Initial version

.gitignore

@@ -0,0 +1 @@
+/.idea

config.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"errors"
+	"github.com/caarlos0/env/v6"
+)
+
+type config struct {
+	Port              int      `env:"PORT" envDefault:"8080"`
+	HoneyPots         []string `env:"HONEYPOTS" envDefault:"_t_email" envSeparator:","`
+	DefaultRecipient  string   `env:"DEFAULT_TO"`
+	AllowedRecipients []string `env:"ALLOWED_TO" envSeparator:","`
+	Sender            string   `env:"EMAIL_FROM"`
+	SmtpUser          string   `env:"SMTP_USER"`
+	SmtpPassword      string   `env:"SMTP_PASS"`
+	SmtpHost          string   `env:"SMTP_HOST"`
+	SmtpPort          int      `env:"SMTP_PORT" envDefault:"587"`
+}
+
+func parseConfig() (config, error) {
+	cfg := config{}
+	if err := env.Parse(&cfg); err != nil {
+		return cfg, errors.New("failed to parse config")
+	}
+	return cfg, nil
+}
+
+func checkRequiredConfig(cfg config) bool {
+	if cfg.DefaultRecipient == "" {
+		return false
+	}
+	if len(cfg.AllowedRecipients) < 1 {
+		return false
+	}
+	if cfg.Sender == "" {
+		return false
+	}
+	if cfg.SmtpUser == "" {
+		return false
+	}
+	if cfg.SmtpPassword == "" {
+		return false
+	}
+	if cfg.SmtpHost == "" {
+		return false
+	}
+	return true
+}

