-
Notifications
You must be signed in to change notification settings - Fork 1
/
marbles_chaincode.go
755 lines (636 loc) · 30.5 KB
/
marbles_chaincode.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
/*
SPDX-License-Identifier: Apache-2.0
*/
// ====CHAINCODE EXECUTION SAMPLES (CLI) ==================
// ==== Invoke marbles ====
// peer chaincode invoke -C myc1 -n marbles -c '{"Args":["initMarble","marble1","blue","35","tom"]}'
// peer chaincode invoke -C myc1 -n marbles -c '{"Args":["initMarble","marble2","red","50","tom"]}'
// peer chaincode invoke -C myc1 -n marbles -c '{"Args":["initMarble","marble3","blue","70","tom"]}'
// peer chaincode invoke -C myc1 -n marbles -c '{"Args":["transferMarble","marble2","jerry"]}'
// peer chaincode invoke -C myc1 -n marbles -c '{"Args":["transferMarblesBasedOnColor","blue","jerry"]}'
// peer chaincode invoke -C myc1 -n marbles -c '{"Args":["delete","marble1"]}'
// ==== Query marbles ====
// peer chaincode query -C myc1 -n marbles -c '{"Args":["readMarble","marble1"]}'
// peer chaincode query -C myc1 -n marbles -c '{"Args":["getMarblesByRange","marble1","marble3"]}'
// peer chaincode query -C myc1 -n marbles -c '{"Args":["getHistoryForMarble","marble1"]}'
// Rich Query (Only supported if CouchDB is used as state database):
// peer chaincode query -C myc1 -n marbles -c '{"Args":["queryMarblesByOwner","tom"]}'
// peer chaincode query -C myc1 -n marbles -c '{"Args":["queryMarbles","{\"selector\":{\"owner\":\"tom\"}}"]}'
// Rich Query with Pagination (Only supported if CouchDB is used as state database):
// peer chaincode query -C myc1 -n marbles -c '{"Args":["queryMarblesWithPagination","{\"selector\":{\"owner\":\"tom\"}}","3",""]}'
// INDEXES TO SUPPORT COUCHDB RICH QUERIES
//
// Indexes in CouchDB are required in order to make JSON queries efficient and are required for
// any JSON query with a sort. As of Hyperledger Fabric 1.1, indexes may be packaged alongside
// chaincode in a META-INF/statedb/couchdb/indexes directory. Each index must be defined in its own
// text file with extension *.json with the index definition formatted in JSON following the
// CouchDB index JSON syntax as documented at:
// http://docs.couchdb.org/en/2.1.1/api/database/find.html#db-index
//
// This marbles02 example chaincode demonstrates a packaged
// index which you can find in META-INF/statedb/couchdb/indexes/indexOwner.json.
// For deployment of chaincode to production environments, it is recommended
// to define any indexes alongside chaincode so that the chaincode and supporting indexes
// are deployed automatically as a unit, once the chaincode has been installed on a peer and
// instantiated on a channel. See Hyperledger Fabric documentation for more details.
//
// If you have access to the your peer's CouchDB state database in a development environment,
// you may want to iteratively test various indexes in support of your chaincode queries. You
// can use the CouchDB Fauxton interface or a command line curl utility to create and update
// indexes. Then once you finalize an index, include the index definition alongside your
// chaincode in the META-INF/statedb/couchdb/indexes directory, for packaging and deployment
// to managed environments.
//
// In the examples below you can find index definitions that support marbles02
// chaincode queries, along with the syntax that you can use in development environments
// to create the indexes in the CouchDB Fauxton interface or a curl command line utility.
//
//Example hostname:port configurations to access CouchDB.
//
//To access CouchDB docker container from within another docker container or from vagrant environments:
// http://couchdb:5984/
//
//Inside couchdb docker container
// http://127.0.0.1:5984/
// Index for docType, owner.
//
// Example curl command line to define index in the CouchDB channel_chaincode database
// curl -i -X POST -H "Content-Type: application/json" -d "{\"index\":{\"fields\":[\"docType\",\"owner\"]},\"name\":\"indexOwner\",\"ddoc\":\"indexOwnerDoc\",\"type\":\"json\"}" http://hostname:port/myc1_marbles/_index
//
// Index for docType, owner, size (descending order).
