Make the home page's AS name search work (closes #151)

The AS Name Search card on the home page said the search was coming
soon. It now asks the new GET /api/v1/search/as?q=<text>, which
searches the AS list built into asinfo, and lists the matches as links
to their AS pages. An empty q answers 400. asinfo.Search now ignores
case and returns its matches in AS number order. asinfo puts each
handle and description in lower case once, when the list loads.

A match can be an AS that the database has no record of. Its AS page
and /api/v1/as/{asn} then take its handle and description from asinfo
and still list its prefixes. They answer 404 only for an AS with no
record, no asinfo entry and no prefix. Empty prefix lists in that JSON
answer are [] rather than null.

Model: opus-5-5

README.md

@@ -56,15 +56,17 @@ Every route answers `HEAD` as it answers `GET`, without the body.
 
 ### Web Interface
 
-- `GET /` - Home page (HTML): headline figures, and lookups by AS number and by
+- `GET /` - Home page (HTML): headline figures, lookups by AS number and by IP
-  IP address
+  address, and a search of AS names
 - `GET /status` - HTML status dashboard, which reads `/api/v1/stats`
 - `GET /status.json` - JSON statistics: feed, memory, database and route figures
 - `GET /.well-known/healthcheck.json` - Health check (JSON): 200 when the
   database answers and the RIS Live feed is connected, otherwise 503;
   `data.status` is `ok` or `error` and `data.checks` says which check failed
 - `GET /as/{asn}` - AS detail page (HTML): the prefixes the AS originates and
-  its peers
+  its peers. When the database has no record of the AS, its handle and
+  description come from the AS list built into RouteWatch. The page then shows
+  no first-seen date.
 - `GET /prefix/{prefix}/{length}` - Prefix detail page (HTML), such as
   `/prefix/192.0.2.0/24`: every live route for the prefix, one per peer, and its
   origin ASes
@@ -93,9 +95,22 @@ Every route answers `HEAD` as it answers `GET`, without the body.
   and 404 when none of the addresses has a live route. A PTR lookup gets 2
   seconds; an address whose lookup takes longer is answered without PTR names.
 - `GET /api/v1/as/{asn}` - The AS and the prefixes it originates, IPv4 and IPv6
-  apart, each with when its newest route was updated
+  apart, each with when its newest route was updated. When the database has no
+  record of the AS, its handle and description come from the AS list built into
+  RouteWatch. The answer then has no `first_seen` or `last_seen`.
 - `GET /api/v1/prefix/{prefix}/{length}` - Every live route for the prefix, one
   per peer, and the same routes grouped by origin AS in `origins`
+- `GET /api/v1/search/as?q={text}` - Finds the ASes whose handle or description
+  contains `{text}`, ignoring case. `data` holds:
+    - `query`: `{text}` without its leading and trailing spaces
+    - `total`: the number of ASes that match
+    - `results`: the first 50 of them in AS number order, each with `asn`,
+      `handle` and `description`
+
+    The search reads the AS list built into RouteWatch, not the database. The
+    list comes from [ipverse/asn-info](https://github.com/ipverse/asn-info). A
+    match can therefore be an AS that the database has no record of. A `q` that
+    is missing, empty or only spaces answers 400.
 
 A JSON answer is `{"status": "ok", "data": ...}`, or for an error
 `{"status": "error", "error": {"msg": ..., "code": ...}}`, and carries an
@@ -106,13 +121,15 @@ took. The health check is the exception: its 503 answer is also
 A request that runs past its time limit answers 504: the limit is 30 seconds,
 and 4 seconds for the database reads behind `/status.json` and `/api/v1/stats`.
 An AS number, prefix or mask length that does not parse answers 400, as does a
-mask length out of range for its IP version. An AS the database does not hold,
+mask length out of range for its IP version. An AS answers 404 when it is not in
-or a prefix with no live route, answers 404. The HTML pages give these errors as
+the AS list built into RouteWatch and the database has neither a record of it
-plain text. Under `/api/v1` and `/ip/`, a path no route matches answers 404 with
+nor a live route it originates. A prefix with no live route answers 404 too. The
-the message `Not found`, and `POST`, `PUT`, `PATCH`, `DELETE`, `OPTIONS`,
+HTML pages give these errors as plain text. Under `/api/v1` and `/ip/`, a path
-`TRACE` or `CONNECT` answers 405 with `Method not allowed`. A 500 answer says
+no route matches answers 404 with the message `Not found`, and `POST`, `PUT`,
-only `Internal server error`, and a host name that does not resolve only
+`PATCH`, `DELETE`, `OPTIONS`, `TRACE` or `CONNECT` answers 405 with
-`could not resolve host name`; the detail goes to the log.
+`Method not allowed`. A 500 answer says only `Internal server error`, and a host
+name that does not resolve only `could not resolve host name`; the detail goes
+to the log.
 
 Every answer carries `Strict-Transport-Security`, `Content-Security-Policy`,
 `X-Frame-Options`, `X-Content-Type-Options`, `Referrer-Policy` and

TODO.md

@@ -33,6 +33,11 @@ tested.
 
