BlenderRestAPI.c

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// // The BlenderRestAPI class provides a way to communicate with Blender from Workbench using a REST API. 
// // See BlenderEndpoints.c for info about available endpoints. 
//
// // Example: 
//
// // Create a connection to Blender. 
// // This will handle launching the Blender process and starting the HTTP server. 
// // If a port is not specified, a random port will be used in the range (50000-65000). 
// // Multiple connections can exist at a time. 
// auto connection = BlenderRestAPI.Create();
//
// // Load the specified .blend file. 
// auto open_blend_result = OpenBlendFile(connection, "W:/my_blender_file.blend");
//
// if (!open_blend_result) 
// {
//  Print("Unable to open blend file", LogLevel.ERROR);
//  return;
// }
//  
// // Get a list of the objects in the scene 
// array<string> objects = GetObjects(connection);
//
// foreach (string object : objects) { 
//  auto transform = GetTransform(connection, object);
//  Print(transform.location);
//  Print(transform.rotation);
//  Print(transform.scale);
// }
// connection.Destroy();
// return;
 
 
 
enum BlenderRestAPIState  {
    WAITING = 0,
    SUCCESS = 1,
    ERROR = 2,
};
 
class BlenderRestAPI
{       
    private void OnRestSuccessCallback(RestCallback cb)
    {   
        m_RestState = BlenderRestAPIState.SUCCESS;
        m_Response = cb.GetData();
    }
    
    private void OnRestErrorCallback(RestCallback cb)
    {   
        m_RestState = BlenderRestAPIState.ERROR;
    }
    
    
    // HTTP API
    
    bool Get(string endpoint, out string data = "")
    { 
        this.m_Response = "";
        m_RestState = BlenderRestAPIState.WAITING;
        
        m_RestContext.GET(m_RestCallback, endpoint);
        
        while (m_RestState == BlenderRestAPIState.WAITING) {
            Sleep(10);
        }
        
        data = m_Response;
        return m_RestState == BlenderRestAPIState.SUCCESS;
    }
    
    // TODO POST, maybe others? 
    
    
    static BlenderRestAPI Create(int port = -1) 
    {
        string path;
        
        if (!EBTConfigPlugin.GetDefaultBlenderPath(path)) {
            Print("Failed to get Blender path. Make sure you have Blender setup using EBT: Config", LogLevel.ERROR);    
            return null;
        }
        
        // See https://en.wikipedia.org/wiki/Ephemeral_port
        if (port == -1) {
            port = 50000 + Math.RandomInt(0, 15000);
        }
        
        string address = string.Format("http://localhost:%1", port);
    
        string python_command = string.Format("import bpy; bpy.ops.ebt.start_http_server(port=%1)", port);
        string cmd = string.Format("\"%1\" --background --python-expr \"%2\"", path, python_command);
        
        Print(string.Format("Running Blender Instance on %1", address));
            
        auto blender_process = Workbench.RunProcess(cmd);
        
        if (!blender_process || !Workbench.IsRunningProcess(blender_process))
        {
            Print("Unable begin Blender process", LogLevel.ERROR);
            return null;
        }
        
        auto rest_context = GetGame().GetRestApi().GetContext(address);
        
        if (!rest_context)
        {
            Print("Unable to obtain REST context for " + address, LogLevel.ERROR);
            return null;
        }
        
        auto instance = BlenderRestAPI();
        instance.m_BlenderProcess = blender_process;
        instance.m_RestContext = rest_context;
        instance.m_RestContext.SetTimeout(200);
        instance.m_RestCallback = RestCallback();
        instance.m_RestCallback.SetOnSuccess(instance.OnRestSuccessCallback);
        instance.m_RestCallback.SetOnError(instance.OnRestErrorCallback);   
        
        return instance;
    }
    
    void Destroy() {
        if (Workbench.IsRunningProcess(m_BlenderProcess)) {
            Workbench.KillProcess(m_BlenderProcess);
        }
    }
    
    private ProcessHandle    m_BlenderProcess;
    private RestContext      m_RestContext;     
    private ref RestCallback m_RestCallback;
    
    // Response Handling
    private string              m_Response = "";    
    private BlenderRestAPIState m_RestState = BlenderRestAPIState.WAITING; 
}