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/*
* MinIO Go Library for Amazon S3 Compatible Cloud Storage
* Copyright 2015-2017 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 (
"context"
"io"
"os"
"path/filepath"
"github.com/minio/minio-go/v7/pkg/s3utils"
)
// FGetObject - download contents of an object to a local file.
// The options can be used to specify the GET request further.
func (c Client) FGetObject(ctx context.Context, bucketName, objectName, filePath string, opts GetObjectOptions) error {
// Input validation.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
return err
}
if err := s3utils.CheckValidObjectName(objectName); err != nil {
return err
}
// Verify if destination already exists.
st, err := os.Stat(filePath)
if err == nil {
// If the destination exists and is a directory.
if st.IsDir() {
return errInvalidArgument("fileName is a directory.")
}
}
// Proceed if file does not exist. return for all other errors.
if err != nil {
if !os.IsNotExist(err) {
return err
}
}
// Extract top level directory.
objectDir, _ := filepath.Split(filePath)
if objectDir != "" {
// Create any missing top level directories.
if err := os.MkdirAll(objectDir, 0700); err != nil {
return err
}
}
// Gather md5sum.
objectStat, err := c.StatObject(ctx, bucketName, objectName, StatObjectOptions(opts))
if err != nil {
return err
}
// Write to a temporary file "fileName.part.minio" before saving.
filePartPath := filePath + objectStat.ETag + ".part.minio"
// If exists, open in append mode. If not create it as a part file.
filePart, err := os.OpenFile(filePartPath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
if err != nil {
return err
}
// If we return early with an error, be sure to close and delete
// filePart. If we have an error along the way there is a chance
// that filePart is somehow damaged, and we should discard it.
closeAndRemove := true
defer func() {
if closeAndRemove {
_ = filePart.Close()
_ = os.Remove(filePartPath)
}
}()
// Issue Stat to get the current offset.
st, err = filePart.Stat()
if err != nil {
return err
}
// Initialize get object request headers to set the
// appropriate range offsets to read from.
if st.Size() > 0 {
opts.SetRange(st.Size(), 0)
}
// Seek to current position for incoming reader.
objectReader, objectStat, _, err := c.getObject(ctx, bucketName, objectName, opts)
if err != nil {
return err
}
// Write to the part file.
if _, err = io.CopyN(filePart, objectReader, objectStat.Size); err != nil {
return err
}
// Close the file before rename, this is specifically needed for Windows users.
closeAndRemove = false
if err = filePart.Close(); err != nil {
return err
}
// Safely completed. Now commit by renaming to actual filename.
if err = os.Rename(filePartPath, filePath); err != nil {
return err
}
// Return.
return nil
}
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