webdav: try to handle HEAD for collection too

The underlying golang webdav library returns Method Not Allowed for
HEAD requests on directories:

https://github.com/golang/net/blob/master/webdav/webdav.go#L210

let's see if we can workaround this inside SFTPGo itself in a similar
way as we do for GET.

The HEAD response will not return a Content-Length, we cannot handle
this inside SFTPGo.

Fixes #294

go.mod

@@ -3,12 +3,12 @@ module github.com/drakkan/sftpgo
 go 1.15
 
 require (
-	cloud.google.com/go v0.75.0 // indirect
+	cloud.google.com/go v0.76.0 // indirect
 	cloud.google.com/go/storage v1.12.0
 	github.com/Azure/azure-storage-blob-go v0.13.0
 	github.com/GehirnInc/crypt v0.0.0-20200316065508-bb7000b8a962
 	github.com/alexedwards/argon2id v0.0.0-20201228115903-cf543ebc1f7b
-	github.com/aws/aws-sdk-go v1.37.1
+	github.com/aws/aws-sdk-go v1.37.2
 	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf // indirect
 	github.com/eikenb/pipeat v0.0.0-20200430215831-470df5986b6d
 	github.com/fclairamb/ftpserverlib v0.12.0
@@ -27,7 +27,7 @@ require (
 	github.com/lib/pq v1.9.0
 	github.com/magiconair/properties v1.8.4 // indirect
 	github.com/mattn/go-sqlite3 v1.14.6
-	github.com/miekg/dns v1.1.37 // indirect
+	github.com/miekg/dns v1.1.38 // indirect
 	github.com/minio/sha256-simd v0.1.1
 	github.com/minio/sio v0.2.1
 	github.com/mitchellh/mapstructure v1.4.1 // indirect
@@ -52,19 +52,15 @@ require (
 	github.com/yl2chen/cidranger v1.0.2
 	go.etcd.io/bbolt v1.3.5
 	go.opencensus.io v0.22.6 // indirect
-	go.uber.org/automaxprocs v1.3.0
+	go.uber.org/automaxprocs v1.4.0
 	gocloud.dev v0.21.0
 	gocloud.dev/secrets/hashivault v0.21.0
 	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad
 	golang.org/x/net v0.0.0-20210119194325-5f4716e94777
-	golang.org/x/oauth2 v0.0.0-20210126194326-f9ce19ea3013 // indirect
+	golang.org/x/oauth2 v0.0.0-20210201163806-010130855d6c // indirect
 	golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c
-	golang.org/x/text v0.3.5 // indirect
 	golang.org/x/time v0.0.0-20201208040808-7e3f01d25324 // indirect
-	golang.org/x/tools v0.1.0 // indirect
 	google.golang.org/api v0.38.0
-	google.golang.org/genproto v0.0.0-20210126160654-44e461bb6506 // indirect
-	google.golang.org/grpc v1.35.0 // indirect
 	gopkg.in/ini.v1 v1.62.0 // indirect
 	gopkg.in/natefinch/lumberjack.v2 v2.0.0
 	gopkg.in/yaml.v2 v2.4.0 // indirect

