12483: Error 405 if writing to PDH, 403 if lacking write permission.
[arvados.git] / services / keep-web / handler.go
index ecc698256a2e8d4b3f815f5ba73b92c5077f900f..c9148a562eb3bc86e53ec27944cffa2a8a6010ff 100644 (file)
@@ -1,3 +1,7 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package main
 
 import (
@@ -6,6 +10,7 @@ import (
        "html"
        "html/template"
        "io"
+       "log"
        "net/http"
        "net/url"
        "os"
@@ -17,14 +22,18 @@ import (
        "git.curoverse.com/arvados.git/sdk/go/arvados"
        "git.curoverse.com/arvados.git/sdk/go/arvadosclient"
        "git.curoverse.com/arvados.git/sdk/go/auth"
+       "git.curoverse.com/arvados.git/sdk/go/health"
        "git.curoverse.com/arvados.git/sdk/go/httpserver"
        "git.curoverse.com/arvados.git/sdk/go/keepclient"
+       "golang.org/x/net/webdav"
 )
 
 type handler struct {
-       Config     *Config
-       clientPool *arvadosclient.ClientPool
-       setupOnce  sync.Once
+       Config        *Config
+       clientPool    *arvadosclient.ClientPool
+       setupOnce     sync.Once
+       healthHandler http.Handler
+       webdavLS      webdav.LockSystem
 }
 
 // parseCollectionIDFromDNSName returns a UUID or PDH if s begins with
@@ -66,7 +75,17 @@ func parseCollectionIDFromURL(s string) string {
 
 func (h *handler) setup() {
        h.clientPool = arvadosclient.MakeClientPool()
+
        keepclient.RefreshServiceDiscoveryOnSIGHUP()
+
+       h.healthHandler = &health.Handler{
+               Token:  h.Config.ManagementToken,
+               Prefix: "/_health/",
+       }
+
+       // Even though we don't accept LOCK requests, every webdav
+       // handler must have a non-nil LockSystem.
+       h.webdavLS = &noLockSystem{}
 }
 
 func (h *handler) serveStatus(w http.ResponseWriter, r *http.Request) {
@@ -78,6 +97,70 @@ func (h *handler) serveStatus(w http.ResponseWriter, r *http.Request) {
        json.NewEncoder(w).Encode(status)
 }
 
+// updateOnSuccess wraps httpserver.ResponseWriter. If the handler
+// sends an HTTP header indicating success, updateOnSuccess first
+// calls the provided update func. If the update func fails, a 500
+// response is sent, and the status code and body sent by the handler
+// are ignored (all response writes return the update error).
+type updateOnSuccess struct {
+       httpserver.ResponseWriter
+       update     func() error
+       sentHeader bool
+       err        error
+}
+
+func (uos *updateOnSuccess) Write(p []byte) (int, error) {
+       if uos.err != nil {
+               return 0, uos.err
+       }
+       if !uos.sentHeader {
+               uos.WriteHeader(http.StatusOK)
+       }
+       return uos.ResponseWriter.Write(p)
+}
+
+func (uos *updateOnSuccess) WriteHeader(code int) {
+       if !uos.sentHeader {
+               uos.sentHeader = true
+               if code >= 200 && code < 400 {
+                       if uos.err = uos.update(); uos.err != nil {
+                               code := http.StatusInternalServerError
+                               if err, ok := uos.err.(*arvados.TransactionError); ok {
+                                       code = err.StatusCode
+                               }
+                               log.Printf("update() changes response to HTTP %d: %T %q", code, uos.err, uos.err)
+                               http.Error(uos.ResponseWriter, uos.err.Error(), code)
+                               return
+                       }
+               }
+       }
+       uos.ResponseWriter.WriteHeader(code)
+}
+
+var (
+       writeMethod = map[string]bool{
+               "DELETE": true,
+               "MKCOL":  true,
+               "MOVE":   true,
+               "PUT":    true,
+               "RMCOL":  true,
+       }
+       webdavMethod = map[string]bool{
+               "DELETE":   true,
+               "MKCOL":    true,
+               "MOVE":     true,
+               "OPTIONS":  true,
+               "PROPFIND": true,
+               "PUT":      true,
+               "RMCOL":    true,
+       }
+       browserMethod = map[string]bool{
+               "GET":  true,
+               "HEAD": true,
+               "POST": true,
+       }
+)
+
 // ServeHTTP implements http.Handler.
 func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
        h.setupOnce.Do(h.setup)
@@ -106,21 +189,25 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
                httpserver.Log(remoteAddr, statusCode, statusText, w.WroteBodyBytes(), r.Method, r.Host, r.URL.Path, r.URL.RawQuery)
        }()
 
