Messages¶

Message structure¶

To exchange data betweeb its nodes, n3rv uses a specific message strucure which has the following format:

/** Main n3rv message struct */
typedef struct message_ {

  /** message sender (automatically filled) */
  std::string sender;
  std::string action;
  std::vector<std::string> args;
  std::string payload;

 } message;

This structure was choosen because it is in my opinion able to handle a wide variety of use cases. Nevertheless if you need extra fields for your own usage, it is easilly modifiable in both src/n3rvproto.hpp and src/protocol/(json|protobuf)

Serialization / Deserialization¶

As you may be already aware of, n3rv is able to encapsulate its messages either in JSON or Google Protocol Buffer format. To be able to support both of these serialization methods, the n3rv messages handler has an abstraction layer which is described in src/n3rvproto.hpp

std::string serialize_msg(n3rv::message& msg);

n3rv::message parse_msg(std::string msgstr);

Raw data (byte sequences) Exchange between nodes¶

You may have seen that the type for the payload member of a n3rv message is std::string. Although not very recommanded to avoid confusion, std::string makes a suitable container for byte arrays (remember, c++ strings are not null-terminated). Nevertheless, if you don’t feel comfy with this statement, then feel free to change the n3rv::message.payload type to eg std::vector<std::byte> or whatever feels appropriate for you.