//
// Example curl command line to define index in the CouchDB channel_chaincode database
// curl -i -X POST -H "Content-Type: application/json" -d "{\"index\":{\"fields\":[{\"size\":\"desc\"},{\"docType\":\"desc\"},{\"owner\":\"desc\"}]},\"ddoc\":\"indexSizeSortDoc\", \"name\":\"indexSizeSortDesc\",\"type\":\"json\"}" http://hostname:port/myc1_marbles/_index
// Rich Query with index design doc and index name specified (Only supported if CouchDB is used as state database):
// peer chaincode query -C myc1 -n marbles -c '{"Args":["queryMarbles","{\"selector\":{\"docType\":\"marble\",\"owner\":\"tom\"}, \"use_index\":[\"_design/indexOwnerDoc\", \"indexOwner\"]}"]}'
// Rich Query with index design doc specified only (Only supported if CouchDB is used as state database):
// peer chaincode query -C myc1 -n marbles -c '{"Args":["queryMarbles","{\"selector\":{\"docType\":{\"$eq\":\"marble\"},\"owner\":{\"$eq\":\"tom\"},\"size\":{\"$gt\":0}},\"fields\":[\"docType\",\"owner\",\"size\"],\"sort\":[{\"size\":\"desc\"}],\"use_index\":\"_design/indexSizeSortDoc\"}"]}'
package main
import (
"bytes"
"encoding/json"
"fmt"
"strconv"
"strings"
"time"
"github.com/hyperledger/fabric/core/chaincode/shim"
pb "github.com/hyperledger/fabric/protos/peer"
)
// SimpleChaincode example simple Chaincode implementation
type SimpleChaincode struct {
}
type marble struct {
ObjectType string `json:"docType"` //docType is used to distinguish the various types of objects in state database
Name string `json:"name"` //the fieldtags are needed to keep case from bouncing around
Color string `json:"color"`
Size int `json:"size"`
Owner string `json:"owner"`
}
// ===================================================================================
// Main
// ===================================================================================
func main() {
err := shim.Start(new(SimpleChaincode))
if err != nil {
fmt.Printf("Error starting Simple chaincode: %s", err)
}
}
// Init initializes chaincode
// ===========================
func (t *SimpleChaincode) Init(stub shim.ChaincodeStubInterface) pb.Response {
return shim.Success(nil)
}
// Invoke - Our entry point for Invocations
// ========================================
func (t *SimpleChaincode) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
function, args := stub.GetFunctionAndParameters()
fmt.Println("invoke is running " + function)
// Handle different functions
if function == "initMarble" { //create a new marble
return t.initMarble(stub, args)
} else if function == "transferMarble" { //change owner of a specific marble
return t.transferMarble(stub, args)
} else if function == "transferMarblesBasedOnColor" { //transfer all marbles of a certain color
return t.transferMarblesBasedOnColor(stub, args)
} else if function == "delete" { //delete a marble
return t.delete(stub, args)
} else if function == "readMarble" { //read a marble
return t.readMarble(stub, args)
} else if function == "queryMarblesByOwner" { //find marbles for owner X using rich query
return t.queryMarblesByOwner(stub, args)
} else if function == "queryMarbles" { //find marbles based on an ad hoc rich query
return t.queryMarbles(stub, args)
} else if function == "getHistoryForMarble" { //get history of values for a marble
return t.getHistoryForMarble(stub, args)
} else if function == "getMarblesByRange" { //get marbles based on range query
return t.getMarblesByRange(stub, args)
} else if function == "getMarblesByRangeWithPagination" {
return t.getMarblesByRangeWithPagination(stub, args)
} else if function == "queryMarblesWithPagination" {
return t.queryMarblesWithPagination(stub, args)
}
fmt.Println("invoke did not find func: " + function) //error
return shim.Error("Received unknown function invocation")
}
// ============================================================
// initMarble - create a new marble, store into chaincode state
// ============================================================
func (t *SimpleChaincode) initMarble(stub shim.ChaincodeStubInterface, args []string) pb.Response {
var err error
// 0 1 2 3
// "asdf", "blue", "35", "bob"
if len(args) != 4 {
return shim.Error("Incorrect number of arguments. Expecting 4")
}
// ==== Input sanitation ====
fmt.Println("- start init marble")
if len(args[0]) <= 0 {
return shim.Error("1st argument must be a non-empty string")
}
if len(args[1]) <= 0 {
return shim.Error("2nd argument must be a non-empty string")
}
if len(args[2]) <= 0 {
