This module is a composite of other open source modules and original code to make interfacing with the Protocol Buffers protocol easy.
Encoding is simple.
1> protobuffs:encode(1, 1, uint32).
<<8,1>>
2> erlang:iolist_to_binary([
protobuffs:encode(1, <<"Nick">>, string),
protobuffs:encode(2, 25, uint32)
]).
<<10,4,78,105,99,107,16,25>>
Decoding is simple too.
1> protobuffs:decode(<<8, 1>>, uint32).
{{1, 1}, <<>>}
2> protobuffs:decode(<<10,4,78,105,99,107,16,25>>, bytes).
{{1, <<"Nick">>}, <<16,25>>}
3> protobuffs:decode(<<16,25>>, bytes).
{{2, 25}, <<>>}
The main objective of this module is to allow developers to use .proto files easily. This module provides very basic functionality to do so.
Consider the t/simple.proto file.
message Person {
required string name = 1;
required string address = 2;
required string phone_number = 3;
required int32 age = 4;
}
From that file we can create an Erlang module that can encode and decode the Person message into records.
1> protobuffs_compile:scan_file("simple.proto").
ok
2> simple_pb:decode_person(<<10,4,78,105,99,107,18,13,77,111,...>>).
{person,<<"Nick">>,<<"Mountain View">>, <<"+1 (000) 555-1234">>,25}
3> simple_pb:encode_person({person, <<"Nick">>, <<"Mountain View">>,
<<"+1 (000) 555-1234">>,25}).
<<10,4,78,105,99,107,18,13,77,111,117,110,116,97,105,110,32,86,105,...>>
How cool is that? From .proto files, we create modules that export encode and decode functions for the messages defined.
It't also posible to create a escript "bin/protoc-erl" this self contained script generates a source code (.erl) file and a header (.hrl) file.
&>./protoc-erl path_to_proto_file
The protobuffs_compile module relies on the pokemon_pb module being compiled with debug info. This is because pokemon_pb serves as a template for generated _pb modules. Running protobuffs_compile:scan_file/1 reads the erlang forms from the pokemon_pb.beam file and expands and alters those forms to create the generated module.
To compile
&>./rebar compile
To run all tests
&>./rebar eunit
&>./rebar ct
Se rebar doc for more information.
A simple makefile is also included
&>make
&>make test
&>make eunit
&>make ct
&>make escriptize
Some of the protobuffs.erl module came from code written by Brian Buchanan.
Some of the protobuffs_compile.erl module came from code written by Tim Fletcher.
Original written by Nick Gerakines. Major contributions have been made by Jacob Vorreuter.
Leex/Yecc parser, and most of the test cases by David Åberg