Support issuing Lets Encrypt SSL certs

ssl.go

@@ -0,0 +1,46 @@
+package directadmin
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/spf13/cast"
+)
+
+// IssueSSL (user) requests a lets encrypt certificate for the given hostnames
+func (c *UserContext) IssueSSL(domain string, hostnamesToCertify ...string) error {
+	var response apiGenericResponse
+
+	if len(hostnamesToCertify) == 0 {
+		return errors.New("at least one hostname is required for the certificate")
+	}
+
+	body := url.Values{
+		"type":          {"create"},
+		"request":       {"letsencrypt"},
+		"name":          {hostnamesToCertify[0]},
+		"domain":        {domain},
+		"keysize":       {"secp384r1"},
+		"encryption":    {"sha256"},
+		"wildcard":      {"no"},
+		"background":    {"auto"},
+		"action":        {"save"},
+		"acme_provider": {"letsencrypt"},
+	}
+
+	for index, certDomain := range hostnamesToCertify {
+		body.Set("le_select"+cast.ToString(index), certDomain)
+	}
+
+	if _, err := c.api.makeRequest(http.MethodPost, "API_SSL", c.credentials, body, &response); err != nil {
+		return err
+	}
+
+	if response.Success != "Certificate and Key Saved." {
+		return fmt.Errorf("failed to issue SSL certificate: %v", response.Result)
+	}
+
+	return nil
+}