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/*
* Minio Go Library for Amazon S3 Compatible Cloud Storage (C) 2015, 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 minio
import (
"net/http"
"strconv"
"strings"
"time"
"github.com/minio/minio-go/pkg/s3utils"
)
// BucketExists verify if bucket exists and you have permission to access it.
func (c Client) BucketExists(bucketName string) (bool, error) {
// Input validation.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
return false, err
}
// Execute HEAD on bucketName.
resp, err := c.executeMethod("HEAD", requestMetadata{
bucketName: bucketName,
contentSHA256Bytes: emptySHA256,
})
defer closeResponse(resp)
if err != nil {
if ToErrorResponse(err).Code == "NoSuchBucket" {
return false, nil
}
return false, err
}
if resp != nil {
if resp.StatusCode != http.StatusOK {
return false, httpRespToErrorResponse(resp, bucketName, "")
}
}
return true, nil
}
// List of header keys to be filtered, usually
// from all S3 API http responses.
var defaultFilterKeys = []string{
"Connection",
"Transfer-Encoding",
"Accept-Ranges",
"Date",
"Server",
"Vary",
"x-amz-bucket-region",
"x-amz-request-id",
"x-amz-id-2",
// Add new headers to be ignored.
}
// Extract only necessary metadata header key/values by
// filtering them out with a list of custom header keys.
func extractObjMetadata(header http.Header) http.Header {
filterKeys := append([]string{
"ETag",
"Content-Length",
"Last-Modified",
"Content-Type",
}, defaultFilterKeys...)
return filterHeader(header, filterKeys)
}
// StatObject verifies if object exists and you have permission to access.
func (c Client) StatObject(bucketName, objectName string) (ObjectInfo, error) {
// Input validation.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
return ObjectInfo{}, err
}
if err := s3utils.CheckValidObjectName(objectName); err != nil {
return ObjectInfo{}, err
}
reqHeaders := NewHeadReqHeaders()
return c.statObject(bucketName, objectName, reqHeaders)
}
// Lower level API for statObject supporting pre-conditions and range headers.
func (c Client) statObject(bucketName, objectName string, reqHeaders RequestHeaders) (ObjectInfo, error) {
// Input validation.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
return ObjectInfo{}, err
}
if err := s3utils.CheckValidObjectName(objectName); err != nil {
return ObjectInfo{}, err
}
customHeader := make(http.Header)
for k, v := range reqHeaders.Header {
customHeader[k] = v
}
// Execute HEAD on objectName.
resp, err := c.executeMethod("HEAD", requestMetadata{
bucketName: bucketName,
objectName: objectName,
contentSHA256Bytes: emptySHA256,
customHeader: customHeader,
})
defer closeResponse(resp)
if err != nil {
return ObjectInfo{}, err
}
if resp != nil {
if resp.StatusCode != http.StatusOK {
return ObjectInfo{}, httpRespToErrorResponse(resp, bucketName, objectName)
}
}
// Trim off the odd double quotes from ETag in the beginning and end.
md5sum := strings.TrimPrefix(resp.Header.Get("ETag"), "\"")
md5sum = strings.TrimSuffix(md5sum, "\"")
// Parse content length is exists
var size int64 = -1
contentLengthStr := resp.Header.Get("Content-Length")
if contentLengthStr != "" {
size, err = strconv.ParseInt(contentLengthStr, 10, 64)
if err != nil {
// Content-Length is not valid
return ObjectInfo{}, ErrorResponse{
Code: "InternalError",
Message: "Content-Length is invalid. " + reportIssue,
BucketName: bucketName,
Key: objectName,
RequestID: resp.Header.Get("x-amz-request-id"),
HostID: resp.Header.Get("x-amz-id-2"),
Region: resp.Header.Get("x-amz-bucket-region"),
}
}
}
// Parse Last-Modified has http time format.
date, err := time.Parse(http.TimeFormat, resp.Header.Get("Last-Modified"))
if err != nil {
return ObjectInfo{}, ErrorResponse{
Code: "InternalError",
Message: "Last-Modified time format is invalid. " + reportIssue,
BucketName: bucketName,
Key: objectName,
RequestID: resp.Header.Get("x-amz-request-id"),
HostID: resp.Header.Get("x-amz-id-2"),
Region: resp.Header.Get("x-amz-bucket-region"),
}
}
// Fetch content type if any present.
contentType := strings.TrimSpace(resp.Header.Get("Content-Type"))
if contentType == "" {
contentType = "application/octet-stream"
}
// Save object metadata info.
return ObjectInfo{
ETag: md5sum,
Key: objectName,
Size: size,
LastModified: date,
ContentType: contentType,
// Extract only the relevant header keys describing the object.
// following function filters out a list of standard set of keys
// which are not part of object metadata.
Metadata: extractObjMetadata(resp.Header),
}, nil
}
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