feat(GraphQL): Custom logic now supports DQL queries #6115

abhimanyusinghgaur · 2020-07-29T14:54:54Z

Fixes GraphQL-600.

This PR adds DQL query (previously known as GraphQL+-) support in GraphQL through the @custom directive. So, now it is possible to do something like this in the GraphQL schema:

type Tweets {
	id: ID!
	text: String! @search(by: [fulltext])
	user: User
	timestamp: DateTime! @search
}
type User {
	screen_name: String! @id
	followers: Int @search
	tweets: [Tweets] @hasInverse(field: user)
}
type UserTweetCount @remote {
	screen_name: String
	tweetCount: Int
}

type Query {
  dqlTweetsByAuthorFollowers: [Tweets] @custom(dql: """
	query {
		var(func: type(Tweets)) @filter(anyoftext(Tweets.text, "DQL")) {
			Tweets.user {
				followers as User.followers
			}
			userFollowerCount as sum(val(followers))
		}
		dqlTweetsByAuthorFollowers(func: uid(userFollowerCount), orderdesc: val(userFollowerCount)) {
			id: uid
			text: Tweets.text
			timestamp: Tweets.timestamp
		}
	}
	""")
	
  filteredTweetsByAuthorFollowers(search: String!): [Tweets] @custom(dql: """
	query t($search: string) {
		var(func: type(Tweets)) @filter(anyoftext(Tweets.text, $search)) {
			Tweets.user {
				followers as User.followers
			}
			userFollowerCount as sum(val(followers))
		}
		filteredTweetsByAuthorFollowers(func: uid(userFollowerCount), orderdesc: val(userFollowerCount)) {
			id: uid
			text: Tweets.text
			timestamp: Tweets.timestamp
		}
	}
	""")

  queryUserTweetCounts: [UserTweetCount] @custom(dql: """
	query {
		queryUserTweetCounts(func: type(User)) {
			screen_name: User.screen_name
			tweetCount: count(User.tweets)
		}
	}
	""")
}

And then you can send a GraphQL query to execute the DQL, like this:

query {
  dqlTweetsByAuthorFollowers {
    id
    text
    timestamp
  }
  filteredTweetsByAuthorFollowers(search: "hello") {
    text
  }
  queryUserTweetCounts {
    screen_name
    tweetCount
  }
}

This change is

pawanrawal

Reviewed 43 of 43 files at r1.
Reviewable status: all files reviewed, 5 unresolved discussions (waiting on @abhimanyusinghgaur)

graphql/resolve/query.go, line 122 at r1 (raw file):

		args := query.Arguments()
		for k, v := range args {
			vStr, err := x.ScalarToString(v)

Add a comment about why do we convert all scalars to string.

graphql/resolve/query.go, line 127 at r1 (raw file):

					k))
			}
			vars["$"+k] = vStr

Also add a comment about this that Query in Alpha expects variable names to be prefixed with $.

graphql/schema/rules.go, line 1226 at r1 (raw file):

				typ.Name, field.Name))
		}
		if _, err := gql.Parse(gql.Request{Str: dqlArg.Value.Raw}); err != nil {

We don't need to these for now.

graphql/schema/wrappers.go, line 1122 at r1 (raw file):

func (q *query) DQLQuery() string {
	if customDir := q.op.inSchema.customDirectives["Query"][q.Name()]; customDir != nil {
		if dqlArg := customDir.Arguments.ForName(dqlArg); dqlArg != nil {

if arg :=

x/x.go, line 1048 at r1 (raw file):

func ScalarToString(val interface{}) (string, error) {
	var str string

Do we need int8, int16 etc. here or only bool, string and float64? Can you verify once and maybe just keep this function in graphql package itself

abhimanyusinghgaur

Reviewable status: 36 of 42 files reviewed, 5 unresolved discussions (waiting on @pawanrawal)

graphql/resolve/query.go, line 122 at r1 (raw file):