restic/Godeps/_workspace/src/github.com/minio/minio-go/utils.go

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/*
* Minio Go Library for Amazon S3 Compatible Cloud Storage (C) 2015 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 (
"encoding/hex"
"io"
"io/ioutil"
"net"
"net/http"
"net/url"
"regexp"
"strings"
"time"
"unicode/utf8"
)
// isPartUploaded - true if part is already uploaded.
func isPartUploaded(objPart objectPart, objectParts map[int]objectPart) (isUploaded bool) {
_, isUploaded = objectParts[objPart.PartNumber]
if isUploaded {
isUploaded = (objPart.ETag == objectParts[objPart.PartNumber].ETag)
}
return
}
// getEndpointURL - construct a new endpoint.
func getEndpointURL(endpoint string, inSecure bool) (*url.URL, error) {
if strings.Contains(endpoint, ":") {
host, _, err := net.SplitHostPort(endpoint)
if err != nil {
return nil, err
}
if !isValidIP(host) && !isValidDomain(host) {
msg := "Endpoint: " + endpoint + " does not follow ip address or domain name standards."
return nil, ErrInvalidArgument(msg)
}
} else {
if !isValidIP(endpoint) && !isValidDomain(endpoint) {
msg := "Endpoint: " + endpoint + " does not follow ip address or domain name standards."
return nil, ErrInvalidArgument(msg)
}
}
// if inSecure is true, use 'http' scheme.
scheme := "https"
if inSecure {
scheme = "http"
}
// Construct a secured endpoint URL.
endpointURLStr := scheme + "://" + endpoint
endpointURL, err := url.Parse(endpointURLStr)
if err != nil {
return nil, err
}
// Validate incoming endpoint URL.
if err := isValidEndpointURL(endpointURL); err != nil {
return nil, err
}
return endpointURL, nil
}
// isValidDomain validates if input string is a valid domain name.
func isValidDomain(host string) bool {
// See RFC 1035, RFC 3696.
host = strings.TrimSpace(host)
if len(host) == 0 || len(host) > 255 {
return false
}
// host cannot start or end with "-"
if host[len(host)-1:] == "-" || host[:1] == "-" {
return false
}
// host cannot start or end with "_"
if host[len(host)-1:] == "_" || host[:1] == "_" {
return false
}
// host cannot start or end with a "."
if host[len(host)-1:] == "." || host[:1] == "." {
return false
}
// All non alphanumeric characters are invalid.
if strings.ContainsAny(host, "`~!@#$%^&*()+={}[]|\\\"';:><?/") {
return false
}
// No need to regexp match, since the list is non-exhaustive.
// We let it valid and fail later.
return true
}
// isValidIP parses input string for ip address validity.
func isValidIP(ip string) bool {
return net.ParseIP(ip) != nil
}
// closeResponse close non nil response with any response Body.
// convenient wrapper to drain any remaining data on response body.
//
// Subsequently this allows golang http RoundTripper
// to re-use the same connection for future requests.
func closeResponse(resp *http.Response) {
// Callers should close resp.Body when done reading from it.
// If resp.Body is not closed, the Client's underlying RoundTripper
// (typically Transport) may not be able to re-use a persistent TCP
// connection to the server for a subsequent "keep-alive" request.
if resp != nil && resp.Body != nil {
// Drain any remaining Body and then close the connection.
// Without this closing connection would disallow re-using
// the same connection for future uses.
// - http://stackoverflow.com/a/17961593/4465767
io.Copy(ioutil.Discard, resp.Body)
resp.Body.Close()
}
}
// isVirtualHostSupported - verify if host supports virtual hosted style.
// Currently only Amazon S3 and Google Cloud Storage would support this.
func isVirtualHostSupported(endpointURL *url.URL) bool {
return isAmazonEndpoint(endpointURL) || isGoogleEndpoint(endpointURL)
}
// Match if it is exactly Amazon S3 endpoint.
func isAmazonEndpoint(endpointURL *url.URL) bool {
if endpointURL == nil {
return false
}
if endpointURL.Host == "s3.amazonaws.com" {
return true
}
return false
}
// Match if it is exactly Google cloud storage endpoint.
func isGoogleEndpoint(endpointURL *url.URL) bool {
if endpointURL == nil {
return false
}
if endpointURL.Host == "storage.googleapis.com" {
return true
}
return false
}
// Verify if input endpoint URL is valid.
func isValidEndpointURL(endpointURL *url.URL) error {
if endpointURL == nil {
return ErrInvalidArgument("Endpoint url cannot be empty.")
}
if endpointURL.Path != "/" && endpointURL.Path != "" {
return ErrInvalidArgument("Endpoing url cannot have fully qualified paths.")
}
if strings.Contains(endpointURL.Host, ".amazonaws.com") {
if !isAmazonEndpoint(endpointURL) {
return ErrInvalidArgument("Amazon S3 endpoint should be 's3.amazonaws.com'.")
}
}
if strings.Contains(endpointURL.Host, ".googleapis.com") {
if !isGoogleEndpoint(endpointURL) {
return ErrInvalidArgument("Google Cloud Storage endpoint should be 'storage.googleapis.com'.")