 # Completed Steps
 
+- 2026-10-26: the home page's AS name search lists the ASes whose handle or
+  description holds the text, as links to their pages, from the new
+  `/api/v1/search/as`; the search ignores case. When the database has no record
+  of an AS, its page takes the handle and description from the AS list built
+  into RouteWatch and still lists the AS's prefixes (closes #151)
 - 2026-10-19: README "HTTP Endpoints" lists every route with what it answers,
   "Database Schema" matches `schema.sql`, and the rest of the README matches the
   code; this file brought up to date (closes #72)

internal/database/database.go

@@ -1748,6 +1748,11 @@ func (d *Database) GetASDetails(asn int) (*ASN, []LiveRoute, error) {
 // GetASDetailsContext returns the AS and the prefixes it originates, the IPv4
 // ones first, each once with the time of its newest route. It makes two index
 // searches per prefix, however many peers carry the prefix.
+//
+// The routes of an AS can be stored before its record in the asns table. When
+// the AS has no record, its handle and description come from the AS info
+// lookup, and it has no seen times. An AS with no record, no lookup entry and
+// no prefix is ErrNoRoute.
 func (d *Database) GetASDetailsContext(
 	ctx context.Context, asn int,
 ) (*ASN, []LiveRoute, error) {
@@ -1763,17 +1768,28 @@ func (d *Database) GetASDetailsContext(
 		asn,
 	).Scan(&asnInfo.ASN, &handle, &description, &asnInfo.FirstSeen,
 		&asnInfo.LastSeen)
-	if err != nil {
+
-		if errors.Is(err, sql.ErrNoRows) {
+	// known is whether the asns table or the AS info lookup holds the AS.
-			return nil, nil, fmt.Errorf("%w: AS%d", ErrNoRoute, asn)
+	known := true
+
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		asnInfo.ASN = asn
+
+		info, ok := asinfo.Get(asn)
+		if ok {
+			asnInfo.Handle = info.Handle
+			asnInfo.Description = info.Description
 		}
 
+		known = ok
+	case err != nil:
 		return nil, nil, fmt.Errorf("failed to query AS: %w", err)
+	default:
+		asnInfo.Handle = handle.String
+		asnInfo.Description = description.String
 	}
 
-	asnInfo.Handle = handle.String
-	asnInfo.Description = description.String
-
 	allPrefixes, err := d.originPrefixes(ctx, asn, ipVersionV4)
 	if err != nil {
 		return &asnInfo, nil, err
@@ -1784,7 +1800,13 @@ func (d *Database) GetASDetailsContext(
 		return &asnInfo, allPrefixes, err
 	}
 
-	return &asnInfo, append(allPrefixes, prefixesV6...), nil
+	allPrefixes = append(allPrefixes, prefixesV6...)
+
+	if !known && len(allPrefixes) == 0 {
+		return nil, nil, fmt.Errorf("%w: AS%d", ErrNoRoute, asn)
+	}
+
+	return &asnInfo, allPrefixes, nil
 }
 
 // ASPeer represents a peering relationship with another AS including handle,

internal/database/database_internal_test.go

@@ -20,6 +20,7 @@ import (
 
 	"git.eeqj.de/sneak/routewatch/internal/config"
 	"git.eeqj.de/sneak/routewatch/internal/logger"
+	"git.eeqj.de/sneak/routewatch/pkg/asinfo"
 	"github.com/mattn/go-sqlite3"
 )
 
@@ -1699,6 +1700,86 @@ func TestGetASDetailsListsEachPrefixOnce(t *testing.T) {
 	}
 }
 
+// TestGetASDetailsOfASNotInDatabase asks for ASes that the database has no
+// record of, some with stored routes. Each gets the prefixes of its routes and
+// no seen times. One that the AS info lookup knows gets its handle and
+// description from it. An AS with no record, no lookup entry and no route is
+// ErrNoRoute. Before the fix an AS with no record got no prefixes, although
+// its routes were stored.
+func TestGetASDetailsOfASNotInDatabase(t *testing.T) {
+	t.Parallel()
+
+	db, err := New(&config.Config{StateDir: t.TempDir()}, logger.New())
+	if err != nil {
+		t.Fatalf("failed to create database: %v", err)
+	}
+	defer func() { _ = db.Close() }()
+
+	ts := time.Date(2026, 1, 2, 3, 4, 5, 0, time.UTC)
+
+	tests := []struct {
+		asn      int
+		listed   bool     // in the AS info lookup
+		prefixes []string // of the routes stored for the AS
+	}{
+		{15169, true, []string{"192.0.2.0/24"}},
+		{13335, true, nil},
+		{4200000000, false, []string{"198.51.100.0/24"}},
+	}
+
+	var routes []*LiveRoute
+
+	for _, tt := range tests {
+		if _, ok := asinfo.Get(tt.asn); ok != tt.listed {
+			t.Fatalf("AS%d in the AS info data: %t, want %t", tt.asn, ok, tt.listed)
+		}
+
+		for _, prefix := range tt.prefixes {
+			routes = append(routes, mkV4Route(t, prefix, tt.asn, ts))
+		}
+	}
+
+	err = db.UpsertLiveRouteBatch(routes)
+	if err != nil {
+		t.Fatalf("UpsertLiveRouteBatch: %v", err)
+	}
+
+	for _, tt := range tests {
+		got, prefixes, err := db.GetASDetails(tt.asn)
+		if err != nil {
+			t.Errorf("GetASDetails(%d): %v", tt.asn, err)
+
+			continue
+		}
+
+		want := ASN{ASN: tt.asn}
+		if info, ok := asinfo.Get(tt.asn); ok {
+			want.Handle, want.Description = info.Handle, info.Description
+		}
+
+		var gotPrefixes []string
+		for _, route := range prefixes {
+			gotPrefixes = append(gotPrefixes, route.Prefix)
+		}
+
+		if *got != want || !slices.Equal(gotPrefixes, tt.prefixes) {
+			t.Errorf("GetASDetails(%d) = %+v with prefixes %v, want %+v with %v",
+				tt.asn, *got, gotPrefixes, want, tt.prefixes)
+		}
+	}
+
+	const absentASN = 4200000001 // no record, no lookup entry and no route
+
+	if _, ok := asinfo.Get(absentASN); ok {
+		t.Fatalf("AS%d is in the AS info data", absentASN)
+	}
+
+	_, _, err = db.GetASDetails(absentASN)
+	if !errors.Is(err, ErrNoRoute) {
+		t.Errorf("GetASDetails(%d): error %v, want %v", absentASN, err, ErrNoRoute)
+	}
+}
+
 // TestASPrefixQueriesUseCoveringIndexes checks the plan of each query that
 // lists the prefixes an AS originates: a search of a covering index and no
 // temporary B-tree, so the list reads one index entry per prefix, not one

