Feat/ntfy (#57)

* implement ntfy notification

* fix notification fields order

* fix schema for ntfy

---------

Co-authored-by: yusing <yusing@6uo.me>

internal/notif/ntfy.go

@@ -0,0 +1,89 @@
+package notif
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/rs/zerolog"
+	E "github.com/yusing/go-proxy/internal/error"
+)
+
+// See https://docs.ntfy.sh/publish
+type Ntfy struct {
+	ProviderBase
+	Topic string    `json:"topic"`
+	Style NtfyStyle `json:"style"`
+}
+
+type NtfyStyle string
+
+const (
+	NtfyStyleMarkdown NtfyStyle = "markdown"
+	NtfyStylePlain    NtfyStyle = "plain"
+)
+
+func (n *Ntfy) Validate() E.Error {
+	if n.URL == "" {
+		return E.New("url is required")
+	}
+	if n.Topic == "" {
+		return E.New("topic is required")
+	}
+	if n.Topic[0] == '/' {
+		return E.New("topic should not start with a slash")
+	}
+	switch n.Style {
+	case "":
+		n.Style = NtfyStyleMarkdown
+	case NtfyStyleMarkdown, NtfyStylePlain:
+	default:
+		return E.Errorf("invalid style, expecting %q or %q, got %q", NtfyStyleMarkdown, NtfyStylePlain, n.Style)
+	}
+	return nil
+}
+
+func (n *Ntfy) GetURL() string {
+	if n.URL[len(n.URL)-1] == '/' {
+		return n.URL + n.Topic
+	}
+	return n.URL + "/" + n.Topic
+}
+
+func (n *Ntfy) GetMIMEType() string {
+	return ""
+}
+
+func (n *Ntfy) GetToken() string {
+	return n.Token
+}
+
+func (n *Ntfy) MakeBody(logMsg *LogMessage) (io.Reader, error) {
+	switch n.Style {
+	case NtfyStyleMarkdown:
+		return strings.NewReader(formatMarkdown(logMsg.Extras)), nil
+	default:
+		return &bytes.Buffer{}, nil
+	}
+}
+
+func (n *Ntfy) SetHeaders(logMsg *LogMessage, headers http.Header) {
+	headers.Set("Title", logMsg.Title)
+
+	switch logMsg.Level {
+	// warning (or other unspecified) uses default priority
+	case zerolog.FatalLevel:
+		headers.Set("Priority", "urgent")
+	case zerolog.ErrorLevel:
+		headers.Set("Priority", "high")
+	case zerolog.InfoLevel:
+		headers.Set("Priority", "low")
+	case zerolog.DebugLevel:
+		headers.Set("Priority", "min")
+	}
+
+	if n.Style == NtfyStyleMarkdown {
+		headers.Set("Markdown", "yes")
+	}
+}