Asset Manager

eldiren

I'm looking into developing my own content browser of sorts. An interface into a a version control system we have at our studio. I was looking into the Url api, and I remembered that you guys have that whole preset:// thing going with lib4d assets. Is it possible using the C++ that I could resolve my own custom URL/URIs to assets and images in C4D, or is the preset:// thing custom logic internal to only the built in content browser.

s_bach

Hello,

as always, please use the Q&A system to mark your post as a question.

You can register a custom URL scheme. This scheme defines how a data connection is created for the given URL.

The Url schemes is defined by implementing IoHandlerInterface; the connection by implementing IoConnectionInterface.

This is a simple example of such implementations:

#include "maxon/ioconnection.h"
#include "maxon/iohandler.h"


class MyIOImpl : public maxon::Component<MyIOImpl, maxon::IoConnectionInterface>
{
  MAXON_COMPONENT(NORMAL, maxon::IoConnectionBaseClass);

public:
  maxon::ResultOk<void> Init(const maxon::Url& name)
  {
    _url = name;

    return maxon::OK;
  }

  maxon::Result<maxon::Url> ResolveMyScheme()
  {
    iferr_scope;

    // resolve custom scheme
    maxon::String resolvedPath { "file:///c:/assets/" };
    resolvedPath.Append(_url.GetPath()) iferr_return;

    return maxon::Url { resolvedPath };
  }

  MAXON_METHOD const maxon::Url& GetUrl() const
  {
    return _url;
  }

  MAXON_METHOD maxon::Result<maxon::OutputStreamRef> OpenOutputStream(maxon::OPENSTREAMFLAGS flags)
  {
    iferr_scope;

    return ResolveMyScheme().OpenOutputStream();
  }

  MAXON_METHOD maxon::Result<maxon::InputStreamRef> OpenInputStream(maxon::OPENSTREAMFLAGS flags)
  {
    iferr_scope;
    return ResolveMyScheme().OpenInputStream();
  }

  MAXON_METHOD maxon::Result<maxon::InOutputStreamRef> OpenInOutputStream(maxon::OPENSTREAMFLAGS flags)
  {
    iferr_scope;
    return ResolveMyScheme().OpenInOutputStream();
  }

  MAXON_METHOD maxon::Result<maxon::IOATTRIBUTES> IoGetAttributes() const
  {
    return maxon::IOATTRIBUTES::GROUP_R | maxon::IOATTRIBUTES::GROUP_W | maxon::IOATTRIBUTES::OWNER_R | maxon::IOATTRIBUTES::OWNER_W | maxon::IOATTRIBUTES::PUBLIC_R | maxon::IOATTRIBUTES::PUBLIC_W;
  }

  MAXON_METHOD maxon::Result<maxon::UniversalDateTime> IoGetTime(maxon::IOTIMEMODE mode) const
  {
    return maxon::UniversalDateTime::GetNow();
  }

private:
  maxon::Url _url;
};

MAXON_COMPONENT_CLASS_REGISTER(MyIOImpl, "net.maxon.class.iocustom");

static maxon::Id g_myAssetScheme { "myassets" };

class MyHandlerImpl : public maxon::Component<MyHandlerImpl, maxon::IoHandlerInterface>
{
  MAXON_COMPONENT(NORMAL, maxon::IoHandlerObjectBaseClass);

public:
  MAXON_METHOD const maxon::Id& GetUrlScheme() const
  {
    return g_myAssetScheme;
  }

  MAXON_METHOD maxon::Result<maxon::IoConnectionRef> OpenConnection(const maxon::Url& name) const
  {
    return MyIOImpl::CreateInit(name);
  }

  MAXON_METHOD maxon::Result<maxon::Url> Normalize(const maxon::Url& url, maxon::NORMALIZEFLAGS flags) const
  {
    return url;
  }

  MAXON_METHOD maxon::Result<maxon::Url> IoNormalize(const maxon::Url& url, maxon::NORMALIZEFLAGS flags) const
  {
    return url;
  }
};

MAXON_COMPONENT_OBJECT_REGISTER(MyHandlerImpl, maxon::IoHandlers, "net.maxon.iohandler.custom");

This is how this scheme would be used:

const maxon::Url myUrl { "myassets:///test.txt"_s };


// open input stream and get file size
const maxon::InputStreamRef inputStream = myUrl.OpenInputStream() iferr_return;
const maxon::Int length = inputStream.GetStreamLength() iferr_return;
maxon::BaseArray<maxon::Char> data;
data.Resize(length) iferr_return;
inputStream.Read(data) iferr_return;

// convert to string
const maxon::String text { data };
DiagnosticOutput("File Content: @", text);

best wishes,
Sebastian

s_bach

Update: the previous version of the code had some ill-formatted statements. You can actually define the scheme as part of the Url, without setting it using SetScheme():

const maxon::Url myUrl { "myassets:///test.txt"_s };

Thus, the path is resolved just by adding the path to the target folder:

maxon::String resolvedPath { "file:///c:/assets/" };
resolvedPath.Append(_url.GetPath()) iferr_return;

best wishes,
Sebastian