Add md5 and sha1 template funcs

docs/content/templates/functions.md

@@ -595,6 +595,33 @@ CJK-like languages.
 ```
 
 
+### md5
+
+`md5` hashes the given input and returns its MD5 checksum.
+
+```html
+{{ md5 "Hello world, gophers!" }}
+<!-- returns the string "b3029f756f98f79e7f1b7f1d1f0dd53b" -->
+```
+
+This can be useful if you want to use Gravatar for generating a unique avatar:
+
+```html
+<img src="https://www.gravatar.com/avatar/{{ md5 "your@email.com" }}?s=100&d=identicon">
+```
+
+
+### sha1
+
+`sha1` hashes the given input and returns its SHA1 checksum.
+
+```html
+{{ sha1 "Hello world, gophers!" }}
+<!-- returns the string "c8b5b0e33d408246e30f53e32b8f7627a7a649d4" -->
+```
+
+
+
 ## URLs
 
 ### absURL, relURL

tpl/template_funcs.go

@@ -15,7 +15,10 @@ package tpl
 
 import (
 	"bytes"
+	_md5 "crypto/md5"
+	_sha1 "crypto/sha1"
 	"encoding/base64"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -1501,6 +1504,28 @@ func singularize(in interface{}) (string, error) {
 	return inflect.Singularize(word), nil
 }
 
+// md5 hashes the given input and returns its MD5 checksum
+func md5(in interface{}) (string, error) {
+	conv, err := cast.ToStringE(in)
+	if err != nil {
+		return "", err
+	}
+
+	hash := _md5.Sum([]byte(conv))
+	return hex.EncodeToString(hash[:]), nil
+}
+
+// sha1 hashes the given input and returns its SHA1 checksum
+func sha1(in interface{}) (string, error) {
+	conv, err := cast.ToStringE(in)
+	if err != nil {
+		return "", err
+	}
+
+	hash := _sha1.Sum([]byte(conv))
+	return hex.EncodeToString(hash[:]), nil
+}
+
 func init() {
 	funcMap = template.FuncMap{
 		"absURL":       func(a string) template.HTML { return template.HTML(helpers.AbsURL(a)) },
@@ -1538,6 +1563,7 @@ func init() {
 		"lower":        func(a string) string { return strings.ToLower(a) },
 		"lt":           lt,
 		"markdownify":  markdownify,
+		"md5":          md5,
 		"mod":          mod,
 		"modBool":      modBool,
 		"mul":          func(a, b interface{}) (interface{}, error) { return doArithmetic(a, b, '*') },
@@ -1556,6 +1582,7 @@ func init() {
 		"sanitizeURL":  helpers.SanitizeURL,
 		"sanitizeurl":  helpers.SanitizeURL,
 		"seq":          helpers.Seq,
+		"sha1":         sha1,
 		"shuffle":      shuffle,
 		"singularize":  singularize,
 		"slice":        slice,

tpl/template_funcs_test.go

@@ -99,6 +99,8 @@ seq: {{ seq 3 }}
 sort: {{ slice "B" "C" "A" | sort }}
 delimit: {{ delimit (slice "A" "B" "C") ", " " and " }}
 jsonify: {{ (slice "A" "B" "C") | jsonify }}
+md5: {{ md5 "Hello world, gophers!" }}
+sha1: {{ sha1 "Hello world, gophers!" }}
 `
 	expected := `chomp: <p>Blockhead</p>
 dateFormat: Wednesday, Jan 21, 2015
@@ -134,6 +136,8 @@ seq: [1 2 3]
 sort: [A B C]
 delimit: A, B and C
 jsonify: ["A","B","C"]
+md5: b3029f756f98f79e7f1b7f1d1f0dd53b
+sha1: c8b5b0e33d408246e30f53e32b8f7627a7a649d4
 `
 
 	var b bytes.Buffer
@@ -155,7 +159,7 @@ jsonify: ["A","B","C"]
 	err = templ.Execute(&b, &data)
 
 	if err != nil {
-		t.Fatal("Gott error on execute", err)
+		t.Fatal("Got error on execute", err)
 	}
 
 	if b.String() != expected {
@@ -2056,3 +2060,51 @@ func TestBase64Encode(t *testing.T) {
 		t.Error("Expected error from base64Encode")
 	}
 }
+
+func TestMD5(t *testing.T) {
+	for i, this := range []struct {
+		input        string
+		expectedHash string
+	}{
+		{"Hello world, gophers!", "b3029f756f98f79e7f1b7f1d1f0dd53b"},
+		{"Lorem ipsum dolor", "06ce65ac476fc656bea3fca5d02cfd81"},
+	} {
+		result, err := md5(this.input)
+		if err != nil {
+			t.Errorf("md5 returned error: %s", err)
+		}
+
+		if result != this.expectedHash {
+			t.Errorf("[%d] md5: expected '%s', got '%s'", i, this.expectedHash, result)
+		}
+
+		_, err = md5(t)
+		if err == nil {
+			t.Error("Expected error from md5")
+		}
+	}
+}
+
+func TestSHA1(t *testing.T) {
+	for i, this := range []struct {
+		input        string
+		expectedHash string
+	}{
+		{"Hello world, gophers!", "c8b5b0e33d408246e30f53e32b8f7627a7a649d4"},
+		{"Lorem ipsum dolor", "45f75b844be4d17b3394c6701768daf39419c99b"},
+	} {
+		result, err := sha1(this.input)
+		if err != nil {
+			t.Errorf("sha1 returned error: %s", err)
+		}
+
+		if result != this.expectedHash {
+			t.Errorf("[%d] sha1: expected '%s', got '%s'", i, this.expectedHash, result)
+		}
+
+		_, err = sha1(t)
+		if err == nil {
+			t.Error("Expected error from sha1")
+		}
+	}
+}