/* eslint no-underscore-dangle: ["error", { "allow": ["__statusCode", "_remoteAddress", "__headers", "_logging"] }] */
const levels = require('./levels');
const DEFAULT_FORMAT =
':remote-addr - -' +
' ":method :url HTTP/:http-version"' +
' :status :content-length ":referrer"' +
' ":user-agent"';
/**
* Return request url path,
* adding this function prevents the Cyclomatic Complexity,
* for the assemble_tokens function at low, to pass the tests.
*
* @param {IncomingMessage} req
* @return {string}
* @api private
*/
function getUrl(req) {
return req.originalUrl || req.url;
}
/**
* Adds custom {token, replacement} objects to defaults,
* overwriting the defaults if any tokens clash
*
* @param {IncomingMessage} req
* @param {ServerResponse} res
* @param {Array} customTokens
* [{ token: string-or-regexp, replacement: string-or-replace-function }]
* @return {Array}
*/
function assembleTokens(req, res, customTokens) {
const arrayUniqueTokens = (array) => {
const a = array.concat();
for (let i = 0; i < a.length; ++i) {
for (let j = i + 1; j < a.length; ++j) {
// not === because token can be regexp object
// eslint-disable-next-line eqeqeq
if (a[i].token == a[j].token) {
a.splice(j--, 1); // eslint-disable-line no-plusplus
}
}
}
return a;
};
const defaultTokens = [];
defaultTokens.push({ token: ':url', replacement: getUrl(req) });
defaultTokens.push({ token: ':protocol', replacement: req.protocol });
defaultTokens.push({ token: ':hostname', replacement: req.hostname });
defaultTokens.push({ token: ':method', replacement: req.method });
defaultTokens.push({
token: ':status',
replacement: res.__statusCode || res.statusCode,
});
defaultTokens.push({
token: ':response-time',
replacement: res.responseTime,
});
defaultTokens.push({ token: ':date', replacement: new Date().toUTCString() });
defaultTokens.push({
token: ':referrer',
replacement: req.headers.referer || req.headers.referrer || '',
});
defaultTokens.push({
token: ':http-version',
replacement: `${req.httpVersionMajor}.${req.httpVersionMinor}`,
});
defaultTokens.push({
token: ':remote-addr',
replacement:
req.headers['x-forwarded-for'] ||
req.ip ||
req._remoteAddress ||
(req.socket &&
(req.socket.remoteAddress ||
(req.socket.socket && req.socket.socket.remoteAddress))),
});
defaultTokens.push({
token: ':user-agent',
replacement: req.headers['user-agent'],
});
defaultTokens.push({
token: ':content-length',
replacement:
res.getHeader('content-length') ||
(res.__headers && res.__headers['Content-Length']) ||
'-',
});
defaultTokens.push({
token: /:req\[([^\]]+)]/g,
replacement(_, field) {
return req.headers[field.toLowerCase()];
},
});
defaultTokens.push({
token: /:res\[([^\]]+)]/g,
replacement(_, field) {
return (
res.getHeader(field.toLowerCase()) ||
(res.__headers && res.__headers[field])
);
},
});
return arrayUniqueTokens(customTokens.concat(defaultTokens));
}
/**
* Return formatted log line.
*
* @param {string} str
* @param {Array} tokens
* @return {string}
* @api private
*/
function format(str, tokens) {
for (let i = 0; i < tokens.length; i++) {
str = str.replace(tokens[i].token, tokens[i].replacement);
}
return str;
}
/**
* Return RegExp Object about nolog
*
* @param {(string|Array)} nolog
* @return {RegExp}
* @api private
*
* syntax
* 1. String
* 1.1 "\\.gif"
* NOT LOGGING http://example.com/hoge.gif and http://example.com/hoge.gif?fuga
* LOGGING http://example.com/hoge.agif
* 1.2 in "\\.gif|\\.jpg$"
* NOT LOGGING http://example.com/hoge.gif and
* http://example.com/hoge.gif?fuga and http://example.com/hoge.jpg?fuga
* LOGGING http://example.com/hoge.agif,
* http://example.com/hoge.ajpg and http://example.com/hoge.jpg?hoge
* 1.3 in "\\.(gif|jpe?g|png)$"
* NOT LOGGING http://example.com/hoge.gif and http://example.com/hoge.jpeg
* LOGGING http://example.com/hoge.gif?uid=2 and http://example.com/hoge.jpg?pid=3
* 2. RegExp
* 2.1 in /\.(gif|jpe?g|png)$/
* SAME AS 1.3
* 3. Array
* 3.1 ["\\.jpg$", "\\.png", "\\.gif"]
* SAME AS "\\.jpg|\\.png|\\.gif"
*/
function createNoLogCondition(nolog) {
let regexp = null;
if (nolog instanceof RegExp) {
regexp = nolog;
}
if (typeof nolog === 'string') {
regexp = new RegExp(nolog);
}
if (Array.isArray(nolog)) {
// convert to strings
const regexpsAsStrings = nolog.map((reg) =>
reg.source ? reg.source : reg
);
regexp = new RegExp(regexpsAsStrings.join('|'));
}
return regexp;
}
/**
* Allows users to define rules around status codes to assign them to a specific
* logging level.
