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blocks_gateway.go
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blocks_gateway.go
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package gateway
import (
"context"
"errors"
"fmt"
"io"
"net/http"
gopath "path"
"strings"
"go.uber.org/multierr"
"github.com/ipfs/go-blockservice"
"github.com/ipfs/go-cid"
bsfetcher "github.com/ipfs/go-fetcher/impl/blockservice"
blockstore "github.com/ipfs/go-ipfs-blockstore"
format "github.com/ipfs/go-ipld-format"
"github.com/ipfs/go-libipfs/blocks"
"github.com/ipfs/go-libipfs/files"
"github.com/ipfs/go-merkledag"
"github.com/ipfs/go-namesys"
"github.com/ipfs/go-namesys/resolve"
ipfspath "github.com/ipfs/go-path"
"github.com/ipfs/go-path/resolver"
ufile "github.com/ipfs/go-unixfs/file"
uio "github.com/ipfs/go-unixfs/io"
"github.com/ipfs/go-unixfsnode"
nsopts "github.com/ipfs/interface-go-ipfs-core/options/namesys"
ifacepath "github.com/ipfs/interface-go-ipfs-core/path"
"github.com/ipld/go-car"
dagpb "github.com/ipld/go-codec-dagpb"
"github.com/ipld/go-ipld-prime"
"github.com/ipld/go-ipld-prime/node/basicnode"
"github.com/ipld/go-ipld-prime/schema"
selectorparse "github.com/ipld/go-ipld-prime/traversal/selector/parse"
routinghelpers "github.com/libp2p/go-libp2p-routing-helpers"
"github.com/libp2p/go-libp2p/core/peer"
"github.com/libp2p/go-libp2p/core/routing"
mc "github.com/multiformats/go-multicodec"
)
type BlocksGateway struct {
blockStore blockstore.Blockstore
blockService blockservice.BlockService
dagService format.DAGService
resolver resolver.Resolver
// Optional routing system to handle /ipns addresses.
namesys namesys.NameSystem
routing routing.ValueStore
}
var _ IPFSBackend = (*BlocksGateway)(nil)
type gwOptions struct {
ns namesys.NameSystem
vs routing.ValueStore
}
// WithNameSystem sets the name system to use for the gateway. If not set it will use a default DNSLink resolver
// along with any configured ValueStore
func WithNameSystem(ns namesys.NameSystem) BlockGatewayOption {
return func(opts *gwOptions) error {
opts.ns = ns
return nil
}
}
// WithValueStore sets the ValueStore to use for the gateway
func WithValueStore(vs routing.ValueStore) BlockGatewayOption {
return func(opts *gwOptions) error {
opts.vs = vs
return nil
}
}
type BlockGatewayOption func(gwOptions *gwOptions) error
func NewBlocksGateway(blockService blockservice.BlockService, opts ...BlockGatewayOption) (*BlocksGateway, error) {
var compiledOptions gwOptions
for _, o := range opts {
if err := o(&compiledOptions); err != nil {
return nil, err
}
}
// Setup the DAG services, which use the CAR block store.
dagService := merkledag.NewDAGService(blockService)
// Setup the UnixFS resolver.
fetcherConfig := bsfetcher.NewFetcherConfig(blockService)
fetcherConfig.PrototypeChooser = dagpb.AddSupportToChooser(func(lnk ipld.Link, lnkCtx ipld.LinkContext) (ipld.NodePrototype, error) {
if tlnkNd, ok := lnkCtx.LinkNode.(schema.TypedLinkNode); ok {
return tlnkNd.LinkTargetNodePrototype(), nil
}
return basicnode.Prototype.Any, nil
})
fetcher := fetcherConfig.WithReifier(unixfsnode.Reify)
r := resolver.NewBasicResolver(fetcher)
// Setup a name system so that we are able to resolve /ipns links.
