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gateway_handler.go
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gateway_handler.go
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package corehttp
import (
"errors"
"fmt"
"io"
"net/http"
gopath "path"
"strings"
"time"
humanize "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/dustin/go-humanize"
"github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
key "github.com/ipfs/go-ipfs/blocks/key"
core "github.com/ipfs/go-ipfs/core"
"github.com/ipfs/go-ipfs/importer"
chunk "github.com/ipfs/go-ipfs/importer/chunk"
dag "github.com/ipfs/go-ipfs/merkledag"
dagutils "github.com/ipfs/go-ipfs/merkledag/utils"
path "github.com/ipfs/go-ipfs/path"
"github.com/ipfs/go-ipfs/routing"
uio "github.com/ipfs/go-ipfs/unixfs/io"
)
const (
ipfsPathPrefix = "/ipfs/"
ipnsPathPrefix = "/ipns/"
)
// gatewayHandler is a HTTP handler that serves IPFS objects (accessible by default at /ipfs/<path>)
// (it serves requests like GET /ipfs/QmVRzPKPzNtSrEzBFm2UZfxmPAgnaLke4DMcerbsGGSaFe/link)
type gatewayHandler struct {
node *core.IpfsNode
config GatewayConfig
}
func newGatewayHandler(node *core.IpfsNode, conf GatewayConfig) (*gatewayHandler, error) {
i := &gatewayHandler{
node: node,
config: conf,
}
return i, nil
}
// TODO(cryptix): find these helpers somewhere else
func (i *gatewayHandler) newDagFromReader(r io.Reader) (*dag.Node, error) {
// TODO(cryptix): change and remove this helper once PR1136 is merged
// return ufs.AddFromReader(i.node, r.Body)
return importer.BuildDagFromReader(
i.node.DAG,
chunk.DefaultSplitter(r),
importer.BasicPinnerCB(i.node.Pinning.GetManual()))
}
// TODO(btc): break this apart into separate handlers using a more expressive muxer
func (i *gatewayHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if i.config.Writable {
switch r.Method {
case "POST":
i.postHandler(w, r)
return
case "PUT":
i.putHandler(w, r)
return
case "DELETE":
i.deleteHandler(w, r)
return
}
}
if r.Method == "GET" || r.Method == "HEAD" {
i.getOrHeadHandler(w, r)
return
}
errmsg := "Method " + r.Method + " not allowed: "
if !i.config.Writable {
w.WriteHeader(http.StatusMethodNotAllowed)
errmsg = errmsg + "read only access"
} else {
w.WriteHeader(http.StatusBadRequest)
errmsg = errmsg + "bad request for " + r.URL.Path
}
fmt.Fprint(w, errmsg)
log.Error(errmsg) // TODO(cryptix): log errors until we have a better way to expose these (counter metrics maybe)
}
func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request) {
ctx, cancel := context.WithCancel(i.node.Context())
defer cancel()
urlPath := r.URL.Path
// If the gateway is behind a reverse proxy and mounted at a sub-path,
// the prefix header can be set to signal this sub-path.
// It will be prepended to links in directory listings and the index.html redirect.
prefix := ""
if prefixHdr := r.Header["X-Ipfs-Gateway-Prefix"]; len(prefixHdr) > 0 {
log.Debugf("X-Ipfs-Gateway-Prefix: %s", prefixHdr[0])
prefix = prefixHdr[0]
}
// IPNSHostnameOption might have constructed an IPNS path using the Host header.
// In this case, we need the original path for constructing redirects
// and links that match the requested URL.
// For example, http://example.net would become /ipns/example.net, and
// the redirects and links would end up as http://example.net/ipns/example.net
originalUrlPath := prefix + urlPath
ipnsHostname := false
if hdr := r.Header["X-Ipns-Original-Path"]; len(hdr) > 0 {
originalUrlPath = prefix + hdr[0]
ipnsHostname = true
}
if i.config.BlockList != nil && i.config.BlockList.ShouldBlock(urlPath) {
w.WriteHeader(http.StatusForbidden)
w.Write([]byte("403 - Forbidden"))
return
}
nd, err := core.Resolve(ctx, i.node, path.Path(urlPath))
if err != nil {
webError(w, "Path Resolve error", err, http.StatusBadRequest)
return
}
etag := gopath.Base(urlPath)
if r.Header.Get("If-None-Match") == etag {
w.WriteHeader(http.StatusNotModified)
return
}
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("X-IPFS-Path", urlPath)
// Suborigin header, sandboxes apps from each other in the browser (even
// though they are served from the same gateway domain).
//
// Omited if the path was treated by IPNSHostnameOption(), for example
// a request for http://example.net/ would be changed to /ipns/example.net/,
// which would turn into an incorrect Suborigin: example.net header.
