add a transporter to logger opts param (#65)

* add transporter

* add unit test suit

* add transporter readme file

* lint

* remove no used

Readme.md

@@ -40,6 +40,30 @@ app.use(logger())
   Recommended that you `.use()` this middleware near the top
   to "wrap" all subsequent middleware.
 
+## Use Custom Transporter
+
+```js
+const logger = require('koa-logger')
+const Koa = require('koa')
+
+const app = new Koa()
+app.use(logger((str, args) => {
+  // redirect koa logger to other output pipe
+  // default is process.stdout(by console.log function)
+}))
+```
+or
+```js
+app.use(logger({
+  transporter: (str, args) => {
+    // ...
+  }
+}))
+```
+
+  Param `str` is output string with ANSI Color, and you can get pure text with other modules like `strip-ansi`  
+  Param `args` is a array by `[format, method, url, status, time, length]`
+
 ## License
 
   MIT

index.js

@@ -7,6 +7,7 @@ const Counter = require('passthrough-counter')
 const humanize = require('humanize-number')
 const bytes = require('bytes')
 const chalk = require('chalk')
+const util = require('util')
 
 /**
  * Expose logger.
@@ -33,10 +34,29 @@ const colorCodes = {
  */
 
 function dev (opts) {
+  // print to console helper.
+  var print = (function () {
+    var transporter
+    if (typeof opts === 'function') {
+      transporter = opts
+    } else if (!!opts && !!opts.transporter) {
+      transporter = opts.transporter
+    }
+
+    return function printFunc (...args) {
+      var str = util.format(...args)
+      if (transporter) {
+        transporter(str, args)
+      } else {
+        console.log(...args)
+      }
+    }
+  }())
+
   return async function logger (ctx, next) {
     // request
     const start = Date.now()
-    console.log('  ' + chalk.gray('<--') +
+    print('  ' + chalk.gray('<--') +
       ' ' + chalk.bold('%s') +
       ' ' + chalk.gray('%s'),
         ctx.method,
@@ -46,7 +66,7 @@ function dev (opts) {
       await next()
     } catch (err) {
       // log uncaught downstream errors
-      log(ctx, start, null, err)
+      log(print, ctx, start, null, err)
       throw err
     }
 
@@ -75,7 +95,7 @@ function dev (opts) {
     function done (event) {
       res.removeListener('finish', onfinish)
       res.removeListener('close', onclose)
-      log(ctx, start, counter ? counter.length : length, null, event)
+      log(print, ctx, start, counter ? counter.length : length, null, event)
     }
   }
 }
@@ -84,7 +104,7 @@ function dev (opts) {
  * Log helper.
  */
 
-function log (ctx, start, len, err, event) {
+function log (print, ctx, start, len, err, event) {
   // get the status code of the response
   const status = err
     ? (err.isBoom ? err.output.statusCode : err.status || 500)
@@ -108,7 +128,7 @@ function log (ctx, start, len, err, event) {
     : event === 'close' ? chalk.yellow('-x-')
     : chalk.gray('-->')
 
-  console.log('  ' + upstream +
+  print('  ' + upstream +
     ' ' + chalk.bold('%s') +
     ' ' + chalk.gray('%s') +
     ' ' + chalk[color]('%s') +

test-server.js

@@ -8,37 +8,39 @@ const Boom = require('boom')
 const _ = require('koa-route')
 const logger = require('./index')
 
-const app = new Koa()
-app.use(logger())
-
-app.use(_.get('/200', function (ctx) {
-  ctx.body = 'hello world'
-}))
-
-app.use(_.get('/301', function (ctx) {
-  ctx.status = 301
-}))
-
-app.use(_.get('/304', function (ctx) {
-  ctx.status = 304
-}))
-
-app.use(_.get('/404', function (ctx) {
-  ctx.status = 404
-  ctx.body = 'not found'
-}))
-
-app.use(_.get('/500', function (ctx) {
-  ctx.status = 500
-  ctx.body = 'server error'
-}))
-
-app.use(_.get('/500-boom', function (ctx) {
-  ctx.throw(Boom.badImplementation('terrible implementation'))
-}))
-
-app.use(_.get('/error', function (ctx) {
-  throw new Error('oh no')
-}))
-
-module.exports = app
+module.exports = function (opts) {
+  const app = new Koa()
+  app.use(logger(opts))
+
+  app.use(_.get('/200', function (ctx) {
+    ctx.body = 'hello world'
+  }))
+
+  app.use(_.get('/301', function (ctx) {
+    ctx.status = 301
+  }))
+
+  app.use(_.get('/304', function (ctx) {
+    ctx.status = 304
+  }))
+
+  app.use(_.get('/404', function (ctx) {
+    ctx.status = 404
+    ctx.body = 'not found'
+  }))
+
+  app.use(_.get('/500', function (ctx) {
+    ctx.status = 500
+    ctx.body = 'server error'
+  }))
+
+  app.use(_.get('/500-boom', function (ctx) {
+    ctx.throw(Boom.badImplementation('terrible implementation'))
+  }))
+
+  app.use(_.get('/error', function (ctx) {
+    throw new Error('oh no')
+  }))
+
+  return app
+}