feat: add proxy blockstore

blockstore.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"crypto/tls"
+	"errors"
 	"net/http"
 	"net/url"
 	"time"
@@ -15,6 +16,8 @@ import (
 	"go.uber.org/zap/zapcore"
 )
 
+var errNotImplemented = errors.New("not implemented")
+
 const GetBlockTimeout = time.Second * 60
 
 func newExchange(orchestrator, loggingEndpoint string) (exchange.Interface, error) {

blockstore_cache.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"errors"
 
 	"github.com/ipfs/go-cid"
 	format "github.com/ipfs/go-ipld-format"
@@ -127,7 +126,7 @@ func (l *cacheBlockStore) PutMany(ctx context.Context, blks []blocks.Block) erro
 }
 
 func (l *cacheBlockStore) AllKeysChan(ctx context.Context) (<-chan cid.Cid, error) {
-	return nil, errors.New("not implemented")
+	return nil, errNotImplemented
 }
 
 func (l *cacheBlockStore) HashOnRead(enabled bool) {

blockstore_proxy.go

@@ -0,0 +1,119 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+
+	"github.com/ipfs/go-cid"
+	blockstore "github.com/ipfs/go-ipfs-blockstore"
+	"github.com/ipfs/go-libipfs/blocks"
+)
+
+type proxyBlockStore struct {
+	httpClient *http.Client
+	gatewayURL string
+	validate   bool
+}
+
+func newProxyBlockStore(gatewayURL string, client *http.Client) blockstore.Blockstore {
+	if client == nil {
+		client = http.DefaultClient
+	}
+
+	return &proxyBlockStore{
+		gatewayURL: gatewayURL,
+		httpClient: client,
+		// Enables block validation by default. Important since we are
+		// proxying block requests to an untrusted gateway.
+		validate: true,
+	}
+}
+
+func (ps *proxyBlockStore) fetch(ctx context.Context, c cid.Cid) (blocks.Block, error) {
+	u, err := url.Parse(fmt.Sprintf("%s/ipfs/%s?format=raw", ps.gatewayURL, c))
+	if err != nil {
+		return nil, err
+	}
+	resp, err := ps.httpClient.Do(&http.Request{
+		Method: http.MethodGet,
+		URL:    u,
+		Header: http.Header{
+			"Accept": []string{"application/vnd.ipld.raw"},
+		},
+	})
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("unexpected status from remote gateway: %s", resp.Status)
+	}
+
+	rb, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if ps.validate {
+		nc, err := c.Prefix().Sum(rb)
+		if err != nil {
+			return nil, blocks.ErrWrongHash
+		}
+		if !nc.Equals(c) {
+			fmt.Printf("got %s vs %s\n", nc, c)
+			return nil, blocks.ErrWrongHash
+		}
+	}
+
+	return blocks.NewBlockWithCid(rb, c)
+}
+
+func (ps *proxyBlockStore) Has(ctx context.Context, c cid.Cid) (bool, error) {
+	blk, err := ps.fetch(ctx, c)
+	if err != nil {
+		return false, err
+	}
+	return blk != nil, nil
+}
+
+func (ps *proxyBlockStore) Get(ctx context.Context, c cid.Cid) (blocks.Block, error) {
+	blk, err := ps.fetch(ctx, c)
+	if err != nil {
+		return nil, err
+	}
+	return blk, nil
+}
+
+func (ps *proxyBlockStore) GetSize(ctx context.Context, c cid.Cid) (int, error) {
+	blk, err := ps.fetch(ctx, c)
+	if err != nil {
+		return 0, err
+	}
+	return len(blk.RawData()), nil
+}
+
+func (ps *proxyBlockStore) HashOnRead(enabled bool) {
+	ps.validate = enabled
+}
+
+func (c *proxyBlockStore) Put(context.Context, blocks.Block) error {
+	return errNotImplemented
+}
+
+func (c *proxyBlockStore) PutMany(context.Context, []blocks.Block) error {
+	return errNotImplemented
+}
+
+func (c *proxyBlockStore) AllKeysChan(ctx context.Context) (<-chan cid.Cid, error) {
+	return nil, errNotImplemented
+}
+
+func (c *proxyBlockStore) DeleteBlock(context.Context, cid.Cid) error {
+	return errNotImplemented
+}
+
+var _ blockstore.Blockstore = (*proxyBlockStore)(nil)