internal/database/models.go

@@ -28,9 +28,10 @@ type ASN struct {
 	RIRRegDate  *time.Time `json:"rir_registration_date,omitempty"`
 	RIRLastMod  *time.Time `json:"rir_last_modified,omitempty"`
 	WHOISRaw    string     `json:"whois_raw,omitempty"`
-	// Timestamps
+	// Timestamps. They are zero, and left out of JSON, for an AS that has no
-	FirstSeen      time.Time  `json:"first_seen"`
+	// record in the asns table.
-	LastSeen       time.Time  `json:"last_seen"`
+	FirstSeen      time.Time  `json:"first_seen,omitzero"`
+	LastSeen       time.Time  `json:"last_seen,omitzero"`
 	WHOISUpdatedAt *time.Time `json:"whois_updated_at,omitempty"`
 }
 

internal/server/handlers.go

@@ -56,10 +56,18 @@ const (
 // Error messages an answer sends, in place of the error behind it where there
 // is one.
 const (
-	invalidPrefixMessage   = "Invalid prefix"
+	invalidPrefixMessage      = "Invalid prefix"
-	hostNotResolvedMessage = "could not resolve host name"
+	hostNotResolvedMessage    = "could not resolve host name"
-	hostNotPublicMessage   = "host name has no public address"
+	hostNotPublicMessage      = "host name has no public address"
-	tooManyTargetsMessage  = "Too many addresses or host names"
+	tooManyTargetsMessage     = "Too many addresses or host names"
+	searchQueryMissingMessage = "Missing search query"
+)
+
+// The AS name search reads the text it looks for from the URL query parameter
+// asSearchQueryParam, and answers with at most maxASSearchResults matches.
+const (
+	asSearchQueryParam = "q"
+	maxASSearchResults = 50
 )
 
 // IP versions as database.LiveRoute.IPVersion records them.
@@ -1001,11 +1009,12 @@ func (s *Server) handleASDetailJSON() http.HandlerFunc {
 	}
 }
 
-// splitRoutesByIPVersion groups routes into the IPv4 and the IPv6 ones.
+// splitRoutesByIPVersion groups routes into the IPv4 and the IPv6 ones. Neither
+// group is nil, so that a JSON answer holds [] for an empty one and not null.
 func splitRoutesByIPVersion(
 	routes []database.LiveRoute,
 ) ([]database.LiveRoute, []database.LiveRoute) {
-	var ipv4Routes, ipv6Routes []database.LiveRoute
+	ipv4Routes, ipv6Routes := []database.LiveRoute{}, []database.LiveRoute{}
 
 	for _, route := range routes {
 		if route.IPVersion == ipVersionV4 {
@@ -1105,6 +1114,46 @@ func (s *Server) handlePrefixDetailJSON() http.HandlerFunc {
 	}
 }
 
+// ASSearchResponse is the answer to an AS name search: the text searched for,
+// the number of ASes that match it, and the first maxASSearchResults of them in
+// AS number order.
+type ASSearchResponse struct {
+	Query   string        `json:"query"`
+	Total   int           `json:"total"`
+	Results []asinfo.Info `json:"results"`
+}
+
+// handleASSearch returns a handler that searches the AS list built into
+// asinfo for the text in the q parameter, without its leading and trailing
+// spaces. It answers 400 when no text is left.
+func (s *Server) handleASSearch() http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		query := strings.TrimSpace(r.URL.Query().Get(asSearchQueryParam))
+		if query == "" {
+			s.writeJSONError(w, http.StatusBadRequest, searchQueryMissingMessage)
+
+			return
+		}
+
+		matches := asinfo.Search(query)
+
+		// results is an empty list rather than nil when nothing matches, so
+		// that the answer holds [] and not null.
+		shown := min(len(matches), maxASSearchResults)
+		results := make([]asinfo.Info, 0, shown)
+		results = append(results, matches[:shown]...)
+
+		err := writeJSONSuccess(w, ASSearchResponse{
+			Query:   query,
+			Total:   len(matches),
+			Results: results,
+		})
+		if err != nil {
+			s.logger.Error("Failed to encode AS search results", "error", err)
+		}
+	}
+}
+
 // handleASDetail returns a handler that serves the AS detail HTML page
 func (s *Server) handleASDetail() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {

internal/server/handlers_internal_test.go

@@ -26,6 +26,7 @@ import (
 // The prefix and peer addresses the prefix page tests store routes for.
 const (
 	testPrefixV4 = "192.0.2.0/24"
+	testPrefixV6 = "2001:db8::/32"
 	testPeerV4   = "198.51.100.1"
 	testPeerV6   = "2001:db8::1"
 )
@@ -194,7 +195,7 @@ func TestStatsHandlersAnswerFromMemory(t *testing.T) {
 }
 
