kubo/core/pathresolver.go
2015-04-26 22:32:12 -07:00

58 lines
1.6 KiB
Go

package core
import (
"errors"
"fmt"
"strings"
merkledag "github.com/ipfs/go-ipfs/merkledag"
path "github.com/ipfs/go-ipfs/path"
)
const maxLinks = 32
var ErrTooManyLinks = errors.New("exceeded maximum number of links in ipns entry")
// Resolves the given path by parsing out /ipns/ entries and then going
// through the /ipfs/ entries and returning the final merkledage node.
// Effectively enables /ipns/ in CLI commands.
func Resolve(n *IpfsNode, p path.Path) (*merkledag.Node, error) {
return resolveRecurse(n, p, 0)
}
func resolveRecurse(n *IpfsNode, p path.Path, depth int) (*merkledag.Node, error) {
if depth >= maxLinks {
return nil, ErrTooManyLinks
}
// for now, we only try to resolve ipns paths if
// they begin with "/ipns/". Otherwise, ambiguity
// emerges when resolving just a <hash>. Is it meant
// to be an ipfs or an ipns resolution?
if strings.HasPrefix(p.String(), "/ipns/") {
// if it's an ipns path, try to resolve it.
// if we can't, we can give that error back to the user.
seg := p.Segments()
if len(seg) < 2 || seg[1] == "" { // just "/ipns/"
return nil, fmt.Errorf("invalid path: %s", string(p))
}
ipnsPath := seg[1]
extensions := seg[2:]
respath, err := n.Namesys.Resolve(n.Context(), ipnsPath)
if err != nil {
return nil, err
}
segments := append(respath.Segments(), extensions...)
respath, err = path.FromSegments(segments...)
if err != nil {
return nil, err
}
return resolveRecurse(n, respath, depth+1)
}
// ok, we have an ipfs path now (or what we'll treat as one)
return n.Resolver.ResolvePath(p)
}