@@ -2,6 +2,8 @@ changelog
 
 ### next
 
++ Filter option to match unknown actors.
+
 + Update some dependencies.
 
 + Watch local.css for changes.

@@ -44,10 +44,8 @@ .Fa Ar actor
 property.
 .It Ar include audience
 Previous match is applied against
-.Fa to
-and
-.Fa cc
-fields as well.
+.It Ar only unknowns
+Previous (domain) match is applied only to unknown actors.
 .It Ar text
 Regular expression match against the post
 .Fa content .
@@ -97,6 +95,9 @@ that can be matched against and will appear if the post is collapsed.
 .Pp
 An optional expiration may be specified as a duration.
 XdYhZm for X days, Y hours, and Z minutes.
+.Sh EXAMPLES
+A rudimentary spam filter may be constructed with where set to mastodon.social,
+checking the only unknowns option, with an action of reject.
 .Sh SEE ALSO
 .Xr honk 1
 .Sh CAVEATS

@@ -19,10 +19,13 @@ import (
 	"net/http"
 	"regexp"
 	"sort"
+	"strconv"
+	"strings"
 	"time"
 	"unicode"
 
 	"humungus.tedunangst.com/r/webs/cache"
+	"humungus.tedunangst.com/r/webs/login"
 )
 
 type Filter struct {
@@ -32,6 +35,7 @@ Name            string
 	Date            time.Time
 	Actor           string `json:",omitempty"`
 	IncludeAudience bool   `json:",omitempty"`
+	OnlyUnknowns    bool   `json:",omitempty"`
 	Text            string `json:",omitempty"`
 	re_text         *regexp.Regexp
 	IsReply         bool   `json:",omitempty"`
@@ -226,6 +230,9 @@ origin = o
 	}
 	filts := rejectfilters(userid, origin)
 	for _, f := range filts {
+		if f.OnlyUnknowns {
+			continue
+		}
 		if isannounce && f.IsAnnounce {
 			if f.AnnounceOf == origin {
 				return true
@@ -259,6 +266,10 @@ if f.IsAnnounce {
 			continue
 		}
 		if f.Actor == origin {
+			if f.OnlyUnknowns && unknownActor(userid, actor) {
+				ilog.Printf("rejecting unknown actor: %s", actor)
+				return true
+			}
 			ilog.Printf("rejecting actor: %s", actor)
 			return true
 		}
@@ -266,6 +277,21 @@ }
 	return false
 }
 
+var knownknowns = cache.New(cache.Options{Filler: func(userid int64) (map[string]bool, bool) {
+	m := make(map[string]bool)
+	honkers := gethonkers(userid)
+	for _, h := range honkers {
+		m[h.XID] = true
+	}
+	return m, true
+}, Invalidator: &honkerinvalidator})
+
+func unknownActor(userid int64, actor string) bool {
+	var knowns map[string]bool
+	knownknowns.Get(userid, &knowns)
+	return !knowns[actor]
+}
+
 func stealthmode(userid int64, r *http.Request) bool {
 	agent := r.UserAgent()
 	agent = originate(agent)
@@ -292,7 +318,7 @@ if f.Actor == h.Honker || f.Actor == h.Oonker {
 			match = true
 			rv = f.Actor
 		}
-		if !match && (f.Actor == originate(h.Honker) ||
+		if !match && !f.OnlyUnknowns && (f.Actor == originate(h.Honker) ||
 			f.Actor == originate(h.Oonker) ||
 			f.Actor == originate(h.XID)) {
 			match = true
@@ -485,3 +511,56 @@ }
 	honks = honks[0:j]
 	return honks
 }
+
+func savehfcs(w http.ResponseWriter, r *http.Request) {
+	userinfo := login.GetUserInfo(r)
+	itsok := r.FormValue("itsok")
+	if itsok == "iforgiveyou" {
+		hfcsid, _ := strconv.ParseInt(r.FormValue("hfcsid"), 10, 0)
+		_, err := stmtDeleteFilter.Exec(userinfo.UserID, hfcsid)
+		if err != nil {
+			elog.Printf("error deleting filter: %s", err)
+		}
+		filtInvalidator.Clear(userinfo.UserID)
+		http.Redirect(w, r, "/hfcs", http.StatusSeeOther)
+		return
+	}
+
+	filt := new(Filter)
+	filt.Name = strings.TrimSpace(r.FormValue("name"))
+	filt.Date = time.Now().UTC()
+	filt.Actor = strings.TrimSpace(r.FormValue("actor"))
+	filt.IncludeAudience = r.FormValue("incaud") == "yes"
+	filt.OnlyUnknowns = r.FormValue("unknowns") == "yes"
+	filt.Text = strings.TrimSpace(r.FormValue("filttext"))
+	filt.IsReply = r.FormValue("isreply") == "yes"
+	filt.IsAnnounce = r.FormValue("isannounce") == "yes"
+	filt.AnnounceOf = strings.TrimSpace(r.FormValue("announceof"))
+	filt.Reject = r.FormValue("doreject") == "yes"
+	filt.SkipMedia = r.FormValue("doskipmedia") == "yes"
+	filt.Hide = r.FormValue("dohide") == "yes"
+	filt.Collapse = r.FormValue("docollapse") == "yes"
+	filt.Rewrite = strings.TrimSpace(r.FormValue("filtrewrite"))
+	filt.Replace = strings.TrimSpace(r.FormValue("filtreplace"))
+	if dur := parseDuration(r.FormValue("filtduration")); dur > 0 {
+		filt.Expiration = time.Now().UTC().Add(dur)
+	}
+	filt.Notes = strings.TrimSpace(r.FormValue("filtnotes"))
+
+	if filt.Actor == "" && filt.Text == "" && !filt.IsAnnounce {
+		ilog.Printf("blank filter")
+		http.Error(w, "can't save a blank filter", http.StatusInternalServerError)
+		return
+	}
+
+	j, err := jsonify(filt)
+	if err == nil {
+		_, err = stmtSaveFilter.Exec(userinfo.UserID, j)
+	}
+	if err != nil {
+		elog.Printf("error saving filter: %s", err)
+	}
+
+	filtInvalidator.Clear(userinfo.UserID)
+	http.Redirect(w, r, "/hfcs", http.StatusSeeOther)
+}

