kubo/core/corehttp/gateway_writable.go
2023-03-17 23:40:35 +01:00

266 lines
7.5 KiB
Go

package corehttp
import (
"context"
"fmt"
"net/http"
"os"
gopath "path"
cid "github.com/ipfs/go-cid"
ipld "github.com/ipfs/go-ipld-format"
"github.com/ipfs/go-libipfs/files"
"github.com/ipfs/go-libipfs/gateway"
dag "github.com/ipfs/go-merkledag"
"github.com/ipfs/go-mfs"
path "github.com/ipfs/go-path"
"github.com/ipfs/go-path/resolver"
iface "github.com/ipfs/interface-go-ipfs-core"
routing "github.com/libp2p/go-libp2p/core/routing"
)
const (
ipfsPathPrefix = "/ipfs/"
)
type writableGatewayHandler struct {
api iface.CoreAPI
config *gateway.Config
}
func (i *writableGatewayHandler) addUserHeaders(w http.ResponseWriter) {
for k, v := range i.config.Headers {
w.Header()[http.CanonicalHeaderKey(k)] = v
}
}
func (i *writableGatewayHandler) postHandler(w http.ResponseWriter, r *http.Request) {
p, err := i.api.Unixfs().Add(r.Context(), files.NewReaderFile(r.Body))
if err != nil {
internalWebError(w, err)
return
}
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("IPFS-Hash", p.Cid().String())
log.Debugw("CID created, http redirect", "from", r.URL, "to", p, "status", http.StatusCreated)
http.Redirect(w, r, p.String(), http.StatusCreated)
}
func (i *writableGatewayHandler) putHandler(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
ds := i.api.Dag()
// Parse the path
rootCid, newPath, err := parseIpfsPath(r.URL.Path)
if err != nil {
webError(w, "WritableGateway: failed to parse the path", err, http.StatusBadRequest)
return
}
if newPath == "" || newPath == "/" {
http.Error(w, "WritableGateway: empty path", http.StatusBadRequest)
return
}
newDirectory, newFileName := gopath.Split(newPath)
// Resolve the old root.
rnode, err := ds.Get(ctx, rootCid)
if err != nil {
webError(w, "WritableGateway: Could not create DAG from request", err, http.StatusInternalServerError)
return
}
pbnd, ok := rnode.(*dag.ProtoNode)
if !ok {
webError(w, "Cannot read non protobuf nodes through gateway", dag.ErrNotProtobuf, http.StatusBadRequest)
return
}
// Create the new file.
newFilePath, err := i.api.Unixfs().Add(ctx, files.NewReaderFile(r.Body))
if err != nil {
webError(w, "WritableGateway: could not create DAG from request", err, http.StatusInternalServerError)
return
}
newFile, err := ds.Get(ctx, newFilePath.Cid())
if err != nil {
webError(w, "WritableGateway: failed to resolve new file", err, http.StatusInternalServerError)
return
}
// Patch the new file into the old root.
root, err := mfs.NewRoot(ctx, ds, pbnd, nil)
if err != nil {
webError(w, "WritableGateway: failed to create MFS root", err, http.StatusBadRequest)
return
}
if newDirectory != "" {
err := mfs.Mkdir(root, newDirectory, mfs.MkdirOpts{Mkparents: true, Flush: false})
if err != nil {
webError(w, "WritableGateway: failed to create MFS directory", err, http.StatusInternalServerError)
return
}
}
dirNode, err := mfs.Lookup(root, newDirectory)
if err != nil {
webError(w, "WritableGateway: failed to lookup directory", err, http.StatusInternalServerError)
return
}
dir, ok := dirNode.(*mfs.Directory)
if !ok {
http.Error(w, "WritableGateway: target directory is not a directory", http.StatusBadRequest)
return
}
err = dir.Unlink(newFileName)
switch err {
case os.ErrNotExist, nil:
default:
webError(w, "WritableGateway: failed to replace existing file", err, http.StatusBadRequest)
return
}
err = dir.AddChild(newFileName, newFile)
if err != nil {
webError(w, "WritableGateway: failed to link file into directory", err, http.StatusInternalServerError)
return
}
nnode, err := root.GetDirectory().GetNode()
if err != nil {
webError(w, "WritableGateway: failed to finalize", err, http.StatusInternalServerError)
return
}
newcid := nnode.Cid()
