console logger. If no console support is enabled this will | ||
|  |  * remain null. Check before using. | ||
|  |  */ | ||
|  | var sConsoleLogger = null; | ||
|  | 
 | ||
|  | // logger flags
 | ||
|  | /** | ||
|  |  * Lock the level at the current value. Used in cases where user config may | ||
|  |  * set the level such that only critical messages are seen but more verbose | ||
|  |  * messages are needed for debugging or other purposes. | ||
|  |  */ | ||
|  | forge.log.LEVEL_LOCKED = (1 << 1); | ||
|  | /** | ||
|  |  * Always call log function. By default, the logging system will check the | ||
|  |  * message level against logger.level before calling the log function. This | ||
|  |  * flag allows the function to do its own check. | ||
|  |  */ | ||
|  | forge.log.NO_LEVEL_CHECK = (1 << 2); | ||
|  | /** | ||
|  |  * Perform message interpolation with the passed arguments. "%" style | ||
|  |  * fields in log messages will be replaced by arguments as needed. Some | ||
|  |  * loggers, such as Firebug, may do this automatically. The original log | ||
|  |  * message will be available as 'message' and the interpolated version will | ||
|  |  * be available as 'fullMessage'. | ||
|  |  */ | ||
|  | forge.log.INTERPOLATE = (1 << 3); | ||
|  | 
 | ||
|  | // setup each log level
 | ||
|  | for(var i = 0; i < forge.log.levels.length; ++i) { | ||
|  |   var level = forge.log.levels[i]; | ||
|  |   sLevelInfo[level] = { | ||
|  |     index: i, | ||
|  |     name: level.toUpperCase() | ||
|  |   }; | ||
|  | } | ||
|  | 
 | ||
|  | /** | ||
|  |  * Message logger. Will dispatch a message to registered loggers as needed. | ||
|  |  * | ||
|  |  * @param message message object | ||
|  |  */ | ||
|  | forge.log.logMessage = function(message) { | ||
|  |   var messageLevelIndex = sLevelInfo[message.level].index; | ||
|  |   for(var i = 0; i < sLoggers.length; ++i) { | ||
|  |     var logger = sLoggers[i]; | ||
|  |     if(logger.flags & forge.log.NO_LEVEL_CHECK) { | ||
|  |       logger.f(message); | ||
|  |     } else { | ||
|  |       // get logger level
 | ||
|  |       var loggerLevelIndex = sLevelInfo[logger.level].index; | ||
|  |       // check level
 | ||
|  |       if(messageLevelIndex <= loggerLevelIndex) { | ||
|  |         // message critical enough, call logger
 | ||
|  |         logger.f(logger, message); | ||
|  |       } | ||
|  |     } | ||
|  |   } | ||
|  | }; | ||
|  | 
 | ||
|  | /** | ||
|  |  * Sets the 'standard' key on a message object to: | ||
|  |  * "LEVEL [category] " + message | ||
|  |  * | ||
|  |  * @param message a message log object | ||
|  |  */ | ||
|  | forge.log.prepareStandard = function(message) { | ||
|  |   if(!('standard' in message)) { | ||
|  |     message.standard = | ||
|  |       sLevelInfo[message.level].name + | ||
|  |       //' ' + +message.timestamp +
 | ||
|  |       ' [' + message.category + '] ' + | ||
|  |       message.message; | ||
|  |   } | ||
|  | }; | ||
|  | 
 | ||
|  | /** | ||
|  |  * Sets the 'full' key on a message object to the original message | ||
|  |  * interpolated via % formatting with the message arguments. | ||
|  |  * | ||
|  |  * @param message a message log object. | ||
|  |  */ | ||
|  | forge.log.prepareFull = function(message) { | ||
|  |   if(!('full' in message)) { | ||
|  |     // copy args and insert message at the front
 | ||
|  |     var args = [message.message]; | ||
|  |     args = args.concat([] || message['arguments']); | ||
|  |     // format the message
 | ||
|  |     message.full = forge.util.format.apply(this, args); | ||
|  |   } | ||
|  | }; | ||
|  | 
 | ||
|  | /** | ||
|  |  * Applies both preparseStandard() and prepareFull() to a message object and | ||
