Add in methods for retrieving updates and doc version

services/track-changes/app/coffee/DiffManager.coffee

@@ -0,0 +1,8 @@
+module.exports = DiffManager =
+	getDiff: (doc_id, fromDate, toDate, callback = (error, diff) ->) ->
+		# Flush diff
+		# Get doc content and version
+		# Get updates from Mongo
+		# Check version matches
+		# Build diff
+		# Return diff

services/track-changes/app/coffee/DocumentUpdaterManager.coffee

@@ -0,0 +1,21 @@
+request = require "request"
+logger = require "logger-sharelatex"
+Settings = require "settings-sharelatex"
+
+module.exports = DocumentUpdaterManager =
+	getDocument: (project_id, doc_id, callback = (error, content, version) ->) ->
+		url = "#{Settings.apis.documentupdater.url}/project/#{project_id}/doc/#{doc_id}"
+		logger.log project_id:project_id, doc_id: doc_id, "getting doc from document updater"
+		request.get url, (error, res, body)->
+			if error?
+				return callback(error)
+			if res.statusCode >= 200 and res.statusCode < 300
+				try
+					body = JSON.parse(body)
+				catch error
+					return callback(error)
+				callback null, body.lines, body.version
+			else
+				error = new Error("doc updater returned a non-success status code: #{res.statusCode}")
+				logger.error err: error, project_id:project_id, doc_id:doc_id, url: url, "error accessing doc updater"
+				callback error

services/track-changes/app/coffee/MongoManager.coffee

@@ -37,4 +37,18 @@ module.exports = MongoManager =
 			op:     update.op
 			meta:   update.meta
 			v:      update.v
-		}, callback
+		}, callback
+
+	getUpdatesBetweenDates:(doc_id, fromDate, toDate, callback = (error, updates) ->) ->
+		db.docHistory
+			.find({
+				doc_id: ObjectId(doc_id.toString())
+				"meta.start_ts" : { $gte: fromDate }
+				"meta.end_ts"   : { $lte: toDate }
+			})
+			.sort( "meta.end_ts": -1 )
+			.toArray callback
+
+	ensureIndices: (callback = (error) ->) ->
+		db.docHistory.ensureIndex { doc_id: 1, "meta.start_ts": 1, "meta.end_ts": 1 }, callback
+