return shim.Error("3rd argument must be a non-empty string")
}
if len(args[3]) <= 0 {
return shim.Error("4th argument must be a non-empty string")
}
marbleName := args[0]
color := strings.ToLower(args[1])
owner := strings.ToLower(args[3])
size, err := strconv.Atoi(args[2])
if err != nil {
return shim.Error("3rd argument must be a numeric string")
}
// ==== Check if marble already exists ====
marbleAsBytes, err := stub.GetState(marbleName)
if err != nil {
return shim.Error("Failed to get marble: " + err.Error())
} else if marbleAsBytes != nil {
fmt.Println("This marble already exists: " + marbleName)
return shim.Error("This marble already exists: " + marbleName)
}
// ==== Create marble object and marshal to JSON ====
objectType := "marble"
marble := &marble{objectType, marbleName, color, size, owner}
marbleJSONasBytes, err := json.Marshal(marble)
if err != nil {
return shim.Error(err.Error())
}
//Alternatively, build the marble json string manually if you don't want to use struct marshalling
//marbleJSONasString := `{"docType":"Marble", "name": "` + marbleName + `", "color": "` + color + `", "size": ` + strconv.Itoa(size) + `, "owner": "` + owner + `"}`
//marbleJSONasBytes := []byte(str)
// === Save marble to state ===
err = stub.PutState(marbleName, marbleJSONasBytes)
if err != nil {
return shim.Error(err.Error())
}
// ==== Index the marble to enable color-based range queries, e.g. return all blue marbles ====
// An 'index' is a normal key/value entry in state.
// The key is a composite key, with the elements that you want to range query on listed first.
// In our case, the composite key is based on indexName~color~name.
// This will enable very efficient state range queries based on composite keys matching indexName~color~*
indexName := "color~name"
colorNameIndexKey, err := stub.CreateCompositeKey(indexName, []string{marble.Color, marble.Name})
if err != nil {
return shim.Error(err.Error())
}
// Save index entry to state. Only the key name is needed, no need to store a duplicate copy of the marble.
// Note - passing a 'nil' value will effectively delete the key from state, therefore we pass null character as value
value := []byte{0x00}
stub.PutState(colorNameIndexKey, value)
// ==== Marble saved and indexed. Return success ====
fmt.Println("- end init marble")
return shim.Success(nil)
}
// ===============================================
// readMarble - read a marble from chaincode state
// ===============================================
func (t *SimpleChaincode) readMarble(stub shim.ChaincodeStubInterface, args []string) pb.Response {
var name, jsonResp string
var err error
if len(args) != 1 {
return shim.Error("Incorrect number of arguments. Expecting name of the marble to query")
}
name = args[0]
valAsbytes, err := stub.GetState(name) //get the marble from chaincode state
if err != nil {
jsonResp = "{\"Error\":\"Failed to get state for " + name + "\"}"
return shim.Error(jsonResp)
} else if valAsbytes == nil {
jsonResp = "{\"Error\":\"Marble does not exist: " + name + "\"}"
return shim.Error(jsonResp)
}
return shim.Success(valAsbytes)
}
// ==================================================
// delete - remove a marble key/value pair from state
// ==================================================
func (t *SimpleChaincode) delete(stub shim.ChaincodeStubInterface, args []string) pb.Response {
var jsonResp string
var marbleJSON marble
if len(args) != 1 {
return shim.Error("Incorrect number of arguments. Expecting 1")
}
marbleName := args[0]
// to maintain the color~name index, we need to read the marble first and get its color
valAsbytes, err := stub.GetState(marbleName) //get the marble from chaincode state
if err != nil {
jsonResp = "{\"Error\":\"Failed to get state for " + marbleName + "\"}"
return shim.Error(jsonResp)
} else if valAsbytes == nil {
jsonResp = "{\"Error\":\"Marble does not exist: " + marbleName + "\"}"
return shim.Error(jsonResp)
}
err = json.Unmarshal([]byte(valAsbytes), &marbleJSON)
if err != nil {
jsonResp = "{\"Error\":\"Failed to decode JSON of: " + marbleName + "\"}"
return shim.Error(jsonResp)
}
err = stub.DelState(marbleName) //remove the marble from chaincode state
if err != nil {
return shim.Error("Failed to delete state:" + err.Error())
}
// maintain the index
indexName := "color~name"
colorNameIndexKey, err := stub.CreateCompositeKey(indexName, []string{marbleJSON.Color, marbleJSON.Name})
if err != nil {
return shim.Error(err.Error())
}
// Delete index entry to state.
