mirror of
https://github.com/gohugoio/hugo.git
synced 2024-11-14 20:37:55 -05:00
105 lines
2.8 KiB
Go
105 lines
2.8 KiB
Go
// Copyright 2018 The Hugo Authors. All rights reserved.
|
|
//
|
|
// 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 integrity
|
|
|
|
import (
|
|
"crypto/md5"
|
|
"crypto/sha256"
|
|
"crypto/sha512"
|
|
"encoding/base64"
|
|
"encoding/hex"
|
|
"fmt"
|
|
"hash"
|
|
"io"
|
|
|
|
"github.com/gohugoio/hugo/resource"
|
|
)
|
|
|
|
const defaultHashAlgo = "sha256"
|
|
|
|
// Client contains methods to fingerprint (cachebusting) and other integrity-related
|
|
// methods.
|
|
type Client struct {
|
|
rs *resource.Spec
|
|
}
|
|
|
|
// New creates a new Client with the given specification.
|
|
func New(rs *resource.Spec) *Client {
|
|
return &Client{rs: rs}
|
|
}
|
|
|
|
type fingerprintTransformation struct {
|
|
algo string
|
|
}
|
|
|
|
func (t *fingerprintTransformation) Key() resource.ResourceTransformationKey {
|
|
return resource.NewResourceTransformationKey("fingerprint", t.algo)
|
|
}
|
|
|
|
// Transform creates a MD5 hash of the Resource content and inserts that hash before
|
|
// the extension in the filename.
|
|
func (t *fingerprintTransformation) Transform(ctx *resource.ResourceTransformationCtx) error {
|
|
algo := t.algo
|
|
|
|
var h hash.Hash
|
|
|
|
switch algo {
|
|
case "md5":
|
|
h = md5.New()
|
|
case "sha256":
|
|
h = sha256.New()
|
|
case "sha512":
|
|
h = sha512.New()
|
|
default:
|
|
return fmt.Errorf("unsupported crypto algo: %q, use either md5, sha256 or sha512", algo)
|
|
}
|
|
|
|
io.Copy(io.MultiWriter(h, ctx.To), ctx.From)
|
|
d, err := digest(h)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
ctx.Data["Integrity"] = integrity(algo, d)
|
|
ctx.AddOutPathIdentifier("." + hex.EncodeToString(d[:]))
|
|
return nil
|
|
}
|
|
|
|
// Fingerprint applies fingerprinting of the given resource and hash algorithm.
|
|
// It defaults to sha256 if none given, and the options are md5, sha256 or sha512.
|
|
// The same algo is used for both the fingerprinting part (aka cache busting) and
|
|
// the base64-encoded Subresource Integrity hash, so you will have to stay away from
|
|
// md5 if you plan to use both.
|
|
// See https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity
|
|
func (c *Client) Fingerprint(res resource.Resource, algo string) (resource.Resource, error) {
|
|
if algo == "" {
|
|
algo = defaultHashAlgo
|
|
}
|
|
|
|
return c.rs.Transform(
|
|
res,
|
|
&fingerprintTransformation{algo: algo},
|
|
)
|
|
}
|
|
|
|
func integrity(algo string, sum []byte) string {
|
|
encoded := base64.StdEncoding.EncodeToString(sum)
|
|
return fmt.Sprintf("%s-%s", algo, encoded)
|
|
|
|
}
|
|
|
|
func digest(h hash.Hash) ([]byte, error) {
|
|
sum := h.Sum(nil)
|
|
return sum, nil
|
|
}
|