diff --git a/src/client/main.cr b/src/client/main.cr
index abb55ac..5fadce6 100644
--- a/src/client/main.cr
+++ b/src/client/main.cr
@@ -126,7 +126,7 @@ def file_transfer(client : IPC::Client, file : File, file_info : FileStorage::Fi
 
 		# Check for the response
 		m = client.read
-		mtype = FileStorage::MessageType.new m.type.to_i32
+		mtype = FileStorage::MessageType.new m.utype.to_i32
 		if mtype != FileStorage::MessageType::Response
 			pp! m
 			raise "Message received was not expected: #{mtype}"
diff --git a/src/common/filestorage.cr b/src/common/filestorage.cr
deleted file mode 100644
index 4b81e23..0000000
--- a/src/common/filestorage.cr
+++ /dev/null
@@ -1,207 +0,0 @@
-require "uuid"
-require "openssl"
-require "json"
-require "base64"
-
-module FileStorage
-
-	extend self
-
-	# 1 MB read buffer, on-disk
-	def file_reading_buffer_size
-		1_000_000
-	end
-
-	# 1 KB message data buffer, on-network
-	def message_buffer_size
-		1_000
-	end
-
-	class Exception < ::Exception
-	end
-
-	enum MessageType
-		Error
-		Authentication
-		UploadRequest
-		DownloadRequest
-		Response
-		Responses
-		Transfer
-	end
-
-	class Chunk
-		include JSON::Serializable
-
-		property n      : Int32   # chunk's number
-		property on     : Int32   # number of chunks
-		property digest : String  # digest of the current chunk
-
-		def initialize(@n, @on, data)
-			@digest = FileStorage.data_digest data.to_slice
-		end
-	end
-
-	# For now, upload and download are sequentials.
-	# In a future version, we will be able to send
-	# arbitrary parts of each file.
-
-	class Token
-		include JSON::Serializable
-
-		property uid   : Int32
-		property login : String
-
-		def initialize(@uid, @login)
-		end
-	end
-
-	# Who knows, maybe someday we will be on UDP, too.
-	#class SHA256
-	#	JSON.mapping({
-	#		chunk: Slice(UInt8)
-	#	})
-	#end
-
-
-	# A file has a name, a size and tags.
-	class FileInfo
-		include JSON::Serializable
-
-		property name      : String
-		property size      : UInt64
-		property nb_chunks : Int32
-		property digest    : String
-
-		# list of SHA256, if we are on UDP
-		# chunks: Array(SHA256),
-		property tags : Array(String)
-
-		def initialize(file : File, tags = nil)
-			@name = File.basename file.path
-			@size = file.size
-			@digest = FileStorage.file_digest file
-			@nb_chunks = (@size / FileStorage.message_buffer_size).ceil.to_i
-			@tags = tags || [] of String
-		end
-	end
-
-	class Message
-	end
-
-	alias Request = UploadRequest | DownloadRequest
-
-	class UploadRequest < Message
-		include JSON::Serializable
-
-		property mid  : String     # autogenerated
-		property file : FileInfo
-
-		def initialize(@file : FileInfo)
-			@mid = UUID.random.to_s
-		end
-	end
-
-
-	# WIP
-	class DownloadRequest < Message
-		include JSON::Serializable
-
-		property mid        : String   # autogenerated
-		property filedigest : String?  # SHA256 digest of the file, used as ID
-		property name       : String?
-		property tags       : Array(String)?
-
-		def initialize(@filedigest = nil, @name = nil, @tags = nil)
-			@mid = UUID.random.to_s
-		end
-	end
-
-	class Authentication < Message
-		include JSON::Serializable
-
-		property mid       : String   # autogenerated
-		property token     : Token
-		property uploads   : Array(UploadRequest)
-		property downloads : Array(DownloadRequest)
-
-		def initialize(@token, @uploads = Array(UploadRequest).new, @downloads = Array(DownloadRequest).new)
-			@mid = UUID.random.to_s
-		end
-	end
-
-	class Response < Message
-		include JSON::Serializable
-
-		property mid      : String
-		property response : String
-		property reason   : String?
-
-		def initialize(@mid, @response, @reason = nil)
-		end
-	end
-
-	class Error < Message
-		include JSON::Serializable
-
-		property mid      : String
-		property response : String   # a response for each request
-		property reason   : String?
-
-		def initialize(@mid, @response, @reason = nil)
-		end
-	end
-
-	class Responses < Message
-		include JSON::Serializable
-
-		property mid       : String
-		property responses : Array(Response)   # a response for each request
-		property response  : String
-		property reason    : String?
-
-		def initialize(@mid, @response, @responses, @reason = nil)
-		end
-	end
-
-	class Transfer < Message
-		include JSON::Serializable
-
-		property mid        : String   # autogenerated
-		property filedigest : String   # SHA256 digest of the entire file
-		property chunk      : Chunk    # For now, just the counter in a string
-		property data       : String   # base64 slice
-
-		def initialize(file_info : FileInfo, count, bindata)
-			# count: chunk number
-
-			@filedigest = file_info.digest
-			@data = Base64.encode bindata
-			@chunk = FileStorage::Chunk.new count, file_info.nb_chunks - 1, @data
-			@mid = UUID.random.to_s
-		end
-	end
-
-	# private function
-	def data_digest(data : Bytes)
-
-		iodata = IO::Memory.new data, false
-		buffer = Bytes.new FileStorage.file_reading_buffer_size
-
-		io = OpenSSL::DigestIO.new(iodata, "SHA256")
-		while io.read(buffer) > 0; end
-
-		io.digest.hexstring
-	end
-
-	# private function
-	def file_digest(file : File)
-		# 1M read buffer
-		buffer = Bytes.new(1_000_000)
-
-		io = OpenSSL::DigestIO.new(file, "SHA256")
-		while io.read(buffer) > 0 ; end
-
-		io.digest.hexstring
-	end
-end
diff --git a/src/common/requests/auth.cr b/src/common/requests/auth.cr
new file mode 100644
index 0000000..173bbde
--- /dev/null
+++ b/src/common/requests/auth.cr
@@ -0,0 +1,80 @@
+
+# We verify the user's rights to upload files.
+# TODO RIGHTS
+# if user wants to upload but not allowed to: Response
+# if user wants to get a file but not allowed to: Response
+
+# The user is authorized to upload files.