-       if r.Method == "OPTIONS" {
-               method := r.Header.Get("Access-Control-Request-Method")
-               if method != "GET" && method != "POST" {
+       if strings.HasPrefix(r.URL.Path, "/_health/") && r.Method == "GET" {
+               h.healthHandler.ServeHTTP(w, r)
+               return
+       }
+
+       if method := r.Header.Get("Access-Control-Request-Method"); method != "" && r.Method == "OPTIONS" {
+               if !browserMethod[method] && !webdavMethod[method] {
                        statusCode = http.StatusMethodNotAllowed
                        return
                }
-               w.Header().Set("Access-Control-Allow-Headers", "Range")
-               w.Header().Set("Access-Control-Allow-Methods", "GET, POST")
+               w.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Type, Range")
+               w.Header().Set("Access-Control-Allow-Methods", "DELETE, GET, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PUT, RMCOL")
                w.Header().Set("Access-Control-Allow-Origin", "*")
                w.Header().Set("Access-Control-Max-Age", "86400")
                statusCode = http.StatusOK
                return
        }
 
-       if r.Method != "GET" && r.Method != "POST" {
+       if !browserMethod[r.Method] && !webdavMethod[r.Method] {
                statusCode, statusText = http.StatusMethodNotAllowed, r.Method
                return
        }
@@ -132,6 +219,7 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
                // SSL certificates. See
                // http://www.w3.org/TR/cors/#user-credentials).
                w.Header().Set("Access-Control-Allow-Origin", "*")
+               w.Header().Set("Access-Control-Expose-Headers", "Content-Range")
        }
 
        arv := h.clientPool.Get()
@@ -165,7 +253,7 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
                h.serveStatus(w, r)
                return
        } else if len(pathParts) >= 1 && strings.HasPrefix(pathParts[0], "c=") {
-               // /c=ID/PATH...
+               // /c=ID[/PATH...]
                targetID = parseCollectionIDFromURL(pathParts[0][2:])
                stripParts = 1
        } else if len(pathParts) >= 2 && pathParts[0] == "collections" {
@@ -204,7 +292,7 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
                // * The token isn't embedded in the URL, so we don't
                //   need to worry about bookmarks and copy/paste.
                tokens = append(tokens, formToken)
-       } else if formToken != "" {
+       } else if formToken != "" && browserMethod[r.Method] {
                // The client provided an explicit token in the query
                // string, or a form in POST body. We must put the
                // token in an HttpOnly cookie, and redirect to the
@@ -311,28 +399,78 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
                return
        }
 
-       basename := targetPath[len(targetPath)-1]
+       var basename string
+       if len(targetPath) > 0 {
+               basename = targetPath[len(targetPath)-1]
+       }
        applyContentDispositionHdr(w, r, basename, attachment)
 
