docs: add delegate upload example

examples/delegate_upload_object.go

@@ -0,0 +1,94 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"time"
+
+	"github.com/bnb-chain/greenfield-go-sdk/client"
+	"github.com/bnb-chain/greenfield-go-sdk/types"
+)
+
+// The example demonstrates the use of the Delegate upload functionality, which streamlines the process compared to the
+// traditional two-stage method of creating and then uploading. With Delegated upload, the uploader interacts solely with
+// the SP without the need to calculate the checksum and create the object meta on-chain initially.
+// Instead, the primary SP handles these on behalf of the uploader.
+func main() {
+	account, err := types.NewAccountFromPrivateKey("test", privateKey)
+	if err != nil {
+		log.Fatalf("New account from private key error, %v", err)
+	}
+	cli, err := client.New(chainId, rpcAddr, client.Option{DefaultAccount: account})
+	if err != nil {
+		log.Fatalf("unable to new greenfield client, %v", err)
+	}
+	ctx := context.Background()
+
+	// get storage providers list
+	spLists, err := cli.ListStorageProviders(ctx, true)
+	if err != nil {
+		log.Fatalf("fail to list in service sps")
+	}
+	// choose the first sp to be the primary SP
+	primarySP := spLists[0].GetOperatorAddress()
+
+	// create bucket
+	_, err = cli.CreateBucket(ctx, bucketName, primarySP, types.CreateBucketOptions{})
+	handleErr(err, "CreateBucket")
+	log.Printf("create bucket %s on SP: %s successfully \n", bucketName, spLists[0].Endpoint)
+
+	// head bucket
+	bucketInfo, err := cli.HeadBucket(ctx, bucketName)
+	handleErr(err, "HeadBucket")
+	log.Println("bucket info:", bucketInfo.String())
+
+	// Create object content
+	var buffer bytes.Buffer
+	line := `0123456789`
+	for i := 0; i < 1024; i++ {
+		buffer.WriteString(fmt.Sprintf("%s", line))
+	}
+
+	err = cli.DelegatePutObject(ctx, bucketName, objectName, int64(buffer.Len()), bytes.NewReader(buffer.Bytes()), types.PutObjectOptions{})
+	handleErr(err, "DelegatePutObject")
+
+	log.Printf("object: %s has been uploaded to SP\n", objectName)
+
+	waitObjectSeal(cli, bucketName, objectName)
+	// wait for block_syncer to sync up data from chain
+	time.Sleep(time.Second * 5)
+
+	// get object
+	reader, info, err := cli.GetObject(ctx, bucketName, objectName, types.GetObjectOptions{})
+	handleErr(err, "GetObject")
+	log.Printf("get object %s successfully, size %d \n", info.ObjectName, info.Size)
+	handleErr(err, "GetObject")
+	objectBytes, err := io.ReadAll(reader)
+	if !bytes.Equal(objectBytes, buffer.Bytes()) {
+		handleErr(errors.New("download content not same"), "GetObject")
+	}
+
+	// the updated content of object
+	var newBuffer bytes.Buffer
+	for i := 0; i < 2048; i++ {
+		newBuffer.WriteString(fmt.Sprintf("%s", line))
+	}
+
+	err = cli.DelegateUpdateObjectContent(ctx, bucketName, objectName, int64(buffer.Len()), bytes.NewReader(newBuffer.Bytes()), types.PutObjectOptions{})
+	handleErr(err, "DelegateUpdateObjectContent")
+
+	// get object
+	reader, info, err = cli.GetObject(ctx, bucketName, objectName, types.GetObjectOptions{})
+	handleErr(err, "GetObject")
+	log.Printf("get object %s successfully, size %d \n", info.ObjectName, info.Size)
+	handleErr(err, "GetObject")
+	objectBytes, err = io.ReadAll(reader)
+	if !bytes.Equal(objectBytes, newBuffer.Bytes()) {
+		handleErr(errors.New("download content not same"), "GetObject")
+	}
+
+}