go.sum

@@ -18,8 +18,8 @@ cloud.google.com/go v0.65.0/go.mod h1:O5N8zS7uWy9vkA9vayVHs65eM1ubvY4h553ofrNHOb
 cloud.google.com/go v0.66.0/go.mod h1:dgqGAjKCDxyhGTtC9dAREQGUJpkceNm1yt590Qno0Ko=
 cloud.google.com/go v0.72.0/go.mod h1:M+5Vjvlc2wnp6tjzE102Dw08nGShTscUx2nZMufOKPI=
 cloud.google.com/go v0.74.0/go.mod h1:VV1xSbzvo+9QJOxLDaJfTjx5e+MePCpCWwvftOeQmWk=
-cloud.google.com/go v0.75.0 h1:XgtDnVJRCPEUG21gjFiRPz4zI1Mjg16R+NYQjfmU4XY=
-cloud.google.com/go v0.75.0/go.mod h1:VGuuCn7PG0dwsd5XPVm2Mm3wlh3EL55/79EKB6hlPTY=
+cloud.google.com/go v0.76.0 h1:Ckw+E/QYZgd/5bpI4wz4h6f+jmpvh9S9uSrKNnbicJI=
+cloud.google.com/go v0.76.0/go.mod h1:r9EvIAvLrunusnetGdQ50M/gKui1x3zdGW/VELGkdpw=
 cloud.google.com/go/bigquery v1.0.1/go.mod h1:i/xbL2UlR5RvWAURpBYZTtm/cXjCha9lbfbpx4poX+o=
 cloud.google.com/go/bigquery v1.3.0/go.mod h1:PjpwJnslEMmckchkHFfq+HTD2DmtT67aNFKH1/VBDHE=
 cloud.google.com/go/bigquery v1.4.0/go.mod h1:S8dzgnTigyfTmLBfrtrhyYhwRxG72rYxvftPBK2Dvzc=
@@ -115,8 +115,8 @@ github.com/aws/aws-sdk-go v1.15.27/go.mod h1:mFuSZ37Z9YOHbQEwBWztmVzqXrEkub65tZo
 github.com/aws/aws-sdk-go v1.23.20/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
 github.com/aws/aws-sdk-go v1.27.0/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
 github.com/aws/aws-sdk-go v1.36.1/go.mod h1:hcU610XS61/+aQV88ixoOzUoG7v3b31pl2zKMmprdro=
-github.com/aws/aws-sdk-go v1.37.1 h1:BTHmuN+gzhxkvU9sac2tZvaY0gV9ihbHw+KxZOecYvY=
-github.com/aws/aws-sdk-go v1.37.1/go.mod h1:hcU610XS61/+aQV88ixoOzUoG7v3b31pl2zKMmprdro=
+github.com/aws/aws-sdk-go v1.37.2 h1:+akLrZr/Qn5tp/4CV9oTvTMtsO+9X8rTnuuzGOEvMrE=
+github.com/aws/aws-sdk-go v1.37.2/go.mod h1:hcU610XS61/+aQV88ixoOzUoG7v3b31pl2zKMmprdro=
 github.com/aws/aws-sdk-go-v2 v0.18.0/go.mod h1:JWVYvqSMppoMJC0x5wdwiImzgXTI9FuZwxzkQq9wy+g=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
@@ -318,7 +318,7 @@ github.com/google/pprof v0.0.0-20200708004538-1a94d8640e99/go.mod h1:ZgVRPoUq/hf
 github.com/google/pprof v0.0.0-20200905233945-acf8798be1f7/go.mod h1:ZgVRPoUq/hfqzAqh7sHMqb3I9Rq5C59dIz2SbBwJ4eM=
 github.com/google/pprof v0.0.0-20201023163331-3e6fc7fc9c4c/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/pprof v0.0.0-20201203190320-1bf35d6f28c2/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
-github.com/google/pprof v0.0.0-20201218002935-b9804c9f04c2/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
+github.com/google/pprof v0.0.0-20210122040257-d980be63207e/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
@@ -483,8 +483,8 @@ github.com/matttproud/golang_protobuf_extensions v1.0.1 h1:4hp9jkHxhMHkqkrB3Ix0j
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/miekg/dns v1.0.14/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
 github.com/miekg/dns v1.1.27/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
-github.com/miekg/dns v1.1.37 h1:+kky2ArpBqk0S/74RkwFjmKM9jja7AB1RN7VUuVq0iM=
-github.com/miekg/dns v1.1.37/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
+github.com/miekg/dns v1.1.38 h1:MtIY+fmHUVVgv1AXzmKMWcwdCYxTRPG1EDjpqF4RCEw=
+github.com/miekg/dns v1.1.38/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
 github.com/minio/sha256-simd v0.1.1 h1:5QHSlgo3nt5yKOJrC7W8w7X+NFl8cMPZm96iu8kKUJU=
 github.com/minio/sha256-simd v0.1.1/go.mod h1:B5e1o+1/KgNmWrSQK08Y6Z1Vb5pwIktudl0J58iy0KM=
 github.com/minio/sio v0.2.1 h1:NjzKiIMSMcHediVQR0AFVx2tp7Wxh9tKPfDI3kH7aHQ=
@@ -701,8 +701,8 @@ go.opencensus.io v0.22.6/go.mod h1:XItmlyltB5F7CS4xOC1DcqMoFqwtC6OG2xF7mCv7P7E=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.5.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