|  |  * store result in 'standardFull'. | ||
|  |  * | ||
|  |  * @param message a message log object. | ||
|  |  */ | ||
|  | forge.log.prepareStandardFull = function(message) { | ||
|  |   if(!('standardFull' in message)) { | ||
|  |     // FIXME implement 'standardFull' logging
 | ||
|  |     forge.log.prepareStandard(message); | ||
|  |     message.standardFull = message.standard; | ||
|  |   } | ||
|  | }; | ||
|  | 
 | ||
|  | // create log level functions
 | ||
|  | if(true) { | ||
|  |   // levels for which we want functions
 | ||
|  |   var levels = ['error', 'warning', 'info', 'debug', 'verbose']; | ||
|  |   for(var i = 0; i < levels.length; ++i) { | ||
|  |     // wrap in a function to ensure proper level var is passed
 | ||
|  |     (function(level) { | ||
|  |       // create function for this level
 | ||
|  |       forge.log[level] = function(category, message/*, args...*/) { | ||
|  |         // convert arguments to real array, remove category and message
 | ||
|  |         var args = Array.prototype.slice.call(arguments).slice(2); | ||
|  |         // create message object
 | ||
|  |         // Note: interpolation and standard formatting is done lazily
 | ||
|  |         var msg = { | ||
|  |           timestamp: new Date(), | ||
|  |           level: level, | ||
|  |           category: category, | ||
|  |           message: message, | ||
|  |           'arguments': args | ||
|  |           /*standard*/ | ||
|  |           /*full*/ | ||
|  |           /*fullMessage*/ | ||
|  |         }; | ||
|  |         // process this message
 | ||
|  |         forge.log.logMessage(msg); | ||
|  |       }; | ||
|  |     })(levels[i]); | ||
|  |   } | ||
|  | } | ||
|  | 
 | ||
|  | /** | ||
|  |  * Creates a new logger with specified custom logging function. | ||
|  |  * | ||
|  |  * The logging function has a signature of: | ||
|  |  *   function(logger, message) | ||
|  |  * logger: current logger | ||
|  |  * message: object: | ||
|  |  *   level: level id | ||
|  |  *   category: category | ||
|  |  *   message: string message | ||
|  |  *   arguments: Array of extra arguments | ||
|  |  *   fullMessage: interpolated message and arguments if INTERPOLATE flag set | ||
|  |  * | ||
|  |  * @param logFunction a logging function which takes a log message object | ||
|  |  *          as a parameter. | ||
|  |  * | ||
|  |  * @return a logger object. | ||
|  |  */ | ||
|  | forge.log.makeLogger = function(logFunction) { | ||
|  |   var logger = { | ||
|  |     flags: 0, | ||
|  |     f: logFunction | ||
|  |   }; | ||
|  |   forge.log.setLevel(logger, 'none'); | ||
|  |   return logger; | ||
|  | }; | ||
|  | 
 | ||
|  | /** | ||
|  |  * Sets the current log level on a logger. | ||
|  |  * | ||
|  |  * @param logger the target logger. | ||
|  |  * @param level the new maximum log level as a string. | ||
|  |  * | ||
|  |  * @return true if set, false if not. | ||
|  |  */ | ||
|  | forge.log.setLevel = function(logger, level) { | ||
|  |   var rval = false; | ||
|  |   if(logger && !(logger.flags & forge.log.LEVEL_LOCKED)) { | ||
|  |     for(var i = 0; i < forge.log.levels.length; ++i) { | ||
|  |       var aValidLevel = forge.log.levels[i]; | ||
|  |       if(level == aValidLevel) { | ||
|  |         // set level
 | ||
|  |         logger.level = level; | ||
|  |         rval = true; | ||
|  |         break; | ||
|  |       } | ||
|  |     } | ||
|  |   } | ||
|  | 
 | ||
|  |   return rval; | ||
|  | }; | ||
|  | 
 | ||
|  | /** | ||
|  |  * Locks the log level at its current value. | ||
|  |  * | ||
|  |  * @param logger the target logger. | ||
|  |  * @param lock boolean lock value, default to true. | ||
