webdav-server/webdav.go
2017-08-05 10:29:09 +01:00

129 lines
2.9 KiB
Go

package webdav
import (
"context"
"net/http"
"regexp"
"strings"
"golang.org/x/net/webdav"
)
// Config is the configuration of a WebDAV instance.
type Config struct {
*User
Users map[string]*User
}
// ServeHTTP determines if the request is for this plugin, and if all prerequisites are met.
func (c *Config) ServeHTTP(w http.ResponseWriter, r *http.Request) {
u := c.User
// Gets the correct user for this request.
username, _, ok := r.BasicAuth()
if ok {
if user, ok := c.Users[username]; ok {
u = user
}
}
// Checks for user permissions relatively to this PATH.
if !u.Allowed(r.URL.Path) {
w.WriteHeader(http.StatusForbidden)
return
}
if r.Method == "HEAD" {
w = newResponseWriterNoBody(w)
}
// If this request modified the files and the user doesn't have permission
// to do so, return forbidden.
if (r.Method == "PUT" || r.Method == "POST" || r.Method == "MKCOL" ||
r.Method == "DELETE" || r.Method == "COPY" || r.Method == "MOVE") &&
!u.Modify {
w.WriteHeader(http.StatusForbidden)
return
}
// Excerpt from RFC4918, section 9.4:
//
// GET, when applied to a collection, may return the contents of an
// "index.html" resource, a human-readable view of the contents of
// the collection, or something else altogether.
//
// Get, when applied to collection, will return the same as PROPFIND method.
if r.Method == "GET" {
info, err := u.Handler.FileSystem.Stat(context.TODO(), r.URL.Path)
if err == nil && info.IsDir() {
r.Method = "PROPFIND"
}
}
// Runs the WebDAV.
u.Handler.ServeHTTP(w, r)
}
// Rule is a dissalow/allow rule.
type Rule struct {
Regex bool
Allow bool
Path string
Regexp *regexp.Regexp
}
// User contains the settings of each user.
type User struct {
Scope string
Modify bool
Rules []*Rule
Handler *webdav.Handler
}
// Allowed checks if the user has permission to access a directory/file
func (u User) Allowed(url string) bool {
var rule *Rule
i := len(u.Rules) - 1
for i >= 0 {
rule = u.Rules[i]
if rule.Regex {
if rule.Regexp.MatchString(url) {
return rule.Allow
}
} else if strings.HasPrefix(url, rule.Path) {
return rule.Allow
}
i--
}
return true
}
// responseWriterNoBody is a wrapper used to suprress the body of the response
// to a request. Mainly used for HEAD requests.
type responseWriterNoBody struct {
http.ResponseWriter
}
// newResponseWriterNoBody creates a new responseWriterNoBody.
func newResponseWriterNoBody(w http.ResponseWriter) *responseWriterNoBody {
return &responseWriterNoBody{w}
}
// Header executes the Header method from the http.ResponseWriter.
func (w responseWriterNoBody) Header() http.Header {
return w.ResponseWriter.Header()
}
// Write suprresses the body.
func (w responseWriterNoBody) Write(data []byte) (int, error) {
return 0, nil
}
// WriteHeader writes the header to the http.ResponseWriter.
func (w responseWriterNoBody) WriteHeader(statusCode int) {
w.ResponseWriter.WriteHeader(statusCode)
}