Search when id is UUID Binary

[Diego Medina]

Hi,

I have an application that uses the java driver to save a java UUID as the _id on a collection. Then I have the string representation of the UUID in Go, and I need to search this collection to get the document from mongoDB

I tried this:

mongoExtSess.Find(bson.M{

"_id": bson.Binary{

Kind: 0x03,

Data: []byte(cookie.Value),

},

}).One(&ext)

cookie.Value is something like `39bc5eba-a25c-4638-90a8-57682885d074`

but this isn't finding anything. I think the problem is that I'm simply converting the string of the UUID into a []byte, but I don't know what's the correct way to do this.

Thanks

Diego

[Diego Medina]

I figured it out!

First you need one of the uuid libraries foe Go, I used github.com/satori/go.uuid

But turns out that the java driver for MongoDB changes the order of the bytes in the uuid, so you need to reorder them in your go code:

//this is my doc in Mongo

var ext1 struct {

ID        bson.Binary `bson:"_id"`

Expires   time.Time

UserID    bson.ObjectId `bson:"userId"`

CompanyID bson.ObjectId `bson:"companyId"`

}

//cookie.Value has the uuid as string generated by the Java driver

u, err := uuid.FromString(cookie.Value)

if err != nil {

fmt.Printf("Something gone wrong: %s\n\n", err)

}

//Here we match the order the java driver uses

var searchID []byte

for x := 7; x > -1; x-- {

searchID = append(searchID, u[x])

}

for x := 15; x > 7; x-- {

searchID = append(searchID, u[x])

}

mongoExtSess.Find(bson.M{

"_id": bson.Binary{

Kind: 0x03,

Data: searchID[:],

},

}).One(&ext1)

//This works now and it finds the right document

log.Printf("search using uuid: %+v\n", searchID[:])

log.Printf("result: %+v\n", ext1.ID)

Thank you.