 // newServerWithTestRoutes returns a server on a new database that holds a
-// route for testPrefixV4 and one for 2001:db8::/32.
+// route for testPrefixV4 and one for testPrefixV6.
 func newServerWithTestRoutes(t *testing.T) *Server {
 	t.Helper()
 
@@ -214,7 +215,7 @@ func newServerWithTestRoutes(t *testing.T) *Server {
 			NextHop: testPeerV4, LastUpdated: ts,
 		},
 		{
-			Prefix: "2001:db8::/32", MaskLength: 32, IPVersion: 6,
+			Prefix: testPrefixV6, MaskLength: 32, IPVersion: 6,
 			OriginASN: 64501, PeerIP: testPeerV6, ASPath: []int{64501},
 			NextHop: testPeerV6, LastUpdated: ts,
 		},
@@ -1166,6 +1167,327 @@ func TestIPLookupHidesPrivateAddresses(t *testing.T) {
 	}
 }
 
+// asSearchPath is the path of the AS name search.
+const asSearchPath = "/api/v1/search/as"
+
+// searchAS sends an AS name search with the URL query rawQuery through s's
+// router, expects a 200 answer, and returns its data.
+func searchAS(t *testing.T, s *Server, rawQuery string) ASSearchResponse {
+	t.Helper()
+
+	rec := httptest.NewRecorder()
+	s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
+		t.Context(), http.MethodGet, asSearchPath+"?"+rawQuery, nil))
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("%s: status %d, want %d; body %s",
+			rawQuery, rec.Code, http.StatusOK, rec.Body)
+	}
+
+	var body struct {
+		Data ASSearchResponse `json:"data"`
+	}
+
+	err := json.Unmarshal(rec.Body.Bytes(), &body)
+	if err != nil {
+		t.Fatalf("%s: decoding the answer %q: %v", rawQuery, rec.Body, err)
+	}
+
+	return body.Data
+}
+
+// TestASSearchAnswersMatches searches for Cloudflare's handle in lower case,
+// with spaces around it, and expects AS13335 among the matches. Before the fix
+// there was no AS name search, and the home page's search card said it was
+// coming soon (https://git.eeqj.de/sneak/routewatch/issues/151).
+func TestASSearchAnswersMatches(t *testing.T) {
+	t.Parallel()
+
+	const query = "cloudflarenet"
+
+	data := searchAS(t, newServerWithTestRoutes(t), "q=%20"+query+"%20")
+
+	if data.Query != query {
+		t.Errorf("query %q, want %q", data.Query, query)
+	}
+
+	if data.Total != len(data.Results) {
+		t.Errorf("total %d, but %d results", data.Total, len(data.Results))
+	}
+
+	cloudflare := asinfo.Info{
+		ASN: 13335, Handle: "CLOUDFLARENET", Description: "Cloudflare, Inc.",
+	}
+	if !slices.Contains(data.Results, cloudflare) {
+		t.Errorf("results %v do not hold %v", data.Results, cloudflare)
+	}
+}
+
+// TestASSearchAnswersEmptyListWhenNothingMatches expects a search that matches
+// nothing to answer 200 with a total of 0 and an empty list, not null.
+func TestASSearchAnswersEmptyListWhenNothingMatches(t *testing.T) {
+	t.Parallel()
+
+	data := searchAS(t, newServerWithTestRoutes(t), "q=XYZABC123456")
+
+	if data.Total != 0 || data.Results == nil || len(data.Results) != 0 {
+		t.Errorf("total %d and results %#v, want 0 and an empty list",
+			data.Total, data.Results)
+	}
+}
+
+// TestASSearchAnswers400ForEmptyQuery expects a search with no q, an empty q
+// or a q of only spaces to answer 400 with the JSON error body.
+func TestASSearchAnswers400ForEmptyQuery(t *testing.T) {
+	t.Parallel()
+
+	s := newServerWithTestRoutes(t)
+
+	for _, path := range []string{
+		asSearchPath, asSearchPath + "?q=", asSearchPath + "?q=%20%20",
+	} {
+		rec := httptest.NewRecorder()
+		s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
+			t.Context(), http.MethodGet, path, nil))
+
+		if rec.Code != http.StatusBadRequest {
+			t.Errorf("%s: status %d, want %d; body %s",
+				path, rec.Code, http.StatusBadRequest, rec.Body)
+		}
+
+		checkJSONErrorCode(t, path, rec, http.StatusBadRequest)
+		checkJSONErrorMessage(t, path, rec, searchQueryMissingMessage)
+	}
+}
+
+// TestASSearchShowsFirstMatchesAndTotal searches for a word with more matches
+// than an answer holds, and expects the first maxASSearchResults of them, in
+// AS number order, and the number of all of them.
+func TestASSearchShowsFirstMatchesAndTotal(t *testing.T) {
+	t.Parallel()
+
+	const query = "university"
+
+	all := asinfo.Search(query)
+	if len(all) <= maxASSearchResults {
+		t.Fatalf("Search(%q) has %d matches; the test needs more than %d",
+			query, len(all), maxASSearchResults)
+	}
+
+	data := searchAS(t, newServerWithTestRoutes(t), "q="+query)
+
+	if data.Total != len(all) {
+		t.Errorf("total %d, want %d", data.Total, len(all))
+	}
+
+	if !slices.Equal(data.Results, all[:maxASSearchResults]) {
+		t.Errorf("results %v, want the first %d matches %v",
+			data.Results, maxASSearchResults, all[:maxASSearchResults])
+	}
+}
+
+// The AS numbers the AS detail tests ask for. storedASN originates the route
+// for testPrefixV4 and is in the database. routeOnlyASN originates the route
+// for testPrefixV6, but the database has no record of the AS itself, as when
+// a route is stored before its AS. builtInOnlyASN is in the AS list built into
+// asinfo but not in the database. unknownASN is in neither.
+const (
+	storedASN      = 64500
+	routeOnlyASN   = 64501
+	builtInOnlyASN = 15169
+	unknownASN     = 4200000000
+)
+
+// zeroDate is how a page writes a time that was never set.
+const zeroDate = "0001-01-01"
+
+// firstSeenCard is the label of the AS page's first-seen date.
+const firstSeenCard = `<div class="info-label">First Seen</div>`
+
+// newServerWithStoredAS returns newServerWithTestRoutes's server with storedASN
+// added to the database. It fails the test when the AS list built into asinfo
+// lacks routeOnlyASN or builtInOnlyASN, or holds unknownASN.
+func newServerWithStoredAS(t *testing.T) *Server {
+	t.Helper()
