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dgraph-1.1.0-rc3-test.go
package main
import (
"context"
"encoding/json"
"fmt"
"log"
"github.com/dgraph-io/dgo/v2"
"github.com/dgraph-io/dgo/v2/protos/api"
"google.golang.org/grpc"
)
type Friend struct {
Uid string `json:"uid,omitempty"`
Name string `json:"name,omitempty"`
Age int `json:"age,omitempty"`
Married bool `json:"married,omitempty"`
DgraphType string `json:"dgraph.type,omitempty"`
}
type Person struct {
Uid string `json:"uid,omitempty"`
Name string `json:"name,omitempty"`
Age int `json:"age,omitempty"`
Married bool `json:"married,omitempty"`
Friends []*Friend `json:"friend,omitempty"`
DgraphType string `json:"dgraph.type,omitempty"`
}
type CancelFunc func()
func main() {
dg, cancel := getDgraphClient()
defer cancel()
// While setting an object if a struct has a Uid then its properties in the graph are updated
// else a new node is created.
// In the example below new nodes for Alice, Bob and Charlie and school are created (since they
// don't have a Uid).
p := Person{
Uid: "_:alice",
Name: "Alice",
Age: 26,
Married: true,
DgraphType: "Person",
Friends: []*Friend{&Friend{
Uid: "_:bob",
Name: "Bob",
Age: 24,
DgraphType: "Friend",
}, &Friend{
Uid: "_:charlie",
Name: "Charlie",
Age: 29,
DgraphType: "Friend",
}},
}
op := &api.Operation{}
op.Schema = `
age: int .
friend: [uid] @reverse .
married: bool .
type Person {
name: string
age: int
married: bool
friend: [Friend]
}
type Friend {
name: string
age: int
married: bool
}
`
ctx := context.Background()
if err := dg.Alter(ctx, op); err != nil {
log.Fatal(err)
}
mu := &api.Mutation{
CommitNow: true,
}
pb, err := json.Marshal(p)
if err != nil {
log.Fatal(err)
}
mu.SetJson = pb
assigned, err := dg.NewTxn().Mutate(ctx, mu)
if err != nil {
log.Fatal(err)
}
// Get Uids
alice := assigned.Uids["alice"]
bob := assigned.Uids["bob"]
// Forward query.
var q = fmt.Sprintf(`{
expander(func: uid(%s)) {
uid
expand(_all_) {
uid
expand(_all_)
}
}
}`, alice)
respf, err := dg.NewTxn().Query(ctx, q)
if err != nil {
log.Fatal(err)
}
fmt.Println()
fmt.Println(string(respf.Json))
// Reverse query
var qr = fmt.Sprintf(`{
expander(func: uid(%s)) {
uid
expand(_all_) {
uid
expand(_all_)
}
}
}`, bob)
respr, err := dg.NewTxn().Query(ctx, qr)
if err != nil {
log.Fatal(err)
}
fmt.Println()
fmt.Println(string(respr.Json))
// Query schema
const sch = `schema{}`
resp, err := dg.NewTxn().Query(ctx, sch)
if err != nil {
log.Fatal(err)
}
fmt.Println()
fmt.Println(string(resp.Json))
}
func getDgraphClient() (*dgo.Dgraph, CancelFunc) {
conn, err := grpc.Dial("127.0.0.1:9080", grpc.WithInsecure())
if err != nil {
log.Fatal("While trying to dial gRPC")
}
dc := api.NewDgraphClient(conn)
dg := dgo.NewDgraphClient(dc)
return dg, func() {
if err := conn.Close(); err != nil {
log.Printf("Error while closing connection:%v", err)
}
}
}
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