Asset Manager
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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.
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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 -
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