SODEP Protocol

SODEP (Simple Operation Data Exchange Protocol) is a binary protocol created and developed for Jolie, in order to provide a simple, safe and efficient protocol for service communications.

Protocol name in port definition: sodep.


SODEP Parameters

type SodepConfiguration:void {
    /*
     * Defines the character set to use for (de-)coding strings.
     *
     * Default: "UTF-8"
     * Supported values: "US-ASCII", "ISO-8859-1", 
     * "UTF-8", ... (all possible Java charsets)
     */
    .charset?:string

    /*
     * Defines whether the underlying connection should be kept open.
     *
     * Default: true
     */
    .keepAlive?:bool
}

SODEP data

SODEP maps three Jolie internal data structures: CommMessage?, FaultException?, and Value.

Basically, a SODEP message is the encoding of a CommMessage? object.

For the sake of clarity, we show (in Java pseudo-code) how these structures are composed and the meaning of their content before giving the formal specifications of the protocol.

CommMessage

  • long id: a unique identifier for this message, generated from the requester;
  • String resourcePath: the resource path this message should be delivered to. If the message is meant to be received from the service you are communicating with, the resource path should be "/";
  • String operationName: the operation name this message refers to;
  • FaultException? fault: the fault exception this message contains, if any;
  • Value value: the data this message contains, if any.

FaultException

  • String faultName: the fault name this FaultException? refers to;
  • Value value: the data regarding this fault, if any.

Value

  • Object content: the content of this value. Can be a String, an Integer, or a Double;
  • Map< String, Value[] > ``: the children vectors of this value, mapped by name.

Formal specification

We represent the protocol encoding by using a BNF-like notation. Raw data types are supplied with additional information in round parentheses, in order to indicate what they represent.

  • true and false are the respective boolean values;
  • null is the Java null value;
  • int is a 32-bit integer value;
  • long is a 64-bit integer value;
  • double is a 64-bit double value;
  • String elements are to be intended as standard UTF-8 encoded strings;
  • * is to be intended as the Kleene star (zero or more repetition);
  • raw numbers annotated with byte are to be considered single bytes;
  • the special keyword epsilon means nothing.
SODEPMessage    ::= long(message id) String(resource path) String(operation name) Fault Value

String     ::= int(string length) string(UTF-8 encoded)

Fault     ::= true String(fault name) Value(fault additional data) | false

Value     ::= ValueContent int(how many ValueChildren) ValueChildren*

ValueContent    ::= 0(byte) | 1(byte) String | 2(byte) int | 3(byte) double | 4(byte) byte array | 5(byte) bool | 6(byte) long

ValueChildren    ::= String(child name) int(how many Value) Value* | epsilon

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