API/CopyObject: If-None-Match should return Precondition failed. (#2164)

This commit is contained in:
Harshavardhana 2016-07-10 17:32:59 -07:00 committed by GitHub
parent aa7079fc7b
commit d676e660c9
2 changed files with 224 additions and 188 deletions

223
object-handlers-common.go Normal file
View File

@ -0,0 +1,223 @@
/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package main
import (
"net/http"
"strings"
"time"
)
// Validates the preconditions. Returns true if object content need not be written to http.ResponseWriter.
func checkPreconditions(r *http.Request, w http.ResponseWriter, objInfo ObjectInfo) bool {
// Return false for methods other than GET and HEAD.
if r.Method != "GET" && r.Method != "HEAD" {
return false
}
// Headers to be set of object content is not going to be written to the client.
writeHeaders := func() {
// set common headers
setCommonHeaders(w)
// set object-related metadata headers
w.Header().Set("Last-Modified", objInfo.ModTime.UTC().Format(http.TimeFormat))
if objInfo.MD5Sum != "" {
w.Header().Set("ETag", "\""+objInfo.MD5Sum+"\"")
}
}
// If-Modified-Since : Return the object only if it has been modified since the specified time,
// otherwise return a 304 (not modified).
ifModifiedSinceHeader := r.Header.Get("If-Modified-Since")
if ifModifiedSinceHeader != "" {
if !ifModifiedSince(objInfo.ModTime, ifModifiedSinceHeader) {
// If the object is not modified since the specified time.
writeHeaders()
w.WriteHeader(http.StatusNotModified)
return true
}
}
// If-Unmodified-Since : Return the object only if it has not been modified since the specified
// time, otherwise return a 412 (precondition failed).
ifUnmodifiedSinceHeader := r.Header.Get("If-Unmodified-Since")
if ifUnmodifiedSinceHeader != "" {
if ifModifiedSince(objInfo.ModTime, ifUnmodifiedSinceHeader) {
// If the object is modified since the specified time.
writeHeaders()
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
// If-Match : Return the object only if its entity tag (ETag) is the same as the one specified;
// otherwise return a 412 (precondition failed).
ifMatchETagHeader := r.Header.Get("If-Match")
if ifMatchETagHeader != "" {
if !isETagEqual(objInfo.MD5Sum, ifMatchETagHeader) {
// If the object ETag does not match with the specified ETag.
writeHeaders()
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
// If-None-Match : Return the object only if its entity tag (ETag) is different from the
// one specified otherwise, return a 304 (not modified).
ifNoneMatchETagHeader := r.Header.Get("If-None-Match")
if ifNoneMatchETagHeader != "" {
if isETagEqual(objInfo.MD5Sum, ifNoneMatchETagHeader) {
// If the object ETag matches with the specified ETag.
writeHeaders()
w.WriteHeader(http.StatusNotModified)
return true
}
}
// Object content should be written to http.ResponseWriter
return false
}
// returns true if object was modified after givenTime.
func ifModifiedSince(objTime time.Time, givenTimeStr string) bool {
if objTime.IsZero() || objTime.Equal(time.Unix(0, 0)) {
// If the object doesn't have a modtime (IsZero), or the modtime
// is obviously garbage (Unix time == 0), then ignore modtimes
// and don't process the If-Modified-Since header.
return false
}
givenTime, err := time.Parse(http.TimeFormat, givenTimeStr)
if err != nil {
return true
}
// The Date-Modified header truncates sub-second precision, so
// use mtime < t+1s instead of mtime <= t to check for unmodified.
if objTime.After(givenTime.Add(1 * time.Second)) {
return true
}
return false
}
// canonicalizeETag returns ETag with leading and trailing double-quotes removed,
// if any present
func canonicalizeETag(etag string) string {
canonicalETag := strings.TrimPrefix(etag, "\"")