err = stub.DelState(colorNameIndexKey)
if err != nil {
return shim.Error("Failed to delete state:" + err.Error())
}
return shim.Success(nil)
}
// ===========================================================
// transfer a marble by setting a new owner name on the marble
// ===========================================================
func (t *SimpleChaincode) transferMarble(stub shim.ChaincodeStubInterface, args []string) pb.Response {
// 0 1
// "name", "bob"
if len(args) < 2 {
return shim.Error("Incorrect number of arguments. Expecting 2")
}
marbleName := args[0]
newOwner := strings.ToLower(args[1])
fmt.Println("- start transferMarble ", marbleName, newOwner)
marbleAsBytes, err := stub.GetState(marbleName)
if err != nil {
return shim.Error("Failed to get marble:" + err.Error())
} else if marbleAsBytes == nil {
return shim.Error("Marble does not exist")
}
marbleToTransfer := marble{}
err = json.Unmarshal(marbleAsBytes, &marbleToTransfer) //unmarshal it aka JSON.parse()
if err != nil {
return shim.Error(err.Error())
}
marbleToTransfer.Owner = newOwner //change the owner
marbleJSONasBytes, _ := json.Marshal(marbleToTransfer)
err = stub.PutState(marbleName, marbleJSONasBytes) //rewrite the marble
if err != nil {
return shim.Error(err.Error())
}
fmt.Println("- end transferMarble (success)")
return shim.Success(nil)
}
// ===========================================================================================
// constructQueryResponseFromIterator constructs a JSON array containing query results from
// a given result iterator
// ===========================================================================================
func constructQueryResponseFromIterator(resultsIterator shim.StateQueryIteratorInterface) (*bytes.Buffer, error) {
// buffer is a JSON array containing QueryResults
var buffer bytes.Buffer
buffer.WriteString("[")
bArrayMemberAlreadyWritten := false
for resultsIterator.HasNext() {
queryResponse, err := resultsIterator.Next()
if err != nil {
return nil, err
}
// Add a comma before array members, suppress it for the first array member
if bArrayMemberAlreadyWritten == true {
buffer.WriteString(",")
}
buffer.WriteString("{\"Key\":")
buffer.WriteString("\"")
buffer.WriteString(queryResponse.Key)
buffer.WriteString("\"")
buffer.WriteString(", \"Record\":")
// Record is a JSON object, so we write as-is
buffer.WriteString(string(queryResponse.Value))
buffer.WriteString("}")
bArrayMemberAlreadyWritten = true
}
buffer.WriteString("]")
return &buffer, nil
}
// ===========================================================================================
// addPaginationMetadataToQueryResults adds QueryResponseMetadata, which contains pagination
// info, to the constructed query results
// ===========================================================================================
func addPaginationMetadataToQueryResults(buffer *bytes.Buffer, responseMetadata *pb.QueryResponseMetadata) *bytes.Buffer {
buffer.WriteString("[{\"ResponseMetadata\":{\"RecordsCount\":")
buffer.WriteString("\"")
buffer.WriteString(fmt.Sprintf("%v", responseMetadata.FetchedRecordsCount))
buffer.WriteString("\"")
buffer.WriteString(", \"Bookmark\":")
buffer.WriteString("\"")
buffer.WriteString(responseMetadata.Bookmark)
buffer.WriteString("\"}}]")
return buffer
}
// ===========================================================================================
// getMarblesByRange performs a range query based on the start and end keys provided.
// Read-only function results are not typically submitted to ordering. If the read-only
// results are submitted to ordering, or if the query is used in an update transaction
// and submitted to ordering, then the committing peers will re-execute to guarantee that
// result sets are stable between endorsement time and commit time. The transaction is
// invalidated by the committing peers if the result set has changed between endorsement
// time and commit time.