+
+# TODO: quotas
+# Quotas are not defined yet.
+
+#class FileStorage::Request
+#	JSONIPC.request Authentication, 10 do
+#		property mid       : String   # autogenerated
+#		property token     : Token
+#		property uploads   : Array(UploadRequest)?
+#		property downloads : Array(DownloadRequest)?
+#
+#		def initialize(@token, @uploads = nil, @downloads = nil)
+#			@mid = UUID.random.to_s
+#		end
+#
+#		# Store the client in connected_users and users_status.
+#		# If already in users_status: 
+#		#   check if the requests are the same
+#		#     if not: add them to the user structure in users_status
+#		def handle(filestoraged : FileStorage::Service, event : IPC::Event::Events)
+#
+#			token  = filestoraged.auth.decode_token @token
+#			userid = token.uid
+#
+#			puts "user authentication: #{userid}"
+#
+#			# Is the user already recorded in users_status?
+#			if filestoraged.users_status[userid]?
+#				puts "We already knew this user"
+#
+#				filestoraged.connected_users[event.connection.fd] = userid
+#				# TODO
+#				pp! filestoraged.connected_users
+#				pp! filestoraged.users_status[userid]
+#
+#				# Let's ignore this error, just continue.
+#				# It could have been a network error, for example.
+#				# return FileStorage::Response::Error.new @mid, "user already connected"
+#			else
+#				# AuthenticationMessage includes requests.
+#				new_user = User.new token, @uploads, @downloads
+#
+#				filestoraged.connected_users[event.connection.fd] = userid
+#
+#				# record the new user in users_status
+#				filestoraged.users_status[userid] = new_user
+#
+#				puts "New user is: #{new_user.token.login}"
+#			end
+#
+#			# The user is now connected.
+#			user = filestoraged.users_status[userid]
+#
+#			responses = filestoraged.storage.requests [ @uploads, @downloads ].flatten,
+#				filestoraged.users_status[userid],
+#				event
+#
+#			# Sending a response, containing a response for each request.
+#			FileStorage::Response::Success.new @mid, responses
+#		end
+#	end
+#	FileStorage.requests << Authentication
+#end
+#
+#class FileStorage::Response
+#	JSONIPC.request AuthenticationSuccess, 10 do
+#		property mid : String
+#		property responses : Array(FileStorage::Response)
+#		def initialize(@mid, @responses)
+#		end
+#	end
+#end
+
diff --git a/src/common/requests/download.cr b/src/common/requests/download.cr
new file mode 100644
index 0000000..e200a0e
--- /dev/null
+++ b/src/common/requests/download.cr
@@ -0,0 +1,55 @@
+class FileStorage::Request
+
+	JSONIPC.request Download, 30 do
+		property mid        : String   # autogenerated
+		property filedigest : String?  # SHA256 digest of the file, used as ID
+		property name       : String?
+		property tags       : Array(String)?
+		def initialize(@filedigest = nil, @name = nil, @tags = nil)
+			@mid = UUID.random.to_s
+		end
+
+		def handle(filestoraged : FileStorage::Service, event : IPC::Event::Events)
+			user = altideald.get_logged_user event
+
+			raise Exception.new "unauthorized" if user.nil?
+
+			# FIXME: Maybe this should be moved to FileStorage::Service
+			fd = event.connection.fd
+
+			user_data = filestoraged.get_user_data user.uid
+
+			filestoraged.storage.download self, event
+		rescue e
+			return Response::Error.new @mid, "unauthorized"
+		end
+	end
+	FileStorage.requests << Download
+end
+
+class FileStorage::Client
+	def download(filedigest = nil, name = nil, tags = nil)
+		request = FileStorage::Request::Download.new filedigest, name, tags
+		send request
+
+		response = parse_message [ FileStorage::Response::Download, FileStorage::Response::Error ], read
+
+		case response
+		when FileStorage::Response::Download
+		when FileStorage::Response::Error
+			raise "Download request denied: #{response.reason}"
+		end
+
+		response
+	end
+end
+
+
+class FileStorage::Response
+	JSONIPC.request Download, 30 do
+		property mid : String
+		def initialize(@mid)
+		end
+	end
+end
+
diff --git a/src/common/requests/login.cr b/src/common/requests/login.cr
new file mode 100644
index 0000000..c1d1e98
--- /dev/null
+++ b/src/common/requests/login.cr
@@ -0,0 +1,59 @@
+require "uuid"
+require "openssl"
+require "json"
+require "base64"
+
+class FileStorage::Request
+	JSONIPC.request Login, 0 do
+		property mid : String
+		property token : String
+		def initialize(@token)
+			@mid = UUID.random.to_s
+		end
+
+		def handle(filestoraged : FileStorage::Service, event : IPC::Event::Events)
+			logged_users = filestoraged.logged_users
+
+			user, _ = filestoraged.decode_token token
+
+			# FIXME: Maybe this should be moved to FileStorage::Service
+			fd = event.connection.fd
+
+			filestoraged.logged_users[fd]       = user
+			filestoraged.logged_connections[fd] = event.connection
+
+			user_data = filestoraged.get_user_data user.uid
+
+			return Response::Login.new @mid
+		rescue e
+			return Response::Error.new "unauthorized"
+		end
+	end
+	FileStorage.requests << Login
+end
+
+class FileStorage::Client
+	def login(token : String)
+		request = FileStorage::Request::Login.new token
+		send request
+
+		response = parse_message [ FileStorage::Response::Login, FileStorage::Response::Error ], read
+
+		case response
+		when FileStorage::Response::Login
+			# Received favorites, likes, etc.
+		when FileStorage::Response::Error
+			raise "user was not logged in: #{response.reason}"
+		end
+
+		response
+	end
+end
+
+class FileStorage::Response
+	JSONIPC.request Login, 5 do
+		property mid : String
+		def initialize(@mid)
+		end
+	end
+end
diff --git a/src/common/requests/transfer.cr b/src/common/requests/transfer.cr
new file mode 100644
index 0000000..a309aba
--- /dev/null
+++ b/src/common/requests/transfer.cr
@@ -0,0 +1,58 @@
+class FileStorage::Request
+	JSONIPC.request Transfer, 40 do
+		property mid        : String   # autogenerated
+		property filedigest : String   # SHA256 digest of the entire file
+		property chunk      : Chunk    # For now, just the counter in a string
+		property data       : String   # base64 slice
+		def initialize(file_info : FileInfo, count, bindata)
+			# count: chunk number
+
+			@filedigest = file_info.digest
+			@data = Base64.encode bindata
+			@chunk = FileStorage::Chunk.new count, file_info.nb_chunks - 1, @data
+			@mid = UUID.random.to_s
+		end
+
+		def handle(filestoraged : FileStorage::Service, event : IPC::Event::Events)
+			user = altideald.get_logged_user event
+
+			raise Exception.new "unauthorized" if user.nil?
