Files
phylum/server/internal/api/webdav/impl/webdav.go
2025-06-13 03:13:16 +05:30

603 lines
18 KiB
Go

// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package webdav provides a WebDAV server implementation.
package webdav // import "golang.org/x/net/webdav"
import (
"errors"
"fmt"
"io"
"net/http"
"net/url"
"path"
"strings"
"time"
"codeberg.org/shroff/phylum/server/internal/api/serve"
"codeberg.org/shroff/phylum/server/internal/core"
"github.com/google/uuid"
)
type Handler struct {
// Prefix is the URL path prefix to strip from WebDAV resource paths.
Prefix string
// FileSystem is the virtual file system.
FileSystem FileSystem
// LockSystem is the lock management system.
LockSystem LockSystem
// Logger is an optional error logger. If non-nil, it will be called
// for all HTTP requests.
Logger func(*http.Request, error)
}
// A FileSystem implements access to a collection of named files. The elements
// in a file path are separated by slash ('/', U+002F) characters, regardless
// of host operating system convention.
type FileSystem interface {
core.ReadFileSystem
CreateResourceByPath(name string, id uuid.UUID, dir, recursive bool, conflictResolution core.ResourceBindConflictResolution) (core.Resource, error)
CreateFileByPath(path string, id, versionID uuid.UUID, conflictResolution core.ResourceBindConflictResolution) (io.WriteCloser, error)
Copy(core.Resource, string, uuid.UUID, bool, core.ResourceBindConflictResolution) (core.Resource, bool, error)
Move(core.Resource, string, core.ResourceBindConflictResolution) (core.Resource, bool, error)
Delete(core.Resource) (core.Resource, error)
}
func (h *Handler) stripPrefix(p string) (string, int, error) {
if h.Prefix == "" {
return p, http.StatusOK, nil
}
if r := strings.TrimPrefix(p, h.Prefix); len(r) < len(p) {
return r, http.StatusOK, nil
}
return p, http.StatusNotFound, errPrefixMismatch
}
func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
status, err := http.StatusBadRequest, errUnsupportedMethod
if h.FileSystem == nil {
status, err = http.StatusInternalServerError, errNoFileSystem
} else if h.LockSystem == nil {
status, err = http.StatusInternalServerError, errNoLockSystem
} else {
switch r.Method {
case "OPTIONS":
status, err = h.handleOptions(w, r)
case "GET", "HEAD", "POST":
status, err = h.handleGetHeadPost(w, r)
case "DELETE":
status, err = h.handleDelete(w, r)
case "PUT":
status, err = h.handlePut(w, r)
case "MKCOL":
status, err = h.handleMkcol(w, r)
case "COPY", "MOVE":
status, err = h.handleCopyMove(w, r)
case "LOCK":
status, err = h.handleLock(w, r)
case "UNLOCK":
status, err = h.handleUnlock(w, r)
case "PROPFIND":
status, err = h.handlePropfind(w, r)
case "PROPPATCH":
status, err = h.handleProppatch(w, r)
}
}
if status != 0 {
w.WriteHeader(status)
if status != http.StatusNoContent {
w.Write([]byte(http.StatusText(status)))
}
}
if h.Logger != nil {
h.Logger(r, err)
}
}
func (h *Handler) lock(now time.Time, root string) (token string, status int, err error) {
token, err = h.LockSystem.Create(now, LockDetails{
Root: root,
Duration: infiniteTimeout,
ZeroDepth: true,
})
if err != nil {
if err == ErrLocked {
return "", http.StatusLocked, err
}
return "", http.StatusInternalServerError, err
}
return token, 0, nil
}
func (h *Handler) confirmLocks(r *http.Request, src, dst string) (release func(), status int, err error) {
hdr := r.Header.Get("If")
if hdr == "" {
// An empty If header means that the client hasn't previously created locks.
