commit efdb116759e0c1f87226668c80b6dd625fd6724c
parent c5847ce44482c2e0b354a566b565b6d03082a5b5
Author: Natasha Kerensikova <natgh@instinctive.eu>
Date: Wed, 11 Jun 2025 20:53:40 +0000
Message filter
Diffstat:
| M | main.go | | | 99 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
1 file changed, 99 insertions(+), 0 deletions(-)
diff --git a/main.go b/main.go
@@ -18,8 +18,10 @@ package main
import (
"errors"
+ "fmt"
"log"
"os"
+ "regexp"
"runtime/debug"
"strings"
@@ -47,6 +49,10 @@ func main() {
}
log.Println("natsim " + version + " started")
+ log.Println("found", len(im.Nats.Filter), "filters")
+ for i, element := range im.Nats.Filter {
+ log.Printf(" %d. %s", i+1, element.String())
+ }
im.irc.Loop()
}
@@ -75,6 +81,7 @@ type NatsConfig struct {
Server string
NkeySeed string
Subjects []string
+ Filter []FilterElement
}
type NatsIM struct {
@@ -274,10 +281,102 @@ func (natsim *NatsIM) ircSender() {
/**************** Nats Callbacks ****************/
func (natsim *NatsIM) natsReceive(m *nats.Msg) {
+ if !IsKept(m.Subject, m.Data, natsim.Nats.Filter, true) {
+ return
+ }
+
msg := packMark(natsim.Irc.Show, m.Subject, string(m.Data))
natsim.ircSend(msg)
}
+/**************** Filters ****************/
+
+type FilterElement struct {
+ Result bool
+ Part FilterPart
+ Test *regexp.Regexp
+}
+
+type FilterPart int
+
+const (
+ FilterSubject FilterPart = iota
+ FilterData
+)
+
+func (element *FilterElement) Match(subject string, data []byte) bool {
+ var b []byte
+ switch element.Part {
+ case FilterSubject:
+ b = []byte(subject)
+ case FilterData:
+ b = data
+ default:
+ panic("Unexpected part")
+ }
+
+ return element.Test.Match(b)
+}
+
+func (element *FilterElement) String() string {
+ r := "drop "
+ if element.Result {
+ r = "pass "
+ }
+
+ p := ""
+ switch element.Part {
+ case FilterSubject:
+ p = "subject "
+ case FilterData:
+ p = "data "
+ default:
+ panic("Unexpected part")
+ }
+
+ return r + p + element.Test.String()
+}
+
+func (element *FilterElement) UnmarshalText(text []byte) error {
+ s := string(text)
+
+ switch {
+ case strings.HasPrefix(s, "pass "):
+ element.Result = true
+ s = s[5:]
+ case strings.HasPrefix(s, "drop "):
+ element.Result = false
+ s = s[5:]
+ default:
+ return fmt.Errorf("malformed filter %q", s)
+ }
+
+ switch {
+ case strings.HasPrefix(s, "subject "):
+ element.Part = FilterSubject
+ s = s[8:]
+ case strings.HasPrefix(s, "data "):
+ element.Part = FilterData
+ s = s[5:]
+ default:
+ return fmt.Errorf("bad filter part %q", s)
+ }
+
+ re, err := regexp.Compile(s)
+ element.Test = re
+ return err
+}
+
+func IsKept(subject string, data []byte, elements []FilterElement, base bool) bool {
+ for _, element := range elements {
+ if element.Match(subject, data) {
+ return element.Result
+ }
+ }
+
+ return base
+}
+
/**************** Tools ****************/
func packMark(mark LineMark, name, arg string) string {