-go.uber.org/automaxprocs v1.3.0 h1:II28aZoGdaglS5vVNnspf28lnZpXScxtIozx1lAjdb0=
-go.uber.org/automaxprocs v1.3.0/go.mod h1:9CWT6lKIep8U41DDaPiH6eFscnTyjfTANNQNx6LrIcA=
+go.uber.org/automaxprocs v1.4.0 h1:CpDZl6aOlLhReez+8S3eEotD7Jx0Os++lemPlMULQP0=
+go.uber.org/automaxprocs v1.4.0/go.mod h1:/mTEdr7LvHhs0v7mjdxDreTz1OG5zdZGqgOnhWiR/+Q=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/multierr v1.3.0/go.mod h1:VgVr7evmIr6uPjLBxg28wmKNXyqE9akIJ5XnfpiKl+4=
 go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee/go.mod h1:vJERXedbb3MVM5f9Ejo0C68/HhF8uaILCdgjnY+goOA=
@@ -756,8 +756,9 @@ golang.org/x/oauth2 v0.0.0-20200902213428-5d25da1a8d43/go.mod h1:KelEdhl1UZF7XfJ
 golang.org/x/oauth2 v0.0.0-20201109201403-9fd604954f58/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
 golang.org/x/oauth2 v0.0.0-20201203001011-0b49973bad19/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
 golang.org/x/oauth2 v0.0.0-20201208152858-08078c50e5b5/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
-golang.org/x/oauth2 v0.0.0-20210126194326-f9ce19ea3013 h1:55H5j7lotzuFCEOKDsMch+fRNUQ9DgtyHOUP31FNqKc=
-golang.org/x/oauth2 v0.0.0-20210126194326-f9ce19ea3013/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
+golang.org/x/oauth2 v0.0.0-20210113205817-d3ed898aa8a3/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
+golang.org/x/oauth2 v0.0.0-20210201163806-010130855d6c h1:HiAZXo96zOhVhtFHchj/ojzoxCFiPrp9/j0GtS38V3g=
+golang.org/x/oauth2 v0.0.0-20210201163806-010130855d6c/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -907,7 +908,6 @@ golang.org/x/tools v0.0.0-20201202200335-bef1c476418a/go.mod h1:emZCQorbCU4vsT4f
 golang.org/x/tools v0.0.0-20201203202102-a1a1cbeaa516/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20201208233053-a543418bbed2/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20210105154028-b0ab187a4818/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
-golang.org/x/tools v0.0.0-20210108195828-e2f9c7f1fc8e/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20210114065538-d78b04bdf963/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.1.0 h1:po9/4sTYwZU9lPhi1tOrb4hCv3qrhiQ77LZfGa2OjwY=
 golang.org/x/tools v0.1.0/go.mod h1:xkSsbof2nBLbhDlRMhhhyNLN/zl3eTqcnHD5viDpcZ0=
@@ -992,9 +992,8 @@ google.golang.org/genproto v0.0.0-20201201144952-b05cb90ed32e/go.mod h1:FWY/as6D
 google.golang.org/genproto v0.0.0-20201203001206-6486ece9c497/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/genproto v0.0.0-20201210142538-e3217bee35cc/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/genproto v0.0.0-20201214200347-8c77b98c765d/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
-google.golang.org/genproto v0.0.0-20210108203827-ffc7fda8c3d7/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
-google.golang.org/genproto v0.0.0-20210126160654-44e461bb6506 h1:uLBY0yHDCj2PMQ98KWDSIDFwn9zK2zh+tgWtbvPPBjI=
-google.golang.org/genproto v0.0.0-20210126160654-44e461bb6506/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
+google.golang.org/genproto v0.0.0-20210202153253-cf70463f6119 h1:m9+RjTMas6brUP8DBxSAa/WIPFy7FIhKpvk+9Ppce8E=
+google.golang.org/genproto v0.0.0-20210202153253-cf70463f6119/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/grpc v1.14.0/go.mod h1:yo6s7OP7yaDglbqo1J04qKzAhqBH6lvTonzMVmEdcZw=
 google.golang.org/grpc v1.17.0/go.mod h1:6QZJwpn2B+Zp71q/5VxRsJ6NXXVCE5NRUHRo+f3cWCs=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=

