1// Copyright 2015 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5package webdav 6 7import ( 8 "bytes" 9 "encoding/xml" 10 "fmt" 11 "io" 12 "mime" 13 "net/http" 14 "os" 15 "path/filepath" 16 "strconv" 17 18 "golang.org/x/net/context" 19) 20 21// Proppatch describes a property update instruction as defined in RFC 4918. 22// See http://www.webdav.org/specs/rfc4918.html#METHOD_PROPPATCH 23type Proppatch struct { 24 // Remove specifies whether this patch removes properties. If it does not 25 // remove them, it sets them. 26 Remove bool 27 // Props contains the properties to be set or removed. 28 Props []Property 29} 30 31// Propstat describes a XML propstat element as defined in RFC 4918. 32// See http://www.webdav.org/specs/rfc4918.html#ELEMENT_propstat 33type Propstat struct { 34 // Props contains the properties for which Status applies. 35 Props []Property 36 37 // Status defines the HTTP status code of the properties in Prop. 38 // Allowed values include, but are not limited to the WebDAV status 39 // code extensions for HTTP/1.1. 40 // http://www.webdav.org/specs/rfc4918.html#status.code.extensions.to.http11 41 Status int 42 43 // XMLError contains the XML representation of the optional error element. 44 // XML content within this field must not rely on any predefined 45 // namespace declarations or prefixes. If empty, the XML error element 46 // is omitted. 47 XMLError string 48 49 // ResponseDescription contains the contents of the optional 50 // responsedescription field. If empty, the XML element is omitted. 51 ResponseDescription string 52} 53 54// makePropstats returns a slice containing those of x and y whose Props slice 55// is non-empty. If both are empty, it returns a slice containing an otherwise 56// zero Propstat whose HTTP status code is 200 OK. 57func makePropstats(x, y Propstat) []Propstat { 58 pstats := make([]Propstat, 0, 2) 59 if len(x.Props) != 0 { 60 pstats = append(pstats, x) 61 } 62 if len(y.Props) != 0 { 63 pstats = append(pstats, y) 64 } 65 if len(pstats) == 0 { 66 pstats = append(pstats, Propstat{ 67 Status: http.StatusOK, 68 }) 69 } 70 return pstats 71} 72 73// DeadPropsHolder holds the dead properties of a resource. 74// 75// Dead properties are those properties that are explicitly defined. In 76// comparison, live properties, such as DAV:getcontentlength, are implicitly 77// defined by the underlying resource, and cannot be explicitly overridden or 78// removed. See the Terminology section of 79// http://www.webdav.org/specs/rfc4918.html#rfc.section.3 80// 81// There is a whitelist of the names of live properties. This package handles 82// all live properties, and will only pass non-whitelisted names to the Patch 83// method of DeadPropsHolder implementations. 84type DeadPropsHolder interface { 85 // DeadProps returns a copy of the dead properties held. 86 DeadProps() (map[xml.Name]Property, error) 87 88 // Patch patches the dead properties held. 89 // 90 // Patching is atomic; either all or no patches succeed. It returns (nil, 91 // non-nil) if an internal server error occurred, otherwise the Propstats 92 // collectively contain one Property for each proposed patch Property. If 93 // all patches succeed, Patch returns a slice of length one and a Propstat 94 // element with a 200 OK HTTP status code. If none succeed, for reasons 95 // other than an internal server error, no Propstat has status 200 OK. 96 // 97 // For more details on when various HTTP status codes apply, see 98 // http://www.webdav.org/specs/rfc4918.html#PROPPATCH-status 99 Patch([]Proppatch) ([]Propstat, error) 100} 101 102// liveProps contains all supported, protected DAV: properties. 103var liveProps = map[xml.Name]struct { 104 // findFn implements the propfind function of this property. If nil, 105 // it indicates a hidden property. 106 findFn func(context.Context, FileSystem, LockSystem, string, os.FileInfo) (string, error) 107 // dir is true if the property applies to directories. 108 dir bool 109}{ 110 {Space: "DAV:", Local: "resourcetype"}: { 111 findFn: findResourceType, 112 dir: true, 113 }, 114 {Space: "DAV:", Local: "displayname"}: { 115 findFn: findDisplayName, 116 dir: true, 117 }, 118 {Space: "DAV:", Local: "getcontentlength"}: { 119 findFn: findContentLength, 120 dir: false, 121 }, 122 {Space: "DAV:", Local: "getlastmodified"}: { 123 findFn: findLastModified, 124 // http://webdav.org/specs/rfc4918.html#PROPERTY_getlastmodified 125 // suggests that getlastmodified should only apply to GETable 126 // resources, and this package does not support GET on directories. 