+
+			# FIXME: Maybe this should be moved to FileStorage::Service
+			fd = event.connection.fd
+
+			user_data = filestoraged.get_user_data user.uid
+
+			filestoraged.storage.transfer self, event
+		rescue e
+			return Response::Error.new @mid, "unauthorized"
+		end
+	end
+	FileStorage.requests << Transfer
+end
+
+class FileStorage::Client
+	def transfer(file_info : FileInfo, count, bindata)
+		request = FileStorage::Request::Transfer.new file_info, count, bindata
+		send request
+
+		response = parse_message [ FileStorage::Response::Transfer, FileStorage::Response::Error ], read
+
+		case response
+		when FileStorage::Response::Transfer
+		when FileStorage::Response::Error
+			raise "File chunk was not transfered: #{response.reason}"
+		end
+
+		response
+	end
+end
+
+
+class FileStorage::Response
+	JSONIPC.request Transfer, 40 do
+		property mid : String
+		def initialize(@mid)
+		end
+	end
+end
diff --git a/src/common/requests/upload.cr b/src/common/requests/upload.cr
new file mode 100644
index 0000000..8ac2758
--- /dev/null
+++ b/src/common/requests/upload.cr
@@ -0,0 +1,63 @@
+
+class FileStorage::Request
+	JSONIPC.request Upload, 20 do
+		property mid  : String     # autogenerated
+		property file : FileInfo
+		def initialize(@file : FileInfo)
+			@mid = UUID.random.to_s
+		end
+
+		def handle(filestoraged : FileStorage::Service, event : IPC::Event::Events)
+			user = altideald.get_logged_user event
+
+			raise Exception.new "unauthorized" if user.nil?
+
+			# FIXME: Maybe this should be moved to FileStorage::Service
+			fd = event.connection.fd
+
+			user_data = filestoraged.get_user_data user.uid
+
+			filestoraged.storage.upload self, event
+		rescue e
+			return Response::Error.new @mid, "unauthorized"
+		end
+	end
+	FileStorage.requests << Upload
+end
+
+class FileStorage::Client
+	def upload(token : String)
+		request = FileStorage::Request::Upload.new token
+		send request
+
+		response = parse_message [ FileStorage::Response::Upload, FileStorage::Response::Error ], read
+
+		case response
+		when FileStorage::Response::Upload
+		when FileStorage::Response::Error
+			raise "Upload request failed: #{response.reason}"
+		end
+
+		response
+	end
+end
+
+class FileStorage::Response
+	JSONIPC.request Upload, 20 do
+		property mid : String
+		def initialize(@mid)
+		end
+	end
+
+	JSONIPC.request Responses, 100 do
+		include JSON::Serializable
+
+		property mid       : String
+		property responses : Array(Response)   # a response for each request
+		property response  : String
+		property reason    : String?
+
+		def initialize(@mid, @response, @responses, @reason = nil)
+		end
+	end
+end
diff --git a/src/server/cli.cr b/src/server/cli.cr
deleted file mode 100644
index 83b3448..0000000
--- a/src/server/cli.cr
+++ /dev/null
@@ -1,17 +0,0 @@
-
-OptionParser.parse do |parser|
-	parser.on "-d storage-directory",
-		"--storage-directory storage-directory",
-		"The directory where to put uploaded files." do |opt|
-		Context.storage_directory = opt
-	end
-
-	parser.on "-s service-name", "--service-name service-name", "Service name." do |name|
-		Context.service_name = name
-	end
-
-	parser.on "-h", "--help", "Show this help" do
-		puts parser
-		exit 0
-	end
-end
diff --git a/src/server/context.cr b/src/server/context.cr
deleted file mode 100644
index 2bba0eb..0000000
--- a/src/server/context.cr
+++ /dev/null
@@ -1,62 +0,0 @@
-
-require "dodb"
-require "json"
-
-# keep track of connected users and their requests
-# TODO: requests should be handled concurrently
-class User
-	property uid : Int32
-	property token : FileStorage::Token
-	property uploads : Array(FileStorage::UploadRequest)
-	property downloads : Array(FileStorage::DownloadRequest)
-
-	def initialize(@token,
-		@uploads = Array(FileStorage::UploadRequest).new,
-		@downloads = Array(FileStorage::DownloadRequest).new)
-		@uid = token.uid
-	end
-end
-
-class TransferInfo
-	include JSON::Serializable
-
-	property owner : Int32
-	property file_info : FileStorage::FileInfo
-	property chunks : Array(Int32)
-
-	def initialize(@owner, @file_info)
-		@chunks = (0...@file_info.nb_chunks).to_a
-	end
-end
-
-class Context
-	class_property service_name        = "filestorage"
-	class_property storage_directory   = "./storage"
-	class_property file_info_directory = "./file-infos"
-
-	class_property db = DODB::DataBase(TransferInfo).new @@file_info_directory
-
-	# search file informations by their index, owner and tags
-	class_property db_by_filedigest : DODB::Index(TransferInfo) = @@db.new_index "filedigest", &.file_info.digest
-	class_property db_by_owner : DODB::Partition(TransferInfo)  = @@db.new_partition "owner",  &.owner.to_s
-	class_property db_by_tags : DODB::Tags(TransferInfo)        = @@db.new_tags "tags",        &.file_info.tags
-
-	def self.db_reconnect
-		# In case file_info_directory changes: database reinstanciation
-		@@db = DODB::DataBase(TransferInfo).new @@file_info_directory
-
-		# recreate indexes, partitions and tags objects, too
-		@@db_by_filedigest = @@db.new_index     "filedigest", &.file_info.digest
-		@@db_by_owner      = @@db.new_partition "owner",      &.owner.to_s
-		@@db_by_tags       = @@db.new_tags      "tags",       &.file_info.tags
-	end
-
-	# list of connected users (fd => uid)
-	class_property connected_users = Hash(Int32, Int32).new
-
-	# users_status: keep track of the users' status even if they are
-	# disconnected, allowing the application to handle connection problems
-	class_property users_status = Hash(Int32, User).new
-
-	class_property service : IPC::Service? = nil
-end
diff --git a/src/server/handlers.cr b/src/server/handlers.cr
deleted file mode 100644
index 93b333d..0000000
--- a/src/server/handlers.cr
+++ /dev/null
@@ -1,180 +0,0 @@
-
-require "dodb"
-require "base64"
-
-require "../common/utils"
-
-# XXX TODO FIXME: architectural questions
-#   wonder why I should keep the user upload and download requests
-#   the server can be just for uploads, delegating downloads to HTTP
-
-
-# reception of a file chunk
-def hdl_transfer(message : FileStorage::Transfer, user : User) : FileStorage::Response
-
-	# We received a message containing a chunk of file.