@@ -18,6 +18,8 @@ <p><label for="actor">who or where:</label><br>
 <input tabindex=1 type="text" name="actor" value="" autocomplete=off>
 <p><span><label class=button for="incaud">include audience:
 <input tabindex=1 type="checkbox" id="incaud" name="incaud" value="yes"><span></span></label></span>
+<span><label class=button for="unknowns">only unknowns:
+<input tabindex=1 type="checkbox" id="unknowns" name="unknowns" value="yes"><span></span></label></span>
 <p><label for="filttext">text matches:</label><br>
 <input tabindex=1 type="text" name="filttext" value="" autocomplete=off>
 <p><span><label class=button for="isreply">is reply:
@@ -55,7 +57,7 @@ <section class="honk">
 <p>Name: {{ .Name }}
 {{ with .Notes }}<p>Notes: {{ . }}{{ end }}
 <p>Date: {{ .Date.Format "2006-01-02" }}
-{{ with .Actor }}<p>Who: {{ . }}{{ end }} {{ with .IncludeAudience }} (inclusive) {{ end }}
+{{ with .Actor }}<p>Who: {{ . }}{{ end }}{{ if .IncludeAudience }} (inclusive){{ end }}{{ if .OnlyUnknowns }} (unknowns){{ end }}
 {{ if .IsReply }}<p>Reply: y{{ end }}
 {{ if .IsAnnounce }}<p>Announce: {{ .AnnounceOf }}{{ end }}
 {{ with .Text }}<p>Text: {{ . }}{{ end }}

@@ -2234,58 +2234,6 @@ elog.Print(err)
 	}
 }
 
-func savehfcs(w http.ResponseWriter, r *http.Request) {
-	userinfo := login.GetUserInfo(r)
-	itsok := r.FormValue("itsok")
-	if itsok == "iforgiveyou" {
-		hfcsid, _ := strconv.ParseInt(r.FormValue("hfcsid"), 10, 0)
-		_, err := stmtDeleteFilter.Exec(userinfo.UserID, hfcsid)
-		if err != nil {
-			elog.Printf("error deleting filter: %s", err)
-		}
-		filtInvalidator.Clear(userinfo.UserID)
-		http.Redirect(w, r, "/hfcs", http.StatusSeeOther)
-		return
-	}
-
-	filt := new(Filter)
-	filt.Name = strings.TrimSpace(r.FormValue("name"))
-	filt.Date = time.Now().UTC()
-	filt.Actor = strings.TrimSpace(r.FormValue("actor"))
-	filt.IncludeAudience = r.FormValue("incaud") == "yes"
-	filt.Text = strings.TrimSpace(r.FormValue("filttext"))
-	filt.IsReply = r.FormValue("isreply") == "yes"
-	filt.IsAnnounce = r.FormValue("isannounce") == "yes"
-	filt.AnnounceOf = strings.TrimSpace(r.FormValue("announceof"))
-	filt.Reject = r.FormValue("doreject") == "yes"
-	filt.SkipMedia = r.FormValue("doskipmedia") == "yes"
-	filt.Hide = r.FormValue("dohide") == "yes"
-	filt.Collapse = r.FormValue("docollapse") == "yes"
-	filt.Rewrite = strings.TrimSpace(r.FormValue("filtrewrite"))
-	filt.Replace = strings.TrimSpace(r.FormValue("filtreplace"))
-	if dur := parseDuration(r.FormValue("filtduration")); dur > 0 {
-		filt.Expiration = time.Now().UTC().Add(dur)
-	}
-	filt.Notes = strings.TrimSpace(r.FormValue("filtnotes"))
-
-	if filt.Actor == "" && filt.Text == "" && !filt.IsAnnounce {
-		ilog.Printf("blank filter")
-		http.Error(w, "can't save a blank filter", http.StatusInternalServerError)
-		return
-	}
-
-	j, err := jsonify(filt)
-	if err == nil {
-		_, err = stmtSaveFilter.Exec(userinfo.UserID, j)
-	}
-	if err != nil {
-		elog.Printf("error saving filter: %s", err)
-	}
-
-	filtInvalidator.Clear(userinfo.UserID)
-	http.Redirect(w, r, "/hfcs", http.StatusSeeOther)
-}
-
 func accountpage(w http.ResponseWriter, r *http.Request) {
 	u := login.GetUserInfo(r)
 	user, _ := butwhatabout(u.Username)