var (
ns namesys.NameSystem
vs routing.ValueStore
)
vs = compiledOptions.vs
if vs == nil {
vs = routinghelpers.Null{}
}
ns = compiledOptions.ns
if ns == nil {
dns, err := NewDNSResolver(nil, nil)
if err != nil {
return nil, err
}
ns, err = namesys.NewNameSystem(vs, namesys.WithDNSResolver(dns))
if err != nil {
return nil, err
}
}
return &BlocksGateway{
blockStore: blockService.Blockstore(),
blockService: blockService,
dagService: dagService,
resolver: r,
routing: vs,
namesys: ns,
}, nil
}
func (api *BlocksGateway) Get(ctx context.Context, path ImmutablePath) (ContentPathMetadata, *GetResponse, error) {
md, nd, err := api.getNode(ctx, path)
if err != nil {
return md, nil, err
}
rootCodec := nd.Cid().Prefix().GetCodec()
// This covers both Raw blocks and terminal IPLD codecs like dag-cbor and dag-json
// Note: while only cbor, json, dag-cbor, and dag-json are currently supported by gateways this could change
if rootCodec != uint64(mc.DagPb) {
return md, NewGetResponseFromFile(files.NewBytesFile(nd.RawData())), nil
}
// This code path covers full graph, single file/directory, and range requests
f, err := ufile.NewUnixfsFile(ctx, api.dagService, nd)
// Note: there is an assumption here that non-UnixFS dag-pb should not be returned which is currently valid
if err != nil {
return md, nil, err
}
if d, ok := f.(files.Directory); ok {
dir, err := uio.NewDirectoryFromNode(api.dagService, nd)
if err != nil {
return md, nil, err
}
sz, err := d.Size()
if err != nil {
return ContentPathMetadata{}, nil, fmt.Errorf("could not get cumulative directory DAG size: %w", err)
}
if sz < 0 {
return ContentPathMetadata{}, nil, fmt.Errorf("directory cumulative DAG size cannot be negative")
}
return md, NewGetResponseFromDirectoryListing(uint64(sz), dir.EnumLinksAsync(ctx)), nil
}
if file, ok := f.(files.File); ok {
return md, NewGetResponseFromFile(file), nil
}
return ContentPathMetadata{}, nil, fmt.Errorf("data was not a valid file or directory: %w", ErrInternalServerError) // TODO: should there be a gateway invalid content type to abstract over the various IPLD error types?
}
func (api *BlocksGateway) GetRange(ctx context.Context, path ImmutablePath, ranges ...GetRange) (ContentPathMetadata, files.File, error) {
md, nd, err := api.getNode(ctx, path)
if err != nil {
return md, nil, err
}
// This code path covers full graph, single file/directory, and range requests
n, err := ufile.NewUnixfsFile(ctx, api.dagService, nd)
if err != nil {
return md, nil, err
}
f, ok := n.(files.File)
if !ok {
return ContentPathMetadata{}, nil, NewErrorResponse(fmt.Errorf("can only do range requests on files, but did not get a file"), http.StatusBadRequest)
}
return md, f, nil
}
func (api *BlocksGateway) GetAll(ctx context.Context, path ImmutablePath) (ContentPathMetadata, files.Node, error) {
md, nd, err := api.getNode(ctx, path)
if err != nil {
return md, nil, err
}
// This code path covers full graph, single file/directory, and range requests
n, err := ufile.NewUnixfsFile(ctx, api.dagService, nd)
if err != nil {
return md, nil, err
}
return md, n, nil
}
func (api *BlocksGateway) GetBlock(ctx context.Context, path ImmutablePath) (ContentPathMetadata, files.File, error) {
md, nd, err := api.getNode(ctx, path)
if err != nil {
return md, nil, err
}
return md, files.NewBytesFile(nd.RawData()), nil
}
func (api *BlocksGateway) Head(ctx context.Context, path ImmutablePath) (ContentPathMetadata, files.Node, error) {
md, nd, err := api.getNode(ctx, path)
if err != nil {
return md, nil, err
}
rootCodec := nd.Cid().Prefix().GetCodec()
if rootCodec != uint64(mc.DagPb) {
return md, files.NewBytesFile(nd.RawData()), nil
}
// TODO: We're not handling non-UnixFS dag-pb. There's a bit of a discrepancy between what we want from a HEAD request and a Resolve request here and we're using this for both
fileNode, err := ufile.NewUnixfsFile(ctx, api.dagService, nd)
if err != nil {
return ContentPathMetadata{}, nil, err
}
return md, fileNode, nil
}
func (api *BlocksGateway) GetCAR(ctx context.Context, path ImmutablePath) (ContentPathMetadata, io.ReadCloser, <-chan error, error) {
// Same go-car settings as dag.export command
store := dagStore{api: api, ctx: ctx}
// TODO: When switching to exposing path blocks we'll want to add these as well
roots, lastSeg, err := api.getPathRoots(ctx, path)
if err != nil {
return ContentPathMetadata{}, nil, nil, err
}
md := ContentPathMetadata{
PathSegmentRoots: roots,
LastSegment: lastSeg,
}
rootCid := lastSeg.Cid()
// TODO: support selectors passed as request param: https://github.com/ipfs/kubo/issues/8769
// TODO: this is very slow if blocks are remote due to linear traversal. Do we need deterministic traversals here?
