This PR adds a `Msg.Read()` method which satisfies the `io.Reader` interface
This commit is contained in:
Winni Neessen 2022-05-28 10:58:19 +02:00
parent c001ac5b94
commit dd02ac229b
Signed by: wneessen
GPG key ID: 385AC9889632126E
3 changed files with 78 additions and 1 deletions

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@ -32,8 +32,9 @@ Some of the features of this library:
* [X] Support for common mail header field generation (Message-ID, Date, Bulk-Precedence, Priority, etc.)
* [X] Reusing the same SMTP connection to send multiple mails
* [X] Support for attachments and inline embeds
* [X] Support for different encodings (existing but not fully tested)
* [X] Support for different encodings
* [X] Support sending mails via a local sendmail command
* [X] Message object satisfies `io.WriteTo` and `io.Reader` interfaces
go-mail works like a programatic email client and provides lots of methods and functionalities you would consider
standard in a MUA.

10
msg.go
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@ -552,6 +552,16 @@ func (m *Msg) WriteToSendmailWithContext(ctx context.Context, sp string, a ...st
return nil
}
// Read outputs the length of p into p to satisfy the io.Reader interface
func (m *Msg) Read(p []byte) (int, error) {
wbuf := bytes.Buffer{}
_, err := m.WriteTo(&wbuf)
if err != nil {
return 0, fmt.Errorf("failed to write message to internal write buffer: %w", err)
}
return wbuf.Read(p)
}
// encodeString encodes a string based on the configured message encoder and the corresponding
// charset for the Msg
func (m *Msg) encodeString(s string) string {

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@ -1272,3 +1272,69 @@ func TestMsg_multipleWrites(t *testing.T) {
t.Errorf("second WriteTo() body does not contain unique string: %s", ts)
}
}
// TestMsg_Read tests the Msg.Read method that implements the io.Reader interface
func TestMsg_Read(t *testing.T) {
tests := []struct {
name string
plen int
}{
{"P length is bigger than the mail", 32000},
{"P length is smaller than the mail", 128},
}
m := NewMsg()
m.SetBodyString(TypeTextPlain, "TEST123")
wbuf := bytes.Buffer{}
_, err := m.Write(&wbuf)
if err != nil {
t.Errorf("failed to write message into temporary buffer: %s", err)
}
elen := wbuf.Len()
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
p := make([]byte, tt.plen)
n, err := m.Read(p)
if err != nil {
t.Errorf("failed to Read(): %s", err)
}
if n == 0 {
t.Errorf("failed to Read() - received 0 bytes of data")
}
if tt.plen >= elen && n != elen {
t.Errorf("failed to Read() - not all data received. Expected: %d, got: %d", elen, n)
}
if tt.plen < elen && n != tt.plen {
t.Errorf("failed to Read() - full length of p wasn't filled with data. Expected: %d, got: %d",
tt.plen, n)
}
})
}
}
// TestMsg_Read_ioCopy tests the Msg.Read method using io.Copy
func TestMsg_Read_ioCopy(t *testing.T) {
wbuf1 := bytes.Buffer{}
wbuf2 := bytes.Buffer{}
m := NewMsg()
m.SetBodyString(TypeTextPlain, "TEST123")
// First we use WriteTo to have something to compare to
_, err := m.WriteTo(&wbuf1)
if err != nil {
t.Errorf("failed to write body to buffer: %s", err)
}
// Then we write to wbuf2 via io.Copy
n, err := io.Copy(&wbuf2, m)
if err != nil {
t.Errorf("failed to use io.Copy on Msg: %s", err)
}
if n != int64(wbuf1.Len()) {
t.Errorf("message length of WriteTo and io.Copy differ. Expected: %d, got: %d", wbuf1.Len(), n)
}
if wbuf1.String() != wbuf2.String() {
t.Errorf("message content of WriteTo and io.Copy differ")
}
}