}
}
return nil
}
// Verify if input expires value is valid.
func isValidExpiry(expires time.Duration) error {
expireSeconds := int64(expires / time.Second)
if expireSeconds < 1 {
return ErrInvalidArgument("Expires cannot be lesser than 1 second.")
}
if expireSeconds > 604800 {
return ErrInvalidArgument("Expires cannot be greater than 7 days.")
}
return nil
}
/// Excerpts from - http://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html
/// When using virtual hostedstyle buckets with SSL, the SSL wild card
/// certificate only matches buckets that do not contain periods.
/// To work around this, use HTTP or write your own certificate verification logic.
// We decided to not support bucketNames with '.' in them.
var validBucketName = regexp.MustCompile(`^[a-z0-9][a-z0-9\-]{1,61}[a-z0-9]$`)
// isValidBucketName - verify bucket name in accordance with
// - http://docs.aws.amazon.com/AmazonS3/latest/dev/UsingBucket.html
func isValidBucketName(bucketName string) error {
if strings.TrimSpace(bucketName) == "" {
return ErrInvalidBucketName("Bucket name cannot be empty.")
}
if len(bucketName) < 3 {
return ErrInvalidBucketName("Bucket name cannot be smaller than 3 characters.")
}
if len(bucketName) > 63 {
return ErrInvalidBucketName("Bucket name cannot be greater than 63 characters.")
}
if bucketName[0] == '.' || bucketName[len(bucketName)-1] == '.' {
return ErrInvalidBucketName("Bucket name cannot start or end with a '.' dot.")
}
if !validBucketName.MatchString(bucketName) {
return ErrInvalidBucketName("Bucket name contains invalid characters.")
}
return nil
}
// isValidObjectName - verify object name in accordance with
// - http://docs.aws.amazon.com/AmazonS3/latest/dev/UsingMetadata.html
func isValidObjectName(objectName string) error {
if strings.TrimSpace(objectName) == "" {
return ErrInvalidObjectName("Object name cannot be empty.")
}
if len(objectName) > 1024 {
return ErrInvalidObjectName("Object name cannot be greater than 1024 characters.")
}
if !utf8.ValidString(objectName) {
return ErrInvalidBucketName("Object name with non UTF-8 strings are not supported.")
}
return nil
}
// isValidObjectPrefix - verify if object prefix is valid.
func isValidObjectPrefix(objectPrefix string) error {
if len(objectPrefix) > 1024 {
return ErrInvalidObjectPrefix("Object prefix cannot be greater than 1024 characters.")
}
if !utf8.ValidString(objectPrefix) {
return ErrInvalidObjectPrefix("Object prefix with non UTF-8 strings are not supported.")
}
return nil
}
// optimalPartSize - calculate the optimal part size for the given objectSize.
//
// NOTE: Assumption here is that for any object to be uploaded to any S3 compatible
// object storage it will have the following parameters as constants.
//
// maxParts - 10000
// minimumPartSize - 5MiB
// maximumPartSize - 5GiB
//
// if the partSize after division with maxParts is greater than minimumPartSize
// then choose miniumPartSize as the new part size, if not return minimumPartSize.
//
// Special cases
//
// - if input object size is -1 then return maxPartSize.
// - if it happens to be that partSize is indeed bigger
// than the maximum part size just return maxPartSize.
//
func optimalPartSize(objectSize int64) int64 {
// if object size is -1 choose part size as 5GiB.
if objectSize == -1 {
return maxPartSize
}
// make sure last part has enough buffer and handle this poperly.
partSize := (objectSize / (maxParts - 1))
if partSize > minimumPartSize {
if partSize > maxPartSize {
return maxPartSize
}
return partSize
}
return minimumPartSize
}
// urlEncodePath encode the strings from UTF-8 byte representations to HTML hex escape sequences
//
// This is necessary since regular url.Parse() and url.Encode() functions do not support UTF-8
// non english characters cannot be parsed due to the nature in which url.Encode() is written
//
// This function on the other hand is a direct replacement for url.Encode() technique to support
// pretty much every UTF-8 character.
func urlEncodePath(pathName string) string {
// if object matches reserved string, no need to encode them
reservedNames := regexp.MustCompile("^[a-zA-Z0-9-_.~/]+$")
if reservedNames.MatchString(pathName) {
return pathName
}
var encodedPathname string
for _, s := range pathName {
if 'A' <= s && s <= 'Z' || 'a' <= s && s <= 'z' || '0' <= s && s <= '9' { // §2.3 Unreserved characters (mark)
encodedPathname = encodedPathname + string(s)
continue
}
switch s {
case '-', '_', '.', '~', '/': // §2.3 Unreserved characters (mark)
encodedPathname = encodedPathname + string(s)
continue
default:
len := utf8.RuneLen(s)
if len < 0 {
// if utf8 cannot convert return the same string as is
return pathName
}
u := make([]byte, len)
utf8.EncodeRune(u, s)
for _, r := range u {
hex := hex.EncodeToString([]byte{r})
encodedPathname = encodedPathname + "%" + strings.ToUpper(hex)
}
}
}
return encodedPathname
}