✨ Implement WebDAV server

cmd_serve.go

@@ -0,0 +1,102 @@
+// Copyright (c) 2020, Andreas Schneider
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above copyright
+//       notice, this list of conditions and the following disclaimer in the
+//       documentation and/or other materials provided with the distribution.
+//     * Neither the name of the <organization> nor the
+//       names of its contributors may be used to endorse or promote products
+//       derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+	"strings"
+
+	"golang.org/x/crypto/bcrypt"
+	"golang.org/x/net/webdav"
+)
+
+type CmdServe struct {
+	ListenAddress string `name:"listen-address" default:":3000" help:"Address to listen on for HTTP requests."`
+}
+
+func (cmd *CmdServe) Run(app *app) error {
+	h := &webdav.Handler{}
+	h.Prefix = "/dav/"
+	h.LockSystem = webdav.NewMemLS()
+	h.FileSystem = BaseDir(app.DataDirectory)
+
+	authenticatedWebdavHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		writeUnauthorized := func() {
+			w.Header().Set("WWW-Authenticate", `Basic realm="ShareDAV"`)
+			http.Error(w, "unauthorized", http.StatusUnauthorized)
+		}
+
+		username, password, ok := r.BasicAuth()
+		if !ok {
+			writeUnauthorized()
+			return
+		}
+
+		usernameParts := strings.Split(username, "/")
+		if len(usernameParts) != 2 {
+			http.Error(w, "invalid username pattern", http.StatusBadRequest)
+			return
+		}
+
+		username = usernameParts[0]
+		loginName := usernameParts[1]
+
+		share, err := app.shareStore.FindShareByLogin(username, loginName)
+		if err == ErrShareNotFound {
+			writeUnauthorized()
+			return
+		} else if err != nil {
+			log.Printf("Cannot process login request: %v", err)
+			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+			return
+		}
+
+		if err := bcrypt.CompareHashAndPassword([]byte(share.Password), []byte(password)); err != nil {
+			writeUnauthorized()
+			return
+		}
+
+		// TODO determine permissions
+
+		directoryMapping := DirectoryMapping{
+			DataDirName: share.UUID.String(),
+		}
+
+		// Use the WebDAV handler to actually serve the request. Also enhance the context
+		// to contain the subdirectory (of the base directory) which contains the data for
+		// the authenticated user.
+		h.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), "mapping", &directoryMapping)))
+	})
+
+	fmt.Printf("Listening on %s\n", cmd.ListenAddress)
+	if err := http.ListenAndServe(cmd.ListenAddress, authenticatedWebdavHandler); err != http.ErrServerClosed && err != nil {
+		return fmt.Errorf("cannot listen: %w", err)
+	}
+	return nil
+}

config.go

@@ -1,32 +0,0 @@
-// Copyright (c) 2020, Andreas Schneider
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//     * Redistributions of source code must retain the above copyright
-//       notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above copyright
-//       notice, this list of conditions and the following disclaimer in the
-//       documentation and/or other materials provided with the distribution.
-//     * Neither the name of the <organization> nor the
-//       names of its contributors may be used to endorse or promote products
-//       derived from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
-// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
-// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-package main
-
-type config struct {
-	ListenAddress string `name:"listen-address" default:":3000" help:"Address to listen on for HTTP requests."`
-	DataDirectory string `name:"data-dir" default:"data" help:"Directory to store all files in."`
-	Db            string `name:"db" default:"ShareDAV.db" help:"Database file to use."`
-}

filesystem.go

@@ -44,8 +44,7 @@ import (
 )
 
 type DirectoryMapping struct {
-	VirtualName string
+	DataDirName string
-	RealName    string
 }
 
 // slashClean is equivalent to but slightly more efficient than
@@ -61,23 +60,17 @@ type BaseDir string
 
 func (d BaseDir) resolve(ctx context.Context, name string) string {
 	directoryMapping := ctx.Value("mapping").(*DirectoryMapping)
-	prefix := directoryMapping.VirtualName + "/"
-	if !strings.HasPrefix(name, prefix) {
-		// something does not add up
-		return ""
-	}
-	nameWithoutPrefix := strings.TrimPrefix(name, prefix)
 
 	// This implementation is based on Dir.Open's code in the standard net/http package.
 	if filepath.Separator != '/' && strings.IndexRune(name, filepath.Separator) >= 0 ||
-		strings.Contains(nameWithoutPrefix, "\x00") {
+		strings.Contains(name, "\x00") {
 		return ""
 	}
 	dir := string(d)
 	if dir == "" {
 		dir = "."
 	}
-	return filepath.Join(dir, directoryMapping.RealName, filepath.FromSlash(slashClean(nameWithoutPrefix)))
+	return filepath.Join(dir, directoryMapping.DataDirName, filepath.FromSlash(slashClean(name)))
 }
 
 func (d BaseDir) Mkdir(ctx context.Context, name string, perm os.FileMode) error {

main.go

@@ -34,10 +34,16 @@ import (
 	"github.com/alecthomas/kong"
 )
 
+type config struct {
+	DataDirectory string `name:"data-dir" default:"data" help:"Directory to store all files in."`
+	Db            string `name:"db" default:"ShareDAV.db" help:"Database file to use."`
+}
+
 type app struct {
 	config
 	CmdUser  CmdUser  `cmd:"" name:"user" help:"Manage users."`
 	CmdShare CmdShare `cmd:"" name:"share" help:"Manage shares."`
+	CmdServe CmdServe `cmd:"" name:"serve" help:"Serve HTTP requests." default:"1"`
 
 	userStore  UserStore
 	shareStore ShareStore
@@ -63,40 +69,4 @@ func main() {
 	app.shareStore = store
 
 	ctx.FatalIfErrorf(ctx.Run(&app))
-
-	//c := LoadConfig(*configFile)
-	//
-	//h := &webdav.Handler{}
-	//h.Prefix = "/share/"
-	//h.LockSystem = webdav.NewMemLS()
-	//h.FileSystem = BaseDir(c.BaseDirectory)
-	//
-	//authenticatedWebdavHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-	//	username, password, ok := r.BasicAuth()
-	//	directory := ""
-	//	if ok {
-	//		ok, directory = c.ValidateDAVUser(username, password)
-	//	}
-	//	if !ok {
-	//		w.Header().Set("WWW-Authenticate", `Basic realm="ShareDAV"`)
-	//		http.Error(w, "unauthorized", http.StatusUnauthorized)
-	//		return
-	//	}
-	//
-	//	shareName := chi.URLParam(r, "share")
-	//	directoryMapping := DirectoryMapping{
-	//		VirtualName: shareName,
-	//		RealName:    directory,
-	//	}
-	//
-	//	// Use the WebDAV handler to actually serve the request. Also enhance the context
-	//	// to contain the subdirectory (of the base directory) which contains the data for
-	//	// the authenticated user.
-	//	h.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), "mapping", &directoryMapping)))
-	//})
-	//
-	//r := chi.NewRouter()
-	//r.Handle("/share/{share}/*", authenticatedWebdavHandler)
-	//
-	//http.ListenAndServe(c.ListenAddress, r)
 }