//
// NOTE: This is not yet widely supported by browsers.
if !ipnsHostname {
pathRoot := strings.SplitN(urlPath, "/", 4)[2]
w.Header().Set("Suborigin", pathRoot)
}
dr, err := uio.NewDagReader(ctx, nd, i.node.DAG)
if err != nil && err != uio.ErrIsDir {
// not a directory and still an error
internalWebError(w, err)
return
}
// set these headers _after_ the error, for we may just not have it
// and dont want the client to cache a 500 response...
// and only if it's /ipfs!
// TODO: break this out when we split /ipfs /ipns routes.
modtime := time.Now()
if strings.HasPrefix(urlPath, ipfsPathPrefix) {
w.Header().Set("Etag", etag)
w.Header().Set("Cache-Control", "public, max-age=29030400")
// set modtime to a really long time ago, since files are immutable and should stay cached
modtime = time.Unix(1, 0)
}
if err == nil {
defer dr.Close()
_, name := gopath.Split(urlPath)
http.ServeContent(w, r, name, modtime, dr)
return
}
// storage for directory listing
var dirListing []directoryItem
// loop through files
foundIndex := false
for _, link := range nd.Links {
if link.Name == "index.html" {
log.Debugf("found index.html link for %s", urlPath)
foundIndex = true
if urlPath[len(urlPath)-1] != '/' {
// See comment above where originalUrlPath is declared.
http.Redirect(w, r, originalUrlPath+"/", 302)
log.Debugf("redirect to %s", originalUrlPath+"/")
return
}
// return index page instead.
nd, err := core.Resolve(ctx, i.node, path.Path(urlPath+"/index.html"))
if err != nil {
internalWebError(w, err)
return
}
dr, err := uio.NewDagReader(ctx, nd, i.node.DAG)
if err != nil {
internalWebError(w, err)
return
}
defer dr.Close()
// write to request
if r.Method != "HEAD" {
io.Copy(w, dr)
}
break
}
// See comment above where originalUrlPath is declared.
di := directoryItem{humanize.Bytes(link.Size), link.Name, gopath.Join(originalUrlPath, link.Name)}
dirListing = append(dirListing, di)
}
if !foundIndex {
if r.Method != "HEAD" {
// construct the correct back link
// https://github.com/ipfs/go-ipfs/issues/1365
var backLink string = prefix + urlPath
// don't go further up than /ipfs/$hash/
pathSplit := strings.Split(backLink, "/")
switch {
// keep backlink
case len(pathSplit) == 3: // url: /ipfs/$hash
// keep backlink
case len(pathSplit) == 4 && pathSplit[3] == "": // url: /ipfs/$hash/
// add the correct link depending on wether the path ends with a slash
default:
if strings.HasSuffix(backLink, "/") {
backLink += "./.."
} else {
backLink += "/.."
}
}
// strip /ipfs/$hash from backlink if IPNSHostnameOption touched the path.
if ipnsHostname {
backLink = prefix + "/"
if len(pathSplit) > 5 {
// also strip the trailing segment, because it's a backlink
backLinkParts := pathSplit[3 : len(pathSplit)-2]
backLink += strings.Join(backLinkParts, "/") + "/"
}
}
// See comment above where originalUrlPath is declared.
tplData := listingTemplateData{
Listing: dirListing,
Path: originalUrlPath,
BackLink: backLink,
}
err := listingTemplate.Execute(w, tplData)
if err != nil {
internalWebError(w, err)
return
}
}
}
}
func (i *gatewayHandler) postHandler(w http.ResponseWriter, r *http.Request) {
nd, err := i.newDagFromReader(r.Body)
if err != nil {
internalWebError(w, err)
return
}
k, err := i.node.DAG.Add(nd)
if err != nil {
internalWebError(w, err)
return
}
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("IPFS-Hash", k.String())
http.Redirect(w, r, ipfsPathPrefix+k.String(), http.StatusCreated)
}
func (i *gatewayHandler) putHandler(w http.ResponseWriter, r *http.Request) {
// TODO(cryptix): move me to ServeHTTP and pass into all handlers
ctx, cancel := context.WithCancel(i.node.Context())
defer cancel()
rootPath, err := path.ParsePath(r.URL.Path)
if err != nil {
webError(w, "putHandler: ipfs path not valid", err, http.StatusBadRequest)
return
}
rsegs := rootPath.Segments()
if rsegs[0] == ipnsPathPrefix {
webError(w, "putHandler: updating named entries not supported", errors.New("WritableGateway: ipns put not supported"), http.StatusBadRequest)
return
}
var newnode *dag.Node
if rsegs[len(rsegs)-1] == "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn" {
newnode = uio.NewEmptyDirectory()
} else {
putNode, err := i.newDagFromReader(r.Body)
if err != nil {
webError(w, "putHandler: Could not create DAG from request", err, http.StatusInternalServerError)
return
}
newnode = putNode
}
var newPath string