127 // 128 // Nonetheless, some WebDAV clients expect child directories to be 129 // sortable by getlastmodified date, so this value is true, not false. 130 // See golang.org/issue/15334. 131 dir: true, 132 }, 133 {Space: "DAV:", Local: "creationdate"}: { 134 findFn: nil, 135 dir: false, 136 }, 137 {Space: "DAV:", Local: "getcontentlanguage"}: { 138 findFn: nil, 139 dir: false, 140 }, 141 {Space: "DAV:", Local: "getcontenttype"}: { 142 findFn: findContentType, 143 dir: false, 144 }, 145 {Space: "DAV:", Local: "getetag"}: { 146 findFn: findETag, 147 // findETag implements ETag as the concatenated hex values of a file's 148 // modification time and size. This is not a reliable synchronization 149 // mechanism for directories, so we do not advertise getetag for DAV 150 // collections. 151 dir: false, 152 }, 153 154 // TODO: The lockdiscovery property requires LockSystem to list the 155 // active locks on a resource. 156 {Space: "DAV:", Local: "lockdiscovery"}: {}, 157 {Space: "DAV:", Local: "supportedlock"}: { 158 findFn: findSupportedLock, 159 dir: true, 160 }, 161} 162 163// TODO(nigeltao) merge props and allprop? 164 165// Props returns the status of the properties named pnames for resource name. 166// 167// Each Propstat has a unique status and each property name will only be part 168// of one Propstat element. 169func props(ctx context.Context, fs FileSystem, ls LockSystem, name string, pnames []xml.Name) ([]Propstat, error) { 170 f, err := fs.OpenFile(ctx, name, os.O_RDONLY, 0) 171 if err != nil { 172 return nil, err 173 } 174 defer f.Close() 175 fi, err := f.Stat() 176 if err != nil { 177 return nil, err 178 } 179 isDir := fi.IsDir() 180 181 var deadProps map[xml.Name]Property 182 if dph, ok := f.(DeadPropsHolder); ok { 183 deadProps, err = dph.DeadProps() 184 if err != nil { 185 return nil, err 186 } 187 } 188 189 pstatOK := Propstat{Status: http.StatusOK} 190 pstatNotFound := Propstat{Status: http.StatusNotFound} 191 for _, pn := range pnames { 192 // If this file has dead properties, check if they contain pn. 193 if dp, ok := deadProps[pn]; ok { 194 pstatOK.Props = append(pstatOK.Props, dp) 195 continue 196 } 197 // Otherwise, it must either be a live property or we don't know it. 198 if prop := liveProps[pn]; prop.findFn != nil && (prop.dir || !isDir) { 199 innerXML, err := prop.findFn(ctx, fs, ls, name, fi) 200 if err != nil { 201 return nil, err 202 } 203 pstatOK.Props = append(pstatOK.Props, Property{ 204 XMLName: pn, 205 InnerXML: []byte(innerXML), 206 }) 207 } else { 208 pstatNotFound.Props = append(pstatNotFound.Props, Property{ 209 XMLName: pn, 210 }) 211 } 212 } 213 return makePropstats(pstatOK, pstatNotFound), nil 214} 215 216// Propnames returns the property names defined for resource name. 217func propnames(ctx context.Context, fs FileSystem, ls LockSystem, name string) ([]xml.Name, error) { 218 f, err := fs.OpenFile(ctx, name, os.O_RDONLY, 0) 219 if err != nil { 220 return nil, err 221 } 222 defer f.Close() 223 fi, err := f.Stat() 224 if err != nil { 225 return nil, err 226 } 227 isDir := fi.IsDir() 228 229 var deadProps map[xml.Name]Property 230 if dph, ok := f.(DeadPropsHolder); ok { 231 deadProps, err = dph.DeadProps() 232 if err != nil { 233 return nil, err 234 } 235 } 236 237 pnames := make([]xml.Name, 0, len(liveProps)+len(deadProps)) 238 for pn, prop := range liveProps { 239 if prop.findFn != nil && (prop.dir || !isDir) { 240 pnames = append(pnames, pn) 241 } 242 } 243 for pn := range deadProps { 244 pnames = append(pnames, pn) 245 } 246 return pnames, nil 247} 248 249// Allprop returns the properties defined for resource name and the properties 250// named in include. 251// 252// Note that RFC 4918 defines 'allprop' to return the DAV: properties defined 253// within the RFC plus dead properties. Other live properties should only be 254// returned if they are named in 'include'. 255// 256// See http://www.webdav.org/specs/rfc4918.html#METHOD_PROPFIND 257func allprop(ctx context.Context, fs FileSystem, ls LockSystem, name string, include []xml.Name) ([]Propstat, error) { 258 pnames, err := propnames(ctx, fs, ls, name) 259 if err != nil { 260 return nil, err 261 } 262 // Add names from include if they are not already covered in pnames. 263 nameset := make(map[xml.Name]bool) 264 for _, pn := range pnames { 265 nameset[pn] = true 266 } 267 for _, pn := range include { 268 if !nameset[pn] { 269 pnames = append(pnames, pn) 270 } 271 } 272 return props(ctx, fs, ls, name, pnames) 273} 274 275// Patch patches the properties of resource name. The return values are 276// constrained in the same manner as DeadPropsHolder.Patch. 