return strings.TrimSuffix(canonicalETag, "\"")
}
// isETagEqual return true if the canonical representations of two ETag strings
// are equal, false otherwise
func isETagEqual(left, right string) bool {
return canonicalizeETag(left) == canonicalizeETag(right)
}
// checkCopySource implements x-amz-copy-source-if-modified-since and
// x-amz-copy-source-if-unmodified-since checks.
//
// modtime is the modification time of the resource to be served, or
// IsZero(). return value is whether this request is now complete.
func checkCopySourceLastModified(w http.ResponseWriter, r *http.Request, modtime time.Time) bool {
// writer always has quoted string
// transform reader's etag to
if r.Method != "PUT" {
return false
}
if modtime.IsZero() || modtime.Equal(time.Unix(0, 0)) {
// If the object doesn't have a modtime (IsZero), or the modtime
// is obviously garbage (Unix time == 0), then ignore modtimes
// and don't process the If-Modified-Since header.
return false
}
// The Date-Modified header truncates sub-second precision, so
// use mtime < t+1s instead of mtime <= t to check for unmodified.
if _, ok := r.Header["x-amz-copy-source-if-modified-since"]; ok {
// Return the object only if it has been modified since the
// specified time, otherwise return a 304 error (not modified).
t, err := time.Parse(http.TimeFormat, r.Header.Get("x-amz-copy-source-if-modified-since"))
if err == nil && modtime.Before(t.Add(1*time.Second)) {
h := w.Header()
// Remove Content headers if set
delete(h, "Content-Type")
delete(h, "Content-Length")
delete(h, "Content-Range")
w.WriteHeader(http.StatusNotModified)
return true
}
} else if _, ok := r.Header["x-amz-copy-source-if-unmodified-since"]; ok {
// Return the object only if it has not been modified since the
// specified time, otherwise return a 412 error (precondition failed).
t, err := time.Parse(http.TimeFormat, r.Header.Get("x-amz-copy-source-if-unmodified-since"))
if err == nil && modtime.After(t.Add(1*time.Second)) {
h := w.Header()
// Remove Content headers if set
delete(h, "Content-Type")
delete(h, "Content-Length")
delete(h, "Content-Range")
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
w.Header().Set("Last-Modified", modtime.UTC().Format(http.TimeFormat))
return false
}
// checkCopySourceETag implements x-amz-copy-source-if-match and
// x-amz-copy-source-if-none-match checks.
//
// The ETag must have been previously set in the ResponseWriter's
// headers. The return value is whether this request is now considered
// complete.
func checkCopySourceETag(w http.ResponseWriter, r *http.Request) bool {
// writer always has quoted string
// transform reader's etag to
if r.Method != "PUT" {
return false
}
etag := w.Header().Get("ETag")
// Tag must be provided...
if etag == "" {
return false
}
if inm := r.Header.Get("x-amz-copy-source-if-none-match"); inm != "" {
// Return the object only if its entity tag (ETag) is
// different from the one specified; otherwise, the
// request returns a 412 HTTP status code error (failed precondition).
if isETagEqual(inm, etag) || isETagEqual(inm, "*") {
h := w.Header()
// Remove Content headers if set
delete(h, "Content-Type")
delete(h, "Content-Length")
delete(h, "Content-Range")
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
} else if inm := r.Header.Get("x-amz-copy-source-if-match"); !isETagEqual(inm, "") {
// Return the object only if its entity tag (ETag) is the same
// as the one specified; otherwise, return a 412 (precondition failed).
if !isETagEqual(inm, etag) {
h := w.Header()
// Remove Content headers if set
delete(h, "Content-Type")
delete(h, "Content-Length")
delete(h, "Content-Range")
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
return false
}

