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Files
kubo/core/pathresolver.go
Steven Allen dfe7ef4fcf gx: update go-multihash
License: MIT
Signed-off-by: Steven Allen <steven@stebalien.com>
2017-12-14 13:09:51 -08:00

101 lines
3.1 KiB
Go

package core
import (
"context"
"errors"
"strings"
namesys "github.com/ipfs/go-ipfs/namesys"
path "github.com/ipfs/go-ipfs/path"
node "gx/ipfs/QmNwUEK7QbwSqyKBu3mMtToo8SUc6wQJ7gdZq4gGGJqfnf/go-ipld-format"
logging "gx/ipfs/QmSpJByNKFX1sCsHBEp3R73FL4NF6FnQTEGyNAXHm2GS52/go-log"
cid "gx/ipfs/QmeSrf6pzut73u6zLQkRFQ3ygt3k6XFT2kjdYP8Tnkwwyg/go-cid"
)
// ErrNoNamesys is an explicit error for when an IPFS node doesn't
// (yet) have a name system
var ErrNoNamesys = errors.New(
"core/resolve: no Namesys on IpfsNode - can't resolve ipns entry")
// Resolve resolves the given path by parsing out protocol-specific
// entries (e.g. /ipns/<node-key>) and then going through the /ipfs/
// entries and returning the final node.
func Resolve(ctx context.Context, nsys namesys.NameSystem, r *path.Resolver, p path.Path) (node.Node, error) {
if strings.HasPrefix(p.String(), "/ipns/") {
evt := log.EventBegin(ctx, "resolveIpnsPath")
defer evt.Done()
// resolve ipns paths
// TODO(cryptix): we sould be able to query the local cache for the path
if nsys == nil {
evt.Append(logging.LoggableMap{"error": ErrNoNamesys.Error()})
return nil, ErrNoNamesys
}
seg := p.Segments()
if len(seg) < 2 || seg[1] == "" { // just "/<protocol/>" without further segments
evt.Append(logging.LoggableMap{"error": path.ErrNoComponents.Error()})
return nil, path.ErrNoComponents
}
extensions := seg[2:]
resolvable, err := path.FromSegments("/", seg[0], seg[1])
if err != nil {
evt.Append(logging.LoggableMap{"error": err.Error()})
return nil, err
}
respath, err := nsys.Resolve(ctx, resolvable.String())
if err != nil {
evt.Append(logging.LoggableMap{"error": err.Error()})
return nil, err
}
segments := append(respath.Segments(), extensions...)
p, err = path.FromSegments("/", segments...)
if err != nil {
evt.Append(logging.LoggableMap{"error": err.Error()})
return nil, err
}
}
// ok, we have an IPFS path now (or what we'll treat as one)
return r.ResolvePath(ctx, p)
}
// ResolveToCid resolves a path to a cid.
//
// It first checks if the path is already in the form of just a cid (<cid> or
// /ipfs/<cid>) and returns immediately if so. Otherwise, it falls back onto
// Resolve to perform resolution of the dagnode being referenced.
func ResolveToCid(ctx context.Context, nsys namesys.NameSystem, r *path.Resolver, p path.Path) (*cid.Cid, error) {
// If the path is simply a cid, parse and return it. Parsed paths are already
// normalized (read: prepended with /ipfs/ if needed), so segment[1] should
// always be the key.
if p.IsJustAKey() {
return cid.Decode(p.Segments()[1])
}
// Fall back onto regular dagnode resolution. Retrieve the second-to-last
// segment of the path and resolve its link to the last segment.
head, tail, err := p.PopLastSegment()
if err != nil {
return nil, err
}
dagnode, err := Resolve(ctx, nsys, r, head)
if err != nil {
return nil, err
}
// Extract and return the cid of the link to the target dag node.
link, _, err := dagnode.ResolveLink([]string{tail})
if err != nil {
return nil, err
}
return link.Cid, nil
}