+
+	for _, asn := range []int{routeOnlyASN, builtInOnlyASN} {
+		if _, ok := asinfo.Get(asn); !ok {
+			t.Fatalf("AS%d is not in the AS info data", asn)
+		}
+	}
+
+	if _, ok := asinfo.Get(unknownASN); ok {
+		t.Fatalf("AS%d is in the AS info data", unknownASN)
+	}
+
+	s := newServerWithTestRoutes(t)
+
+	_, err := s.db.GetOrCreateASN(storedASN, time.Date(2026, 1, 2, 3, 4, 5, 0, time.UTC))
+	if err != nil {
+		t.Fatalf("GetOrCreateASN: %v", err)
+	}
+
+	return s
+}
+
+// TestASDetailJSONAnswersBuiltInAS asks /api/v1/as/ for each of the ASes above.
+// All but unknownASN answer 200 with the handle and description from the
+// built-in AS list and their prefixes, as lists even when empty. Only storedASN
+// has a first_seen time. unknownASN answers 404. Before the fix builtInOnlyASN
+// answered 404, so a result of the AS name search could lead nowhere
+// (https://git.eeqj.de/sneak/routewatch/issues/151), and routeOnlyASN listed
+// no prefixes.
+func TestASDetailJSONAnswersBuiltInAS(t *testing.T) {
+	t.Parallel()
+
+	s := newServerWithStoredAS(t)
+
+	tests := []struct {
+		asn           int
+		wantCode      int
+		wantPrefixes  []string
+		wantFirstSeen bool
+	}{
+		{storedASN, http.StatusOK, []string{testPrefixV4}, true},
+		{routeOnlyASN, http.StatusOK, []string{testPrefixV6}, false},
+		{builtInOnlyASN, http.StatusOK, nil, false},
+		{unknownASN, http.StatusNotFound, nil, false},
+	}
+
+	for _, tt := range tests {
+		path := "/api/v1/as/" + strconv.Itoa(tt.asn)
+		rec := httptest.NewRecorder()
+		s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
+			t.Context(), http.MethodGet, path, nil))
+
+		if rec.Code != tt.wantCode {
+			t.Errorf("%s: status %d, want %d; body %s",
+				path, rec.Code, tt.wantCode, rec.Body)
+
+			continue
+		}
+
+		if tt.wantCode != http.StatusOK {
+			checkJSONErrorCode(t, path, rec, tt.wantCode)
+
+			continue
+		}
+
+		//nolint:tagliatelle // field names are the existing JSON API
+		var body struct {
+			Data struct {
+				ASN          database.ASN         `json:"asn"`
+				IPv4Prefixes []database.LiveRoute `json:"ipv4_prefixes"`
+				IPv6Prefixes []database.LiveRoute `json:"ipv6_prefixes"`
+			} `json:"data"`
+		}
+
+		err := json.Unmarshal(rec.Body.Bytes(), &body)
+		if err != nil {
+			t.Errorf("%s: decoding the answer %q: %v", path, rec.Body, err)
+
+			continue
+		}
+
+		info, _ := asinfo.Get(tt.asn)
+		got := body.Data.ASN
+
+		if got.ASN != tt.asn || got.Handle != info.Handle ||
+			got.Description != info.Description {
+			t.Errorf("%s: AS %d %q %q, want %d %q %q", path, got.ASN,
+				got.Handle, got.Description, tt.asn, info.Handle, info.Description)
+		}
+
+		if body.Data.IPv4Prefixes == nil || body.Data.IPv6Prefixes == nil {
+			t.Errorf("%s: a prefix list is null; body %s", path, rec.Body)
+		}
+
+		routes := slices.Concat(body.Data.IPv4Prefixes, body.Data.IPv6Prefixes)
+
+		gotPrefixes := make([]string, 0, len(routes))
+		for _, route := range routes {
+			gotPrefixes = append(gotPrefixes, route.Prefix)
+		}
+
+		if !slices.Equal(gotPrefixes, tt.wantPrefixes) {
+			t.Errorf("%s: prefixes %v, want %v", path, gotPrefixes, tt.wantPrefixes)
+		}
+
+		gotFirstSeen := strings.Contains(rec.Body.String(), `"first_seen"`)
+		if gotFirstSeen != tt.wantFirstSeen {
+			t.Errorf("%s: has first_seen %t, want %t; body %s",
+				path, gotFirstSeen, tt.wantFirstSeen, rec.Body)
+		}
+	}
+}
+
+// TestASDetailPageShowsBuiltInAS asks /as/ for each of the ASes above. All but
+// unknownASN answer 200 with the handle and description from the built-in AS
+// list. storedASN and routeOnlyASN list their prefixes, and builtInOnlyASN says
+// the AS announces none. Only storedASN shows a first-seen date, and no page
+// shows a date that was never set. unknownASN answers 404. Before the fix
+// builtInOnlyASN answered 404, so a result of the AS name search led nowhere
+// (https://git.eeqj.de/sneak/routewatch/issues/151), and routeOnlyASN listed no
+// prefixes.
+func TestASDetailPageShowsBuiltInAS(t *testing.T) {
+	t.Parallel()
+
+	s := newServerWithStoredAS(t)
+
+	tests := []struct {
+		asn           int
+		wantCode      int
+		wantText      string
+		wantFirstSeen bool
+	}{
+		{storedASN, http.StatusOK, testPrefixV4, true},
+		{routeOnlyASN, http.StatusOK, testPrefixV6, false},
+		{builtInOnlyASN, http.StatusOK, "No prefixes announced by this AS", false},
+		{unknownASN, http.StatusNotFound, "", false},
+	}
+
+	for _, tt := range tests {
+		path := "/as/" + strconv.Itoa(tt.asn)
+		rec := httptest.NewRecorder()
+		s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
+			t.Context(), http.MethodGet, path, nil))
+
+		if rec.Code != tt.wantCode {
+			t.Errorf("%s: status %d, want %d; body %s",
+				path, rec.Code, tt.wantCode, rec.Body)
+
+			continue
+		}
+
+		if tt.wantCode != http.StatusOK {
+			continue
+		}
+
+		info, _ := asinfo.Get(tt.asn)
+		page := rec.Body.String()
+
+		for _, want := range []string{
+			html.EscapeString(info.Handle),
+			html.EscapeString(info.Description),
+			tt.wantText,
+		} {
+			if !strings.Contains(page, want) {
+				t.Errorf("%s: page does not show %q", path, want)
+			}
+		}
+
+		if strings.Contains(page, zeroDate) {
+			t.Errorf("%s: page shows the date %s", path, zeroDate)
+		}
+
+		gotFirstSeen := strings.Contains(page, firstSeenCard)
+		if gotFirstSeen != tt.wantFirstSeen {
+			t.Errorf("%s: shows a first-seen date %t, want %t",
+				path, gotFirstSeen, tt.wantFirstSeen)
+		}
+	}
+}
+
 // settledGoroutineCount lets transient goroutines finish, then reports the
 // current count.
 func settledGoroutineCount() int {