// Therefore, range queries are a safe option for performing update transactions based on query results.
// ===========================================================================================
func (t *SimpleChaincode) getMarblesByRange(stub shim.ChaincodeStubInterface, args []string) pb.Response {
if len(args) < 2 {
return shim.Error("Incorrect number of arguments. Expecting 2")
}
startKey := args[0]
endKey := args[1]
resultsIterator, err := stub.GetStateByRange(startKey, endKey)
if err != nil {
return shim.Error(err.Error())
}
defer resultsIterator.Close()
buffer, err := constructQueryResponseFromIterator(resultsIterator)
if err != nil {
return shim.Error(err.Error())
}
fmt.Printf("- getMarblesByRange queryResult:\n%s\n", buffer.String())
return shim.Success(buffer.Bytes())
}
// ==== Example: GetStateByPartialCompositeKey/RangeQuery =========================================
// transferMarblesBasedOnColor will transfer marbles of a given color to a certain new owner.
// Uses a GetStateByPartialCompositeKey (range query) against color~name 'index'.
// Committing peers will re-execute range queries to guarantee that result sets are stable
// between endorsement time and commit time. The transaction is invalidated by the
// committing peers if the result set has changed between endorsement time and commit time.
// Therefore, range queries are a safe option for performing update transactions based on query results.
// ===========================================================================================
func (t *SimpleChaincode) transferMarblesBasedOnColor(stub shim.ChaincodeStubInterface, args []string) pb.Response {
// 0 1
// "color", "bob"
if len(args) < 2 {
return shim.Error("Incorrect number of arguments. Expecting 2")
}
color := args[0]
newOwner := strings.ToLower(args[1])
fmt.Println("- start transferMarblesBasedOnColor ", color, newOwner)
// Query the color~name index by color
// This will execute a key range query on all keys starting with 'color'
coloredMarbleResultsIterator, err := stub.GetStateByPartialCompositeKey("color~name", []string{color})
if err != nil {
return shim.Error(err.Error())
}
defer coloredMarbleResultsIterator.Close()
// Iterate through result set and for each marble found, transfer to newOwner
var i int
for i = 0; coloredMarbleResultsIterator.HasNext(); i++ {
// Note that we don't get the value (2nd return variable), we'll just get the marble name from the composite key
responseRange, err := coloredMarbleResultsIterator.Next()
if err != nil {
return shim.Error(err.Error())
}
// get the color and name from color~name composite key
objectType, compositeKeyParts, err := stub.SplitCompositeKey(responseRange.Key)
if err != nil {
return shim.Error(err.Error())
}
returnedColor := compositeKeyParts[0]
returnedMarbleName := compositeKeyParts[1]
fmt.Printf("- found a marble from index:%s color:%s name:%s\n", objectType, returnedColor, returnedMarbleName)
// Now call the transfer function for the found marble.
// Re-use the same function that is used to transfer individual marbles
response := t.transferMarble(stub, []string{returnedMarbleName, newOwner})
// if the transfer failed break out of loop and return error
if response.Status != shim.OK {
return shim.Error("Transfer failed: " + response.Message)
}
}
responsePayload := fmt.Sprintf("Transferred %d %s marbles to %s", i, color, newOwner)
fmt.Println("- end transferMarblesBasedOnColor: " + responsePayload)
return shim.Success([]byte(responsePayload))
}
// =======Rich queries =========================================================================
// Two examples of rich queries are provided below (parameterized query and ad hoc query).
// Rich queries pass a query string to the state database.
// Rich queries are only supported by state database implementations
// that support rich query (e.g. CouchDB).
// The query string is in the syntax of the underlying state database.
// With rich queries there is no guarantee that the result set hasn't changed between
// endorsement time and commit time, aka 'phantom reads'.
// Therefore, rich queries should not be used in update transactions, unless the
// application handles the possibility of result set changes between endorsement and commit time.
// Rich queries can be used for point-in-time queries against a peer.
// ============================================================================================
// ===== Example: Parameterized rich query =================================================
// queryMarblesByOwner queries for marbles based on a passed in owner.
// This is an example of a parameterized query where the query logic is baked into the chaincode,
// and accepting a single query parameter (owner).
