ipfs fetcher

pkg/ipfs/fetcher.go

@@ -0,0 +1,64 @@
+// 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 ipfs
+
+import (
+	"context"
+
+	"github.com/ipfs/go-block-format"
+	"github.com/ipfs/go-blockservice"
+	"github.com/ipfs/go-cid"
+)
+
+// IPLDFetcher is the interface for fetching IPLD objects from IPFS
+type IPLDFetcher interface {
+	Fetch(cid cid.Cid) (blocks.Block, error)
+	FetchBatch(cids []cid.Cid) []blocks.Block
+}
+
+// Fetcher is the underlying struct which supports the IPLDFetcher interface
+type Fetcher struct {
+	BlockService blockservice.BlockService
+}
+
+// NewIPLDFetcher creates a pointer to a new Fetcher which satisfies the IPLDFetcher interface
+func NewIPLDFetcher(ipfsPath string) (*Fetcher, error) {
+	blockService, err := InitIPFSBlockService(ipfsPath)
+	if err != nil {
+		return nil, err
+	}
+	return &Fetcher{
+		BlockService: blockService,
+	}, nil
+}
+
+// Fetch is used to fetch a batch of IPFS data blocks by cid
+func (f *Fetcher) 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 *Fetcher) 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
+}

pkg/ipfs/fetcher_test.go

@@ -0,0 +1,17 @@
+// 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 ipfs

pkg/ipfs/helpers.go

@@ -0,0 +1,43 @@
+// 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 ipfs
+
+import (
+	"context"
+
+	"github.com/ipfs/go-blockservice"
+	"github.com/ipfs/go-ipfs/core"
+	"github.com/ipfs/go-ipfs/repo/fsrepo"
+)
+
+// InitIPFSBlockService is used to configure and return a BlockService using an ipfs repo path (e.g. ~/.ipfs)
+func InitIPFSBlockService(ipfsPath string) (blockservice.BlockService, error) {
+	r, err := fsrepo.Open(ipfsPath)
+	if err != nil {
+		return nil, err
+	}
+	ctx := context.Background()
+	cfg := &core.BuildCfg{
+		Online: false,
+		Repo:   r,
+	}
+	ipfsNode, err := core.NewNode(ctx, cfg)
+	if err != nil {
+		return nil, err
+	}
+	return ipfsNode.Blocks, nil
+}