dag := car.Dag{Root: rootCid, Selector: selectorparse.CommonSelector_ExploreAllRecursively}
c := car.NewSelectiveCar(ctx, store, []car.Dag{dag}, car.TraverseLinksOnlyOnce())
r, w := io.Pipe()
errCh := make(chan error, 1)
go func() {
carWriteErr := c.Write(w)
pipeCloseErr := w.Close()
errCh <- multierr.Combine(carWriteErr, pipeCloseErr)
close(errCh)
}()
return md, r, errCh, nil
}
func (api *BlocksGateway) getNode(ctx context.Context, path ImmutablePath) (ContentPathMetadata, format.Node, error) {
roots, lastSeg, err := api.getPathRoots(ctx, path)
if err != nil {
return ContentPathMetadata{}, nil, err
}
md := ContentPathMetadata{
PathSegmentRoots: roots,
LastSegment: lastSeg,
}
lastRoot := lastSeg.Cid()
nd, err := api.dagService.Get(ctx, lastRoot)
if err != nil {
return ContentPathMetadata{}, nil, err
}
return md, nd, err
}
func (api *BlocksGateway) getPathRoots(ctx context.Context, contentPath ImmutablePath) ([]cid.Cid, ifacepath.Resolved, error) {
/*
These are logical roots where each CID represent one path segment
and resolves to either a directory or the root block of a file.
The main purpose of this header is allow HTTP caches to do smarter decisions
around cache invalidation (eg. keep specific subdirectory/file if it did not change)
A good example is Wikipedia, which is HAMT-sharded, but we only care about
logical roots that represent each segment of the human-readable content
path:
Given contentPath = /ipns/en.wikipedia-on-ipfs.org/wiki/Block_of_Wikipedia_in_Turkey
rootCidList is a generated by doing `ipfs resolve -r` on each sub path:
/ipns/en.wikipedia-on-ipfs.org → bafybeiaysi4s6lnjev27ln5icwm6tueaw2vdykrtjkwiphwekaywqhcjze
/ipns/en.wikipedia-on-ipfs.org/wiki/ → bafybeihn2f7lhumh4grizksi2fl233cyszqadkn424ptjajfenykpsaiw4
/ipns/en.wikipedia-on-ipfs.org/wiki/Block_of_Wikipedia_in_Turkey → bafkreibn6euazfvoghepcm4efzqx5l3hieof2frhp254hio5y7n3hv5rma
The result is an ordered array of values:
X-Ipfs-Roots: bafybeiaysi4s6lnjev27ln5icwm6tueaw2vdykrtjkwiphwekaywqhcjze,bafybeihn2f7lhumh4grizksi2fl233cyszqadkn424ptjajfenykpsaiw4,bafkreibn6euazfvoghepcm4efzqx5l3hieof2frhp254hio5y7n3hv5rma
Note that while the top one will change every time any article is changed,
the last root (responsible for specific article) may not change at all.
*/
var sp strings.Builder
var pathRoots []cid.Cid
contentPathStr := contentPath.String()
pathSegments := strings.Split(contentPathStr[6:], "/")
sp.WriteString(contentPathStr[:5]) // /ipfs or /ipns
var lastPath ifacepath.Resolved
for _, root := range pathSegments {
if root == "" {
continue
}
sp.WriteString("/")
sp.WriteString(root)
resolvedSubPath, err := api.resolvePath(ctx, ifacepath.New(sp.String()))
if err != nil {
// TODO: should we be more explicit here and is this part of the Gateway API contract?
