Executing Stored Function with params

[M.]

Hello,

I'm trying to execute a stored function like this from node.js.

this.db.eval('identity', 100, function(err, doc) {
console.log(doc);
});

Inside the database, there is identity function like this.

db.system.js.save(
{
_id : 'identity',
value : function (id) {
return id;
}
}
);

The result I want is 100 but it returns identity function itself. It
could be done something like db.eval('identity(100)', function(..)
{...})
However, I'd really love to pass parameters by object format, not by
textual representation.

Any idea?

Thanks.

[christkv]

examples of usage in

https://github.com/christkv/node-mongodb-native/blob/master/test/db_test.js#L130

but basically

client.eval('function (x, y) {return x + y;}', [2, 3], function(err, result) {

  test.equal(5, result);

});

[Phill Rosen]

Did you ever get this resolved? I am seeing issues with this currently. Save database, same credentials.

From console I do:

db.system.js.save({ "_id" : "echo", "value" : function(x){return x;} })  

> db.eval("echo('test')")

test

However from the node driver:

db.eval("echo('test')", function (err, res) {

console.log(err);

}

Produces:

eval failed: invoke failed: JS Error: ReferenceError: echo is not defined nofile... (length: 84)

[christkv]

can you post a ticket with some code on github. I'll have a look during the week.

One big observation that will save you a lot of pain and suffering. Don't execute javascript on the server as part of you business logic it will seriously hamper your scalability. The reasons are very simple.

1. The javascript engine is single threaded (spidermonkey)

2. Eval will take out a write lock for the entire duration of the execution limiting your ability to scale writes.

I know it's tempting but javascript on mongodb was never designed to be mongodb stored procedures. The only valid reason is if you are using them during f.ex map-reduce jobs.