// Only available on state databases that support rich query (e.g. CouchDB)
// =========================================================================================
func (t *SimpleChaincode) queryMarblesByOwner(stub shim.ChaincodeStubInterface, args []string) pb.Response {
// 0
// "bob"
if len(args) < 1 {
return shim.Error("Incorrect number of arguments. Expecting 1")
}
owner := strings.ToLower(args[0])
queryString := fmt.Sprintf("{\"selector\":{\"docType\":\"marble\",\"owner\":\"%s\"}}", owner)
queryResults, err := getQueryResultForQueryString(stub, queryString)
if err != nil {
return shim.Error(err.Error())
}
return shim.Success(queryResults)
}
// ===== Example: Ad hoc rich query ========================================================
// queryMarbles uses a query string to perform a query for marbles.
// Query string matching state database syntax is passed in and executed as is.
// Supports ad hoc queries that can be defined at runtime by the client.
// If this is not desired, follow the queryMarblesForOwner example for parameterized queries.
// Only available on state databases that support rich query (e.g. CouchDB)
// =========================================================================================
func (t *SimpleChaincode) queryMarbles(stub shim.ChaincodeStubInterface, args []string) pb.Response {
// 0
// "queryString"
if len(args) < 1 {
return shim.Error("Incorrect number of arguments. Expecting 1")
}
queryString := args[0]
queryResults, err := getQueryResultForQueryString(stub, queryString)
if err != nil {
return shim.Error(err.Error())
}
return shim.Success(queryResults)
}
// =========================================================================================
// getQueryResultForQueryString executes the passed in query string.
// Result set is built and returned as a byte array containing the JSON results.
// =========================================================================================
func getQueryResultForQueryString(stub shim.ChaincodeStubInterface, queryString string) ([]byte, error) {
fmt.Printf("- getQueryResultForQueryString queryString:\n%s\n", queryString)
resultsIterator, err := stub.GetQueryResult(queryString)
if err != nil {
return nil, err
}
defer resultsIterator.Close()
buffer, err := constructQueryResponseFromIterator(resultsIterator)
if err != nil {
return nil, err
}
fmt.Printf("- getQueryResultForQueryString queryResult:\n%s\n", buffer.String())
return buffer.Bytes(), nil
}
// ====== Pagination =========================================================================
// Pagination provides a method to retrieve records with a defined pagesize and
// start point (bookmark). An empty string bookmark defines the first "page" of a query
// result. Paginated queries return a bookmark that can be used in
// the next query to retrieve the next page of results. Paginated queries extend
// rich queries and range queries to include a pagesize and bookmark.
//
// Two examples are provided in this example. The first is getMarblesByRangeWithPagination
// which executes a paginated range query.
// The second example is a paginated query for rich ad-hoc queries.
// =========================================================================================
// ====== Example: Pagination with Range Query ===============================================
// getMarblesByRangeWithPagination performs a range query based on the start & end key,
// page size and a bookmark.
// The number of fetched records will be equal to or lesser than the page size.
// Paginated range queries are only valid for read only transactions.
// ===========================================================================================
func (t *SimpleChaincode) getMarblesByRangeWithPagination(stub shim.ChaincodeStubInterface, args []string) pb.Response {
if len(args) < 4 {
return shim.Error("Incorrect number of arguments. Expecting 4")
}
startKey := args[0]
endKey := args[1]
//return type of ParseInt is int64
pageSize, err := strconv.ParseInt(args[2], 10, 32)
if err != nil {
return shim.Error(err.Error())
}
bookmark := args[3]
resultsIterator, responseMetadata, err := stub.GetStateByRangeWithPagination(startKey, endKey, int32(pageSize), bookmark)
if err != nil {
return shim.Error(err.Error())
}
defer resultsIterator.Close()
buffer, err := constructQueryResponseFromIterator(resultsIterator)
if err != nil {
return shim.Error(err.Error())
}
bufferWithPaginationInfo := addPaginationMetadataToQueryResults(buffer, responseMetadata)
fmt.Printf("- getMarblesByRange queryResult:\n%s\n", bufferWithPaginationInfo.String())
return shim.Success(buffer.Bytes())
}
// ===== Example: Pagination with Ad hoc Rich Query ========================================================
// queryMarblesWithPagination uses a query string, page size and a bookmark to perform a query
// for marbles. Query string matching state database syntax is passed in and executed as is.