internal/server/routes.go

@@ -87,6 +87,7 @@ func (s *Server) setupRoutes() {
 		r.Get("/ip/{ip}", s.handleIPLookup())
 		r.Get("/as/{asn}", s.handleASDetailJSON())
 		r.Get("/prefix/{prefix}/{len}", s.handlePrefixDetailJSON())
+		r.Get("/search/as", s.handleASSearch())
 	})
 
 	s.router = r

internal/server/server.go

@@ -1,4 +1,8 @@
-// Package server provides HTTP endpoints for status monitoring and statistics
+// Package server serves RouteWatch's web pages and JSON API:
+//   - the home page, the status figures and the health check
+//   - the AS, prefix and prefix length pages, and the JSON answers behind them
+//   - the IP lookups
+//   - the AS name search
 package server
 
 import (

internal/templates/as_detail.html

@@ -233,10 +233,12 @@
                 <div class="info-label">Peer ASNs</div>
                 <div class="info-value">{{.PeerCount}}</div>
             </div>
+            {{if not .ASN.FirstSeen.IsZero}}
             <div class="info-card">
                 <div class="info-label">First Seen</div>
                 <div class="info-value">{{.ASN.FirstSeen.Format "2006-01-02"}}</div>
             </div>
+            {{end}}
         </div>
 
         {{if .IPv4Prefixes}}

internal/templates/index.html

@@ -174,6 +174,38 @@
         #asname-results .search-message {
             font-size: 13px;
         }
+        #asname-results .error {
+            color: #c00;
+        }
+        .asname-list {
+            list-style: none;
+            margin: 12px 0 0 0;
+            padding: 0;
+            max-height: 400px;
+            overflow-y: auto;
+        }
+        .asname-list li {
+            border-bottom: 1px solid #eee;
+        }
+        .asname-list a {
+            display: block;
+            padding: 8px 4px;
+            color: #2c3e50;
+            text-decoration: none;
+            font-size: 14px;
+        }
+        .asname-list a:hover {
+            background: #f5f5f5;
+        }
+        .asname-list .asn {
+            font-weight: 600;
+            color: #3498db;
+        }
+        .asname-list .description {
+            display: block;
+            color: #7f8c8d;
+            font-size: 12px;
+        }
 