View File

@ -163,7 +163,7 @@ func (api objectAPIHandlers) GetObjectHandler(w http.ResponseWriter, r *http.Req
if !dataWritten {
// Error response only if no data has been written to client yet. i.e if
// partial data has already been written before an error
// occured then no point in setting StatusCode and
// occurred then no point in setting StatusCode and
// sending error XML.
apiErr := toAPIErrorCode(err)
writeErrorResponse(w, r, apiErr, r.URL.Path)
@ -178,96 +178,6 @@ func (api objectAPIHandlers) GetObjectHandler(w http.ResponseWriter, r *http.Req
}
}
// Validates the preconditions. Returns true if object content need not be written to http.ResponseWriter.
func checkPreconditions(r *http.Request, w http.ResponseWriter, objInfo ObjectInfo) bool {
// Headers to be set of object content is not going to be written to the client.
writeHeaders := func() {
// set common headers
setCommonHeaders(w)
// set object-related metadata headers
w.Header().Set("Last-Modified", objInfo.ModTime.UTC().Format(http.TimeFormat))
if objInfo.MD5Sum != "" {
w.Header().Set("ETag", "\""+objInfo.MD5Sum+"\"")
}
}
// If-Modified-Since : Return the object only if it has been modified since the specified time,
// otherwise return a 304 (not modified).
ifModifiedSinceHeader := r.Header.Get("If-Modified-Since")
if ifModifiedSinceHeader != "" {
if !ifModifiedSince(objInfo.ModTime, ifModifiedSinceHeader) {
// If the object is not modified since the specified time.
writeHeaders()
w.WriteHeader(http.StatusNotModified)
return true
}
}
// If-Unmodified-Since : Return the object only if it has not been modified since the specified
// time, otherwise return a 412 (precondition failed).
ifUnmodifiedSinceHeader := r.Header.Get("If-Unmodified-Since")
if ifUnmodifiedSinceHeader != "" {
if ifModifiedSince(objInfo.ModTime, ifUnmodifiedSinceHeader) {
// If the object is modified since the specified time.
writeHeaders()
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
// If-Match : Return the object only if its entity tag (ETag) is the same as the one specified;
// otherwise return a 412 (precondition failed).
ifMatchETagHeader := r.Header.Get("If-Match")
if ifMatchETagHeader != "" {
if !isETagEqual(objInfo.MD5Sum, ifMatchETagHeader) {
// If the object ETag does not match with the specified ETag.
writeHeaders()
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
// If-None-Match : Return the object only if its entity tag (ETag) is different from the
// one specified otherwise, return a 304 (not modified).
ifNoneMatchETagHeader := r.Header.Get("If-None-Match")
if ifNoneMatchETagHeader != "" {
if isETagEqual(objInfo.MD5Sum, ifNoneMatchETagHeader) {
// If the object ETag matches with the specified ETag.
writeHeaders()
w.WriteHeader(http.StatusNotModified)
return true
}
}
// Object content should be written to http.ResponseWriter
return false
}
// returns true if object was modified after givenTime.
func ifModifiedSince(objTime time.Time, givenTimeStr string) bool {
givenTime, err := time.Parse(http.TimeFormat, givenTimeStr)
if err != nil {
return true
}
if objTime.After(givenTime) {
return true
}
return false
}
// canonicalizeETag returns ETag with leading and trailing double-quotes removed,
// if any present
func canonicalizeETag(etag string) string {
canonicalETag := strings.TrimPrefix(etag, "\"")
return strings.TrimSuffix(canonicalETag, "\"")
}
// isETagEqual return true if the canonical representations of two ETag strings
// are equal, false otherwise
func isETagEqual(left, right string) bool {
return canonicalizeETag(left) == canonicalizeETag(right)
}
// HeadObjectHandler - HEAD Object
// -----------
// The HEAD operation retrieves metadata from an object without returning the object itself.
@ -458,103 +368,6 @@ func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Re
pipeReader.Close()
}
// checkCopySource implements x-amz-copy-source-if-modified-since and
// x-amz-copy-source-if-unmodified-since checks.
//
// modtime is the modification time of the resource to be served, or
// IsZero(). return value is whether this request is now complete.
func checkCopySourceLastModified(w http.ResponseWriter, r *http.Request, modtime time.Time) bool {
// writer always has quoted string
// transform reader's etag to
if r.Method != "PUT" {
return false
}
if modtime.IsZero() || modtime.Equal(time.Unix(0, 0)) {
// If the object doesn't have a modtime (IsZero), or the modtime
// is obviously garbage (Unix time == 0), then ignore modtimes
// and don't process the If-Modified-Since header.
return false
}
// The Date-Modified header truncates sub-second precision, so
// use mtime < t+1s instead of mtime <= t to check for unmodified.
if _, ok := r.Header["x-amz-copy-source-if-modified-since"]; ok {
// Return the object only if it has been modified since the
// specified time, otherwise return a 304 error (not modified).
t, err := time.Parse(http.TimeFormat, r.Header.Get("x-amz-copy-source-if-modified-since"))
if err == nil && modtime.Before(t.Add(1*time.Second)) {
h := w.Header()
// Remove Content headers if set
delete(h, "Content-Type")
delete(h, "Content-Length")
delete(h, "Content-Range")
w.WriteHeader(http.StatusNotModified)
return true
}
} else if _, ok := r.Header["x-amz-copy-source-if-unmodified-since"]; ok {
// Return the object only if it has not been modified since the
// specified time, otherwise return a 412 error (precondition failed).
t, err := time.Parse(http.TimeFormat, r.Header.Get("x-amz-copy-source-if-unmodified-since"))
if err == nil && modtime.After(t.Add(1*time.Second)) {
h := w.Header()
// Remove Content headers if set
delete(h, "Content-Type")
delete(h, "Content-Length")
delete(h, "Content-Range")
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
w.Header().Set("Last-Modified", modtime.UTC().Format(http.TimeFormat))
return false
}
// checkCopySourceETag implements x-amz-copy-source-if-match and
// x-amz-copy-source-if-none-match checks.
//
// The ETag must have been previously set in the ResponseWriter's
// headers. The return value is whether this request is now considered
// complete.
func checkCopySourceETag(w http.ResponseWriter, r *http.Request) bool {
// writer always has quoted string
// transform reader's etag to
if r.Method != "PUT" {
return false
}
etag := w.Header().Get("ETag")
// Tag must be provided...
if etag == "" {
return false
}
if inm := r.Header.Get("x-amz-copy-source-if-none-match"); inm != "" {
// Return the object only if its entity tag (ETag) is
// different from the one specified; otherwise, return a 304
// (not modified).
if isETagEqual(inm, etag) || isETagEqual(inm, "*") {
h := w.Header()
// Remove Content headers if set
delete(h, "Content-Type")
delete(h, "Content-Length")
delete(h, "Content-Range")
w.WriteHeader(http.StatusNotModified)
return true
}
} else if inm := r.Header.Get("x-amz-copy-source-if-match"); !isETagEqual(inm, "") {
// Return the object only if its entity tag (ETag) is the same
// as the one specified; otherwise, return a 412 (precondition failed).
if !isETagEqual(inm, etag) {
h := w.Header()
// Remove Content headers if set
delete(h, "Content-Type")
delete(h, "Content-Length")
delete(h, "Content-Range")
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
return false
}
// PutObjectHandler - PUT Object
// ----------
// This implementation of the PUT operation adds an object to a bucket.