277func patch(ctx context.Context, fs FileSystem, ls LockSystem, name string, patches []Proppatch) ([]Propstat, error) { 278 conflict := false 279loop: 280 for _, patch := range patches { 281 for _, p := range patch.Props { 282 if _, ok := liveProps[p.XMLName]; ok { 283 conflict = true 284 break loop 285 } 286 } 287 } 288 if conflict { 289 pstatForbidden := Propstat{ 290 Status: http.StatusForbidden, 291 XMLError: `<D:cannot-modify-protected-property xmlns:D="DAV:"/>`, 292 } 293 pstatFailedDep := Propstat{ 294 Status: StatusFailedDependency, 295 } 296 for _, patch := range patches { 297 for _, p := range patch.Props { 298 if _, ok := liveProps[p.XMLName]; ok { 299 pstatForbidden.Props = append(pstatForbidden.Props, Property{XMLName: p.XMLName}) 300 } else { 301 pstatFailedDep.Props = append(pstatFailedDep.Props, Property{XMLName: p.XMLName}) 302 } 303 } 304 } 305 return makePropstats(pstatForbidden, pstatFailedDep), nil 306 } 307 308 f, err := fs.OpenFile(ctx, name, os.O_RDWR, 0) 309 if err != nil { 310 return nil, err 311 } 312 defer f.Close() 313 if dph, ok := f.(DeadPropsHolder); ok { 314 ret, err := dph.Patch(patches) 315 if err != nil { 316 return nil, err 317 } 318 // http://www.webdav.org/specs/rfc4918.html#ELEMENT_propstat says that 319 // "The contents of the prop XML element must only list the names of 320 // properties to which the result in the status element applies." 321 for _, pstat := range ret { 322 for i, p := range pstat.Props { 323 pstat.Props[i] = Property{XMLName: p.XMLName} 324 } 325 } 326 return ret, nil 327 } 328 // The file doesn't implement the optional DeadPropsHolder interface, so 329 // all patches are forbidden. 330 pstat := Propstat{Status: http.StatusForbidden} 331 for _, patch := range patches { 332 for _, p := range patch.Props { 333 pstat.Props = append(pstat.Props, Property{XMLName: p.XMLName}) 334 } 335 } 336 return []Propstat{pstat}, nil 337} 338 339func escapeXML(s string) string { 340 for i := 0; i < len(s); i++ { 341 // As an optimization, if s contains only ASCII letters, digits or a 342 // few special characters, the escaped value is s itself and we don't 343 // need to allocate a buffer and convert between string and []byte. 344 switch c := s[i]; { 345 case c == ' ' || c == '_' || 346 ('+' <= c && c <= '9') || // Digits as well as + , - . and / 347 ('A' <= c && c <= 'Z') || 348 ('a' <= c && c <= 'z'): 349 continue 350 } 351 // Otherwise, go through the full escaping process. 352 var buf bytes.Buffer 353 xml.EscapeText(&buf, []byte(s)) 354 return buf.String() 355 } 356 return s 357} 358 359func findResourceType(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) { 360 if fi.IsDir() { 361 return `<D:collection xmlns:D="DAV:"/>`, nil 362 } 363 return "", nil 364} 365 366func findDisplayName(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) { 367 if slashClean(name) == "/" { 368 // Hide the real name of a possibly prefixed root directory. 369 return "", nil 370 } 371 return escapeXML(fi.Name()), nil 372} 373 374func findContentLength(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) { 375 return strconv.FormatInt(fi.Size(), 10), nil 376} 377 378func findLastModified(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) { 379 return fi.ModTime().Format(http.TimeFormat), nil 380} 381 382func findContentType(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) { 383 f, err := fs.OpenFile(ctx, name, os.O_RDONLY, 0) 384 if err != nil { 385 return "", err 386 } 387 defer f.Close() 388 // This implementation is based on serveContent's code in the standard net/http package. 389 ctype := mime.TypeByExtension(filepath.Ext(name)) 390 if ctype != "" { 391 return ctype, nil 392 } 393 // Read a chunk to decide between utf-8 text and binary. 394 var buf [512]byte 395 n, err := io.ReadFull(f, buf[:]) 396 if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF { 397 return "", err 398 } 399 ctype = http.DetectContentType(buf[:n]) 400 // Rewind file. 401 _, err = f.Seek(0, os.SEEK_SET) 402 return ctype, err 403} 404 405func findETag(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) { 406 // The Apache http 2.4 web server by default concatenates the 407 // modification time and size of a file. We replicate the heuristic 408 // with nanosecond granularity. 409 return fmt.Sprintf(`"%x%x"`, fi.ModTime().UnixNano(), fi.Size()), nil 410} 411 412func findSupportedLock(ctx context.Context, fs FileSystem, ls LockSystem, name string, fi os.FileInfo) (string, error) { 413 return `` + 414 `<D:lockentry xmlns:D="DAV:">` + 415 `<D:lockscope><D:exclusive/></D:lockscope>` + 416 `<D:locktype><D:write/></D:locktype>` + 417 `</D:lockentry>`, nil 418} 419