We are using protobuf-net to handle our Protocol Buffer needs in a C# application. Since we share our .proto files with other, non-managed applications, we are generating our code from the .proto files (not using the code-first protobuf-net approach). In order to stay as DRY as possible, we keep a lot of interface documentation inside the .proto files themselves. We generate the C# code by means of protogen.exe, called by a project build target.
Now, is there any way to (automatically) transfer these comments into the compiled C# code?
Basically, given a .proto like this:
// This message is used to request a resource from the server
message GetResource
{
// The identifier of the requested resource
required string resourceId = 1;
}
...I would like something like this (IExtensible methods omitted for readability):
/// <summary>
/// This message is used to request a resource from the server
/// </summary>
[global::System.Serializable,global::ProtoBuf.ProtoContract(Name=@"GetResource")]
public partial class GetResource : global::ProtoBuf.IExtensible
{
public GetResource() {}
private string _resourceId;
/// <summary>
/// The identifier of the requested resource
/// [Required] <-- Would be nice...
/// </summary>
[global::ProtoBuf.ProtoMember(1, IsRequired = true, Name=@"resourceId",
DataFormat = global::ProtoBuf.DataFormat.Default)]
public string ResourceId
{
get { return _resourceId; }
set { _resourceId = value; }
}
}
At the current time, I believe the answer is "no". To the best of my knowledge, "protoc" (Google's tool for parsing .proto files, which is used under the hood) silently discards the comments - so there is nothing available to read from. If a custom parser was written, then yes it would be possible, but there is also a language ambiguity about which comments apply to which lines, for example:
// this probably relates to resourceId
required string resourceId = 1;
required int foo = 2; // but... is this foo? or bar?
// and what about this?
// what does this relate to? and why?
// and this? what are the rules?
required int bar = 3;
So for 2 different reasons: at the moment, no. All suggestions considered, though... especially if they come with a custom parser included :)
Note that AFAIK this information is missing from most (all?) implementations for this reason. I'm happy to be corrected, though.