-
-	mid = message.mid
-	mid ||= "no message id"
-
-	# Get the transfer info from the db
-	transfer_info = Context.db_by_filedigest.get message.filedigest
-
-	if transfer_info.nil?
-		# The user has to send an upload request before sending anything
-		# If not the case, it should be discarded
-		raise "file not recorded"
-	end
-
-	chunk_number = message.chunk.n
-
-	data = Base64.decode message.data
-
-	# TODO: verify that the chunk sent was really missing
-	if transfer_info.chunks.select(chunk_number).size > 0
-		write_a_chunk user.uid.to_s, transfer_info.file_info, chunk_number, data
-	else
-		raise "non existent chunk or already uploaded"
-	end
-
-	remove_chunk_from_db transfer_info, chunk_number
-
-	# TODO: verify the digest, if no more chunks
-
-	FileStorage::Response.new mid, "Ok"
-
-rescue e
-	puts "Error handling transfer: #{e.message}"
-	FileStorage::Response.new mid.not_nil!, "Not Ok", "Unexpected error: #{e.message}"
-end
-
-# the client sent an upload request
-def hdl_upload(request : FileStorage::UploadRequest, user : User) : FileStorage::Response
-
-	mid = request.mid
-	mid ||= "no message id"
-
-	puts "hdl upload: mid=#{request.mid}"
-	pp! request
-
-	# TODO: verify the rights and quotas of the user
-	# file_info attributes: name, size, nb_chunks, digest, tags
-
-	# First: check if the file already exists
-	transfer_info = Context.db_by_filedigest.get? request.file.digest
-	if transfer_info.nil?
-		# In case file informations aren't already registered
-		# which is normal at this point
-		transfer_info = TransferInfo.new user.uid, request.file
-		Context.db << transfer_info
-	else
-		# File information already exists, request may be duplicated
-		# In this case: ignore the upload request
-	end
-
-	FileStorage::Response.new request.mid, "Upload OK"
-rescue e
-	puts "Error handling transfer: #{e.message}"
-	FileStorage::Response.new mid.not_nil!, "Not Ok", "Unexpected error: #{e.message}"
-end
-
-# TODO
-# the client sent a download request
-def hdl_download(request : FileStorage::DownloadRequest,
-	user : User) : FileStorage::Response
-
-	puts "hdl download: mid=#{request.mid}"
-	pp! request
-
-	FileStorage::Response.new request.mid, "Download OK"
-end
-
-
-# Entry point for request management
-# Each request should have a response.
-# Then, responses are sent in a single message.
-def hdl_requests(requests : Array(FileStorage::Request),
-	user : User,
-	event : IPC::Event::Message) : Array(FileStorage::Response)
-
-	puts "hdl request"
-	responses = Array(FileStorage::Response).new
-
-	requests.each do |request|
-		case request
-		when FileStorage::DownloadRequest
-			responses << hdl_download request, user
-		when FileStorage::UploadRequest
-			responses << hdl_upload request, user
-		else
-			raise "request not understood"
-		end
-
-		puts
-	end
-
-	responses
-end
-
-# store the client in connected_users and users_status
-# if already in users_status: 
-#   check if the requests are the same
-#     if not: add them to the user structure in users_status
-def hdl_authentication(event : IPC::Event::Message)
-
-	authentication_message =
-		FileStorage::Authentication.from_json(
-			String.new event.message.payload
-		)
-
-	userid = authentication_message.token.uid
-
-	puts "user authentication: #{userid}"
-
-	# Is the user already recorded in users_status?
-	if Context.users_status[userid]?
-		puts "We already knew this user"
-
-		Context.connected_users[event.connection.fd] = userid
-		# TODO
-		pp! Context.connected_users
-		pp! Context.users_status[userid]
-	else
-		# AuthenticationMessage includes requests.
-		new_user =
-			User.new authentication_message.token,
-				authentication_message.uploads,
-				authentication_message.downloads
-
-		Context.connected_users[event.connection.fd] = userid
-
-		# record the new user in users_status
-		Context.users_status[userid] = new_user
-
-		puts "New user is: #{new_user.token.login}"
-	end
-
-	# The user is now connected.
-	user = Context.users_status[userid]
-
-	# We verify the user's rights to upload files.
-	# TODO RIGHTS
-	# if user wants to upload but not allowed to: Response
-	# if user wants to get a file but not allowed to: Response
-
-	# The user is authorized to upload files.
-
-	# TODO: quotas
-	# Quotas are not defined yet.
-
-	responses = hdl_requests [ authentication_message.uploads, authentication_message.downloads ].flatten,
-		Context.users_status[userid],
-		event
-
-	# Sending a response, containing a response for each request.
-	# The response is "Ok" when the message is well received and authorized.