         /* IP Lookup result */
         .ip-result {
@@ -306,7 +338,7 @@
                     <input type="text" id="asname-input" placeholder="e.g., Google, Cloudflare" autocomplete="off">
                     <button type="submit">Search</button>
                 </form>
-                <p class="search-hint">Search for autonomous systems by organization name</p>
+                <p class="search-hint">Search for autonomous systems by organization name or handle</p>
                 <div id="asname-results"></div>
             </div>
 
@@ -387,24 +419,82 @@
             }
         });
 
-        // AS name search
+        // AS name search. The handles and descriptions come from outside data,
+        // so the results are built with textContent, never innerHTML.
+        const asNameResults = document.getElementById('asname-results');
+
+        // Replace the search results with one line of text.
+        function showASNameMessage(text, className) {
+            const line = document.createElement('p');
+            line.className = className;
+            line.textContent = text;
+            asNameResults.replaceChildren(line);
+        }
+
+        // List the matches of a search answer, each as a link to its AS page,
+        // and say how many more matched than the answer holds.
+        function showASNameMatches(data) {
+            if (data.total === 0) {
+                showASNameMessage('No AS matches "' + data.query + '".', 'search-message');
+                return;
+            }
+
+            const list = document.createElement('ul');
+            list.className = 'asname-list';
+            for (const match of data.results) {
+                const asn = document.createElement('span');
+                asn.className = 'asn';
+                asn.textContent = 'AS' + match.asn;
+
+                const description = document.createElement('span');
+                description.className = 'description';
+                description.textContent = match.description;
+
+                const link = document.createElement('a');
+                link.href = '/as/' + match.asn;
+                link.append(asn, ' ' + match.handle, description);
+
+                const item = document.createElement('li');
+                item.append(link);
+                list.append(item);
+            }
+            asNameResults.replaceChildren(list);
+
+            const more = data.total - data.results.length;
+            if (more > 0) {
+                const line = document.createElement('p');
+                line.className = 'search-message';
+                line.textContent = more.toLocaleString() + ' more matched. Narrow the search to see them.';
+                asNameResults.append(line);
+            }
+        }
+
         document.getElementById('asname-form').addEventListener('submit', function(e) {
             e.preventDefault();
             const query = document.getElementById('asname-input').value.trim();
             if (!query) return;
 
-            const resultsDiv = document.getElementById('asname-results');
+            // A number, or AS and a number, opens that AS's page
-            resultsDiv.innerHTML = '<p class="loading">Searching...</p>';
+            const asn = query.replace(/^AS/i, '');
-
+            if (/^\d+$/.test(asn)) {
-            // Use a simple client-side search against the asinfo data
+                window.location.href = '/as/' + asn;
-            // For now, redirect to AS page if it looks like an ASN
-            if (/^\d+$/.test(query)) {
-                window.location.href = '/as/' + query;
                 return;
             }
 
-            // Show a message that server-side search is coming
+            showASNameMessage('Searching...', 'loading');
-            resultsDiv.innerHTML = '<p class="search-message">AS name search coming soon. For now, try an AS number.</p>';
+
+            fetch('/api/v1/search/as?q=' + encodeURIComponent(query))
+                .then(response => response.json())
+                .then(response => {
+                    if (response.status === 'error') {
+                        showASNameMessage('Error: ' + response.error.msg, 'error');
+                    } else {
+                        showASNameMatches(response.data);
+                    }
+                })
+                .catch(error => {
+                    showASNameMessage('Error: ' + error.message, 'error');
+                });
         });
 
         // IP lookup

pkg/asinfo/asinfo.go

@@ -2,10 +2,13 @@ package asinfo
 
 import (
 	"bytes"
+	"cmp"
 	"compress/gzip"
 	_ "embed"
 	"encoding/json"
 	"io"
+	"slices"
+	"strings"
 	"sync"
 )
 
@@ -23,6 +26,17 @@ type Info struct {
 type Registry struct {
 	mu    sync.RWMutex
 	byASN map[int]*Info
+	// searchEntries holds every entry in AS number order, for Search.
+	searchEntries []searchEntry
+}
+
+// searchEntry is an entry with its handle and description in lower case. They
+// are put in lower case once, when the data loads, so that Search only
+// compares.
+type searchEntry struct {
+	info             *Info
+	lowerHandle      string
+	lowerDescription string
 }
 
 var (
@@ -59,9 +73,21 @@ func initRegistry() {
 		panic("failed to unmarshal embedded AS data: " + err.Error())
 	}
 
+	slices.SortFunc(asInfos, func(a, b Info) int {
+		return cmp.Compare(a.ASN, b.ASN)
+	})
+
+	defaultRegistry.searchEntries = make([]searchEntry, 0, len(asInfos))
+
 	for i := range asInfos {
 		info := &asInfos[i]
 		defaultRegistry.byASN[info.ASN] = info
+		defaultRegistry.searchEntries = append(defaultRegistry.searchEntries,
+			searchEntry{
+				info:             info,
+				lowerHandle:      strings.ToLower(info.Handle),
+				lowerDescription: strings.ToLower(info.Description),
+			})
 	}
 }
 