// The issue here was that we returned datamodel.ErrWrongKind instead of this resolver error
if isErrNotFound(err) {
return nil, nil, resolver.ErrNoLink{Name: root, Node: lastPath.Cid()}
}
return nil, nil, err
}
lastPath = resolvedSubPath
pathRoots = append(pathRoots, lastPath.Cid())
}
pathRoots = pathRoots[:len(pathRoots)-1]
return pathRoots, lastPath, nil
}
// FIXME(@Jorropo): https://github.com/ipld/go-car/issues/315
type dagStore struct {
api *BlocksGateway
ctx context.Context
}
func (ds dagStore) Get(_ context.Context, c cid.Cid) (blocks.Block, error) {
return ds.api.blockService.GetBlock(ds.ctx, c)
}
func (api *BlocksGateway) ResolveMutable(ctx context.Context, p ifacepath.Path) (ImmutablePath, error) {
err := p.IsValid()
if err != nil {
return ImmutablePath{}, err
}
ipath := ipfspath.Path(p.String())
switch ipath.Segments()[0] {
case "ipns":
ipath, err = resolve.ResolveIPNS(ctx, api.namesys, ipath)
if err != nil {
return ImmutablePath{}, err
}
imPath, err := NewImmutablePath(ifacepath.New(ipath.String()))
if err != nil {
return ImmutablePath{}, err
}
return imPath, nil
case "ipfs":
imPath, err := NewImmutablePath(ifacepath.New(ipath.String()))
if err != nil {
return ImmutablePath{}, err
}
return imPath, nil
default:
return ImmutablePath{}, NewErrorResponse(fmt.Errorf("unsupported path namespace: %s", p.Namespace()), http.StatusNotImplemented)
}
}
func (api *BlocksGateway) GetIPNSRecord(ctx context.Context, c cid.Cid) ([]byte, error) {
if api.routing == nil {
return nil, NewErrorResponse(errors.New("IPNS Record responses are not supported by this gateway"), http.StatusNotImplemented)
}
// Fails fast if the CID is not an encoded Libp2p Key, avoids wasteful
// round trips to the remote routing provider.
if mc.Code(c.Type()) != mc.Libp2pKey {
return nil, NewErrorResponse(errors.New("cid codec must be libp2p-key"), http.StatusBadRequest)
}
// The value store expects the key itself to be encoded as a multihash.
id, err := peer.FromCid(c)
if err != nil {
return nil, err
}
return api.routing.GetValue(ctx, "/ipns/"+string(id))
}
func (api *BlocksGateway) GetDNSLinkRecord(ctx context.Context, hostname string) (ifacepath.Path, error) {
if api.namesys != nil {
p, err := api.namesys.Resolve(ctx, "/ipns/"+hostname, nsopts.Depth(1))
if err == namesys.ErrResolveRecursion {
err = nil
}
return ifacepath.New(p.String()), err
}
return nil, NewErrorResponse(errors.New("not implemented"), http.StatusNotImplemented)
}
func (api *BlocksGateway) IsCached(ctx context.Context, p ifacepath.Path) bool {
rp, err := api.resolvePath(ctx, p)
if err != nil {
return false
}
has, _ := api.blockStore.Has(ctx, rp.Cid())
return has
}
func (api *BlocksGateway) ResolvePath(ctx context.Context, path ImmutablePath) (ContentPathMetadata, error) {
roots, lastSeg, err := api.getPathRoots(ctx, path)
if err != nil {
return ContentPathMetadata{}, err
}
md := ContentPathMetadata{
PathSegmentRoots: roots,
LastSegment: lastSeg,
}
return md, nil
}
func (api *BlocksGateway) resolvePath(ctx context.Context, p ifacepath.Path) (ifacepath.Resolved, error) {
if _, ok := p.(ifacepath.Resolved); ok {
return p.(ifacepath.Resolved), nil
}
err := p.IsValid()
if err != nil {
return nil, err
}
ipath := ipfspath.Path(p.String())
if ipath.Segments()[0] == "ipns" {
ipath, err = resolve.ResolveIPNS(ctx, api.namesys, ipath)
if err != nil {
return nil, err
}
}
if ipath.Segments()[0] != "ipfs" {
return nil, fmt.Errorf("unsupported path namespace: %s", p.Namespace())
}
node, rest, err := api.resolver.ResolveToLastNode(ctx, ipath)
if err != nil {
return nil, err
}
root, err := cid.Parse(ipath.Segments()[1])
if err != nil {
return nil, err
}
return ifacepath.NewResolvedPath(ipath, node, root, gopath.Join(rest...)), nil
}