-       fs := collection.FileSystem(&arvados.Client{
+       client := &arvados.Client{
                APIHost:   arv.ApiServer,
                AuthToken: arv.ApiToken,
                Insecure:  arv.ApiInsecure,
-       }, kc)
+       }
+       fs, err := collection.FileSystem(client, kc)
+       if err != nil {
+               statusCode, statusText = http.StatusInternalServerError, err.Error()
+               return
+       }
+       if webdavMethod[r.Method] {
+               writing := !arvadosclient.PDHMatch(targetID) && writeMethod[r.Method]
+               if writing {
+                       // Save the collection only if/when all
+                       // webdav->filesystem operations succeed --
+                       // and send a 500 error if the modified
+                       // collection can't be saved.
+                       w = &updateOnSuccess{
+                               ResponseWriter: w,
+                               update: func() error {
+                                       return h.Config.Cache.Update(client, *collection, fs)
+                               }}
+               }
+               h := webdav.Handler{
+                       Prefix: "/" + strings.Join(pathParts[:stripParts], "/"),
+                       FileSystem: &webdavFS{
+                               collfs:  fs,
+                               writing: writing,
+                       },
+                       LockSystem: h.webdavLS,
+                       Logger: func(_ *http.Request, err error) {
+                               if err != nil {
+                                       log.Printf("error from webdav handler: %q", err)
+                               }
+                       },
+               }
+               h.ServeHTTP(w, r)
+               return
+       }
+
        openPath := "/" + strings.Join(targetPath, "/")
        if f, err := fs.Open(openPath); os.IsNotExist(err) {
+               // Requested non-existent path
                statusCode = http.StatusNotFound
        } else if err != nil {
+               // Some other (unexpected) error
                statusCode, statusText = http.StatusInternalServerError, err.Error()
        } else if stat, err := f.Stat(); err != nil {
+               // Can't get Size/IsDir (shouldn't happen with a collectionFS!)
                statusCode, statusText = http.StatusInternalServerError, err.Error()
        } else if stat.IsDir() && !strings.HasSuffix(r.URL.Path, "/") {
-               h.seeOtherWithCookie(w, r, basename+"/", credentialsOK)
+               // If client requests ".../dirname", redirect to
+               // ".../dirname/". This way, relative links in the
+               // listing for "dirname" can always be "fnm", never
+               // "dirname/fnm".
+               h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
        } else if stat.IsDir() {
                h.serveDirectory(w, r, collection.Name, fs, openPath, stripParts)
        } else {
                http.ServeContent(w, r, basename, stat.ModTime(), f)
-               if int64(w.WroteBodyBytes()) != stat.Size() {
+               if r.Header.Get("Range") == "" && int64(w.WroteBodyBytes()) != stat.Size() {
+                       // If we wrote fewer bytes than expected, it's
+                       // too late to change the real response code
+                       // or send an error message to the client, but
+                       // at least we can try to put some useful
+                       // debugging info in the logs.
                        n, err := f.Read(make([]byte, 1024))
                        statusCode, statusText = http.StatusInternalServerError, fmt.Sprintf("f.Size()==%d but only wrote %d bytes; read(1024) returns %d, %s", stat.Size(), w.WroteBodyBytes(), n, err)
 
@@ -377,9 +515,13 @@ the entire collection with wget, try:</P>
 
 <H2>File Listing</H2>
 
+{{if .Files}}
 <UL>
 {{range .Files}}  <LI>{{.Size | printf "%15d  " | nbsp}}<A href="{{.Name}}">{{.Name}}</A></LI>{{end}}
 </UL>
+{{else}}
+<P>(No files; this collection is empty.)</P>
+{{end}}
 
 <HR noshade>
 <DIV class="footer">
@@ -479,16 +621,16 @@ func applyContentDispositionHdr(w http.ResponseWriter, r *http.Request, filename
 }
 
 func (h *handler) seeOtherWithCookie(w http.ResponseWriter, r *http.Request, location string, credentialsOK bool) {
-       if !credentialsOK {
-               // It is not safe to copy the provided token
-               // into a cookie unless the current vhost
-               // (origin) serves only a single collection or
-               // we are in TrustAllContent mode.
-               w.WriteHeader(http.StatusBadRequest)
-               return
-       }
-
        if formToken := r.FormValue("api_token"); formToken != "" {
+               if !credentialsOK {
+                       // It is not safe to copy the provided token
+                       // into a cookie unless the current vhost
+                       // (origin) serves only a single collection or
+                       // we are in TrustAllContent mode.
+                       w.WriteHeader(http.StatusBadRequest)
+                       return
+               }
+
                // The HttpOnly flag is necessary to prevent
                // JavaScript code (included in, or loaded by, a page
                // in the collection being served) from employing the
@@ -500,7 +642,6 @@ func (h *handler) seeOtherWithCookie(w http.ResponseWriter, r *http.Request, loc
                // bar, and in the case of a POST request to avoid
                // raising warnings when the user refreshes the
                // resulting page.
-
                http.SetCookie(w, &http.Cookie{
                        Name:     "arvados_api_token",
                        Value:    auth.EncodeTokenCookie([]byte(formToken)),