config_test.go

@@ -0,0 +1,140 @@
+package main
+
+import (
+	"os"
+	"reflect"
+	"testing"
+)
+
+func Test_parseConfig(t *testing.T) {
+	t.Run("Default config", func(t *testing.T) {
+		os.Clearenv()
+		cfg, err := parseConfig()
+		if err != nil {
+			t.Error()
+			return
+		}
+		if cfg.Port != 8080 {
+			t.Error("Default Port not 8080")
+		}
+		if len(cfg.HoneyPots) != 1 || cfg.HoneyPots[0] != "_t_email" {
+			t.Error("Default HoneyPots are wrong")
+		}
+		if cfg.SmtpPort != 587 {
+			t.Error("SMTP Port not 587")
+		}
+	})
+	t.Run("Correct config parsing", func(t *testing.T) {
+		os.Clearenv()
+		_ = os.Setenv("PORT", "1111")
+		_ = os.Setenv("HONEYPOTS", "pot,abc")
+		_ = os.Setenv("DEFAULT_TO", "mail@example.com")
+		_ = os.Setenv("ALLOWED_TO", "mail@example.com,test@example.com")
+		_ = os.Setenv("EMAIL_FROM", "forms@example.com")
+		_ = os.Setenv("SMTP_USER", "test@example.com")
+		_ = os.Setenv("SMTP_PASS", "secret")
+		_ = os.Setenv("SMTP_HOST", "smtp.example.com")
+		_ = os.Setenv("SMTP_PORT", "100")
+		cfg, err := parseConfig()
+		if err != nil {
+			t.Error()
+			return
+		}
+		if !reflect.DeepEqual(cfg.Port, 1111) {
+			t.Error("Port is wrong")
+		}
+		if !reflect.DeepEqual(cfg.HoneyPots, []string{"pot", "abc"}) {
+			t.Error("HoneyPots are wrong")
+		}
+		if !reflect.DeepEqual(cfg.DefaultRecipient, "mail@example.com") {
+			t.Error("DefaultRecipient is wrong")
+		}
+		if !reflect.DeepEqual(cfg.AllowedRecipients, []string{"mail@example.com", "test@example.com"}) {
+			t.Error("AllowedRecipients are wrong")
+		}
+		if !reflect.DeepEqual(cfg.Sender, "forms@example.com") {
+			t.Error("Sender is wrong")
+		}
+		if !reflect.DeepEqual(cfg.SmtpUser, "test@example.com") {
+			t.Error("SMTP user is wrong")
+		}
+		if !reflect.DeepEqual(cfg.SmtpPassword, "secret") {
+			t.Error("SMTP password is wrong")
+		}
+		if !reflect.DeepEqual(cfg.SmtpHost, "smtp.example.com") {
+			t.Error("SMTP host is wrong")
+		}
+		if !reflect.DeepEqual(cfg.SmtpPort, 100) {
+			t.Error("SMTP port is wrong")
+		}
+	})
+	t.Run("Error when wrong config", func(t *testing.T) {
+		os.Clearenv()
+		_ = os.Setenv("PORT", "ABC")
+		_, err := parseConfig()
+		if err == nil {
+			t.Error()
+		}
+	})
+}
+
+func Test_checkRequiredConfig(t *testing.T) {
+	validConfig := config{
+		Port:              8080,
+		HoneyPots:         []string{"_t_email"},
+		DefaultRecipient:  "mail@example.com",
+		AllowedRecipients: []string{"mail@example.com"},
+		Sender:            "forms@example.com",
+		SmtpUser:          "test@example.com",
+		SmtpPassword:      "secret",
+		SmtpHost:          "smtp.example.com",
+		SmtpPort:          587,
+	}
+	t.Run("Valid config", func(t *testing.T) {
+		if true != checkRequiredConfig(validConfig) {
+			t.Error()
+		}
+	})
+	t.Run("Default recipient missing", func(t *testing.T) {
+		newConfig := validConfig
+		newConfig.DefaultRecipient = ""
+		if false != checkRequiredConfig(newConfig) {
+			t.Error()
+		}
+	})
+	t.Run("Allowed recipients missing", func(t *testing.T) {
+		newConfig := validConfig
+		newConfig.AllowedRecipients = nil
+		if false != checkRequiredConfig(newConfig) {
+			t.Error()
+		}
+	})
+	t.Run("Sender missing", func(t *testing.T) {
+		newConfig := validConfig
+		newConfig.Sender = ""
+		if false != checkRequiredConfig(newConfig) {
+			t.Error()
+		}
+	})
+	t.Run("SMTP user missing", func(t *testing.T) {
+		newConfig := validConfig
+		newConfig.SmtpUser = ""
+		if false != checkRequiredConfig(newConfig) {
+			t.Error()
+		}
+	})
+	t.Run("SMTP password missing", func(t *testing.T) {
+		newConfig := validConfig
+		newConfig.SmtpPassword = ""
+		if false != checkRequiredConfig(newConfig) {
+			t.Error()
+		}
+	})
+	t.Run("SMTP host missing", func(t *testing.T) {
+		newConfig := validConfig
+		newConfig.SmtpHost = ""
+		if false != checkRequiredConfig(newConfig) {
+			t.Error()
+		}
+	})
+}

form.html

@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<html lang="en">
+	<head>
+  		<title>Test-Form</title>
+	</head>
+	<body>
+  		<form action="//localhost:8080" method="post">
+    		<input type="hidden" name="_to" value="test@example.com">
+    		<input type="hidden" name="_formName" value="Test Form">
+    		<input type="hidden" name="_redirectTo" value="https://example.com">
+				<label for="TEmail" style="display: none;">Test</label>
+				<input id="TEmail" type="email" name="_t_email" style="display: none;">
+				<label for="Email">Email</label>
+    		<br />
+    		<input id="Email" type="email" name="_replyTo" required>
+    		<br />
+    		<label for="Name">Name</label>
+    		<br />
+    		<input id="Name" type="text" name="Name" required>
+    		<br />
+				<label for="Message">Message</label>
+				<br />
+        <textarea id="Message" name="Message"></textarea>
+				<br />
+    		<input type="submit" value="Send">
+  		</form>
+	</body>
+</html>
+