webdavd/server.go

@@ -105,18 +105,23 @@ func (s *webDavServer) verifyTLSConnection(state tls.ConnectionState) error {
 	return nil
 }
 
-func (s *webDavServer) checkRequestMethod(ctx context.Context, r *http.Request, connection *Connection, prefix string) {
+// returns true if a response was sent
+func (s *webDavServer) checkRequestMethod(ctx context.Context, r *http.Request, connection *Connection, prefix string) bool {
 	// see RFC4918, section 9.4
-	if r.Method == http.MethodGet {
+	if r.Method == http.MethodGet || r.Method == http.MethodHead {
 		p := strings.TrimPrefix(path.Clean(r.URL.Path), prefix)
 		info, err := connection.Stat(ctx, p)
 		if err == nil && info.IsDir() {
+			if r.Method == http.MethodHead {
+				return true
+			}
 			r.Method = "PROPFIND"
 			if r.Header.Get("Depth") == "" {
 				r.Header.Add("Depth", "1")
 			}
 		}
 	}
+	return false
 }
 
 // ServeHTTP implements the http.Handler interface
@@ -183,7 +188,12 @@ func (s *webDavServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	dataprovider.UpdateLastLogin(user) //nolint:errcheck
 
 	prefix := path.Join("/", user.Username)
-	s.checkRequestMethod(ctx, r, connection, prefix)
+	if s.checkRequestMethod(ctx, r, connection, prefix) {
+		w.Header().Set("Content-Type", "text/xml; charset=utf-8")
+		w.WriteHeader(http.StatusMultiStatus)
+		w.Write([]byte("")) //nolint:errcheck
+		return
+	}
 
 	handler := webdav.Handler{
 		Prefix:     prefix,

webdavd/webdavd_test.go

@@ -1314,6 +1314,29 @@ func TestBytesRangeRequests(t *testing.T) {
 	assert.NoError(t, err)
 }
 
+func TestHEAD(t *testing.T) {
+	u := getTestUser()
+	user, _, err := httpdtest.AddUser(u, http.StatusCreated)
+	assert.NoError(t, err)
+	rootPath := fmt.Sprintf("http://%v/%v", webDavServerAddr, user.Username)
+	httpClient := httpclient.GetHTTPClient()
+	req, err := http.NewRequest(http.MethodHead, rootPath, nil)
+	if assert.NoError(t, err) {
+		req.SetBasicAuth(u.Username, u.Password)
+		resp, err := httpClient.Do(req)
+		if assert.NoError(t, err) {
+			assert.Equal(t, http.StatusMultiStatus, resp.StatusCode)
+			assert.Equal(t, "text/xml; charset=utf-8", resp.Header.Get("Content-Type"))
+			resp.Body.Close()
+		}
+	}
+
+	_, err = httpdtest.RemoveUser(user, http.StatusOK)
+	assert.NoError(t, err)
+	err = os.RemoveAll(user.GetHomeDir())
+	assert.NoError(t, err)
+}
+
 func TestGETAsPROPFIND(t *testing.T) {
 	u := getTestUser()
 	subDir1 := "/sub1"