dgraph/graphql/dgraph/graphquery.go at dgraph-personal · unigraph-dev/dgraph · GitHub

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* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

* http://www.apache.org/licenses/LICENSE-2.0

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

package dgraph

import (

"fmt"

"strings"

"github.com/dgraph-io/dgraph/gql"

"github.com/dgraph-io/dgraph/graphql/schema"

"github.com/dgraph-io/dgraph/x"

)

// AsString writes query as an indented dql query string. AsString doesn't

// validate query, and so doesn't return an error if query is 'malformed' - it might

// just write something that wouldn't parse as a Dgraph query.

func AsString(queries []*gql.GraphQuery) string {

if queries == nil {

return ""

}

var b strings.Builder

x.Check2(b.WriteString("query {\n"))

numRewrittenQueries := 0

for _, q := range queries {

if q == nil {

// Don't call writeQuery on a nil query

continue

}

writeQuery(&b, q, " ")

numRewrittenQueries++

}

x.Check2(b.WriteString("}"))

if numRewrittenQueries == 0 {

// In case writeQuery has not been called on any query or all queries

// are nil. Then, return empty string. This case needs to be considered as

// we don't want to return query{} in this case.

return ""

}

return b.String()

}

func writeQuery(b *strings.Builder, query *gql.GraphQuery, prefix string) {

if query.Var != "" || query.Alias != "" || query.Attr != "" {

x.Check2(b.WriteString(prefix))

}

if query.Var != "" {

x.Check2(b.WriteString(fmt.Sprintf("%s as ", query.Var)))

}

if query.Alias != "" {

x.Check2(b.WriteString(query.Alias))

x.Check2(b.WriteString(" : "))

}

if query.IsCount {

x.Check2(b.WriteString(fmt.Sprintf("count(%s)", query.Attr)))

} else if query.Attr != "val" {

x.Check2(b.WriteString(query.Attr))

} else if isAggregateFn(query.Func) {

x.Check2(b.WriteString("sum(val("))

writeNeedVar(b, query)

x.Check2(b.WriteRune(')'))

} else {

x.Check2(b.WriteString("val("))

writeNeedVar(b, query)

x.Check2(b.WriteRune(')'))

}

if query.Func != nil {

writeRoot(b, query)

x.Check2(b.WriteRune(')'))

}

if query.Filter != nil {

x.Check2(b.WriteString(" @filter("))

writeFilter(b, query.Filter)

x.Check2(b.WriteRune(')'))

}

if query.Func == nil && hasOrderOrPage(query) {

x.Check2(b.WriteString(" ("))

writeOrderAndPage(b, query, false)

x.Check2(b.WriteRune(')'))

}

if len(query.Cascade) != 0 {

if query.Cascade[0] == "__all__" {

x.Check2(b.WriteString(" @cascade"))

} else {

x.Check2(b.WriteString(" @cascade("))

x.Check2(b.WriteString(strings.Join(query.Cascade, ", ")))

x.Check2(b.WriteRune(')'))

}

if query.IsGroupby {

x.Check2(b.WriteString(" @groupby("))

writeGroupByAttributes(b, query.GroupbyAttrs)

x.Check2(b.WriteRune(')'))

}

switch {

case len(query.Children) > 0:

prefixAdd := ""

if query.Attr != "" {

x.Check2(b.WriteString(" {\n"))

prefixAdd = " "

}

for _, c := range query.Children {

writeQuery(b, c, prefix+prefixAdd)

}

if query.Attr != "" {

x.Check2(b.WriteString(prefix))

x.Check2(b.WriteString("}\n"))

}

case query.Var != "" || query.Alias != "" || query.Attr != "":

x.Check2(b.WriteString("\n"))

}

// writeNeedVar writes the NeedsVar of the query. For eg :-

// `userFollowerCount as sum(val(followers))` has `followers`

// as NeedsVar.

func writeNeedVar(b *strings.Builder, query *gql.GraphQuery) {

for i, v := range query.NeedsVar {

if i != 0 {

x.Check2(b.WriteString(", "))

}

x.Check2(b.WriteString(v.Name))

}

func isAggregateFn(f *gql.Function) bool {

if f == nil {

return false

}

switch f.Name {

case "min", "max", "avg", "sum":

return true

}

return false

}

func writeGroupByAttributes(b *strings.Builder, attrList []gql.GroupByAttr) {

for i, attr := range attrList {

if i != 0 {

x.Check2(b.WriteString(", "))

}

if attr.Alias != "" {

x.Check2(b.WriteString(attr.Alias))

x.Check2(b.WriteString(" : "))

}

x.Check2(b.WriteString(attr.Attr))

}

func writeUIDFunc(b *strings.Builder, uids []uint64, args []gql.Arg, needVar []gql.VarContext) {

x.Check2(b.WriteString("uid("))

if len(uids) > 0 {

// uid function with uint64 - uid(0x123, 0x456, ...)

for i, uid := range uids {

if i != 0 {

x.Check2(b.WriteString(", "))

}

x.Check2(b.WriteString(fmt.Sprintf("%#x", uid)))

}

} else if len(args) > 0 {

// uid function with a Dgraph query variable - uid(Post1)

for i, arg := range args {

if i != 0 {

x.Check2(b.WriteString(", "))

}

x.Check2(b.WriteString(arg.Value))

}

} else {

for i, v := range needVar {

if i != 0 {

x.Check2(b.WriteString(", "))

}

x.Check2(b.WriteString(v.Name))

}

x.Check2(b.WriteString(")"))

}

// writeRoot writes the root function as well as any ordering and paging

// specified in q.

