C++ client unable to access the blob data

[liusitan]

Describe your problem

I was trying to use the c++ client to put "hello vineyard" into the vineyard instance and get "hello vineyard" from the instance. However, the blob that I got from the vineyard instance can not provide the "hello vineyard".
Here is the screenshot

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If is is a bug report, to help us reproducing this bug, please provide information below:

1. Your Operation System version (macos 12.6):
2. The version of vineyard you use ('0.6`):
3. Versions of crucial packages:
   Apple clang version 13.1.6 (clang-1316.0.21.2)
   Target: x86_64-apple-darwin21.4.0
   Thread model: posix
4. Minimized code to reproduce the error:

My main.cc

#include<vineyard/client/client.h>
#include<vineyard/client/ds/blob.h>
#include<vineyard/client/ds/core_types.h>
#include<vineyard/client/ds/i_object.h>
using namespace vineyard;
int main(){
    vineyard::Client* c = new vineyard::Client();
    VINEYARD_CHECK_OK( c->Connect("/var/run/vineyard.sock3"));

    //create a metadata and store it in the vineyard instance
    auto id = vineyard::InvalidObjectID();
    auto om = vineyard::ObjectMeta();
    om.AddKeyValue("date","xxx");
    om.AddKeyValue("location","xxx");
    om.SetTypeName("string");
    std::string str ( "Hello Vineyard");
    std::unique_ptr<BlobWriter> blob;
    VINEYARD_CHECK_OK(c->CreateBlob(str.size(), blob));
    std::memcpy(blob->data(), str.c_str(), str.size());
    om.AddMember("_buffer",blob->Seal(*c));
    std::cout<<blob->data()<<"blob size"<<blob->size()<<std::endl;
    VINEYARD_CHECK_OK(c->CreateMetaData(om,id));


    //get the object from vienayrd instance
    std::unique_ptr<ObjectMeta> rom;//received object meta
    c->GetMetaData(id,*rom);
    auto buffer = rom->GetMember("_buffer");
    // auto receivedBlob =  std::reinterpret_pointer_cast<Blob>(buffer);
    auto receivedBlob = std::dynamic_pointer_cast<vineyard::Blob>(buffer);
    receivedBlob->data();
    std::cout<<receivedBlob->data()<<std::endl;


}

My CMakeLists.txt:

PROJECT(FuseWrapper)
SET(SRC_LIST main.cc)
set(VINEYARD_CLIENT_HEADER /usr/local/include)
set(VINEYARD_HEADER /usr/local/include/vineyard)
set(VINEYARD_COMMON_HEADER  /usr/local/include/vineyard/common)
set(VINEYARD_CONTRIB_HEADER /usr/local/include/vineyard/contrib)
# set(VIENYARD_CLIENT_DS_HEADER  /usr/local/include/vineyard/client/ds)
link_directories(BEFORE /usr/local/lib)
include_directories(BEFORE SYSTEM ${VINEYARD_CLIENT_HEADER} ${VINEYARD_HEADER} ${VINEYARD_COMMON_HEADER} ${VINEYARD_CONTRIB_HEADER})
add_executable(hello_vineyard ${SRC_LIST})
set_property(TARGET hello_vineyard PROPERTY CXX_STANDARD 14)

# target_link_libraries(hello_vineyard -L)
target_link_libraries(hello_vineyard PUBLIC vineyard_client
                                           vineyard_basic)

[liusitan]

Then I tried to create a vineyard object through the python client first, and access the data from the c++ client, however, it also failed.
Same environment as above. Below is my screenshot

codes are as following:

#include<vineyard/client/client.h>
#include<vineyard/client/ds/blob.h>
#include<vineyard/client/ds/core_types.h>
#include<vineyard/client/ds/i_object.h>
using namespace vineyard;
int main(){
    vineyard::Client* c = new vineyard::Client();
    VINEYARD_CHECK_OK( c->Connect("/var/run/vineyard.sock"));
    auto id = 0x000005bfffe9e5f6;
    std::unique_ptr<ObjectMeta> rom;//received object meta
    VINEYARD_CHECK_OK(c->GetMetaData(id,*rom));
    std::cout<<rom->ToString();
    return 0 ;
}

import vineyard
c = vineyard.connect('/var/run/vineyard.sock')
c.put('hello vineyard')
id = _
c.get(id)

[sighingnow]

The error is because you are dereferencing a null std::unique_ptr. To make your code work, you need

    //get the object from vienayrd instance
-   std::unique_ptr<ObjectMeta> rom;//received object meta
+   std::unique_ptr<ObjectMeta> rom(new ObjectMeta{});//received object meta
    c->GetMetaData(id,*rom);
    auto buffer = rom->GetMember("_buffer");
    // auto receivedBlob =  std::reinterpret_pointer_cast<Blob>(buffer);
    auto receivedBlob = std::dynamic_pointer_cast<vineyard::Blob>(buffer);
    receivedBlob->data();
    std::cout<<receivedBlob->data()<<std::endl;

[sighingnow]

Close as answered.