forms.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"github.com/microcosm-cc/bluemonday"
+	"net/http"
+	"net/url"
+)
+
+type FormValues map[string][]string
+
+func FormHandler(w http.ResponseWriter, r *http.Request) {
+	if r.Method == http.MethodGet {
+		_, _ = w.Write([]byte("MailyGo works!"))
+		return
+	}
+	if r.Method != http.MethodPost {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		_, _ = w.Write([]byte("The HTTP method is not allowed, make a POST request"))
+		return
+	}
+	_ = r.ParseForm()
+	sanitizedForm := sanitizeForm(r.PostForm)
+	if !isBot(sanitizedForm) {
+		sendForm(sanitizedForm)
+	}
+	sendResponse(sanitizedForm, w)
+	return
+}
+
+func sanitizeForm(values url.Values) FormValues {
+	p := bluemonday.StrictPolicy()
+	sanitizedForm := make(FormValues)
+	for key, values := range values {
+		var sanitizedValues []string
+		for _, value := range values {
+			sanitizedValues = append(sanitizedValues, p.Sanitize(value))
+		}
+		sanitizedForm[p.Sanitize(key)] = sanitizedValues
+	}
+	return sanitizedForm
+}
+
+func isBot(values FormValues) bool {
+	for _, honeyPot := range appConfig.HoneyPots {
+		if len(values[honeyPot]) > 0 {
+			for _, value := range values[honeyPot] {
+				if value != "" {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
+func sendResponse(values FormValues, w http.ResponseWriter) {
+	if len(values["_redirectTo"]) == 1 && values["_redirectTo"][0] != "" {
+		w.Header().Add("Location", values["_redirectTo"][0])
+		w.WriteHeader(http.StatusSeeOther)
+		_, _ = w.Write([]byte("Go to " + values["_redirectTo"][0]))
+		return
+	} else {
+		w.WriteHeader(http.StatusCreated)
+		_, _ = w.Write([]byte("Submitted form"))
+		return
+	}
+}

forms_test.go

@@ -0,0 +1,118 @@
+package main
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"reflect"
+	"testing"
+)
+
+func Test_sanitizeForm(t *testing.T) {
+	t.Run("Sanitize form", func(t *testing.T) {
+		result := sanitizeForm(url.Values{"<b>Test</b>": {"<a href=\"https://example.com\">Test</a>"}})
+		want := FormValues{"Test": {"Test"}}
+		if !reflect.DeepEqual(result, want) {
+			t.Error()
+		}
+	})
+}
+
+func TestFormHandler(t *testing.T) {
+	t.Run("GET request to FormHandler", func(t *testing.T) {
+		req := httptest.NewRequest("GET", "http://example.com/", nil)
+		w := httptest.NewRecorder()
+		FormHandler(w, req)
+		resp := w.Result()
+		if resp.StatusCode != http.StatusOK {
+			t.Error()
+		}
+	})
+	t.Run("POST request to FormHandler", func(t *testing.T) {
+		req := httptest.NewRequest("POST", "http://example.com/", nil)
+		w := httptest.NewRecorder()
+		FormHandler(w, req)
+		resp := w.Result()
+		if resp.StatusCode != http.StatusCreated {
+			t.Error()
+		}
+	})
+	t.Run("Wrong method request to FormHandler", func(t *testing.T) {
+		req := httptest.NewRequest("DELETE", "http://example.com/", nil)
+		w := httptest.NewRecorder()
+		FormHandler(w, req)
+		resp := w.Result()
+		if resp.StatusCode != http.StatusMethodNotAllowed {
+			t.Error()
+		}
+	})
+}
+
+func Test_isBot(t *testing.T) {
+	t.Run("No bot", func(t *testing.T) {
+		os.Clearenv()
+		result := isBot(FormValues{"_t_email": {""}})
+		if !reflect.DeepEqual(result, false) {
+			t.Error()
+		}
+	})
+	t.Run("No honeypot", func(t *testing.T) {
+		os.Clearenv()
+		result := isBot(FormValues{})
+		if !reflect.DeepEqual(result, false) {
+			t.Error()
+		}
+	})
+	t.Run("Bot", func(t *testing.T) {
+		os.Clearenv()
+		result := isBot(FormValues{"_t_email": {"Test", ""}})
+		if !reflect.DeepEqual(result, true) {
+			t.Error()
+		}
+	})
+}
+
+func Test_sendResponse(t *testing.T) {
+	t.Run("No redirect", func(t *testing.T) {
+		values := FormValues{}
+		w := httptest.NewRecorder()
+		sendResponse(values, w)
+		if w.Code != http.StatusCreated {
+			t.Error()
+		}
+	})
+	t.Run("No redirect 2", func(t *testing.T) {
+		values := FormValues{
+			"_redirectTo": {""},
+		}
+		w := httptest.NewRecorder()
+		sendResponse(values, w)
+		if w.Code != http.StatusCreated {
+			t.Error()
+		}
+	})
+	t.Run("No redirect 3", func(t *testing.T) {
+		values := FormValues{
+			"_redirectTo": {"abc", "def"},
+		}
+		w := httptest.NewRecorder()
+		sendResponse(values, w)
+		if w.Code != http.StatusCreated {
+			t.Error()
+		}
+	})
+	t.Run("Redirect", func(t *testing.T) {
+		values := FormValues{
+			"_redirectTo": {"https://example.com"},
+		}
+		w := httptest.NewRecorder()
+		sendResponse(values, w)
+		if w.Code != http.StatusSeeOther {
+			t.Error()
+		}
+		if w.Header().Get("Location") != "https://example.com" {
+			t.Error()
+		}
+	})
+}

