erpcgen

Erlang RPC Stub Generator - A code generator for Sun ONC/RPC (RFC 1831/1832) client and server stubs.

Overview

erpcgen generates Erlang source code from XDR (External Data Representation) specification files (.x files). It creates encoder/decoder modules, client stubs, and server stubs for building RPC-based distributed systems in Erlang.

This package conforms to RFC 1831 (RPC) and RFC 1832 (XDR).

Features

• Generate XDR encoder/decoder modules from .x specification files
• Generate RPC client stub modules
• Generate RPC server stub modules (gen_server or callback-based)
• Support for all XDR data types: int, hyper, float, double, bool, enum, struct, union, arrays, strings, opaque
• TCP and UDP protocol support

Requirements

• Erlang/OTP 22 or later (tested up to OTP 28)
• rebar3

Build

make compile
# or
rebar3 compile

Test

make test

Usage

API

%% Generate all stubs (header, client, server, xdr)
erpcgen:file(proto).

%% Generate with specific options
erpcgen:file(proto, [client]).

%% Generate with different output basename
erpcgen:file(proto, output, [xdrlib]).

Options

Option	Description
hrl	Generate <Out>.hrl header file
clnt	Generate <Out>_clnt.erl client module
svc	Generate <Out>_svc.erl server module (gen_server)
svc_callback	Generate <Out>_svc.erl server module (rpc_server callback)
xdr	Generate <Out>_xdr.erl encoder/decoder module
xdr_inc	Generate <Out>_xdr.hrl include file
client	Shortcut for [hrl, clnt, xdr]
server	Shortcut for [hrl, svc, xdr, svc_stub]
xdrlib	Shortcut for [hrl, xdr]
all	Shortcut for [hrl, clnt, svc, xdr, svc_stub] (default)

Example

Given an XDR specification file myproto.x:

enum status {
  OK = 0,
  ERROR = 1
};

struct request {
  int id;
  string name<255>;
};

struct response {
  status stat;
  opaque data<>;
};

program MYPROTO_PROG {
  version MYPROTO_VERS {
    response PROCESS(request) = 1;
  } = 1;
} = 100000;

Generate the Erlang modules:

1> erpcgen:file(myproto, [all]).
[ok,ok,ok,ok,ok]

This generates:

• myproto.hrl - Header file with constants
• myproto_xdr.erl - XDR encoder/decoder functions
• myproto_clnt.erl - Client stub functions
• myproto_svc.erl - Server stub functions

XDR Data Type Representation in Erlang

XDR Type	Erlang Representation
int, unsigned int	integer
hyper, unsigned hyper	integer
float, double	float
bool	true | false
string	binary
opaque	binary
enum	atom (e.g., 'OK')
struct	tuple
union	{Discriminant, Value}
array	list

Generated XDR Functions

%% Encode a term to iolist
myproto_xdr:enc_request({1, <<"hello">>}).

%% Decode binary to term
{Term, NewOffset} = myproto_xdr:dec_request(Binary, Offset).

Documentation

See doc/README and doc/API.txt for detailed API documentation.

License

Apache License 2.0

Authors

• Original: Sendmail, Inc. (2000-2001)
• Maintained by: Lions Data, Ltd.