how to fetch the unknown mongo doc via mgo - mongodb

Question

Here is the piece of code that is trying to fetch all the docs from the mongodb.
func fetchAll(db *mgo.Database) map[string]interface {
var msg map[string]interface{}
err := db.C("msg").Find(nil).All(&msg)
if err != nil {
panic(err)
}
return msg
}
I got the error: syntax error: unexpected var
What is wrong here? And is there a better way to fetch the arbitrary mongo docs via mgo?
thanks

Answer 1

First, fix the syntax error:
func fetchAll(db *mgo.Database) map[string]interface{} {
var msg map[string]interface{}
err := db.C("msg").Find(nil).All(&msg)
if err != nil {
panic(err)
}
return msg
}
Note the {} in the function return type declaration.
But there's more. All() retrieves all documents from the result set to a slice. Change the return type to a slice of maps:
func fetchAll(db *mgo.Database) []map[string]interface{} {
var msgs []map[string]interface{}
err := db.C("msg").Find(nil).All(&msgs)
if err != nil {
panic(err)
}
return msgs
}
While we are at it, let's return the error instead of panicking.
func fetchAll(db *mgo.Database) ([]map[string]interface{}, error) {
var msgs []map[string]interface{}
err := db.C("msg").Find(nil).All(&msgs)
return msgs, err
}