go.mod

@@ -0,0 +1,9 @@
+module codeberg.org/jlelse/mailygo
+
+go 1.14
+
+require (
+	github.com/caarlos0/env/v6 v6.2.1
+	github.com/microcosm-cc/bluemonday v1.0.3-0.20191119130333-0a75d7616912
+	golang.org/x/net v0.0.0-20200301022130-244492dfa37a // indirect
+)

go.sum

@@ -0,0 +1,28 @@
+github.com/aymerick/douceur v0.2.0 h1:Mv+mAeH1Q+n9Fr+oyamOlAkUNPWPlA8PPGR0QAaYuPk=
+github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd30/FjWUq4=
+github.com/caarlos0/env/v6 v6.2.1 h1:/bFpX1dg4TNioJjg7mrQaSrBoQvRfLUHNfXivdFbbEo=
+github.com/caarlos0/env/v6 v6.2.1/go.mod h1:3LpmfcAYCG6gCiSgDLaFR5Km1FRpPwFvBbRcjHar6Sw=
+github.com/chris-ramon/douceur v0.2.0 h1:IDMEdxlEUUBYBKE4z/mJnFyVXox+MjuEVDJNN27glkU=
+github.com/chris-ramon/douceur v0.2.0/go.mod h1:wDW5xjJdeoMm1mRt4sD4c/LbF/mWdEpRXQKjTR8nIBE=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gorilla/css v1.0.0 h1:BQqNyPTi50JCFMTw/b67hByjMVXZRwGha6wxVGkeihY=
+github.com/gorilla/css v1.0.0/go.mod h1:Dn721qIggHpt4+EFCcTLTU/vk5ySda2ReITrtgBl60c=
+github.com/microcosm-cc/bluemonday v1.0.3-0.20191119130333-0a75d7616912 h1:hJde9rA24hlTcAYSwJoXpDUyGtfKQ/jsofw+WaDqGrI=
+github.com/microcosm-cc/bluemonday v1.0.3-0.20191119130333-0a75d7616912/go.mod h1:8iwZnFn2CDDNZ0r6UXhF4xawGvzaqzCRa1n3/lO3W2w=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
+github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20181220203305-927f97764cc3 h1:eH6Eip3UpmR+yM/qI9Ijluzb1bNv/cAU/n+6l8tRSis=
+golang.org/x/net v0.0.0-20181220203305-927f97764cc3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20200301022130-244492dfa37a h1:GuSPYbZzB5/dcLNCwLQLsg3obCJtX9IJhpXkvY7kzk0=
+golang.org/x/net v0.0.0-20200301022130-244492dfa37a/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