|  |  */ | ||
|  | forge.log.lock = function(logger, lock) { | ||
|  |   if(typeof lock === 'undefined' || lock) { | ||
|  |     logger.flags |= forge.log.LEVEL_LOCKED; | ||
|  |   } else { | ||
|  |     logger.flags &= ~forge.log.LEVEL_LOCKED; | ||
|  |   } | ||
|  | }; | ||
|  | 
 | ||
|  | /** | ||
|  |  * Adds a logger. | ||
|  |  * | ||
|  |  * @param logger the logger object. | ||
|  |  */ | ||
|  | forge.log.addLogger = function(logger) { | ||
|  |   sLoggers.push(logger); | ||
|  | }; | ||
|  | 
 | ||
|  | // setup the console logger if possible, else create fake console.log
 | ||
|  | if(typeof(console) !== 'undefined' && 'log' in console) { | ||
|  |   var logger; | ||
|  |   if(console.error && console.warn && console.info && console.debug) { | ||
|  |     // looks like Firebug-style logging is available
 | ||
|  |     // level handlers map
 | ||
|  |     var levelHandlers = { | ||
|  |       error: console.error, | ||
|  |       warning: console.warn, | ||
|  |       info: console.info, | ||
|  |       debug: console.debug, | ||
|  |       verbose: console.debug | ||
|  |     }; | ||
|  |     var f = function(logger, message) { | ||
|  |       forge.log.prepareStandard(message); | ||
|  |       var handler = levelHandlers[message.level]; | ||
|  |       // prepend standard message and concat args
 | ||
|  |       var args = [message.standard]; | ||
|  |       args = args.concat(message['arguments'].slice()); | ||
|  |       // apply to low-level console function
 | ||
|  |       handler.apply(console, args); | ||
|  |     }; | ||
|  |     logger = forge.log.makeLogger(f); | ||
|  |   } else { | ||
|  |     // only appear to have basic console.log
 | ||
|  |     var f = function(logger, message) { | ||
|  |       forge.log.prepareStandardFull(message); | ||
|  |       console.log(message.standardFull); | ||
|  |     }; | ||
|  |     logger = forge.log.makeLogger(f); | ||
|  |   } | ||
|  |   forge.log.setLevel(logger, 'debug'); | ||
|  |   forge.log.addLogger(logger); | ||
|  |   sConsoleLogger = logger; | ||
|  | } else { | ||
|  |   // define fake console.log to avoid potential script errors on
 | ||
|  |   // browsers that do not have console logging
 | ||
|  |   console = { | ||
|  |     log: function() {} | ||
|  |   }; | ||
|  | } | ||
|  | 
 | ||
|  | /* | ||
|  |  * Check for logging control query vars in current URL. | ||
|  |  * | ||
|  |  * console.level=<level-name> | ||
|  |  * Set's the console log level by name.  Useful to override defaults and | ||
|  |  * allow more verbose logging before a user config is loaded. | ||
|  |  * | ||
|  |  * console.lock=<true|false> | ||
|  |  * Lock the console log level at whatever level it is set at.  This is run | ||
|  |  * after console.level is processed.  Useful to force a level of verbosity | ||
|  |  * that could otherwise be limited by a user config. | ||
|  |  */ | ||
|  | if(sConsoleLogger !== null && | ||
|  |   typeof window !== 'undefined' && window.location | ||
|  | ) { | ||
|  |   var query = new URL(window.location.href).searchParams; | ||
|  |   if(query.has('console.level')) { | ||
|  |     // set with last value
 | ||
|  |     forge.log.setLevel( | ||
|  |       sConsoleLogger, query.get('console.level').slice(-1)[0]); | ||
|  |   } | ||
|  |   if(query.has('console.lock')) { | ||
|  |     // set with last value
 | ||
|  |     var lock = query.get('console.lock').slice(-1)[0]; | ||
|  |     if(lock == 'true') { | ||
|  |       forge.log.lock(sConsoleLogger); | ||
|  |     } | ||
|  |   } | ||
|  | } | ||
|  | 
 | ||
|  | // provide public access to console logger
 | ||
|  | forge.log.consoleLogger = sConsoleLogger; |