* There are two types of rules:
* - RANGE: matches a code within a certain range
* E.g. { 'from': 200, 'to': 299, 'level': 'info' }
* - CONTAINS: matches a code to a set of expected codes
* E.g. { 'codes': [200, 203], 'level': 'debug' }
* Note*: Rules are respected only in order of prescendence.
*
* @param {Number} statusCode
* @param {Level} currentLevel
* @param {Object} ruleSet
* @return {Level}
* @api private
*/
function matchRules(statusCode, currentLevel, ruleSet) {
let level = currentLevel;
if (ruleSet) {
const matchedRule = ruleSet.find((rule) => {
let ruleMatched = false;
if (rule.from && rule.to) {
ruleMatched = statusCode >= rule.from && statusCode <= rule.to;
} else {
ruleMatched = rule.codes.indexOf(statusCode) !== -1;
}
return ruleMatched;
});
if (matchedRule) {
level = levels.getLevel(matchedRule.level, level);
}
}
return level;
}
/**
* Log requests with the given `options` or a `format` string.
*
* Options:
*
* - `format` Format string, see below for tokens
* - `level` A log4js levels instance. Supports also 'auto'
* - `nolog` A string or RegExp to exclude target logs or function(req, res): boolean
* - `statusRules` A array of rules for setting specific logging levels base on status codes
* - `context` Whether to add a response of express to the context
*
* Tokens:
*
* - `:req[header]` ex: `:req[Accept]`
* - `:res[header]` ex: `:res[Content-Length]`
* - `:http-version`
* - `:response-time`
* - `:remote-addr`
* - `:date`
* - `:method`
* - `:url`
* - `:referrer`
* - `:user-agent`
* - `:status`
*
* @return {Function}
* @param logger4js
* @param options
* @api public
*/
module.exports = function getLogger(logger4js, options) {
if (typeof options === 'string' || typeof options === 'function') {
options = { format: options };
} else {
options = options || {};
}
const thisLogger = logger4js;
let level = levels.getLevel(options.level, levels.INFO);
const fmt = options.format || DEFAULT_FORMAT;
return (req, res, next) => {
// mount safety
if (typeof req._logging !== 'undefined') return next();
// nologs
if (typeof options.nolog !== 'function') {
const nolog = createNoLogCondition(options.nolog);
if (nolog && nolog.test(req.originalUrl)) return next();
}
if (thisLogger.isLevelEnabled(level) || options.level === 'auto') {
const start = new Date();
const { writeHead } = res;
// flag as logging
req._logging = true;
// proxy for statusCode.
res.writeHead = (code, headers) => {
res.writeHead = writeHead;
res.writeHead(code, headers);
res.__statusCode = code;
res.__headers = headers || {};
};
// hook on end request to emit the log entry of the HTTP request.
let finished = false;
const handler = () => {
if (finished) {
return;
}
finished = true;
// nologs
if (typeof options.nolog === 'function') {
if (options.nolog(req, res) === true) {
req._logging = false;
return;
}
}
res.responseTime = new Date() - start;
// status code response level handling
if (res.statusCode && options.level === 'auto') {
level = levels.INFO;
if (res.statusCode >= 300) level = levels.WARN;
if (res.statusCode >= 400) level = levels.ERROR;
}
level = matchRules(res.statusCode, level, options.statusRules);
const combinedTokens = assembleTokens(req, res, options.tokens || []);
if (options.context) thisLogger.addContext('res', res);
if (typeof fmt === 'function') {
const line = fmt(req, res, (str) => format(str, combinedTokens));
if (line) thisLogger.log(level, line);
} else {
thisLogger.log(level, format(fmt, combinedTokens));
}
if (options.context) thisLogger.removeContext('res');
};
res.on('end', handler);
res.on('finish', handler);
res.on('error', handler);
res.on('close', handler);
}
// ensure next gets always called
return next();
};
};