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