Progress

.idea/.gitignore

@@ -1,8 +0,0 @@
-# Default ignored files
-/shelf/
-/workspace.xml
-# Editor-based HTTP Client requests
-/httpRequests/
-# Datasource local storage ignored files
-/dataSources/
-/dataSources.local.xml

.idea/markdown.xml

@@ -1,9 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="MarkdownSettings">
-    <enabledExtensions>
-      <entry key="MermaidLanguageExtension" value="false" />
-      <entry key="PlantUMLLanguageExtension" value="false" />
-    </enabledExtensions>
-  </component>
-</project>

client.go

@@ -40,6 +40,9 @@ type Client struct {
 	// HELO/EHLO string for the greeting the target SMTP server
 	helo string
 
+	// enc indicates if a Client connection is encrypted or not
+	enc bool
+
 	// The SMTP client that is set up when using the Dial*() methods
 	sc *smtp.Client
 }
@@ -55,9 +58,9 @@ var (
 // NewClient returns a new Session client object
 func NewClient(h string, o ...Option) (*Client, error) {
 	c := &Client{
+		cto:       DefaultTimeout,
 		host:      h,
 		port:      DefaultPort,
-		cto:       DefaultTimeout,
 		tlspolicy: TLSMandatory,
 		tlsconfig: &tls.Config{ServerName: h},
 	}
@@ -112,6 +115,20 @@ func WithHELO(h string) Option {
 	}
 }
 
+// WithTLSPolicy tells the client to use the provided TLSPolicy
+func WithTLSPolicy(p TLSPolicy) Option {
+	return func(c *Client) {
+		c.tlspolicy = p
+	}
+}
+
+// WithTLSConfig tells the client to use the provided *tls.Config
+func WithTLSConfig(co *tls.Config) Option {
+	return func(c *Client) {
+		c.tlsconfig = co
+	}
+}
+
 // TLSPolicy returns the currently set TLSPolicy as string
 func (c *Client) TLSPolicy() string {
 	return fmt.Sprintf("%s", c.tlspolicy)
@@ -127,6 +144,11 @@ func (c *Client) SetTLSPolicy(p TLSPolicy) {
 	c.tlspolicy = p
 }
 
+// SetTLSConfig overrides the current *tls.Config with the given *tls.Config value
+func (c *Client) SetTLSConfig(co *tls.Config) {
+	c.tlsconfig = co
+}
+
 // Send sends out the mail message
 func (c *Client) Send() error {
 	return nil
@@ -163,6 +185,7 @@ func (c *Client) DialWithContext(uctx context.Context) error {
 	var co net.Conn
 	var err error
 	if c.ssl {
+		c.enc = true
 		co, err = td.DialContext(ctx, "tcp", c.ServerAddr())
 	}
 	if !c.ssl {
@@ -181,13 +204,26 @@ func (c *Client) DialWithContext(uctx context.Context) error {
 	}
 
 	if !c.ssl && c.tlspolicy != NoTLS {
-		if ok, _ := c.sc.Extension("STARTTLS"); !ok {
-			return fmt.Errorf("STARTTLS mode set to: %q, but target host does not support STARTTLS",
-				c.tlspolicy)
+		est := false
+		st, _ := c.sc.Extension("STARTTLS")
+		if c.tlspolicy == TLSMandatory {
+			est = true
+			if !st {
+				return fmt.Errorf("STARTTLS mode set to: %q, but target host does not support STARTTLS",
+					c.tlspolicy)
+			}
 		}
-		if err := c.sc.StartTLS(c.tlsconfig); err != nil {
-			return err
+		if c.tlspolicy == TLSOpportunistic {
+			if st {
+				est = true
+			}
 		}
+		if est {
+			if err := c.sc.StartTLS(c.tlsconfig); err != nil {
+				return err
+			}
+		}
+		_, c.enc = c.sc.TLSConnectionState()
 	}
 
 	return nil

cmd/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"crypto/tls"
 	"fmt"
 	"github.com/wneessen/go-mail"
 	"os"
@@ -10,11 +11,22 @@ import (
 
 func main() {
 	th := os.Getenv("TEST_HOST")
-	c, err := mail.NewClient(th, mail.WithTimeout(time.Millisecond*500))
+	if th == "" {
+		fmt.Printf("$TEST_HOST env variable cannot be empty\n")
+		os.Exit(1)
+	}
+	c, err := mail.NewClient(th, mail.WithTimeout(time.Millisecond*500), mail.WithTLSPolicy(mail.TLSOpportunistic))
 	if err != nil {
 		fmt.Printf("failed to create new client: %s\n", err)
 		os.Exit(1)
 	}
+	//c.SetTLSPolicy(mail.TLSMandatory)
+	tc := &tls.Config{
+		ServerName: th,
+		MinVersion: tls.VersionTLS10,
+		MaxVersion: tls.VersionTLS10,
+	}
+	c.SetTLSConfig(tc)
 
 	ctx, cfn := context.WithCancel(context.Background())
 	defer cfn()