Rename "roles" to "units". Put units in their own folders.

lib/units/storage/plugins/image/index.js

@@ -0,0 +1,52 @@
+var http = require('http')
+
+var express = require('express')
+
+var logger = require('../../../../util/logger')
+var requtil = require('../../../../util/requtil')
+
+var parseCrop = require('./param/crop')
+var parseGravity = require('./param/gravity')
+var get = require('./task/get')
+var transform = require('./task/transform')
+
+module.exports = function(options) {
+  var log = logger.createLogger('storage:plugins:image')
+    , app = express()
+    , server = http.createServer(app)
+
+  app.set('strict routing', true)
+  app.set('case sensitive routing', true)
+  app.set('trust proxy', true)
+
+  app.get(
+    '/api/v1/s/image/:id/*'
+  , requtil.limit(options.concurrency, function(req, res) {
+      return get(req.url, options)
+        .then(function(stream) {
+          return transform(stream, {
+            crop: parseCrop(req.query.crop)
+          , gravity: parseGravity(req.query.gravity)
+          })
+        })
+        .then(function(out) {
+          res.status(200)
+          out.pipe(res)
+        })
+        .catch(function(err) {
+          log.error(
+            'Unable to transform resource "%s"'
+          , req.params.id
+          , err.stack
+          )
+          res.status(500)
+            .json({
+              success: false
+            })
+        })
+    })
+  )
+
+  server.listen(options.port)
+  log.info('Listening on port %d', options.port)
+}

lib/units/storage/plugins/image/param/crop.js

@@ -0,0 +1,14 @@
+var RE_CROP = /^([0-9]*)x([0-9]*)$/
+
+module.exports = function(raw) {
+  var parsed
+
+  if (raw && (parsed = RE_CROP.exec(raw))) {
+    return {
+      width: +parsed[1] || 0
+    , height: +parsed[2] || 0
+    }
+  }
+
+  return null
+}

lib/units/storage/plugins/image/param/gravity.js

@@ -0,0 +1,21 @@
+var GRAVITY = {
+  northwest: 'NorthWest'
+, north: 'North'
+, northeast: 'NorthEast'
+, west: 'West'
+, center: 'Center'
+, east: 'East'
+, southwest: 'SouthWest'
+, south: 'South'
+, southeast: 'SouthEast'
+}
+
+module.exports = function(raw) {
+  var parsed
+
+  if (raw && (parsed = GRAVITY[raw])) {
+    return parsed
+  }
+
+  return null
+}

lib/units/storage/plugins/image/task/get.js

@@ -0,0 +1,20 @@
+var util = require('util')
+var http = require('http')
+var url = require('url')
+
+var Promise = require('bluebird')
+
+module.exports = function(path, options) {
+  return new Promise(function(resolve, reject) {
+    http.get(url.resolve(options.storageUrl, path))
+      .on('response', function(res) {
+        if (res.statusCode !== 200) {
+          reject(new Error(util.format('HTTP %d', res.statusCode)))
+        }
+        else {
+          resolve(res)
+        }
+      })
+      .on('error', reject)
+  })
+}

lib/units/storage/plugins/image/task/transform.js

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+var gm = require('gm')
+var Promise = require('bluebird')
+
+module.exports = function(stream, options) {
+  return new Promise(function(resolve, reject) {
+    var transform = gm(stream)
+
+    if (options.gravity) {
+      transform.gravity(options.gravity)
+    }
+
+    if (options.crop) {
+      transform.geometry(options.crop.width, options.crop.height, '^')
+      transform.crop(options.crop.width, options.crop.height, 0, 0)
+    }
+
+    transform.stream(function(err, stdout) {
+      if (err) {
+        reject(err)
+      }
+      else {
+        resolve(stdout)
+      }
+    })
+  })
+}