// Even if this client doesn't care about locks, we still need to check that
// the resources aren't locked by another client, so we create temporary
// locks that would conflict with another client's locks. These temporary
// locks are unlocked at the end of the HTTP request.
now, srcToken, dstToken := time.Now(), "", ""
if src != "" {
srcToken, status, err = h.lock(now, src)
if err != nil {
return nil, status, err
}
}
if dst != "" {
dstToken, status, err = h.lock(now, dst)
if err != nil {
if srcToken != "" {
h.LockSystem.Unlock(now, srcToken)
}
return nil, status, err
}
}
return func() {
if dstToken != "" {
h.LockSystem.Unlock(now, dstToken)
}
if srcToken != "" {
h.LockSystem.Unlock(now, srcToken)
}
}, 0, nil
}
ih, ok := parseIfHeader(hdr)
if !ok {
return nil, http.StatusBadRequest, errInvalidIfHeader
}
// ih is a disjunction (OR) of ifLists, so any ifList will do.
for _, l := range ih.lists {
lsrc := l.resourceTag
if lsrc == "" {
lsrc = src
} else {
u, err := url.Parse(lsrc)
if err != nil {
continue
}
if u.Host != r.Host {
continue
}
lsrc, status, err = h.stripPrefix(u.Path)
if err != nil {
return nil, status, err
}
}
release, err = h.LockSystem.Confirm(time.Now(), lsrc, dst, func(path, etag string) (bool, error) {
if res, err := h.FileSystem.ResourceByPath(path); err != nil {
return false, err
} else if res.Dir() {
return false, errors.New("cannot check etag for directories")
} else {
return res.LatestVersion().SHA256 == etag, nil
}
}, l.conditions...)
if err == ErrConfirmationFailed {
continue
}
if err != nil {
return nil, http.StatusInternalServerError, err
}
return release, 0, nil
}
// Section 10.4.1 says that "If this header is evaluated and all state lists
// fail, then the request must fail with a 412 (Precondition Failed) status."
// We follow the spec even though the cond_put_corrupt_token test case from
// the litmus test warns on seeing a 412 instead of a 423 (Locked).
return nil, http.StatusPreconditionFailed, ErrLocked
}
func (h *Handler) handleOptions(w http.ResponseWriter, r *http.Request) (status int, err error) {
reqPath, status, err := h.stripPrefix(r.URL.Path)
if err != nil {
return status, err
}
allow := "OPTIONS, LOCK, PUT, MKCOL"
if fi, err := h.FileSystem.ResourceByPath(reqPath); err == nil {
if fi.Dir() {
allow = "OPTIONS, LOCK, DELETE, PROPPATCH, COPY, MOVE, UNLOCK, PROPFIND"
} else {
allow = "OPTIONS, LOCK, GET, HEAD, POST, DELETE, PROPPATCH, COPY, MOVE, UNLOCK, PROPFIND, PUT"
}
}
w.Header().Set("Allow", allow)
// http://www.webdav.org/specs/rfc4918.html#dav.compliance.classes
w.Header().Set("DAV", "1, 2")
// http://msdn.microsoft.com/en-au/library/cc250217.aspx
w.Header().Set("MS-Author-Via", "DAV")
return 0, nil
}
func (h *Handler) handleGetHeadPost(w http.ResponseWriter, r *http.Request) (status int, err error) {
reqPath, status, err := h.stripPrefix(r.URL.Path)
if err != nil {
return status, err
}
// TODO: check locks for read-only access??
res, err := h.FileSystem.ResourceByPath(reqPath)
if err != nil {
return http.StatusNotFound, err
}
w.Header().Set("Content-Disposition", "attachment; filename=\""+res.Name()+"\"")
serve.Serve(w, r, h.FileSystem, res)
return 0, nil
}
func (h *Handler) handleDelete(_ http.ResponseWriter, r *http.Request) (status int, err error) {
reqPath, status, err := h.stripPrefix(r.URL.Path)
if err != nil {
return status, err
}
release, status, err := h.confirmLocks(r, reqPath, "")
if err != nil {
return status, err
}
defer release()
if r, err := h.FileSystem.ResourceByPath(reqPath); err != nil {
if errors.Is(err, core.ErrResourceNotFound) {
return http.StatusNotFound, err
}
return http.StatusMethodNotAllowed, err
} else if _, err := h.FileSystem.Delete(r); err != nil {
return http.StatusMethodNotAllowed, err
}
return http.StatusNoContent, nil
}
func (h *Handler) handlePut(w http.ResponseWriter, r *http.Request) (status int, err error) {
reqPath, status, err := h.stripPrefix(r.URL.Path)
if err != nil {
return status, err
}
release, status, err := h.confirmLocks(r, reqPath, "")
if err != nil {
return status, err
}
defer release()
// TODO(rost): Support the If-Match, If-None-Match headers? See bradfitz'
// comments in http.checkEtag.
