RexPro Messages

Communication over RexPro is achieved by sending and receiving messages that adhere to the format specified on this page. There are several clients that communicate via RexPro that would serve as good examples for how communication over RexPro works:

• Rexster Console
• RexsterClient – A Java language binding
• rexpro-python – A Python languge binding

Basic Message Structure

Evern RexPro message consists of the following segments:

[protocol version][message type][message size][message body]

segment	type(bytes)	description
protocol version	byte(1)	The version of RexPro. Currently this value should be zero.
message type	byte(1)	The type of message as described below.
message size	int(4)	The length of the message body
message body	int(n)	The body of the message itself containing the instructions for the RexPro Server.

Message Definitions

RexPro messages are divided into those that deal with requests made from the client and those that involved a response from the server. The following table represents an overview of the basic message set:

message	type	description
session	request	A request to open or close the session with the RexPro Server.
session	response	The response from the RexPro Server to a session request containing session information.
script	request	A request to process a Gremlin script on the RexPro Server.
script	response	A response to a script request. Script response messages actually refer to a set of response messages that are unique to each serialization channel (i.e. MsgPack, GraphSON, and Console).
error	response	A response from the RexPro Server indicating a problem has occurred.