paginated range queries

examples/api/json_query/json_query.go

@@ -218,7 +218,7 @@ func insertData(session bcdb.DBSession) error {
 }
 
 func validQueries(session bcdb.DBSession) error {
-	q, err := session.JSONQuery()
+	q, err := session.Query()
 	if err != nil {
 		fmt.Printf("Failed to return handler to access bcdb data through JSON query, reason: %s\n", err.Error())
 		return err
@@ -243,7 +243,7 @@ func validQueries(session bcdb.DBSession) error {
 		}
 	}
 	`
-	kvs, err := q.Execute("db", query1)
+	kvs, err := q.ExecuteJSONQuery("db", query1)
 	if err != nil {
 		fmt.Printf("Failed to execute JSON query, reason: %s\n", err.Error())
 		return err
@@ -274,7 +274,7 @@ func validQueries(session bcdb.DBSession) error {
 		}
 	}
 	`
-	kvs, err = q.Execute("db", query2)
+	kvs, err = q.ExecuteJSONQuery("db", query2)
 	if err != nil {
 		fmt.Printf("Failed to execute JSON query, reason: %s\n", err.Error())
 		return err
@@ -309,7 +309,7 @@ func validQueries(session bcdb.DBSession) error {
 		}
 	}
 	`
-	kvs, err = q.Execute("db", query3)
+	kvs, err = q.ExecuteJSONQuery("db", query3)
 	if err != nil {
 		fmt.Printf("Failed to execute JSON query, reason: %s\n", err.Error())
 		return err
@@ -339,7 +339,7 @@ func validQueries(session bcdb.DBSession) error {
 		}
 	}
 	`
-	kvs, err = q.Execute("db", query4)
+	kvs, err = q.ExecuteJSONQuery("db", query4)
 	if err != nil {
 		fmt.Printf("Failed to execute JSON query, reason: %s\n", err.Error())
 		return err
@@ -370,7 +370,7 @@ func validQueries(session bcdb.DBSession) error {
 		}
 	}
 	`
-	kvs, err = q.Execute("db", query5)
+	kvs, err = q.ExecuteJSONQuery("db", query5)
 	if err != nil {
 		fmt.Printf("Failed to execute JSON query, reason: %s\n", err.Error())
 		return err
@@ -402,7 +402,7 @@ func validQueries(session bcdb.DBSession) error {
 		}
 	}
 	`
-	kvs, err = q.Execute("db", query6)
+	kvs, err = q.ExecuteJSONQuery("db", query6)
 	if err != nil {
 		fmt.Printf("Failed to execute JSON query, reason: %s\n", err.Error())
 		return err
@@ -425,7 +425,7 @@ func validQueries(session bcdb.DBSession) error {
 }
 
 func invalidQuery(session bcdb.DBSession) error {
-	q, err := session.JSONQuery()
+	q, err := session.Query()
 	if err != nil {
 		fmt.Printf("Failed to return handler to access bcdb data through JSON query, reason: %s\n", err.Error())
 		return err
@@ -442,7 +442,7 @@ func invalidQuery(session bcdb.DBSession) error {
 		}
 	}
 	`
-	_, err = q.Execute("db", query)
+	_, err = q.ExecuteJSONQuery("db", query)
 	if err != nil {
 		fmt.Printf("As expected, failed to execute JSON query, reason: %s\n", err.Error())
 	} else {

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/golang/protobuf v1.5.2
 	github.com/google/uuid v1.3.0 // indirect
 	github.com/gorilla/mux v1.8.0 // indirect
-	github.com/hyperledger-labs/orion-server v0.2.4-0.20220531080909-badd4d7bb1f5
+	github.com/hyperledger-labs/orion-server v0.2.4-0.20220621134147-6a9aeaf38f9a
 	github.com/kr/text v0.2.0 // indirect
 	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/pkg/errors v0.9.1

go.sum

@@ -365,6 +365,8 @@ github.com/hyperledger-labs/orion-server v0.2.3 h1:vY9IQRO2sHdWUwLNKz6J7x+kZJXYL
 github.com/hyperledger-labs/orion-server v0.2.3/go.mod h1:8kXVAU1wvFYGbFL1qmXwMi2i8gKV2smOdp1F1kq0HMk=
 github.com/hyperledger-labs/orion-server v0.2.4-0.20220531080909-badd4d7bb1f5 h1:qy4M67EISCrlmCmH1ePY0PPVXDoUKHL9Ir9pGQzZULg=
 github.com/hyperledger-labs/orion-server v0.2.4-0.20220531080909-badd4d7bb1f5/go.mod h1:8kXVAU1wvFYGbFL1qmXwMi2i8gKV2smOdp1F1kq0HMk=
+github.com/hyperledger-labs/orion-server v0.2.4-0.20220621134147-6a9aeaf38f9a h1:2gWosqOFXOyB+Daox6chgWrExTEqJ4O0UwogZjkQ3Mo=
+github.com/hyperledger-labs/orion-server v0.2.4-0.20220621134147-6a9aeaf38f9a/go.mod h1:8kXVAU1wvFYGbFL1qmXwMi2i8gKV2smOdp1F1kq0HMk=
 github.com/iancoleman/strcase v0.2.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=

