github.com/linchen2chris/hugo@v0.0.0-20230307053224-cec209389705/tpl/crypto/crypto.go (about)

     1  // Copyright 2017 The Hugo Authors. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  // http://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  // Package crypto provides template functions for cryptographic operations.
    15  package crypto
    16  
    17  import (
    18  	"crypto/hmac"
    19  	"crypto/md5"
    20  	"crypto/sha1"
    21  	"crypto/sha256"
    22  	"crypto/sha512"
    23  	"encoding/hex"
    24  	"fmt"
    25  	"hash"
    26  	"hash/fnv"
    27  
    28  	"github.com/spf13/cast"
    29  )
    30  
    31  // New returns a new instance of the crypto-namespaced template functions.
    32  func New() *Namespace {
    33  	return &Namespace{}
    34  }
    35  
    36  // Namespace provides template functions for the "crypto" namespace.
    37  type Namespace struct{}
    38  
    39  // MD5 hashes the v and returns its MD5 checksum.
    40  func (ns *Namespace) MD5(v any) (string, error) {
    41  	conv, err := cast.ToStringE(v)
    42  	if err != nil {
    43  		return "", err
    44  	}
    45  
    46  	hash := md5.Sum([]byte(conv))
    47  	return hex.EncodeToString(hash[:]), nil
    48  }
    49  
    50  // SHA1 hashes v and returns its SHA1 checksum.
    51  func (ns *Namespace) SHA1(v any) (string, error) {
    52  	conv, err := cast.ToStringE(v)
    53  	if err != nil {
    54  		return "", err
    55  	}
    56  
    57  	hash := sha1.Sum([]byte(conv))
    58  	return hex.EncodeToString(hash[:]), nil
    59  }
    60  
    61  // SHA256 hashes v and returns its SHA256 checksum.
    62  func (ns *Namespace) SHA256(v any) (string, error) {
    63  	conv, err := cast.ToStringE(v)
    64  	if err != nil {
    65  		return "", err
    66  	}
    67  
    68  	hash := sha256.Sum256([]byte(conv))
    69  	return hex.EncodeToString(hash[:]), nil
    70  }
    71  
    72  // FNV32a hashes v using fnv32a algorithm.
    73  func (ns *Namespace) FNV32a(v any) (int, error) {
    74  	conv, err := cast.ToStringE(v)
    75  	if err != nil {
    76  		return 0, err
    77  	}
    78  	algorithm := fnv.New32a()
    79  	algorithm.Write([]byte(conv))
    80  	return int(algorithm.Sum32()), nil
    81  }
    82  
    83  // HMAC returns a cryptographic hash that uses a key to sign a message.
    84  func (ns *Namespace) HMAC(h any, k any, m any, e ...any) (string, error) {
    85  	ha, err := cast.ToStringE(h)
    86  	if err != nil {
    87  		return "", err
    88  	}
    89  
    90  	var hash func() hash.Hash
    91  	switch ha {
    92  	case "md5":
    93  		hash = md5.New
    94  	case "sha1":
    95  		hash = sha1.New
    96  	case "sha256":
    97  		hash = sha256.New
    98  	case "sha512":
    99  		hash = sha512.New
   100  	default:
   101  		return "", fmt.Errorf("hmac: %s is not a supported hash function", ha)
   102  	}
   103  
   104  	msg, err := cast.ToStringE(m)
   105  	if err != nil {
   106  		return "", err
   107  	}
   108  
   109  	key, err := cast.ToStringE(k)
   110  	if err != nil {
   111  		return "", err
   112  	}
   113  
   114  	mac := hmac.New(hash, []byte(key))
   115  	_, err = mac.Write([]byte(msg))
   116  	if err != nil {
   117  		return "", err
   118  	}
   119  
   120  	var encoding = "hex"
   121  	if len(e) > 0 && e[0] != nil {
   122  		encoding, err = cast.ToStringE(e[0])
   123  		if err != nil {
   124  			return "", err
   125  		}
   126  	}
   127  
   128  	switch encoding {
   129  	case "binary":
   130  		return string(mac.Sum(nil)[:]), nil
   131  	case "hex":
   132  		return hex.EncodeToString(mac.Sum(nil)[:]), nil
   133  	default:
   134  		return "", fmt.Errorf("%q is not a supported encoding method", encoding)
   135  	}
   136  
   137  }