f, err := h.FileSystem.CreateFileByPath(reqPath, uuid.Nil, uuid.Nil, core.ResourceBindConflictResolutionEnsure)
if err != nil {
if errors.Is(err, core.ErrParentNotFound) {
return http.StatusConflict, err
}
return http.StatusInternalServerError, err
}
_, copyErr := io.Copy(f, r.Body)
closeErr := f.Close()
if copyErr != nil {
return http.StatusInternalServerError, copyErr
}
if closeErr != nil {
if errors.Is(closeErr, core.ErrResourceCollection) {
return http.StatusConflict, closeErr
}
return http.StatusNotFound, closeErr
}
fi, statErr := h.FileSystem.ResourceByPath(reqPath)
if statErr != nil {
return http.StatusInternalServerError, statErr
}
w.Header().Set("ETag", fi.LatestVersion().SHA256)
return http.StatusCreated, nil
}
func (h *Handler) handleMkcol(_ http.ResponseWriter, r *http.Request) (status int, err error) {
reqPath, status, err := h.stripPrefix(r.URL.Path)
if err != nil {
return status, err
}
release, status, err := h.confirmLocks(r, reqPath, "")
if err != nil {
return status, err
}
defer release()
if r.ContentLength > 0 {
return http.StatusUnsupportedMediaType, nil
}
if _, err := h.FileSystem.CreateResourceByPath(reqPath, uuid.Nil, true, false, core.ResourceBindConflictResolutionError); err != nil {
if errors.Is(err, core.ErrParentNotFound) {
return http.StatusConflict, err
}
return http.StatusMethodNotAllowed, err
}
return http.StatusCreated, nil
}
func (h *Handler) handleLock(w http.ResponseWriter, r *http.Request) (retStatus int, retErr error) {
duration, err := parseTimeout(r.Header.Get("Timeout"))
if err != nil {
return http.StatusBadRequest, err
}
li, status, err := readLockInfo(r.Body)
if err != nil {
return status, err
}
token, ld, now, created := "", LockDetails{}, time.Now(), false
if li == (lockInfo{}) {
// An empty lockInfo means to refresh the lock.
ih, ok := parseIfHeader(r.Header.Get("If"))
if !ok {
return http.StatusBadRequest, errInvalidIfHeader
}
if len(ih.lists) == 1 && len(ih.lists[0].conditions) == 1 {
token = ih.lists[0].conditions[0].Token
}
if token == "" {
return http.StatusBadRequest, errInvalidLockToken
}
ld, err = h.LockSystem.Refresh(now, token, duration)
if err != nil {
if err == ErrNoSuchLock {
return http.StatusPreconditionFailed, err
}
return http.StatusInternalServerError, err
}
} else {
// Section 9.10.3 says that "If no Depth header is submitted on a LOCK request,
// then the request MUST act as if a "Depth:infinity" had been submitted."
depth := infiniteDepth
if hdr := r.Header.Get("Depth"); hdr != "" {
depth = parseDepth(hdr)
if depth != 0 && depth != infiniteDepth {
// Section 9.10.3 says that "Values other than 0 or infinity must not be
// used with the Depth header on a LOCK method".
