API/CopyObject: Refactor the code and handle if-modified-since as well. (#2183)

This completes the S3 spec behavior for CopyObject API as reported
by `s3verify`.
This commit is contained in:
Harshavardhana 2016-07-11 19:24:34 -07:00 committed by GitHub
parent bef72f26db
commit e9647b5f12
2 changed files with 98 additions and 122 deletions

View file

@ -22,12 +22,104 @@ import (
"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 {
// Validates the preconditions for CopyObject, returns true if CopyObject operation should not proceed.
// Preconditions supported are:
// x-amz-copy-source-if-modified-since
// x-amz-copy-source-if-unmodified-since
// x-amz-copy-source-if-match
// x-amz-copy-source-if-none-match
func checkCopyObjectPreconditions(w http.ResponseWriter, r *http.Request, objInfo ObjectInfo) bool {
// Return false for methods other than GET and HEAD.
if r.Method != "PUT" {
return false
}
// 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.
if objInfo.ModTime.IsZero() || objInfo.ModTime.Equal(time.Unix(0, 0)) {
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+"\"")
}
}
// x-amz-copy-source-if-modified-since: Return the object only if it has been modified
// since the specified time otherwise return 412 (precondition failed).
ifModifiedSinceHeader := r.Header.Get("x-amz-copy-source-if-modified-since")
if ifModifiedSinceHeader != "" {
if !ifModifiedSince(objInfo.ModTime, ifModifiedSinceHeader) {
// If the object is not modified since the specified time.
writeHeaders()
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
// x-amz-copy-source-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("x-amz-copy-source-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
}
}
// x-amz-copy-source-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("x-amz-copy-source-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("x-amz-copy-source-if-none-match")
if ifNoneMatchETagHeader != "" {
if isETagEqual(objInfo.MD5Sum, ifNoneMatchETagHeader) {
// If the object ETag matches with the specified ETag.
writeHeaders()
writeErrorResponse(w, r, ErrPreconditionFailed, r.URL.Path)
return true
}
}
// Object content should be written to http.ResponseWriter
return false
}
// Validates the preconditions. Returns true if GET/HEAD operation should not proceed.
// Preconditions supported are:
// If-Modified-Since
// If-Unmodified-Since
// If-Match
// If-None-Match
func checkPreconditions(w http.ResponseWriter, r *http.Request, objInfo ObjectInfo) bool {
// Return false for methods other than GET and HEAD.
if r.Method != "GET" && r.Method != "HEAD" {
return false
}
// 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.
if objInfo.ModTime.IsZero() || objInfo.ModTime.Equal(time.Unix(0, 0)) {
return false
}
// Headers to be set of object content is not going to be written to the client.
writeHeaders := func() {
@ -94,12 +186,6 @@ func checkPreconditions(r *http.Request, w http.ResponseWriter, objInfo ObjectIn
// 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
@ -124,100 +210,3 @@ func canonicalizeETag(etag string) string {
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

@ -130,7 +130,7 @@ func (api objectAPIHandlers) GetObjectHandler(w http.ResponseWriter, r *http.Req
}
// Validate pre-conditions if any.
if checkPreconditions(r, w, objInfo) {
if checkPreconditions(w, r, objInfo) {
return
}
@ -217,7 +217,7 @@ func (api objectAPIHandlers) HeadObjectHandler(w http.ResponseWriter, r *http.Re
}
// Validate pre-conditions if any.
if checkPreconditions(r, w, objInfo) {
if checkPreconditions(w, r, objInfo) {
return
}
@ -295,21 +295,8 @@ func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Re
return
}
// Verify before writing.
// Verify x-amz-copy-source-if-modified-since and
// x-amz-copy-source-if-unmodified-since.
lastModified := objInfo.ModTime
if checkCopySourceLastModified(w, r, lastModified) {
return
}
if objInfo.MD5Sum != "" {
w.Header().Set("ETag", "\""+objInfo.MD5Sum+"\"")
}
// Verify x-amz-copy-source-if-match and x-amz-copy-source-if-none-match.
if checkCopySourceETag(w, r) {
// Verify before x-amz-copy-source preconditions before continuing with CopyObject.
if checkCopyObjectPreconditions(w, r, objInfo) {
return
}