-	response = FileStorage::Responses.new authentication_message.mid, "Ok", responses
-	event.connection.send FileStorage::MessageType::Responses.to_u8, response.to_json
-	pp! FileStorage::MessageType::Responses.to_u8
-	pp! response
-end
diff --git a/src/server/main-loop.cr b/src/server/main-loop.cr
deleted file mode 100644
index 33bd0f9..0000000
--- a/src/server/main-loop.cr
+++ /dev/null
@@ -1,119 +0,0 @@
-
-Context.service = IPC::Service.new Context.service_name
-
-Context.service.not_nil!.loop do |event|
-	case event
-	when IPC::Event::Timer
-		puts "#{CORANGE}IPC::Event::Timer#{CRESET}"
-
-	when IPC::Event::Connection
-		puts "#{CBLUE}IPC::Event::Connection: #{event.connection.fd}#{CRESET}"
-
-	when IPC::Event::Disconnection
-		puts "#{CBLUE}IPC::Event::Disconnection: #{event.connection.fd}#{CRESET}"
-
-		Context.connected_users.select! do |fd, uid|
-			fd != event.connection.fd
-		end
-
-	when IPC::Event::ExtraSocket
-		puts "#{CRED}IPC::Event::ExtraSocket: should not happen in this service#{CRESET}"
-
-	when IPC::Event::Switch
-		puts "#{CRED}IPC::Event::Switch: should not happen in this service#{CRESET}"
-
-	# IPC::Event::Message has to be the last entry
-	# because ExtraSocket and Switch inherit from Message class
-	when IPC::Event::Message
-		puts "#{CBLUE}IPC::Event::Message#{CRESET}: #{event.connection.fd}"
-
-		# The first message sent to the server has to be the AuthenticationMessage.
-		# Users sent their token (JWT) to authenticate themselves.
-		# The token contains the user id, its login and a few other parameters.
-		# (see the authd documentation).
-		# TODO: for now, the token is replaced by a hardcoded one, for debugging
-
-		mtype = FileStorage::MessageType.new event.message.type.to_i32
-
-		# First, the user has to be authenticated unless we are receiving its first message
-		userid = Context.connected_users[event.connection.fd]?
-
-		# if the user is not yet connected but does not try to perform authentication
-		if ! userid && mtype != FileStorage::MessageType::Authentication
-			# TODO: replace this with an Error message?
-			mid = "no message id"
-			response = FileStorage::Response.new mid, "Not OK", "Action on non connected user"
-			do_response event, response
-		end
-
-		case mtype
-		when .authentication?
-			puts "Receiving an authentication message"
-			# 1. test if the client is already authenticated
-			if userid
-				user = Context.users_status[userid]
-				raise "Authentication message while the user was already connected: this should not happen"
-			else
-				puts "User is not currently connected"
-				hdl_authentication event
-			end
-		when .upload_request?
-			puts "Upload request"
-			request = FileStorage::UploadRequest.from_json(
-				String.new event.message.payload
-			)
-			response = hdl_upload request, Context.users_status[userid]
-
-			do_response event, response
-		when .download_request?
-			puts "Download request"
-			request = FileStorage::DownloadRequest.from_json(
-				String.new event.message.payload
-			)
-			response = hdl_download request, Context.users_status[userid]
-
-			do_response event, response
-		when .response?
-			puts "Response message"
-			raise "not implemented yet"
-		when .responses?
-			puts "Responses message"
-			raise "not implemented yet"
-		when .error?
-			puts "Error message"
-			raise "not implemented yet"
-		when .transfer?
-			# throw an error if the user isn't recorded
-			unless user = Context.users_status[userid]?
-				raise "The user isn't recorded in the users_status structure"
-			end
-
-			transfer = FileStorage::Transfer.from_json(
-				String.new event.message.payload
-			)
-			response = hdl_transfer transfer, Context.users_status[userid]
-
-			do_response event, response
-		end
-	else
-		raise "Event type not supported."
-	end
-rescue e
-	puts "A problem occured : #{e.message}"
-end
-
-def do_response(event : IPC::Event::Message,
-	response : FileStorage::Message)
-
-	case response
-	when FileStorage::Response
-		event.connection.send FileStorage::MessageType::Response.to_u8, response.to_json
-	when FileStorage::Responses
-		event.connection.send FileStorage::MessageType::Responses.to_u8, response.to_json
-	when FileStorage::Error
-		event.connection.send FileStorage::MessageType::Error.to_u8, response.to_json
-	else
-		puts "response should not happen: #{response}"
-		pp! response
-	end
-end
diff --git a/src/server/main.cr b/src/server/main.cr
index 49f1964..81052e4 100644
--- a/src/server/main.cr
+++ b/src/server/main.cr
@@ -1,12 +1,10 @@
 require "option_parser"
 require "ipc"
 require "json"
+require "authd"
 
 require "../common/colors"
-require "../common/filestorage.cr"
-
-require "./context.cr"
-require "./handlers.cr"
+# require "../common/filestorage.cr"
 
 # TODO: if the user is disconnected, we should ask him if it still want to process
 #       for old requests.
@@ -17,19 +15,305 @@ require "./handlers.cr"
 #          upload or download its files.
 
 # TODO:
-# * elegantly handling errors
-# * store the file, /files/userid/UID.bin for example: /files/1002/UID.bin
-# * metadata should be in a dodb
+# * Authd integration.
+# * Elegantly handling errors.
+# * Store the file, /files/userid/UID.bin for example: /files/1002/UID.bin.
+# * Metadata should be in a dodb.
 #   /storage/partitions/by_uid/UID.json -> content:
 #     data: /files/uid/UID.bin (storing raw files)
 #     uid: 1002
 #     name: "The File About Things"
 #     size: 1500
 #     tags: thing1 thing2
-# * authd integration
-# * knowing which parts of the files are still to be sent
-# * rights
-# * quotas
+# * Knowing which parts of the files are still to be sent.
+# * Rights.
+# * Quotas.
 
-require "./cli.cr" 
-require "./main-loop.cr"
+require "./storage.cr"
+require "./network.cr"
+####  require "./sample.cr"
+
+require "dodb"
+require "json"
+
+class FileStorage::Service < IPC::Service
+	# List of connected users (fd => uid).
+	property connected_users = Hash(Int32, Int32).new
+
+	# users_status: keep track of the users' status even if they are disconnected,
+	#               allowing the application to handle connection problems.
+	property users_status = Hash(Int32, User).new
+
+	# Actual storage.
+	getter storage             : FileStorage::Storage
+
+	getter logged_users        : Hash(Int32, AuthD::User::Public)
+	getter logged_connections  : Hash(Int32, IPC::Connection)
+	getter all_connections     : Array(Int32)
+
+	@auth : AuthD::Client
+	@auth_key : String
+
+	def initialize(storage_directory, file_info_directory, @auth_key)
+		# Data and metadata storage directories.
