Use templates for issue e-mail subject and body (#8329)

* Add template capability for issue mail subject

* Remove test string

* Fix trim subject length

* Add comment to template and run make fmt

* Add information for the template

* Rename defaultMailSubject() to fallbackMailSubject()

* General rewrite of the mail template code

* Fix .Doer name

* Use text/template for subject instead of html

* Fix subject Re: prefix

* Fix mail tests

* Fix static templates

* [skip ci] Updated translations via Crowdin

* Expose db.SetMaxOpenConns and allow non MySQL dbs to set conn pool params (#8528)

* Expose db.SetMaxOpenConns and allow other dbs to set their connection params
* Add note about port exhaustion

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Prevent .code-view from overriding font on icon fonts (#8614)

* Correct some outdated statements in the contributing guidelines (#8612)

* More information for drone-cli in CONTRIBUTING.md

* Increases the version of drone-cli to 1.2.0
* Adds a note for the Docker Toolbox on Windows

Signed-off-by: LukBukkit <luk.bukkit@gmail.com>

* Fix the url for the blog repository (now on gitea.com)

Signed-off-by: LukBukkit <luk.bukkit@gmail.com>

* Remove TrN due to lack of lang context

* Redo templates to match previous code

* Fix extra character in template

* Unify PR & Issue tempaltes, fix format

* Remove default subject

* Add template tests

* Fix template

* Remove replaced function

* Provide User as models.User for better consistency

* Add docs

* Fix doc inaccuracies, improve examples

* Change mail footer to math AppName

* Add test for mail subject/body template separation

* Add support for code review comments

* Update docs/content/doc/advanced/mail-templates-us.md

Co-Authored-By: 6543 <24977596+6543@users.noreply.github.com>

4 files changed, 211 insertions, 30 deletions

diff --git a/modules/templates/dynamic.go b/modules/templates/dynamic.go
index 6217f1c3b0..6153e8d027 100644
--- a/modules/templates/dynamic.go
+++ b/modules/templates/dynamic.go
@@ -11,6 +11,7 @@ import (
 	"io/ioutil"
 	"path"
 	"strings"
+	texttmpl "text/template"
 
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -20,7 +21,8 @@ import (
 )
 
 var (
-	templates = template.New("")
+	subjectTemplates = texttmpl.New("")
+	bodyTemplates    = template.New("")
 )
 
 // HTMLRenderer implements the macaron handler for serving HTML templates.
@@ -59,9 +61,12 @@ func JSRenderer() macaron.Handler {
 }
 
 // Mailer provides the templates required for sending notification mails.
-func Mailer() *template.Template {
+func Mailer() (*texttmpl.Template, *template.Template) {
+	for _, funcs := range NewTextFuncMap() {
+		subjectTemplates.Funcs(funcs)
+	}
 	for _, funcs := range NewFuncMap() {
-		templates.Funcs(funcs)
+		bodyTemplates.Funcs(funcs)
 	}
 
 	staticDir := path.Join(setting.StaticRootPath, "templates", "mail")
@@ -84,15 +89,7 @@ func Mailer() *template.Template {
 					continue
 				}
 
-				_, err = templates.New(
-					strings.TrimSuffix(
-						filePath,
-						".tmpl",
-					),
-				).Parse(string(content))
-				if err != nil {
-					log.Warn("Failed to parse template %v", err)
-				}
+				buildSubjectBodyTemplate(subjectTemplates, bodyTemplates, strings.TrimSuffix(filePath, ".tmpl"), content)
 			}
 		}
 	}
@@ -117,18 +114,10 @@ func Mailer() *template.Template {
 					continue
 				}
 
-				_, err = templates.New(
-					strings.TrimSuffix(
-						filePath,
-						".tmpl",
-					),
-				).Parse(string(content))
-				if err != nil {
-					log.Warn("Failed to parse template %v", err)
-				}
+				buildSubjectBodyTemplate(subjectTemplates, bodyTemplates, strings.TrimSuffix(filePath, ".tmpl"), content)
 			}
 		}
 	}
 
-	return templates
+	return subjectTemplates, bodyTemplates
 }
diff --git a/modules/templates/helper.go b/modules/templates/helper.go
index 2d7a1aee9b..1347835b80 100644
--- a/modules/templates/helper.go
+++ b/modules/templates/helper.go
@@ -16,8 +16,10 @@ import (
 	"mime"
 	"net/url"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"strings"
+	texttmpl "text/template"
 	"time"
 	"unicode"
 
