Make screenshots work again.

lib/units/device/plugins/screen.js

@@ -5,15 +5,21 @@ var http = require('http')
 var Promise = require('bluebird')
 var syrup = require('stf-syrup')
 var httpProxy = require('http-proxy')
+var adbkit = require('adbkit')
 
 var logger = require('../../../util/logger')
 var lifecycle = require('../../../util/lifecycle')
 var streamutil = require('../../../util/streamutil')
+var wire = require('../../../wire')
+var wireutil = require('../../../wire/util')
 
 module.exports = syrup.serial()
   .dependency(require('../support/adb'))
+  .dependency(require('../support/router'))
+  .dependency(require('../support/push'))
+  .dependency(require('../support/storage'))
   .dependency(require('../resources/minicap'))
-  .define(function(options, adb, minicap) {
+  .define(function(options, adb, router, push, storage, minicap) {
     var log = logger.createLogger('device:plugins:screen')
     var plugin = Object.create(null)
 
@@ -110,6 +116,53 @@ module.exports = syrup.serial()
       })
     }
 
+    plugin.capture = function() {
+      log.info('Capturing screenshot')
+
+      var file = util.format('/data/local/tmp/minicap_%d.jpg', Date.now())
+      return run(util.format('-s >%s', file))
+        .then(adbkit.util.readAll)
+        .then(function() {
+          return adb.stat(options.serial, file)
+        })
+        .then(function(stats) {
+          if (stats.size === 0) {
+            throw new Error('Empty screenshot; possibly secure screen?')
+          }
+
+          return adb.pull(options.serial, file)
+            .then(function(transfer) {
+              return storage.store('image', transfer, {
+                filename: util.format('%s.jpg', options.serial)
+              , contentType: 'image/jpeg'
+              , knownLength: stats.size
+              })
+            })
+        })
+        .finally(function() {
+          return adb.shell(options.serial, ['rm', '-f', file])
+            .then(adbkit.util.readAll)
+        })
+    }
+
+    router.on(wire.ScreenCaptureMessage, function(channel) {
+      var reply = wireutil.reply(options.serial)
+      plugin.capture()
+        .then(function(file) {
+          push.send([
+            channel
+          , reply.okay('success', file)
+          ])
+        })
+        .catch(function(err) {
+          log.error('Screen capture failed', err.stack)
+          push.send([
+            channel
+          , reply.fail(err.message)
+          ])
+        })
+    })
+
     return startService()
       .then(forwardService)
       .then(startProxy)