+		# storage_directory   : String
+		# file_info_directory : String
+
+		@storage = FileStorage::Storage.new storage_directory, file_info_directory
+
+		@logged_users       = Hash(Int32, AuthD::User::Public).new
+		@logged_connections = Hash(Int32, IPC::Connection).new
+		@all_connections    = Array(Int32).new
+
+		@auth = AuthD::Client.new
+		@auth.key = @auth_key
+
+		super "filestorage"
+	end
+
+	def get_logged_user(event : IPC::Event::Events)
+		fd = event.connection.fd
+
+		@logged_users[fd]?
+	end
+
+	def info(message)
+		STDOUT << ":: ".colorize(:green) << message.colorize(:white) << "\n"
+	end
+	def warning(message)
+		STDERR << "?? ".colorize(:yellow) << message.colorize(:yellow) << "\n"
+	end
+	def error(message)
+		STDERR << "!! ".colorize(:red) << message.colorize(:red) << "\n"
+	end
+
+	def decode_token(token : String)
+		@auth.decode_token token
+	end
+
+	def get_user_data(uid : Int32)
+		@storage.user_data_per_user.get uid.to_s
+	rescue e : DODB::MissingEntry
+		entry = UserData.new uid
+		entry
+	end
+
+	def get_user_data(user : ::AuthD::User::Public)
+		get_user_data user.uid
+	end
+
+	def update_user_data(user_data : UserData)
+		@storage.user_data_per_user.update_or_create user_data.uid.to_s, user_data
+	end
+
+	# TODO: could be useful to send notifications.
+	#def send_notifications(fd : Int32, value : Int32)
+		# @all_connections.select(&.!=(fd)).each do |fd| ... end
+		# IPC::Connection.new(fd).send Response::Something.new ...
+	#end
+
+	def run
+		info "Starting filestoraged"
+
+		self.loop do |event|
+			begin
+
+				case event
+				when IPC::Event::Timer
+					puts "#{CORANGE}IPC::Event::Timer#{CRESET}"
+
+				when IPC::Event::Connection
+					puts "#{CBLUE}IPC::Event::Connection: #{event.connection.fd}#{CRESET}"
+					@all_connections << event.connection.fd
+
+				when IPC::Event::Disconnection
+					puts "#{CBLUE}IPC::Event::Disconnection: #{event.connection.fd}#{CRESET}"
+					fd = event.connection.fd
+
+					@logged_connections.delete fd
+					@logged_users.delete fd
+					@all_connections.select! &.!=(fd)
+
+					@connected_users.select! do |fd, uid|
+						fd != event.connection.fd
+					end
+
+				when IPC::Event::ExtraSocket
+					puts "#{CRED}IPC::Event::ExtraSocket: should not happen in this service#{CRESET}"
+
+				when IPC::Event::Switch
+					puts "#{CRED}IPC::Event::Switch: should not happen in this service#{CRESET}"
+
+				# IPC::Event::Message has to be the last entry
+				# because ExtraSocket and Switch inherit from Message class
+				when IPC::Event::Message
+					puts "#{CBLUE}IPC::Event::Message#{CRESET}: #{event.connection.fd}"
+
+					request_start = Time.utc
+
+					request = parse_message FileStorage.requests, event.message
+
+					if request.nil?
+						raise "unknown request type"
+					end
+
+					info "<< #{request.class.name.sub /^FileStorage::Request::/, ""}"
+
+					response = request.handle self, event
+
+					if response.is_a? FileStorage::Response::Error
+						warning ">> #{response.class.name.sub /^FileStorage::Response::/, ""} (#{response.reason})"
+					else
+						info ">> #{response.class.name.sub /^FileStorage::Response::/, ""}"
+					end
+
+
+					#################################################################
+					# THERE START
+					#################################################################
+
+#					# The first message sent to the server has to be the AuthenticationMessage.
+#					# Users sent their token (JWT) to authenticate themselves.
+#					# The token contains the user id, its login and a few other parameters.
+#					# (see the authd documentation).
+#					# TODO: for now, the token is replaced by a hardcoded one, for debugging
+#
+#					mtype = FileStorage::MessageType.new event.message.utype.to_i32
+#
+#					# First, the user has to be authenticated unless we are receiving its first message.
+#					userid = Context.connected_users[event.connection.fd]?
+#
+#					# If the user is not yet connected but does not try to perform authentication.
+#					if ! userid && mtype != FileStorage::MessageType::Authentication
+#						# TODO: replace this with an Error message.
+#						mid = "no message id"
+#						response = FileStorage::Response.new mid, "Not OK", "Action on non connected user"
+#						do_response event, response
+#					end
+#
+#					case mtype
+#					when .authentication?
+#						puts "Receiving an authentication message"
+#						# Test if the client is already authenticated.
+#						if userid
+#							user = Context.users_status[userid]
+#							raise "Authentication message while the user was already connected: this should not happen"
+#						else
+#							puts "User is not currently connected"
+#							hdl_authentication event
+#						end
+#
+#					when .upload_request?
+#						puts "Upload request"
+#						request = FileStorage::UploadRequest.from_json(
+#							String.new event.message.payload
+#						)
+#						response = hdl_upload request, Context.users_status[userid]
+#						do_response event, response
+#
+#					when .download_request?
+#						puts "Download request"
+#						request = FileStorage::DownloadRequest.from_json(
+#							String.new event.message.payload
+#						)
+#						response = hdl_download request, Context.users_status[userid]
+#						do_response event, response
+#
+#					when .transfer?
+#						# throw an error if the user isn't recorded
+#						unless user = Context.users_status[userid]?
+#							raise "The user isn't recorded in the users_status structure"
+#						end
+#
+#						transfer = FileStorage::Transfer.from_json(
+#							String.new event.message.payload
+#						)
+#						response = hdl_transfer transfer, Context.users_status[userid]
+#
+#						do_response event, response
+#					end
+
+					#################################################################
+					# FINISH
+					#################################################################
+
+
+					# If clients sent requests with an “id” field, it is copied
+					# in the responses. Allows identifying responses easily.