@@ -34,6 +36,9 @@ import (
 	"github.com/editorconfig/editorconfig-core-go/v2"
 )
 
+// Used from static.go && dynamic.go
+var mailSubjectSplit = regexp.MustCompile(`(?m)^-{3,}[\s]*$`)
+
 // NewFuncMap returns functions for injecting to templates
 func NewFuncMap() []template.FuncMap {
 	return []template.FuncMap{map[string]interface{}{
@@ -261,6 +266,112 @@ func NewFuncMap() []template.FuncMap {
 	}}
 }
 
+// NewTextFuncMap returns functions for injecting to text templates
+// It's a subset of those used for HTML and other templates
+func NewTextFuncMap() []texttmpl.FuncMap {
+	return []texttmpl.FuncMap{map[string]interface{}{
+		"GoVer": func() string {
+			return strings.Title(runtime.Version())
+		},
+		"AppName": func() string {
+			return setting.AppName
+		},
+		"AppSubUrl": func() string {
+			return setting.AppSubURL
+		},
+		"AppUrl": func() string {
+			return setting.AppURL
+		},
+		"AppVer": func() string {
+			return setting.AppVer
+		},
+		"AppBuiltWith": func() string {
+			return setting.AppBuiltWith
+		},
+		"AppDomain": func() string {
+			return setting.Domain
+		},
+		"TimeSince":     timeutil.TimeSince,
+		"TimeSinceUnix": timeutil.TimeSinceUnix,
+		"RawTimeSince":  timeutil.RawTimeSince,
+		"DateFmtLong": func(t time.Time) string {
+			return t.Format(time.RFC1123Z)
+		},
+		"DateFmtShort": func(t time.Time) string {
+			return t.Format("Jan 02, 2006")
+		},
+		"List": List,
+		"SubStr": func(str string, start, length int) string {
+			if len(str) == 0 {
+				return ""
+			}
+			end := start + length
+			if length == -1 {
+				end = len(str)
+			}
+			if len(str) < end {
+				return str
+			}
+			return str[start:end]
+		},
+		"EllipsisString": base.EllipsisString,
+		"URLJoin":        util.URLJoin,
+		"Dict": func(values ...interface{}) (map[string]interface{}, error) {
+			if len(values)%2 != 0 {
+				return nil, errors.New("invalid dict call")
+			}
+			dict := make(map[string]interface{}, len(values)/2)
+			for i := 0; i < len(values); i += 2 {
+				key, ok := values[i].(string)
+				if !ok {
+					return nil, errors.New("dict keys must be strings")
+				}
+				dict[key] = values[i+1]
+			}
+			return dict, nil
+		},
+		"Printf":   fmt.Sprintf,
+		"Escape":   Escape,
+		"Sec2Time": models.SecToTime,
+		"ParseDeadline": func(deadline string) []string {
+			return strings.Split(deadline, "|")
+		},
+		"dict": func(values ...interface{}) (map[string]interface{}, error) {
+			if len(values) == 0 {
+				return nil, errors.New("invalid dict call")
+			}
+
+			dict := make(map[string]interface{})
+
+			for i := 0; i < len(values); i++ {
+				switch key := values[i].(type) {
+				case string:
+					i++
+					if i == len(values) {
+						return nil, errors.New("specify the key for non array values")
+					}
+					dict[key] = values[i]
+				case map[string]interface{}:
+					m := values[i].(map[string]interface{})
+					for i, v := range m {
+						dict[i] = v
+					}
+				default:
+					return nil, errors.New("dict values must be maps")
+				}
+			}
+			return dict, nil
+		},
+		"percentage": func(n int, values ...int) float32 {
+			var sum = 0
+			for i := 0; i < len(values); i++ {
+				sum += values[i]
+			}
+			return float32(n) * 100 / float32(sum)
+		},
+	}}
+}
+
 // Safe render raw as HTML
 func Safe(raw string) template.HTML {
 	return template.HTML(raw)
@@ -551,3 +662,22 @@ func MigrationIcon(hostname string) string {
 		return "fa-git-alt"
 	}
 }
+
+func buildSubjectBodyTemplate(stpl *texttmpl.Template, btpl *template.Template, name string, content []byte) {
+	// Split template into subject and body
+	var subjectContent []byte
+	bodyContent := content
+	loc := mailSubjectSplit.FindIndex(content)
+	if loc != nil {
+		subjectContent = content[0:loc[0]]
+		bodyContent = content[loc[1]:]
+	}
+	if _, err := stpl.New(name).
+		Parse(string(subjectContent)); err != nil {
+		log.Warn("Failed to parse template [%s/subject]: %v", name, err)
+	}
+	if _, err := btpl.New(name).
+		Parse(string(bodyContent)); err != nil {
+		log.Warn("Failed to parse template [%s/body]: %v", name, err)
+	}
+}
diff --git a/modules/templates/helper_test.go b/modules/templates/helper_test.go
new file mode 100644
index 0000000000..e2997cb853
--- /dev/null
+++ b/modules/templates/helper_test.go
@@ -0,0 +1,55 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package templates
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSubjectBodySeparator(t *testing.T) {
+	test := func(input, subject, body string) {
+		loc := mailSubjectSplit.FindIndex([]byte(input))
+		if loc == nil {
+			assert.Empty(t, subject, "no subject found, but one expected")
+			assert.Equal(t, body, input)
+		} else {
+			assert.Equal(t, subject, string(input[0:loc[0]]))
+			assert.Equal(t, body, string(input[loc[1]:]))
+		}
+	}
+
+	test("Simple\n---------------\nCase",
+		"Simple\n",
+		"\nCase")
+	test("Only\nBody",
+		"",
+		"Only\nBody")
+	test("Minimal\n---\nseparator",
+		"Minimal\n",
+		"\nseparator")
+	test("False --- separator",
+		"",
+		"False --- separator")
+	test("False\n--- separator",
+		"",
+		"False\n--- separator")
+	test("False ---\nseparator",
+		"",
+		"False ---\nseparator")
+	test("With extra spaces\n-----   \t   \nBody",
+		"With extra spaces\n",
+		"\nBody")
+	test("With leading spaces\n   -------\nOnly body",
+		"",
+		"With leading spaces\n   -------\nOnly body")
+	test("Multiple\n---\n-------\n---\nSeparators",
+		"Multiple\n",
+		"\n-------\n---\nSeparators")
+	test("Insuficient\n--\nSeparators",
+		"",
+		"Insuficient\n--\nSeparators")
+}
diff --git a/modules/templates/static.go b/modules/templates/static.go
index f7e53ce887..435ccb1f95 100644
--- a/modules/templates/static.go
+++ b/modules/templates/static.go
@@ -14,6 +14,7 @@ import (
 	"io/ioutil"
 	"path"
 	"strings"
+	texttmpl "text/template"
 