@@ -129,36 +155,28 @@ func All() []Info {
 	return result
 }
 
-// Search searches for AS entries where the handle or description contains the query
+// Search returns the AS entries whose handle or description contains query,
-// This is a simple case-sensitive substring search
+// ignoring case, in AS number order. An empty query matches nothing.
 func Search(query string) []Info {
 	once.Do(initRegistry)
 
+	if query == "" {
+		return nil
+	}
+
+	query = strings.ToLower(query)
+
 	defaultRegistry.mu.RLock()
 	defer defaultRegistry.mu.RUnlock()
 
 	var results []Info
 
-	for _, info := range defaultRegistry.byASN {
+	for _, entry := range defaultRegistry.searchEntries {
-		if contains(info.Handle, query) || contains(info.Description, query) {
+		if strings.Contains(entry.lowerHandle, query) ||
-			results = append(results, *info)
+			strings.Contains(entry.lowerDescription, query) {
+			results = append(results, *entry.info)
 		}
 	}
 
 	return results
 }
-
-// contains is a simple substring search
-func contains(s, substr string) bool {
-	return len(substr) > 0 && len(s) >= len(substr) && containsImpl(s, substr)
-}
-
-func containsImpl(s, substr string) bool {
-	for i := 0; i <= len(s)-len(substr); i++ {
-		if s[i:i+len(substr)] == substr {
-			return true
-		}
-	}
-
-	return false
-}

pkg/asinfo/asinfo_test.go

@@ -1,6 +1,7 @@
 package asinfo_test
 
 import (
+	"slices"
 	"strings"
 	"testing"
 
@@ -140,11 +141,6 @@ func TestSearch(t *testing.T) {
 			query:   "University",
 			wantMin: 10,
 		},
-		{
-			name:    "Empty search",
-			query:   "",
-			wantMin: 0,
-		},
 		{
 			name:    "Non-existent org",
 			query:   "XYZABC123456",
@@ -162,20 +158,65 @@ func TestSearch(t *testing.T) {
 					tt.query, len(results), tt.wantMin)
 			}
 
-			// Verify all results contain the query
+			// Verify all results contain the query, ignoring case
-			if tt.query != "" {
+			query := strings.ToLower(tt.query)
-				for _, r := range results {
+			for _, r := range results {
-					if !strings.Contains(r.Handle, tt.query) &&
+				if !strings.Contains(strings.ToLower(r.Handle), query) &&
-						!strings.Contains(r.Description, tt.query) {
+					!strings.Contains(strings.ToLower(r.Description), query) {
-						t.Errorf("Search result ASN %d doesn't contain query %q",
+					t.Errorf("Search result ASN %d doesn't contain query %q",
-							r.ASN, tt.query)
+						r.ASN, tt.query)
-					}
 				}
 			}
 		})
 	}
 }
 
+// TestSearchEmptyQueryMatchesNothing expects an empty query to match no AS,
+// although every handle contains the empty string.
+func TestSearchEmptyQueryMatchesNothing(t *testing.T) {
+	t.Parallel()
+
+	results := asinfo.Search("")
+	if len(results) != 0 {
+		t.Errorf(`Search("") returned %d results, want none`, len(results))
+	}
+}
+
+// TestSearchIgnoresCase searches for Cloudflare's handle in lower case and its
+// description in upper case, and expects both searches to find AS13335.
+func TestSearchIgnoresCase(t *testing.T) {
+	t.Parallel()
+
+	const cloudflareASN = 13335 // handle CLOUDFLARENET, "Cloudflare, Inc."
+
+	isCloudflare := func(info asinfo.Info) bool {
+		return info.ASN == cloudflareASN
+	}
+
+	for _, query := range []string{"cloudflarenet", "CLOUDFLARE, INC."} {
+		if !slices.ContainsFunc(asinfo.Search(query), isCloudflare) {
+			t.Errorf("Search(%q) did not find AS%d", query, cloudflareASN)
+		}
+	}
+}
+
+// TestSearchOrdersByASN expects the matches of a search with many of them to
+// come in AS number order.
+func TestSearchOrdersByASN(t *testing.T) {
+	t.Parallel()
+
+	const query = "University"
+
+	results := asinfo.Search(query)
+
+	for i := 1; i < len(results); i++ {
+		if results[i-1].ASN >= results[i].ASN {
+			t.Fatalf("Search(%q): AS%d comes after AS%d",
+				query, results[i].ASN, results[i-1].ASN)
+		}
+	}
+}
+
 func TestDataIntegrity(t *testing.T) {
 	t.Parallel()
 

pkg/asinfo/doc.go

@@ -16,8 +16,9 @@ Basic usage:
 	// Get just the description
 	desc := asinfo.GetDescription(15169) // "Google LLC"
 
-	// Search for AS entries
+	// Search the handles and descriptions, ignoring case; the matches come
-	results := asinfo.Search("University")
+	// in AS number order
+	results := asinfo.Search("university")
 	for _, as := range results {
 		fmt.Printf("AS%d: %s\n", as.ASN, as.Description)
 	}

pkg/asinfo/example_test.go

@@ -21,7 +21,7 @@ func ExampleGetDescription() {
 }
 
 func ExampleSearch() {
-	results := asinfo.Search("MIT-GATEWAY")
+	results := asinfo.Search("mit-gateway")
 	for _, info := range results {
 		fmt.Printf("AS%d: %s - %s\n", info.ASN, info.Handle, info.Description)
 	}