return http.StatusBadRequest, errInvalidDepth
}
}
reqPath, status, err := h.stripPrefix(r.URL.Path)
if err != nil {
return status, err
}
ld = LockDetails{
Root: reqPath,
Duration: duration,
OwnerXML: li.Owner.InnerXML,
ZeroDepth: depth == 0,
}
token, err = h.LockSystem.Create(now, ld)
if err != nil {
if err == ErrLocked {
return http.StatusLocked, err
}
return http.StatusInternalServerError, err
}
defer func() {
if retErr != nil {
h.LockSystem.Unlock(now, token)
}
}()
// Create the resource if it didn't previously exist.
if _, err := h.FileSystem.ResourceByPath(reqPath); err != nil {
_, err = h.FileSystem.CreateResourceByPath(reqPath, uuid.Nil, false, false, core.ResourceBindConflictResolutionEnsure)
if err != nil {
if errors.Is(err, core.ErrParentNotFound) {
return http.StatusConflict, err
}
return http.StatusNotFound, err
}
created = true
}
// http://www.webdav.org/specs/rfc4918.html#HEADER_Lock-Token says that the
// Lock-Token value is a Coded-URL. We add angle brackets.
w.Header().Set("Lock-Token", "<"+token+">")
}
w.Header().Set("Content-Type", "application/xml; charset=utf-8")
if created {
// This is "w.WriteHeader(http.StatusCreated)" and not "return
// http.StatusCreated, nil" because we write our own (XML) response to w
// and Handler.ServeHTTP would otherwise write "Created".
w.WriteHeader(http.StatusCreated)
}
writeLockInfo(w, token, ld)
return 0, nil
}
func (h *Handler) handleUnlock(_ http.ResponseWriter, r *http.Request) (status int, err error) {
// http://www.webdav.org/specs/rfc4918.html#HEADER_Lock-Token says that the
// Lock-Token value is a Coded-URL. We strip its angle brackets.
t := r.Header.Get("Lock-Token")
if len(t) < 2 || t[0] != '<' || t[len(t)-1] != '>' {
return http.StatusBadRequest, errInvalidLockToken
}
t = t[1 : len(t)-1]
switch err = h.LockSystem.Unlock(time.Now(), t); err {
case nil:
return http.StatusNoContent, err
case ErrForbidden:
return http.StatusForbidden, err
case ErrLocked:
return http.StatusLocked, err
case ErrNoSuchLock:
return http.StatusConflict, err
default:
return http.StatusInternalServerError, err
}
}
func (h *Handler) handlePropfind(w http.ResponseWriter, request *http.Request) (status int, err error) {
reqPath, status, err := h.stripPrefix(request.URL.Path)
if err != nil {
return status, err
}
fi, err := h.FileSystem.ResourceByPath(reqPath)
if err != nil {
if errors.Is(err, core.ErrResourceNotFound) {
return http.StatusNotFound, err
}
return http.StatusMethodNotAllowed, err
}
depth := infiniteDepth
if hdr := request.Header.Get("Depth"); hdr != "" {
depth = parseDepth(hdr)
if depth == invalidDepth {
return http.StatusBadRequest, errInvalidDepth
}
}
pf, status, err := readPropfind(request.Body)
if err != nil {
return status, err
}
mw := multistatusWriter{w: w}
writePropStat := func(r core.Resource, p string) error {
var pstats []Propstat
if pf.Propname != nil {
pnames, err := propnames(h.FileSystem, h.LockSystem, r)
if err != nil {
return err
}
pstat := Propstat{Status: http.StatusOK}
for _, xmlname := range pnames {
pstat.Props = append(pstat.Props, Property{XMLName: xmlname})
}
pstats = append(pstats, pstat)
} else if pf.Allprop != nil {
pstats, err = allprop(h.FileSystem, h.LockSystem, r, pf.Prop)
} else {
pstats, err = props(h.FileSystem, h.LockSystem, r, pf.Prop)
}
if err != nil {
return err
}
href := path.Join(request.URL.Path, p)
if href != "/" && r.Dir() {
href += "/"
}
return mw.write(makePropstatResponse(href, pstats))
}
walkErr := h.FileSystem.Walk(fi, depth, writePropStat)