if len(rsegs) > 1 {
newPath = strings.Join(rsegs[2:], "/")
}
var newkey key.Key
rnode, err := core.Resolve(ctx, i.node, rootPath)
switch ev := err.(type) {
case path.ErrNoLink:
// ev.Node < node where resolve failed
// ev.Name < new link
// but we need to patch from the root
rnode, err := i.node.DAG.Get(ctx, key.B58KeyDecode(rsegs[1]))
if err != nil {
webError(w, "putHandler: Could not create DAG from request", err, http.StatusInternalServerError)
return
}
e := dagutils.NewDagEditor(i.node.DAG, rnode)
err = e.InsertNodeAtPath(ctx, newPath, newnode, uio.NewEmptyDirectory)
if err != nil {
webError(w, "putHandler: InsertNodeAtPath failed", err, http.StatusInternalServerError)
return
}
newkey, err = e.GetNode().Key()
if err != nil {
webError(w, "putHandler: could not get key of edited node", err, http.StatusInternalServerError)
return
}
case nil:
// object set-data case
rnode.Data = newnode.Data
newkey, err = i.node.DAG.Add(rnode)
if err != nil {
nnk, _ := newnode.Key()
rk, _ := rnode.Key()
webError(w, fmt.Sprintf("putHandler: Could not add newnode(%q) to root(%q)", nnk.B58String(), rk.B58String()), err, http.StatusInternalServerError)
return
}
default:
log.Warningf("putHandler: unhandled resolve error %T", ev)
webError(w, "could not resolve root DAG", ev, http.StatusInternalServerError)
return
}
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("IPFS-Hash", newkey.String())
http.Redirect(w, r, gopath.Join(ipfsPathPrefix, newkey.String(), newPath), http.StatusCreated)
}
func (i *gatewayHandler) deleteHandler(w http.ResponseWriter, r *http.Request) {
urlPath := r.URL.Path
ctx, cancel := context.WithCancel(i.node.Context())
defer cancel()
ipfsNode, err := core.Resolve(ctx, i.node, path.Path(urlPath))
if err != nil {
// FIXME HTTP error code
webError(w, "Could not resolve name", err, http.StatusInternalServerError)
return
}
k, err := ipfsNode.Key()
if err != nil {
webError(w, "Could not get key from resolved node", err, http.StatusInternalServerError)
return
}
h, components, err := path.SplitAbsPath(path.FromKey(k))
if err != nil {
webError(w, "Could not split path", err, http.StatusInternalServerError)
return
}
tctx, cancel := context.WithTimeout(ctx, time.Minute)
defer cancel()
rootnd, err := i.node.Resolver.DAG.Get(tctx, key.Key(h))
if err != nil {
webError(w, "Could not resolve root object", err, http.StatusBadRequest)
return
}
pathNodes, err := i.node.Resolver.ResolveLinks(tctx, rootnd, components[:len(components)-1])
if err != nil {
webError(w, "Could not resolve parent object", err, http.StatusBadRequest)
return
}
// TODO(cyrptix): assumes len(pathNodes) > 1 - not found is an error above?
err = pathNodes[len(pathNodes)-1].RemoveNodeLink(components[len(components)-1])
if err != nil {
webError(w, "Could not delete link", err, http.StatusBadRequest)
return
}
newnode := pathNodes[len(pathNodes)-1]
for i := len(pathNodes) - 2; i >= 0; i-- {
newnode, err = pathNodes[i].UpdateNodeLink(components[i], newnode)
if err != nil {
webError(w, "Could not update node links", err, http.StatusInternalServerError)
return
}
}
if err := i.node.DAG.AddRecursive(newnode); err != nil {
webError(w, "Could not add recursively new node", err, http.StatusInternalServerError)
return
}
// Redirect to new path
key, err := newnode.Key()
if err != nil {
webError(w, "Could not get key of new node", err, http.StatusInternalServerError)
return
}
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("IPFS-Hash", key.String())
http.Redirect(w, r, ipfsPathPrefix+key.String()+"/"+strings.Join(components[:len(components)-1], "/"), http.StatusCreated)
}
func (i *gatewayHandler) addUserHeaders(w http.ResponseWriter) {
for k, v := range i.config.Headers {
w.Header()[k] = v
}
}
func webError(w http.ResponseWriter, message string, err error, defaultCode int) {
if _, ok := err.(path.ErrNoLink); ok {
webErrorWithCode(w, message, err, http.StatusNotFound)
} else if err == routing.ErrNotFound {
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) {
w.WriteHeader(code)
log.Errorf("%s: %s", message, err) // TODO(cryptix): log errors until we have a better way to expose these (counter metrics maybe)
fmt.Fprintf(w, "%s: %s", message, err)
}
// return a 500 error and log
func internalWebError(w http.ResponseWriter, err error) {
webErrorWithCode(w, "internalWebError", err, http.StatusInternalServerError)
}