User search with Golang mgo

Question

Getting a string as input (from a user search), I am trying to construct a bson.M object for mgo to search through the mongo database and find x number of items.

Something like this

func Search (w http.ResponseWriter, r *http.Request) {

    q := r.FormValue("q")
    filter := bson.M{}
    // magic happens here 

    // do db connection stuff
    things := []*thing{}
    err := db.Find(&filter).Limit(10).All(&things)
    // check error, send things, etc
}

What I need the search to be based on is

ignore case (I found this answer which takes me part of the way)
the title in the stored data must, somewhere, include each of the words in the q.

So for instance if the stored data looks like {title: "abcde"}, then

Abc will match
de Bc will match
ac will not match

Edit: Solution

I finally figured it out. The magic part looks like this:

q := r.FormValue("q")
qs := strings.Split(q, " ")
and := make([]bson.M, len(qs))
for i, q := range qs {
    and[i] = bson.M{"title": bson.M{
        "$regex": bson.RegEx{Pattern: ".*" + q + ".*", Options: "i"},
    }}
}
filter := bson.M{"$and": and}

Steve · Accepted Answer · 2017-03-13 20:56:39Z

1

The mongo filter can take regex, for example;

        bson.M{"title": bson.M{"$regex": bson.RegEx{Pattern: title, Options: "i"}}}

So in this case the title variable would be something like; .*abc*.. The Options: "i" enables case insensitivity.

As for matching the substring (scenario 2) I am not sure how to achieve within regex.

edited Mar 13, 2017 at 20:56

answered Mar 13, 2017 at 20:49

Steve

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5 Comments

user1816631 Over a year ago

Thanks! – Pattern: title ? You mean Pattern: q right? And do you know how to do if q consists of more than one word?

Steve Over a year ago

Yes, but you need to add the relevant regex and I would suggest escaping/validating the input to ensure you are not exposed to a NoSql injection style attack.

Steve Over a year ago

Regarding the multiple words. I would imagine you can do some sort of string split and then use the $and keyword to chain the regex. (docs.mongodb.com/manual/reference/operator/query/and)

user1816631 Over a year ago

I feel I should be able to, but even that won't work for me. The googling continues..

user1816631 Over a year ago

I'll accept your answer since it was the answer that helped me the most, and so the question is considered to have a solution. :)

Sandun Priyanka · Accepted Answer · 2018-03-12 19:10:19Z

0

Simple use this,

wordOffset := q

selector:= bson.M{"title": bson.M{"$regex": wordOffset}}

answered Mar 12, 2018 at 19:10

Sandun Priyanka

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