How to specify certain fields only in the query property - elasticsearch

Question

I am using a service which wraps requests to Elastic Search. This service only allows me to send the query property to Elastic Search. I want to tell Elastic Search to look only for matches in a certain field in a document.
For example, if this is my document:
{
name: 'foo',
value: 'true'
}
Then I want to tell Elastic Search to look only for documents where name equals foo.
The Elastic Search documentation says to do this by using the fields property like so:
{
"multi_match" : {
"query" : "this is a test",
"fields" : [ "subject^3", "message" ]
}
}
But I can ONLY access the query property, so I can't specify fields. Lower down on the page, under best fields it says that this is equivalent to doing something like +first_name:will +first_name:smith. But when I put this, it's looking for text that actually matches +first_name:will +first_name:smith in the value, rather than looking for a first_name field that has a value will.
Is it possible to specify what field to search in with Elastic Search using only the query property?

Answer 1

This sounds like a perfect match for query_string(https://www.elastic.co/guide/en/elasticsearch/reference/1.x/query-dsl-query-string-query.html). You can do something like this with it:
"query_string" : {
"query" : "subject:whatever OR message:whatever"
}
So, if you can change multi_match to query_string this would be what you are looking for.

Answer 2

Lucene supports fielded data. When performing a search you can either specify a field, or use the default field. The field names and default field is implementation specific.
You can search any field by typing the field name followed by a colon ":" and then the term you are looking for.
{
"query": {
"query_string": {
"query": "Name:\"foo bar cook\"",
"default_operator" : "or"
}
}
}
use default_operator and to perform AND operation, or to perform OR kind of operation among the values