✨ Add Hash generator

Taskfile.yml

@@ -26,6 +26,7 @@ tasks:
     desc: Vet go code
     sources:
       - '**/*.go'
+    deps: [gen]
     cmds:
       - go vet ./...
 
@@ -81,7 +82,7 @@ tasks:
 
   test:
     desc: Run unit tests
-    deps: [fmt, vet]
+    deps: [fmt, vet, gen]
     sources:
       - '**/*.go'
     generates:

generators.go

@@ -1,8 +1,12 @@
 package nomino
 
 import (
+	"crypto/md5"
+	"crypto/sha1"
+	"crypto/sha256"
 	"errors"
 	"fmt"
+	"hash"
 	"strconv"
 	"time"
 
@@ -185,3 +189,44 @@ func SlugWithLang(lang string) Generator {
 		return slug.MakeLang(name, lang), err
 	}
 }
+
+// HashingFunc is a function that generates a hash.Hash
+type HashingFunc func() hash.Hash
+
+//go:generate stringer -type=HashType
+
+// HashType represents a particular hashing algorithm
+type HashType uint8
+
+const (
+	MD5 HashType = iota + 1
+	SHA1
+	SHA256
+)
+
+// ErrInvalidHashType is returned by the Hash generator when an invalid HashType is passed
+var ErrInvalidHashType = errors.New("invalid hash type")
+
+var hashMap = map[HashType]HashingFunc{
+	MD5:    md5.New,
+	SHA1:   sha1.New,
+	SHA256: sha256.New,
+}
+
+// Hash generates a name from a hash of the filename.
+// When this is used, the original filename will be removed from the final filename.
+func Hash(t HashType) Generator {
+	f, ok := hashMap[t]
+	return func(c *Config) (string, error) {
+		if !ok {
+			return "", fmt.Errorf("%w: %s", ErrInvalidHashType, t)
+		}
+		name, err := getOriginal(c)
+		if err != nil {
+			return "", err
+		}
+		hs := f()
+		hs.Write([]byte(name))
+		return fmt.Sprintf("%x", hs.Sum(nil)), nil
+	}
+}

generators_examples_test.go

@@ -161,3 +161,33 @@ func ExampleSlugWithLang() {
 
 	// Output: diese-und-dass.txt
 }
+
+func ExampleHash_mD5() {
+	conf := NewConfig(
+		WithOriginal("foobar"),
+		WithGenerator(Hash(MD5)),
+	)
+	str, _ := Make(conf)
+	fmt.Println(str)
+	// Output: 3858f62230ac3c915f300c664312c63f.txt
+}
+
+func ExampleHash_sHA1() {
+	conf := NewConfig(
+		WithOriginal("foobar"),
+		WithGenerator(Hash(SHA1)),
+	)
+	str, _ := Make(conf)
+	fmt.Println(str)
+	// Output: 8843d7f92416211de9ebb963ff4ce28125932878.txt
+}
+
+func ExampleHash_sHA256() {
+	conf := NewConfig(
+		WithOriginal("foobar"),
+		WithGenerator(Hash(SHA256)),
+	)
+	str, _ := Make(conf)
+	fmt.Println(str)
+	// Output: c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2.txt
+}

generators_test.go

@@ -2,6 +2,7 @@ package nomino
 
 import (
 	"errors"
+	"fmt"
 	"testing"
 	"time"
 
@@ -120,3 +121,23 @@ func TestSlugRemovesOriginal(t *testing.T) {
 	assert.Equal(t, "hello-world", st)
 	assert.NoError(t, err)
 }
+
+func TestHashBadHash(t *testing.T) {
+	conf := NewConfig(WithOriginal("foobar"), WithGenerator(Hash(0)))
+	st, err := conf.generator(&conf)
+	assert.Equal(t, "", st)
+	assert.ErrorIs(t, err, ErrInvalidHashType)
+	assert.ErrorContains(t, err, "invalid hash type: HashType(0)")
+}
+
+func TestHashMissingOriginal(t *testing.T) {
+	conf := NewConfig(WithGenerator(Hash(MD5)))
+	st, err := conf.generator(&conf)
+	assert.Equal(t, "", st)
+	assert.ErrorIs(t, err, ErrMissingOriginal)
+}
+
+func TestHashTypeStringer(t *testing.T) {
+	s := fmt.Sprintf("%s", MD5)
+	assert.Equal(t, "MD5", s)
+}

hashtype_string.go

@@ -0,0 +1,26 @@
+// Code generated by "stringer -type=HashType"; DO NOT EDIT.
+
+package nomino
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[MD5-1]
+	_ = x[SHA1-2]
+	_ = x[SHA256-3]
+}
+
+const _HashType_name = "MD5SHA1SHA256"
+
+var _HashType_index = [...]uint8{0, 3, 7, 13}
+
+func (i HashType) String() string {
+	i -= 1
+	if i >= HashType(len(_HashType_index)-1) {
+		return "HashType(" + strconv.FormatInt(int64(i+1), 10) + ")"
+	}
+	return _HashType_name[_HashType_index[i]:_HashType_index[i+1]]
+}