I'm trying to use protobuf in a C# project, using protobuf-net, and am wondering what is the best way to organise this into a Visual Studio project structure.
When manually using the protogen tool to generate code into C#, life seems easy but it doesn't feel right.
I'd like the .proto file to be considered to be the primary source-code file, generating C# files as a by-product, but before the C# compiler gets involved.
The options seem to be:
- Custom tool for proto tools (although I can't see where to start there)
- Pre-build step (calling protogen or a batch-file which does that)
I have struggled with 2) above as it keeps giving me "The system cannot find the file specified" unless I use absolute paths (and I don't like forcing projects to be explicitly located).
Is there a convention (yet) for this?
Edit: Based upon @jon's comments, I retried the pre-build step method and used this (protogen's location hardcoded for now), using Google's address-book example:
c:\bin\protobuf\protogen "-i:$(ProjectDir)AddressBook.proto"
"-o:$(ProjectDir)AddressBook.cs" -t:c:\bin\protobuf\csharp.xslt
Edit2: Taking @jon's recommendation to minimise build-time by not processing the .proto files if they haven't changed, I've knocked together a basic tool to check for me (this could probably be expanded to a full Custom-Build tool):
using System;
using System.Diagnostics;
using System.IO;
namespace PreBuildChecker
{
public class Checker
{
static int Main(string[] args)
{
try
{
Check(args);
return 0;
}
catch (Exception e)
{
Console.WriteLine(e.Message);
return 1;
}
}
public static void Check(string[] args)
{
if (args.Length < 3)
{
throw new ArgumentException(
"Command line must be supplied with source, target and command-line [plus options]");
}
string source = args[0];
string target = args[1];
string executable = args[2];
string arguments = args.Length > 3 ? GetCommandLine(args) : null;
FileInfo targetFileInfo = new FileInfo(target);
FileInfo sourceFileInfo = new FileInfo(source);
if (!sourceFileInfo.Exists)
{
throw new ArgumentException(string.Format(
"Source file {0} not found", source));
}
if (!targetFileInfo.Exists ||
sourceFileInfo.LastWriteTimeUtc > targetFileInfo.LastAccessTimeUtc)
{
Process process = new Process();
process.StartInfo.FileName = executable;
process.StartInfo.Arguments = arguments;
process.StartInfo.ErrorDialog = true;
Console.WriteLine(string.Format(
"Source newer than target, launching tool: {0} {1}",
executable,
arguments));
process.Start();
}
}
private static string GetCommandLine(string[] args)
{
string[] arguments = new string[args.Length - 3];
Array.Copy(args, 3, arguments, 0, arguments.Length);
return String.Join(" ", arguments);
}
}
}
My pre-build command is now (all on one line):
$(SolutionDir)PreBuildChecker\$(OutDir)PreBuildChecker
$(ProjectDir)AddressBook.proto
$(ProjectDir)AddressBook.cs
c:\bin\protobuf\protogen
"-i:$(ProjectDir)AddressBook.proto"
"-o:$(ProjectDir)AddressBook.cs"
-t:c:\bin\protobuf\csharp.xslt