// Only uid(0x123, 0x124), type(...) and eq(Type.Predicate, ...) functions are supported at root.

// Multiple arguments for `eq` filter will be required in case of resolving `entities` query.

func writeRoot(b *strings.Builder, q *gql.GraphQuery) {

if q.Func == nil {

return

}

switch {

case q.Func.Name == "has":

x.Check2(b.WriteString(fmt.Sprintf("(func: has(%s)", q.Func.Attr)))

case q.Func.Name == "uid":

x.Check2(b.WriteString("(func: "))

writeUIDFunc(b, q.Func.UID, q.Func.Args, q.Func.NeedsVar)

case q.Func.Name == "type" && len(q.Func.Args) == 1:

x.Check2(b.WriteString(fmt.Sprintf("(func: type(%s)", q.Func.Args[0].Value)))

case q.Func.Name == "eq":

x.Check2(b.WriteString("(func: eq("))

writeFilterArguments(b, q.Func)

x.Check2(b.WriteRune(')'))

}

writeOrderAndPage(b, q, true)

}

// writeFilterArguments writes the filter arguments. If the filter

// is constructed in graphql query rewriting then `Attr` is an empty

// string since we add Attr in the argument itself.

func writeFilterArguments(b *strings.Builder, q *gql.Function) {

if q.Attr != "" {

x.Check2(b.WriteString(q.Attr))

}

for i, arg := range q.Args {

if i != 0 || q.Attr != "" {

x.Check2(b.WriteString(", "))

}

if q.Attr != "" {

// quote the arguments since this is the case of

// @custom DQL string.

arg.Value = schema.MaybeQuoteArg(q.Name, arg.Value)

}

x.Check2(b.WriteString(arg.Value))

}

func writeFilterFunction(b *strings.Builder, f *gql.Function) {

if f == nil {

return

}

switch {

case f.Name == "uid":

writeUIDFunc(b, f.UID, f.Args, f.NeedsVar)

default:

x.Check2(b.WriteString(fmt.Sprintf("%s(", f.Name)))

writeFilterArguments(b, f)

x.Check2(b.WriteRune(')'))

}

func writeFilter(b *strings.Builder, ft *gql.FilterTree) {

if ft == nil {

return

}

switch ft.Op {

case "and", "or":

x.Check2(b.WriteRune('('))

for i, child := range ft.Child {

if i > 0 && i <= len(ft.Child)-1 {

x.Check2(b.WriteString(fmt.Sprintf(" %s ", strings.ToUpper(ft.Op))))

}

writeFilter(b, child)

}

x.Check2(b.WriteRune(')'))

case "not":

if len(ft.Child) > 0 {

x.Check2(b.WriteString("NOT ("))

writeFilter(b, ft.Child[0])

x.Check2(b.WriteRune(')'))

}

default:

writeFilterFunction(b, ft.Func)

}

func hasOrderOrPage(q *gql.GraphQuery) bool {

_, hasFirst := q.Args["first"]

_, hasOffset := q.Args["offset"]

return len(q.Order) > 0 || hasFirst || hasOffset

}

func IsValueVar(attr string, q *gql.GraphQuery) bool {

for _, vars := range q.NeedsVar {

if attr == vars.Name && vars.Typ == 2 {

return true

}

return false

}

func writeOrderAndPage(b *strings.Builder, query *gql.GraphQuery, root bool) {

var wroteOrder, wroteFirst bool

for _, ord := range query.Order {

if root || wroteOrder {

x.Check2(b.WriteString(", "))

}

if ord.Desc {

x.Check2(b.WriteString("orderdesc: "))

} else {

x.Check2(b.WriteString("orderasc: "))

}

if IsValueVar(ord.Attr, query) {

x.Check2(b.WriteString("val("))

x.Check2(b.WriteString(ord.Attr))

x.Check2(b.WriteRune(')'))

} else {

x.Check2(b.WriteString(ord.Attr))

}

wroteOrder = true

}

if first, ok := query.Args["first"]; ok {

if root || wroteOrder {

x.Check2(b.WriteString(", "))

}

x.Check2(b.WriteString("first: "))

x.Check2(b.WriteString(first))

wroteFirst = true

}

if offset, ok := query.Args["offset"]; ok {

if root || wroteOrder || wroteFirst {

x.Check2(b.WriteString(", "))

}

x.Check2(b.WriteString("offset: "))

x.Check2(b.WriteString(offset))

}

dgraph/graphql/dgraph/graphquery.go at dgraph-personal · unigraph-dev/dgraph · GitHub

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