// The number of fetched records would be equal to or lesser than the specified page size.
// Supports ad hoc queries that can be defined at runtime by the client.
// If this is not desired, follow the queryMarblesForOwner example for parameterized queries.
// Only available on state databases that support rich query (e.g. CouchDB)
// Paginated queries are only valid for read only transactions.
// =========================================================================================
func (t *SimpleChaincode) queryMarblesWithPagination(stub shim.ChaincodeStubInterface, args []string) pb.Response {
// 0
// "queryString"
if len(args) < 3 {
return shim.Error("Incorrect number of arguments. Expecting 3")
}
queryString := args[0]
//return type of ParseInt is int64
pageSize, err := strconv.ParseInt(args[1], 10, 32)
if err != nil {
return shim.Error(err.Error())
}
bookmark := args[2]
queryResults, err := getQueryResultForQueryStringWithPagination(stub, queryString, int32(pageSize), bookmark)
if err != nil {
return shim.Error(err.Error())
}
return shim.Success(queryResults)
}
// =========================================================================================
// getQueryResultForQueryStringWithPagination executes the passed in query string with
// pagination info. Result set is built and returned as a byte array containing the JSON results.
// =========================================================================================
func getQueryResultForQueryStringWithPagination(stub shim.ChaincodeStubInterface, queryString string, pageSize int32, bookmark string) ([]byte, error) {
fmt.Printf("- getQueryResultForQueryString queryString:\n%s\n", queryString)
resultsIterator, responseMetadata, err := stub.GetQueryResultWithPagination(queryString, pageSize, bookmark)
if err != nil {
return nil, err
}
defer resultsIterator.Close()
buffer, err := constructQueryResponseFromIterator(resultsIterator)
if err != nil {
return nil, err
}
bufferWithPaginationInfo := addPaginationMetadataToQueryResults(buffer, responseMetadata)
fmt.Printf("- getQueryResultForQueryString queryResult:\n%s\n", bufferWithPaginationInfo.String())
return buffer.Bytes(), nil
}
func (t *SimpleChaincode) getHistoryForMarble(stub shim.ChaincodeStubInterface, args []string) pb.Response {
if len(args) < 1 {
return shim.Error("Incorrect number of arguments. Expecting 1")
}
marbleName := args[0]
fmt.Printf("- start getHistoryForMarble: %s\n", marbleName)
resultsIterator, err := stub.GetHistoryForKey(marbleName)
if err != nil {
return shim.Error(err.Error())
}
defer resultsIterator.Close()
// buffer is a JSON array containing historic values for the marble
var buffer bytes.Buffer
buffer.WriteString("[")
bArrayMemberAlreadyWritten := false
for resultsIterator.HasNext() {
response, err := resultsIterator.Next()
if err != nil {
return shim.Error(err.Error())
}
// Add a comma before array members, suppress it for the first array member
if bArrayMemberAlreadyWritten == true {
buffer.WriteString(",")
}
buffer.WriteString("{\"TxId\":")
buffer.WriteString("\"")
buffer.WriteString(response.TxId)
buffer.WriteString("\"")
buffer.WriteString(", \"Value\":")
// if it was a delete operation on given key, then we need to set the
//corresponding value null. Else, we will write the response.Value
//as-is (as the Value itself a JSON marble)
if response.IsDelete {
buffer.WriteString("null")
} else {
buffer.WriteString(string(response.Value))
}
buffer.WriteString(", \"Timestamp\":")
buffer.WriteString("\"")
buffer.WriteString(time.Unix(response.Timestamp.Seconds, int64(response.Timestamp.Nanos)).String())
buffer.WriteString("\"")
buffer.WriteString(", \"IsDelete\":")
buffer.WriteString("\"")
buffer.WriteString(strconv.FormatBool(response.IsDelete))
buffer.WriteString("\"")
buffer.WriteString("}")
bArrayMemberAlreadyWritten = true
}
buffer.WriteString("]")
fmt.Printf("- getHistoryForMarble returning:\n%s\n", buffer.String())
return shim.Success(buffer.Bytes())
}