mongodbperlresponseupsertbless

Attempt to access upserted_id property in perl MongoDB Driver returns useless HASH(0x3572074)

I have a Perl script that pulls a table from a SQL database ($row variable) and attempts to do a MongoDB update like so: 

my $res = $users->update({"meeting_id" => $row[0]},
            {'$set' => {
                "meeting_id" => $row[0],
                "case_id" => $row[1],
                "case_desc" => $row[2],
                "date" => $row[3],
                "start_time" => $row[4],
                "end_time" => $row[5],
                #"mediator_LawyerID" => $row[6],
                "mediator_LawyerIDs" => \@medLawIds,
                "case_number" => $row[6],
                "case_name" => $row[7],
                "location" => $row[8],
                "number_of_parties" => $row[9],
                "case_manager" => $row[10],
                "last_updated" => $row[11],
                "meeting_result" => $row[12],
                "parties" => \@partyList
                }},
                {'upsert' => 1}) or die "I ain't update!!!";

My client now wants ICS style calendar invites sent to their mediators. Thus, I need to know whether an update or insert happened. The documentation for MongoDB::UpdateResult implies that this is how you access such a property:

my $id = $res->upserted_id;

So I tried:

bless ($res,"MongoDB::UpdateResult");
my $id = $res->upserted_id;

After this code $id is like:

HASH(0x356f8fc)

Are these the actual IDs? If so, how do I convert to a hexadecimal string that can be cast to Mongo's ObjectId type? It should be noted I know absolutely nothing about perl; if more of the code is relevant, at request I will post any section ASAP. Its 300 lines so I didn't want to include the whole file off the bat.

EDIT: I should mention before anyone suggests this that using update_one instead of update returns the exact same result.

Solution

  • HASH(0x356f8fc) is a Perl Hash reference. It's basically some kind of (internal) memory address of some data.

    The easiest way to get the contents is Data::Dumper:

    use Data::Dumper
[...]
my $result = $res->upserted_id;
print Dumper($result);

    HASH(0x356f8fc) is just the human readable representation of the real pointer. You must dump it in the same process and can't pass it from one to another.

    You'll probably end up with something like

    `my $id = $result->{_id};`

    See the PerlRef manpage for details.

    See also the MongoDB documentation about write concern.

    PS: Also remember that you could use your own IDs for MongoDB. You don't need to work with the generated ones.