+					response.id = request.id
+
+					event.connection.send response
+
+					duration = Time.utc - request_start
+					puts "request took: #{duration}"
+				else
+					warning "unhandled IPC event: #{event.class}"
+				end
+
+				# TODOOOOOOOOOO TODO FIXME
+
+
+
+			rescue exception
+				error "exception: #{typeof(exception)} - #{exception.message}"
+			end
+		end
+	end
+
+	def self.from_cli
+		storage_directory = "file-data-storage"
+		file_info_directory = "file-info-storage"
+		key = "nico-nico-nii" # Default authd key, as per the specs. :eyes:
+
+		OptionParser.parse do |parser|
+			parser.banner = "usage: filestoraged [options]"
+
+			parser.on "-d storage-directory",
+				"--storage-directory storage-directory",
+				"The directory where to put uploaded files." do |opt|
+				storage_directory = opt
+			end
+
+			parser.on "-m metadata-directory",
+				"--metadata-directory storage-directory",
+				"The directory where to put metadata of uploaded files." do |opt|
+				file_info_directory = opt
+			end
+
+			parser.on "-h",
+				"--help",
+				"Displays this help and exits." do
+				puts parser
+				exit 0
+			end
+
+			# FIXME: Either make this mandatory or print a warning if missing.
+			parser.on "-k file",
+				"--key file",
+				"Reads the authentication key from the provided file." do |file|
+				key = File.read(file).chomp
+			end
+		end
+
+		::FileStorage::Service.new storage_directory, file_info_directory, key
+	end
+
+	# TODO: this will probably be dropped at some point.
+#	def do_response(event : IPC::Event::Message,
+#		response : FileStorage::Message)
+#
+#		case response
+#		when FileStorage::Response
+#			event.connection.send FileStorage::MessageType::Response.to_u8, response.to_json
+#		when FileStorage::Responses
+#			event.connection.send FileStorage::MessageType::Responses.to_u8, response.to_json
+#		when FileStorage::Error
+#			event.connection.send FileStorage::MessageType::Error.to_u8, response.to_json
+#		else
+#			puts "response should not happen: #{response}"
+#			pp! response
+#		end
+#	end
+end
+
+FileStorage::Service.from_cli.run
diff --git a/src/server/network.cr b/src/server/network.cr
new file mode 100644
index 0000000..4e8c06d
--- /dev/null
+++ b/src/server/network.cr
@@ -0,0 +1,74 @@
+require "ipc"
+require "json"
+
+class JSONIPC
+	include JSON::Serializable
+
+	getter       type = -1
+	class_getter type = -1
+
+	property     id   : JSON::Any?
+
+	def handle(service : IPC::Service, event : IPC::Event::Events)
+		raise "unimplemented"
+	end
+
+	macro request(id, type, &block)
+		class {{id}} < ::JSONIPC
+			include JSON::Serializable
+
+			@@type = {{type}}
+			def type
+				@@type
+			end
+
+			{{yield}}
+		end
+	end
+end
+
+class IPC::Connection
+	def send(request : JSONIPC)
+		send request.type.to_u8, request.to_json
+	end
+end
+
+class FileStorage
+	class_getter requests  = [] of JSONIPC.class
+	class_getter responses = [] of JSONIPC.class
+end
+
+class FileStorage::Client < IPC::Client
+	def initialize
+		initialize "filestorage"
+	end
+end
+
+class FileStorage::Response
+	JSONIPC.request Error, 0 do
+		property mid : String
+		property reason : String | Array(String)
+
+		def initialize(@mid, @reason)
+		end
+	end
+	JSONIPC.request Success, 1 do
+		property mid : String
+		def initialize(@mid)
+		end
+	end
+end
+
+def parse_message(requests : Array(JSONIPC.class), message : IPC::Message) : JSONIPC?
+	request_type = requests.find &.type.==(message.utype)
+
+	payload = String.new message.payload
+
+	if request_type.nil?
+		raise "invalid request type (#{message.utype})"
+	end
+
+	request_type.from_json payload
+end
+
+require "../common/requests/*"
diff --git a/src/server/storage.cr b/src/server/storage.cr
new file mode 100644
index 0000000..afea7b9
--- /dev/null
+++ b/src/server/storage.cr
@@ -0,0 +1,150 @@
+require "json"
+require "uuid"
+require "uuid/json"
+require "openssl"
+
+require "dodb"
+require "base64"
+
+require "../common/utils"
+
+require "./storage/*"
+
+# private function
+def digest(value : String)
+
+	underlying_io = IO::Memory.new value
+	buffer = Bytes.new(4096)
+
+	io = OpenSSL::DigestIO.new underlying_io, "SHA256"
+	io.read buffer
+
+	io.digest.hexstring
+end
+
+# XXX TODO FIXME: architectural questions
+#   Why keeping upload and download requests?
+#   The server can be just for uploads, delegating downloads to HTTP.
+#   In environment without HTTP integration, this could still be pertinent.
+
+class FileStorage::Storage
+	property db : DODB::DataBase(TransferInfo)
+
+	# Search file informations by their index, owner and tags.
+	property db_by_filedigest : DODB::Index(TransferInfo)
+	property db_by_owner      : DODB::Partition(TransferInfo)
+	property db_by_tags       : DODB::Tags(TransferInfo)
+
+	def initialize(storage_directory, file_info_directory)
+		@db = DODB::DataBase(TransferInfo).new @file_info_directory
+
+		# Create indexes, partitions and tags objects.
+		@db_by_filedigest   = @db.new_index     "filedigest", &.file_info.digest
+		@db_by_owner        = @db.new_partition "owner",      &.owner.to_s
+		@db_by_tags         = @db.new_tags      "tags",       &.file_info.tags
+	end
+
+	# Reception of a file chunk.
+	def transfer(message : FileStorage::Transfer, user : User) : FileStorage::Response
+
+		# We received a message containing a chunk of file.
+		mid = message.mid
+		mid ||= "no message id"
+
+		# Get the transfer info from the db
+		transfer_info = @db_by_filedigest.get message.filedigest
+
+		if transfer_info.nil?
+			# The user has to send an upload request before sending anything.
+			# If not the case, it should be discarded.
+			raise "file not recorded"
+		end
+
+		chunk_number = message.chunk.n
+
+		data = Base64.decode message.data
+
+		# TODO: verify that the chunk sent was really missing.