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("IPFS-Hash", newcid.String())
redirectURL := gopath.Join(ipfsPathPrefix, newcid.String(), newPath)
log.Debugw("CID replaced, redirect", "from", r.URL, "to", redirectURL, "status", http.StatusCreated)
http.Redirect(w, r, redirectURL, http.StatusCreated)
}
func (i *writableGatewayHandler) deleteHandler(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
// parse the path
rootCid, newPath, err := parseIpfsPath(r.URL.Path)
if err != nil {
webError(w, "WritableGateway: failed to parse the path", err, http.StatusBadRequest)
return
}
if newPath == "" || newPath == "/" {
http.Error(w, "WritableGateway: empty path", http.StatusBadRequest)
return
}
directory, filename := gopath.Split(newPath)
// lookup the root
rootNodeIPLD, err := i.api.Dag().Get(ctx, rootCid)
if err != nil {
webError(w, "WritableGateway: failed to resolve root CID", err, http.StatusInternalServerError)
return
}
rootNode, ok := rootNodeIPLD.(*dag.ProtoNode)
if !ok {
http.Error(w, "WritableGateway: empty path", http.StatusInternalServerError)
return
}
// construct the mfs root
root, err := mfs.NewRoot(ctx, i.api.Dag(), rootNode, nil)
if err != nil {
webError(w, "WritableGateway: failed to construct the MFS root", err, http.StatusBadRequest)
return
}
// lookup the parent directory
parentNode, err := mfs.Lookup(root, directory)
if err != nil {
webError(w, "WritableGateway: failed to look up parent", err, http.StatusInternalServerError)
return
}
parent, ok := parentNode.(*mfs.Directory)
if !ok {
http.Error(w, "WritableGateway: parent is not a directory", http.StatusInternalServerError)
return
}
// delete the file
switch parent.Unlink(filename) {
case nil, os.ErrNotExist:
default:
webError(w, "WritableGateway: failed to remove file", err, http.StatusInternalServerError)
return
}
nnode, err := root.GetDirectory().GetNode()
if err != nil {
webError(w, "WritableGateway: failed to finalize", err, http.StatusInternalServerError)
return
}
ncid := nnode.Cid()
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("IPFS-Hash", ncid.String())
redirectURL := gopath.Join(ipfsPathPrefix+ncid.String(), directory)
// note: StatusCreated is technically correct here as we created a new resource.
log.Debugw("CID deleted, redirect", "from", r.RequestURI, "to", redirectURL, "status", http.StatusCreated)
http.Redirect(w, r, redirectURL, http.StatusCreated)
}
func parseIpfsPath(p string) (cid.Cid, string, error) {
rootPath, err := path.ParsePath(p)
if err != nil {
return cid.Cid{}, "", err
}
// Check the path.
rsegs := rootPath.Segments()
if rsegs[0] != "ipfs" {
return cid.Cid{}, "", fmt.Errorf("WritableGateway: only ipfs paths supported")
}
rootCid, err := cid.Decode(rsegs[1])
if err != nil {
return cid.Cid{}, "", err
}
return rootCid, path.Join(rsegs[2:]), nil
}
func webError(w http.ResponseWriter, message string, err error, defaultCode int) {
if _, ok := err.(resolver.ErrNoLink); ok {
webErrorWithCode(w, message, err, http.StatusNotFound)
} else if err == routing.ErrNotFound {
webErrorWithCode(w, message, err, http.StatusNotFound)
} else if ipld.IsNotFound(err) {
webErrorWithCode(w, message, err, http.StatusNotFound)
} else if err == context.DeadlineExceeded {
webErrorWithCode(w, message, err, http.StatusRequestTimeout)
} else {
webErrorWithCode(w, message, err, defaultCode)
}
}
func webErrorWithCode(w http.ResponseWriter, message string, err error, code int) {
http.Error(w, fmt.Sprintf("%s: %s", message, err), code)
if code >= 500 {
log.Warnf("server error: %s: %s", message, err)
}
}
// return a 500 error and log
func internalWebError(w http.ResponseWriter, err error) {
webErrorWithCode(w, "internalWebError", err, http.StatusInternalServerError)
}