ipld-eth-server/pkg/btc/ipld_fetcher.go

136 lines
4.0 KiB
Go

// VulcanizeDB
// Copyright © 2019 Vulcanize
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package btc
import (
"context"
"errors"
"fmt"
"github.com/ipfs/go-block-format"
"github.com/ipfs/go-blockservice"
"github.com/ipfs/go-cid"
log "github.com/sirupsen/logrus"
"github.com/vulcanize/ipfs-blockchain-watcher/pkg/ipfs"
"github.com/vulcanize/ipfs-blockchain-watcher/pkg/shared"
)
var (
errUnexpectedNumberOfIPLDs = errors.New("ipfs batch fetch returned unexpected number of IPLDs")
)
// IPLDFetcher satisfies the IPLDFetcher interface for ethereum
type IPLDFetcher struct {
BlockService blockservice.BlockService
}
// NewIPLDFetcher creates a pointer to a new IPLDFetcher
// It interfaces with PG-IPFS through an internalized IPFS node interface
func NewIPLDFetcher(ipfsPath string) (*IPLDFetcher, error) {
blockService, err := ipfs.InitIPFSBlockService(ipfsPath)
if err != nil {
return nil, err
}
return &IPLDFetcher{
BlockService: blockService,
}, nil
}
// Fetch is the exported method for fetching and returning all the IPLDS specified in the CIDWrapper
func (f *IPLDFetcher) Fetch(cids shared.CIDsForFetching) (shared.IPLDs, error) {
cidWrapper, ok := cids.(*CIDWrapper)
if !ok {
return nil, fmt.Errorf("btc fetcher: expected cids type %T got %T", &CIDWrapper{}, cids)
}
log.Debug("fetching iplds")
iplds := IPLDs{}
iplds.BlockNumber = cidWrapper.BlockNumber
var err error
iplds.Header, err = f.FetchHeader(cidWrapper.Header)
if err != nil {
return nil, err
}
iplds.Transactions, err = f.FetchTrxs(cidWrapper.Transactions)
if err != nil {
return nil, err
}
return iplds, nil
}
// FetchHeaders fetches headers
// It uses the f.fetch method
func (f *IPLDFetcher) FetchHeader(c HeaderModel) (ipfs.BlockModel, error) {
log.Debug("fetching header ipld")
dc, err := cid.Decode(c.CID)
if err != nil {
return ipfs.BlockModel{}, err
}
header, err := f.fetch(dc)
if err != nil {
return ipfs.BlockModel{}, err
}
return ipfs.BlockModel{
Data: header.RawData(),
CID: header.Cid().String(),
}, nil
}
// FetchTrxs fetches transactions
// It uses the f.fetchBatch method
func (f *IPLDFetcher) FetchTrxs(cids []TxModel) ([]ipfs.BlockModel, error) {
log.Debug("fetching transaction iplds")
trxCids := make([]cid.Cid, len(cids))
for i, c := range cids {
dc, err := cid.Decode(c.CID)
if err != nil {
return nil, err
}
trxCids[i] = dc
}
trxs := f.fetchBatch(trxCids)
trxIPLDs := make([]ipfs.BlockModel, len(trxs))
for i, trx := range trxs {
trxIPLDs[i] = ipfs.BlockModel{
Data: trx.RawData(),
CID: trx.Cid().String(),
}
}
if len(trxIPLDs) != len(trxCids) {
log.Errorf("ipfs fetcher: number of transaction blocks returned (%d) does not match number expected (%d)", len(trxs), len(trxCids))
return trxIPLDs, errUnexpectedNumberOfIPLDs
}
return trxIPLDs, nil
}
// fetch is used to fetch a single cid
func (f *IPLDFetcher) fetch(cid cid.Cid) (blocks.Block, error) {
return f.BlockService.GetBlock(context.Background(), cid)
}
// fetchBatch is used to fetch a batch of IPFS data blocks by cid
// There is no guarantee all are fetched, and no error in such a case, so
// downstream we will need to confirm which CIDs were fetched in the result set
func (f *IPLDFetcher) fetchBatch(cids []cid.Cid) []blocks.Block {
fetchedBlocks := make([]blocks.Block, 0, len(cids))
blockChan := f.BlockService.GetBlocks(context.Background(), cids)
for block := range blockChan {
fetchedBlocks = append(fetchedBlocks, block)
}
return fetchedBlocks
}