Saving and reading binary content into postgres - c++

Question

I'm trying to save binary data from a file metadata.mfs into the postgres database and then reading from the database, grab the saved binary data and load it into a file. For the purpose of illustrating my goal lets also call it metadata.mfs with the same name but in a different directory. When I run md5sum metadata.mfs on both files I am expecting to see the same hash. (Essentially I want whatever is saved into the database from file1 be exactly the same as what I extract from the database in file2)
Currently I am not able to achieve that.
Below is what I have so far:
string readFile2(const string &fileName)
{
ifstream ifs(fileName.c_str(), ios::in | ios::binary | ios::ate);
ifs.seekg(0, ios::end);
ifstream::pos_type fileSize = ifs.tellg();
ifs.seekg(0, ios::beg);
vector<char> bytes(fileSize);
ifs.read(bytes.data(), fileSize);
cout.write(bytes.data(),bytes.size());
cout << "\n";
cout << fileSize;
cout << "\n";
// return bytes.data();
return string(bytes.data(), fileSize);
}
int main() {
string content;
string test = "h";
char test1 = 'C';
try {
cout << "A1 \n";;
content = readFile2("/var/opt/lizardfs/lib/lizardfs/metadata.mfs");
pqxx::connection c("postgresql://mark#localhost:26257/metadata");
pqxx::nontransaction w(c);
w.exec("CREATE TABLE IF NOT EXISTS binary (id INT PRIMARY KEY, meta bytea)");
w.exec("INSERT INTO binary (id,meta) VALUES (18, '"+w.esc_raw(content)+"')");
pqxx::result r = w.exec("SELECT meta FROM binary WHERE id='18'");
std::ofstream outfile("metadata.mfs");
for (auto row: r) {
cout << row[0] << endl;
outfile << row[0] << endl;
}
outfile.close();
w.commit()
}
The problem is that cout.write(bytes.data(),bytes.size()); prints out exactly the same as what I would see in the linux terminal if I run cat metadata.mfs, but from cout << row[0] << endl I see everything in hex, ie, \x4c495a4d20322e39000021....
I suspect this is because I am using w.esc_raw() on the binary content before inserting into postgres. Does that mean I need to unescape, ie using w.unesc_raw() after extracting the binary data from the database? But how would I do that? I've been looking at the docs here: https://libpqxx.readthedocs.io/en/6.1.1/a00225.html