pkg/bcdb/data_query.go

@@ -0,0 +1,130 @@
+// Copyright IBM Corp. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package bcdb
+
+import (
+	"encoding/json"
+
+	"github.com/hyperledger-labs/orion-server/pkg/constants"
+	"github.com/hyperledger-labs/orion-server/pkg/types"
+	"github.com/pkg/errors"
+)
+
+type QueryExecutor struct {
+	*commonTxContext
+}
+
+func (q *QueryExecutor) ExecuteJSONQuery(dbName, query string) ([]*types.KVWithMetadata, error) {
+	marshaledJSONQuery, err := json.Marshal(query)
+	if err != nil {
+		return nil, errors.WithMessage(err, "check whether the query string passed is in JSON format")
+	}
+	path := constants.URLForJSONQuery(dbName)
+	resEnv := &types.DataQueryResponseEnvelope{}
+	if err = q.handleRequestWithPost(
+		path,
+		marshaledJSONQuery,
+		&types.DataJSONQuery{
+			UserId: q.userID,
+			DbName: dbName,
+			Query:  query,
+		},
+		resEnv,
+	); err != nil {
+		q.logger.Errorf("failed to execute ledger block query %s, due to %s", path, err)
+		return nil, err
+	}
+
+	return resEnv.GetResponse().KVs, nil
+}
+
+func (q *QueryExecutor) GetDataByRange(dbName, startKey, endKey string, limit uint64) (Iterator, error) {
+	kvs, pendingResult, nextStartKey, err := q.getDataByRange(dbName, startKey, endKey, limit)
+	if err != nil {
+		return nil, err
+	}
+
+	return &RangeQueryIterator{
+		kvs:           kvs,
+		currentLoc:    0,
+		pendingResult: pendingResult,
+		dbName:        dbName,
+		nextStartKey:  nextStartKey,
+		endKey:        endKey,
+		limit:         limit,
+		limitReached:  false,
+		q:             q,
+	}, nil
+}
+
+func (q *QueryExecutor) getDataByRange(dbName, startKey, endKey string, limit uint64) ([]*types.KVWithMetadata, bool, string, error) {
+	path := constants.URLForGetDataRange(dbName, startKey, endKey, limit)
+	resEnv := &types.GetDataRangeResponseEnvelope{}
+	if err := q.handleRequest(
+		path,
+		&types.GetDataRangeQuery{
+			UserId:   q.userID,
+			DbName:   dbName,
+			StartKey: startKey,
+			EndKey:   endKey,
+			Limit:    limit,
+		},
+		resEnv,
+	); err != nil {
+		q.logger.Errorf("failed to execute range query %s, due to %s", path, err)
+		return nil, false, "", err
+	}
+
+	return resEnv.GetResponse().KVs, resEnv.GetResponse().PendingResult, resEnv.GetResponse().NextStartKey, nil
+}
+
+type RangeQueryIterator struct {
+	kvs           []*types.KVWithMetadata
+	currentLoc    int
+	pendingResult bool
+	dbName        string
+	nextStartKey  string
+	endKey        string
+	limit         uint64
+	limitReached  bool
+	q             *QueryExecutor
+}
+
+func (i *RangeQueryIterator) Next() (*types.KVWithMetadata, bool, error) {
+	if i.currentLoc < len(i.kvs) {
+		return i.fetchNextAndAdjustReaminingResultCount()
+	}
+
+	if !i.pendingResult || i.limitReached {
+		return nil, false, nil
+	}
+
+	kvs, pending, next, err := i.q.getDataByRange(i.dbName, i.nextStartKey, i.endKey, i.limit)
+	if err != nil {
+		return nil, false, err
+	}
+	if len(kvs) == 0 {
+		return nil, false, nil
+	}
+
+	i.kvs = kvs
+	i.pendingResult = pending
+	i.nextStartKey = next
+	i.currentLoc = 0
+
+	return i.fetchNextAndAdjustReaminingResultCount()
+}
+
+func (i *RangeQueryIterator) fetchNextAndAdjustReaminingResultCount() (*types.KVWithMetadata, bool, error) {
+	kv := i.kvs[i.currentLoc]
+	i.currentLoc++
+	if i.limit > 0 {
+		i.limit--
+		if i.limit == 0 {
+			i.limitReached = true
+		}
+	}
+
+	return kv, true, nil
+}