+		if transfer_info.chunks.select(chunk_number).size > 0
+			write_a_chunk user.uid.to_s, transfer_info.file_info, chunk_number, data
+		else
+			raise "non existent chunk or already uploaded"
+		end
+
+		remove_chunk_from_db transfer_info, chunk_number
+
+		# TODO: verify the digest, if no more chunks.
+
+		FileStorage::Response::Transfer.new mid
+	rescue e
+		puts "Error handling transfer: #{e.message}"
+		FileStorage::Response.new mid.not_nil!, "Not Ok", "Unexpected error: #{e.message}"
+	end
+
+	# the client sent an upload request
+	def upload(request : FileStorage::Request::Upload, user : User) : FileStorage::Response
+
+		mid = request.mid
+		mid ||= "no message id"
+
+		puts "hdl upload: mid=#{request.mid}"
+		pp! request
+
+		# TODO: verify the rights and quotas of the user
+		# file_info attributes: name, size, nb_chunks, digest, tags
+
+		# First: check if the file already exists
+		transfer_info = @db_by_filedigest.get? request.file.digest
+		if transfer_info.nil?
+			# In case file informations aren't already registered
+			# which is normal at this point
+			transfer_info = TransferInfo.new user.uid, request.file
+			@db << transfer_info
+		else
+			# File information already exists, request may be duplicated
+			# In this case: ignore the upload request
+		end
+
+		FileStorage::Response::Upload.new request.mid
+	rescue e
+		puts "Error handling transfer: #{e.message}"
+		FileStorage::Response.new mid.not_nil!, "Not Ok", "Unexpected error: #{e.message}"
+	end
+
+	# TODO
+	# The client sent a download request.
+	def download(request : FileStorage::DownloadRequest, user : User) : FileStorage::Response
+
+		puts "hdl download: mid=#{request.mid}"
+		pp! request
+
+		FileStorage::Response::Download.new request.mid
+	end
+
+
+	# Entry point for request management
+	# Each request should have a response.
+	# Then, responses are sent in a single message.
+	def requests(requests : Array(FileStorage::Request),
+		user : User,
+		event : IPC::Event::Message) : Array(FileStorage::Response)
+
+		puts "hdl request"
+		responses = Array(FileStorage::Response).new
+
+		requests.each do |request|
+			case request
+			when FileStorage::DownloadRequest
+				responses << download request, user
+			when FileStorage::UploadRequest
+				responses << upload request, user
+			else
+				raise "request not understood"
+			end
+
+			puts
+		end
+
+		responses
+	end
+end
diff --git a/src/server/storage/file_info.cr b/src/server/storage/file_info.cr
new file mode 100644
index 0000000..cf69ed6
--- /dev/null
+++ b/src/server/storage/file_info.cr
@@ -0,0 +1,85 @@
+
+# For now, upload and download are sequentials.
+# In a future version, we will be able to send
+# arbitrary parts of each file.
+
+	# Who knows, maybe someday we will be on UDP, too.
+	#class SHA256
+	#	JSON.mapping({
+	#		chunk: Slice(UInt8)
+	#	})
+	#end
+
+class FileStorage
+
+	# 1 MB read buffer, on-disk
+	def self.file_reading_buffer_size
+		1_000_000
+	end
+
+	# 1 KB message data buffer, on-network
+	def self.message_buffer_size
+		1_000
+	end
+
+	# private function
+	def self.data_digest(data : Bytes)
+
+		iodata = IO::Memory.new data, false
+		buffer = Bytes.new FileStorage.file_reading_buffer_size
+
+		io = OpenSSL::DigestIO.new(iodata, "SHA256")
+		while io.read(buffer) > 0; end
+
+		io.digest.hexstring
+	end
+
+	# private function
+	def self.file_digest(file : File)
+		# 1M read buffer
+		buffer = Bytes.new(1_000_000)
+
+		io = OpenSSL::DigestIO.new(file, "SHA256")
+		while io.read(buffer) > 0 ; end
+
+		io.digest.hexstring
+	end
+end
+
+
+class FileStorage::Exception < ::Exception
+end
+
+class FileStorage::Chunk
+	include JSON::Serializable
+
+	property n      : Int32   # chunk's number
+	property on     : Int32   # number of chunks
+	property digest : String  # digest of the current chunk
+
+	def initialize(@n, @on, data)
+		@digest = FileStorage.data_digest data.to_slice
+	end
+end
+
+# A file has a name, a size and tags.
+class FileStorage::FileInfo
+	include JSON::Serializable
+
+	property name      : String
+	property size      : UInt64
+	property nb_chunks : Int32
+	property digest    : String
+
+	# list of SHA256, if we are on UDP
+	# chunks: Array(SHA256),
+	property tags : Array(String)
+
+	def initialize(file : File, tags = nil)
+		@name = File.basename file.path
+		@size = file.size
+		@digest = FileStorage.file_digest file
+		@nb_chunks = (@size / FileStorage.message_buffer_size).ceil.to_i
+		@tags = tags || [] of String
+	end
+end
diff --git a/src/server/storage/transfer-info.cr b/src/server/storage/transfer-info.cr
new file mode 100644
index 0000000..0b3539c
--- /dev/null
+++ b/src/server/storage/transfer-info.cr
@@ -0,0 +1,13 @@
+
+class TransferInfo
+	include JSON::Serializable
+
+	property owner : Int32
+	property file_info : FileStorage::FileInfo
+	property chunks : Array(Int32)
+
+	def initialize(@owner, @file_info)
+		@chunks = (0...@file_info.nb_chunks).to_a
+	end
+end
+
diff --git a/src/server/storage/user-data.cr b/src/server/storage/user-data.cr
new file mode 100644
index 0000000..5d8d9ca
--- /dev/null
+++ b/src/server/storage/user-data.cr
@@ -0,0 +1,21 @@
+require "json"
+require "uuid"
+require "uuid/json"
+
+
+# Keep track of connected users and their requests.
+# TODO: requests should be handled concurrently.
+class FileStorage::UserData
+	include JSON::Serializable
+
+	property uid       : Int32
+	property token     : AuthD::User::Public
+	property uploads   : Array(FileStorage::Request::Upload)
+	property downloads : Array(FileStorage::Request::Download)
+
+	def initialize(@token,
+		@uploads   = Array(FileStorage::Request::Upload).new,
+		@downloads = Array(FileStorage::Request::Download).new)
+		@uid = token.uid
+	end
+end