mail.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"net/smtp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func sendForm(values FormValues) {
+	recipient := findRecipient(values)
+	sendMail(recipient, buildMessage(recipient, time.Now(), values))
+}
+
+func buildMessage(recipient string, date time.Time, values FormValues) string {
+	var msgBuffer bytes.Buffer
+	_, _ = fmt.Fprintf(&msgBuffer, "From: Forms <%s>", appConfig.Sender)
+	_, _ = fmt.Fprintln(&msgBuffer)
+	_, _ = fmt.Fprintf(&msgBuffer, "To: %s", recipient)
+	_, _ = fmt.Fprintln(&msgBuffer)
+	if replyTo := findReplyTo(values); replyTo != "" {
+		_, _ = fmt.Fprintf(&msgBuffer, "Reply-To: %s", replyTo)
+		_, _ = fmt.Fprintln(&msgBuffer)
+	}
+	_, _ = fmt.Fprintf(&msgBuffer, "Date: %s", date.Format(time.RFC1123Z))
+	_, _ = fmt.Fprintln(&msgBuffer)
+	_, _ = fmt.Fprintf(&msgBuffer, "Subject: New submission on %s", findFormName(values))
+	_, _ = fmt.Fprintln(&msgBuffer)
+	_, _ = fmt.Fprintln(&msgBuffer)
+	for key, value := range removeMetaValues(values) {
+		_, _ = fmt.Fprint(&msgBuffer, key)
+		_, _ = fmt.Fprint(&msgBuffer, ": ")
+		_, _ = fmt.Fprintln(&msgBuffer, strings.Join(value, ", "))
+	}
+	return msgBuffer.String()
+}
+
+func sendMail(to, message string) {
+	auth := smtp.PlainAuth("", appConfig.SmtpUser, appConfig.SmtpPassword, appConfig.SmtpHost)
+	err := smtp.SendMail(appConfig.SmtpHost+":"+strconv.Itoa(appConfig.SmtpPort), auth, appConfig.Sender, []string{to}, []byte(message))
+	if err != nil {
+		fmt.Println("Failed to send mail:", err.Error())
+	}
+}
+
+func findRecipient(values FormValues) string {
+	if len(values["_to"]) == 1 && values["_to"][0] != "" {
+		formDefinedRecipient := values["_to"][0]
+		for _, allowed := range appConfig.AllowedRecipients {
+			if formDefinedRecipient == allowed {
+				return formDefinedRecipient
+			}
+		}
+	}
+	return appConfig.DefaultRecipient
+}
+
+func findFormName(values FormValues) string {
+	if len(values["_formName"]) == 1 && values["_formName"][0] != "" {
+		return values["_formName"][0]
+	}
+	return "a form"
+}
+
+func findReplyTo(values FormValues) string {
+	if len(values["_replyTo"]) == 1 && values["_replyTo"][0] != "" {
+		return values["_replyTo"][0]
+	}
+	return ""
+}
+
+func removeMetaValues(values FormValues) FormValues {
+	cleanedValues := FormValues{}
+	for key, value := range values {
+		if !strings.HasPrefix(key, "_") {
+			cleanedValues[key] = value
+		}
+	}
+	return cleanedValues
+}