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -23,7 +24,8 @@ import (
 )
 
 var (
-	templates = template.New("")
+	subjectTemplates = texttmpl.New("")
+	bodyTemplates    = template.New("")
 )
 
 type templateFileSystem struct {
@@ -140,9 +142,12 @@ func JSRenderer() macaron.Handler {
 }
 
 // Mailer provides the templates required for sending notification mails.
-func Mailer() *template.Template {
+func Mailer() (*texttmpl.Template, *template.Template) {
+	for _, funcs := range NewTextFuncMap() {
+		subjectTemplates.Funcs(funcs)
+	}
 	for _, funcs := range NewFuncMap() {
-		templates.Funcs(funcs)
+		bodyTemplates.Funcs(funcs)
 	}
 
 	for _, assetPath := range AssetNames() {
@@ -161,7 +166,8 @@ func Mailer() *template.Template {
 			continue
 		}
 
-		templates.New(
+		buildSubjectBodyTemplate(subjectTemplates,
+			bodyTemplates,
 			strings.TrimPrefix(
 				strings.TrimSuffix(
 					assetPath,
@@ -169,7 +175,7 @@ func Mailer() *template.Template {
 				),
 				"mail/",
 			),
-		).Parse(string(content))
+			content)
 	}
 
 	customDir := path.Join(setting.CustomPath, "templates", "mail")
@@ -192,17 +198,18 @@ func Mailer() *template.Template {
 					continue
 				}
 
-				templates.New(
+				buildSubjectBodyTemplate(subjectTemplates,
+					bodyTemplates,
 					strings.TrimSuffix(
 						filePath,
 						".tmpl",
 					),
-				).Parse(string(content))
+					content)
 			}
 		}
 	}
 
-	return templates
+	return subjectTemplates, bodyTemplates
 }
 
 func Asset(name string) ([]byte, error) {