JSON format ... doesn't differentiate between INT/FLOAT

Issues Dgraph Clients
, ,
1

Moved from GitHub dgo/66

Posted by jvsteiner:

Since the mutation input is in JSON format which doesn’t differentiate between INT/FLOAT (everything is a number), the server gets a float and stores the facet as such. This is, unfortunately, a limitation of the JSON format and the fact that facets don’t have a fixed type.

I would recommend setting a property on a node (instead of facet) if the type is important to you or using the RDF mutation format.

_Originally posted by @pawanrawal in Bug: Mutation issue with facets integer · Issue #3 · dgraph-io/dgo · GitHub

This seems like a more general problem affecting node predicates as well. It seems at the moment, the only choices are:

  1. use mutation JSON, in which case I can’t get my integers back out of the database, because they get converted to floats during unmarshalling
  2. Use NQuads and construct them myself.

In my use case, I have dynamic data, and I don’t know what it looks like ahead of time, so I cannot unmarshal into a predefined struct.

I think a modified json.Unmarshaler which does not coerce ints might be helpful. Perhaps the standard lib code could be repurposed and modified relatively easily…

2

jvsteiner commented :

on second thought, anything that traverses the wire as JSON isn’t going to work. Maybe then, some helper methods to construct the relevant NQuads from the users structs or proto.Messages?

3

mangalaman93 commented :

@jvsteiner I am not able to reproduce this issue. I ran the following code:

package main

import (
	"context"
	"encoding/json"
	"fmt"

	"github.com/dgraph-io/dgo/v2"
	"github.com/dgraph-io/dgo/v2/protos/api"
	"google.golang.org/grpc"
)

type GraphCollection struct {
	Uid    string      `json:"uid"`
	Weight []GraphNode `json:"weight,omitempty"`
}

type GraphNode struct {
	Uid          string `json:"uid"`
	WeightFacets int64  `json:"weight|score,omitempty"`
}

func main() {
	data := GraphCollection{
		Weight: []GraphNode{
			{
				WeightFacets: 1,
			},
		},
	}

	conn, err := grpc.Dial("localhost:9180", grpc.WithInsecure())
	if err != nil {
		panic(err)
	}
	dg := dgo.NewDgraphClient(api.NewDgraphClient(conn))
	dg.Login(context.Background(), "groot", "password")

	err = dg.Alter(context.Background(), &api.Operation{DropAll: true})
	if err != nil {
		panic(err)
	}
	pb, err := json.Marshal(data)
	if err != nil {
		panic(err)
	}

	ctx := context.Background()
	_, err = dg.NewTxn().Mutate(ctx, &api.Mutation{SetJson: pb, CommitNow: true})
	if err != nil {
		panic(err)
	}

	q := fmt.Sprintf(`{
	  me(func: has(weight)) {
	    weight @facets {
	      uid
	    }
	  }
	}`)

	txn := dg.NewTxn()
	resp, err := txn.Query(ctx, q)
	if err != nil {
		panic(err)
	}

	fmt.Println(string(resp.Json))
}

and response was:

{"me":[{"weight":[{"uid":"0x10"}],"weight|score":{"0":1}}]}

let me know if I am doing something wrong.

4

mangalaman93 commented :

Closing this issue for now, feel free to reopen.