mail_test.go

@@ -0,0 +1,137 @@
+package main
+
+import (
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+)
+
+func Test_findRecipient(t *testing.T) {
+	prepare := func() {
+		os.Clearenv()
+		_ = os.Setenv("ALLOWED_TO", "mail@example.com,test@example.com")
+		_ = os.Setenv("DEFAULT_TO", "mail@example.com")
+		appConfig, _ = parseConfig()
+	}
+	t.Run("No recipient specified", func(t *testing.T) {
+		prepare()
+		values := FormValues{}
+		result := findRecipient(values)
+		if result != "mail@example.com" {
+			t.Error()
+		}
+	})
+	t.Run("Multiple recipients specified", func(t *testing.T) {
+		prepare()
+		values := FormValues{
+			"_to": {"abc@example.com", "def@example.com"},
+		}
+		result := findRecipient(values)
+		if result != "mail@example.com" {
+			t.Error()
+		}
+	})
+	t.Run("Allowed recipient specified", func(t *testing.T) {
+		prepare()
+		values := FormValues{
+			"_to": {"test@example.com"},
+		}
+		result := findRecipient(values)
+		if result != "test@example.com" {
+			t.Error()
+		}
+	})
+	t.Run("Forbidden recipient specified", func(t *testing.T) {
+		prepare()
+		values := FormValues{
+			"_to": {"forbidden@example.com"},
+		}
+		result := findRecipient(values)
+		if result != "mail@example.com" {
+			t.Error()
+		}
+	})
+}
+
+func Test_findFormName(t *testing.T) {
+	t.Run("No form name", func(t *testing.T) {
+		if "a form" != findFormName(FormValues{}) {
+			t.Error()
+		}
+	})
+	t.Run("Multiple form names", func(t *testing.T) {
+		if "a form" != findFormName(FormValues{"_formName": {"Test", "ABC"}}) {
+			t.Error()
+		}
+	})
+	t.Run("Form name", func(t *testing.T) {
+		if "Test" != findFormName(FormValues{"_formName": {"Test"}}) {
+			t.Error()
+		}
+	})
+}
+
+func Test_findReplyTo(t *testing.T) {
+	t.Run("No replyTo", func(t *testing.T) {
+		if "" != findReplyTo(FormValues{}) {
+			t.Error()
+		}
+	})
+	t.Run("Multiple replyTo", func(t *testing.T) {
+		if "" != findReplyTo(FormValues{"_replyTo": {"test@example.com", "test2@example.com"}}) {
+			t.Error()
+		}
+	})
+	t.Run("replyTo", func(t *testing.T) {
+		if "test@example.com" != findReplyTo(FormValues{"_replyTo": {"test@example.com"}}) {
+			t.Error()
+		}
+	})
+}
+
+func Test_removeMetaValues(t *testing.T) {
+	t.Run("Remove meta values", func(t *testing.T) {
+		result := removeMetaValues(FormValues{
+			"_test": {"abc"},
+			"test":  {"def"},
+		})
+		want := FormValues{
+			"test": {"def"},
+		}
+		if !reflect.DeepEqual(result, want) {
+			t.Error()
+		}
+	})
+}
+
+func Test_buildMessage(t *testing.T) {
+	t.Run("Test message", func(t *testing.T) {
+		os.Clearenv()
+		_ = os.Setenv("EMAIL_TO", "mail@example.com")
+		_ = os.Setenv("ALLOWED_TO", "mail@example.com,test@example.com")
+		_ = os.Setenv("EMAIL_FROM", "forms@example.com")
+		appConfig, _ = parseConfig()
+		values := FormValues{
+			"_formName":   {"Testform"},
+			"_replyTo":    {"reply@example.com"},
+			"Testkey":     {"Testvalue"},
+			"Another Key": {"Test", "ABC"},
+		}
+		date := time.Now()
+		result := buildMessage("test@example.com", date, values)
+		if !strings.Contains(result, "Reply-To: reply@example.com") {
+			t.Error()
+		}
+		if !strings.Contains(result, "Subject: New submission on Testform") {
+			t.Error()
+		}
+		if !strings.Contains(result, "Testkey: Testvalue") {
+			t.Error()
+		}
+		if !strings.Contains(result, "Another Key: Test, ABC") {
+			t.Error()
+		}
+	})
+}

mailygo.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"strconv"
+)
+
+var appConfig config
+
+func init() {
+	cfg, err := parseConfig()
+	if err != nil {
+		log.Fatal(err)
+	}
+	appConfig = cfg
+}
+
+func main() {
+	if !checkRequiredConfig(appConfig) {
+		log.Fatal("Not all required configurations are set")
+	}
+	http.HandleFunc("/", FormHandler)
+	log.Fatal(http.ListenAndServe(":"+strconv.Itoa(appConfig.Port), nil))
+}