closeErr := mw.close()
if walkErr != nil {
return http.StatusInternalServerError, walkErr
}
if closeErr != nil {
return http.StatusInternalServerError, closeErr
}
return 0, nil
}
func (h *Handler) handleProppatch(w http.ResponseWriter, r *http.Request) (status int, err error) {
reqPath, status, err := h.stripPrefix(r.URL.Path)
if err != nil {
return status, err
}
release, status, err := h.confirmLocks(r, reqPath, "")
if err != nil {
return status, err
}
defer release()
if _, err := h.FileSystem.ResourceByPath(reqPath); err != nil {
if errors.Is(err, core.ErrResourceNotFound) {
return http.StatusNotFound, err
}
return http.StatusMethodNotAllowed, err
}
patches, status, err := readProppatch(r.Body)
if err != nil {
return status, err
}
pstats, err := patch(h.FileSystem, h.LockSystem, reqPath, patches)
if err != nil {
return http.StatusInternalServerError, err
}
mw := multistatusWriter{w: w}
writeErr := mw.write(makePropstatResponse(r.URL.Path, pstats))
closeErr := mw.close()
if writeErr != nil {
return http.StatusInternalServerError, writeErr
}
if closeErr != nil {
return http.StatusInternalServerError, closeErr
}
return 0, nil
}
func makePropstatResponse(href string, pstats []Propstat) *response {
resp := response{
Href: []string{(&url.URL{Path: href}).EscapedPath()},
Propstat: make([]propstat, 0, len(pstats)),
}
for _, p := range pstats {
var xmlErr *xmlError
if p.XMLError != "" {
xmlErr = &xmlError{InnerXML: []byte(p.XMLError)}
}
resp.Propstat = append(resp.Propstat, propstat{
Status: fmt.Sprintf("HTTP/1.1 %d %s", p.Status, http.StatusText(p.Status)),
Prop: p.Props,
ResponseDescription: p.ResponseDescription,
Error: xmlErr,
})
}
return &resp
}
const (
infiniteDepth = -1
invalidDepth = -2
)
// parseDepth maps the strings "0", "1" and "infinity" to 0, 1 and
// infiniteDepth. Parsing any other string returns invalidDepth.
//
// Different WebDAV methods have further constraints on valid depths:
// - PROPFIND has no further restrictions, as per section 9.1.
// - COPY accepts only "0" or "infinity", as per section 9.8.3.
// - MOVE accepts only "infinity", as per section 9.9.2.
// - LOCK accepts only "0" or "infinity", as per section 9.10.3.
//
// These constraints are enforced by the handleXxx methods.
func parseDepth(s string) int {
switch s {
case "0":
return 0
case "1":
return 1
case "infinity":
return infiniteDepth
}
return invalidDepth
}
var (
errDestinationEqualsSource = errors.New("webdav: destination equals source")
errDirectoryNotEmpty = errors.New("webdav: directory not empty")
errInvalidDepth = errors.New("webdav: invalid depth")
errInvalidDestination = errors.New("webdav: invalid destination")
errInvalidIfHeader = errors.New("webdav: invalid If header")
errInvalidLockInfo = errors.New("webdav: invalid lock info")
errInvalidLockToken = errors.New("webdav: invalid lock token")
errInvalidPropfind = errors.New("webdav: invalid propfind")
errInvalidProppatch = errors.New("webdav: invalid proppatch")
errInvalidResponse = errors.New("webdav: invalid response")
errInvalidTimeout = errors.New("webdav: invalid timeout")
errNoFileSystem = errors.New("webdav: no file system")
errNoLockSystem = errors.New("webdav: no lock system")
errNotADirectory = errors.New("webdav: not a directory")
errPrefixMismatch = errors.New("webdav: prefix mismatch")
errRecursionTooDeep = errors.New("webdav: recursion too deep")
errUnsupportedLockInfo = errors.New("webdav: unsupported lock info")
errUnsupportedMethod = errors.New("webdav: unsupported method")
)