Respond to lstn.lv being renamed to lsn.lv

Closes #1

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2016 - 2024, Přemysl Eric Janouch <p@janouch.name>
+Copyright (c) 2016 - 2025, Přemysl Eric Janouch <p@janouch.name>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted.

go.mod

@@ -1,3 +1,3 @@
 module janouch.name/bbc-on-ice
 
-go 1.22.0
+go 1.20.0

main.go

@@ -6,10 +6,10 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
+	"net/url"
 	"os"
 	"path"
 	"regexp"
@@ -21,26 +21,110 @@ import (
 )
 
 const (
-	targetURI = "http://as-hls-%s-live.akamaized.net/pool_904/live/%s/" +
+	targetURI = "http://as-hls-%s-live.akamaized.net/pool_%s/live/%s/" +
 		"%s/%s.isml/%s-audio%%3d%s.norewind.m3u8"
+	networksURI1 = "https://rms.api.bbc.co.uk/radio/networks.json"
+	networksURI2 = "https://rms.api.bbc.co.uk/v2/networks/%s"
 	metaURI      = "https://rms.api.bbc.co.uk/v2/services/%s/segments/latest"
 )
 
+var client = &http.Client{Transport: &http.Transport{}}
+
+func get(url string) (resp *http.Response, err error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	// lsn.lv returned 403 for the default net.http User-Agent.
+	req.Header.Set("User-Agent", "bbc-on-ice/1")
+	return client.Do(req)
+}
+
+func getServiceTitle1(name string) (string, error) {
+	resp, err := get(networksURI1)
+	if resp != nil {
+		defer resp.Body.Close()
+	}
+	if err != nil {
+		return name, err
+	}
+	b, err := io.ReadAll(resp.Body)
+
+	var v struct {
+		Results []struct {
+			Services []struct {
+				ID    string `json:"id"`
+				Title string `json:"title"`
+			} `json:"services"`
+		} `json:"results"`
+	}
+	err = json.Unmarshal(b, &v)
+	if err != nil {
+		return name, errors.New("invalid metadata response")
+	}
+
+	for _, network := range v.Results {
+		for _, service := range network.Services {
+			if service.ID == name {
+				return service.Title, nil
+			}
+		}
+	}
+	return name, errors.New("unknown service")
+}
+
+// getServiceTitle returns a human-friendly identifier for a BBC service ID.
+func getServiceTitle(name string) (string, error) {
+	// This endpoint is incomplete,
+	// but it contains the kind of service titles we want.
+	title, err := getServiceTitle1(name)
+	if err == nil {
+		return title, nil
+	}
+
+	// Network IDs tend to coincide with service IDs.
+	resp, err := get(fmt.Sprintf(networksURI2, name))
+	if resp != nil {
+		defer resp.Body.Close()
+	}
+	if err != nil {
+		return name, err
+	}
+	b, err := io.ReadAll(resp.Body)
+
+	var v struct {
+		LongTitle string `json:"long_title"`
+	}
+	err = json.Unmarshal(b, &v)
+	if err != nil {
+		return name, errors.New("invalid metadata response")
+	}
+	if v.LongTitle == "" {
+		return name, errors.New("unknown service")
+	}
+	return v.LongTitle, nil
+}
+
 type meta struct {
 	title   string // what's playing right now
 	timeout uint   // timeout for the next poll in ms
 }
 
+var errNoSong = errors.New("no song is playing")
+
 // getMeta retrieves and decodes metadata info from an independent webservice.
 func getMeta(name string) (*meta, error) {
-	resp, err := http.Get(fmt.Sprintf(metaURI, name))
+	resp, err := get(fmt.Sprintf(metaURI, name))
 	if resp != nil {
 		defer resp.Body.Close()
 	}
 	if err != nil {
 		return nil, err
 	}
-	b, err := ioutil.ReadAll(resp.Body)
+	b, err := io.ReadAll(resp.Body)
+	if os.Getenv("DEBUG") != "" {
+		log.Println(string(b))
+	}
 
 	// TODO: update more completely for the new OpenAPI
 	//  - `broadcasts/poll/bbc_radio_one` looks almost useful
@@ -63,32 +147,33 @@ func getMeta(name string) (*meta, error) {
 		return nil, errors.New("invalid metadata response")
 	}
 	if len(v.Data) == 0 || !v.Data[0].Offset.NowPlaying {
-		return nil, errors.New("no song is playing")
+		return nil, errNoSong
 	}
 
 	titles := v.Data[0].Titles
-	parts := []string{}
-	if titles.Tertiary != nil {
-		parts = append(parts, *titles.Tertiary)
-	}
+	parts := []string{titles.Primary}
 	if titles.Secondary != nil {
 		parts = append(parts, *titles.Secondary)
 	}
-	parts = append(parts, titles.Primary)
+	if titles.Tertiary != nil {
+		parts = append(parts, *titles.Tertiary)
+	}
 	return &meta{timeout: 5000, title: strings.Join(parts, " - ")}, nil
 }
 
 // resolveM3U8 resolves an M3U8 playlist to the first link that seems to
 // be playable, possibly recursing.
 func resolveM3U8(target string) (out []string, err error) {
-	resp, err := http.Get(target)
-	if resp != nil {
-		defer resp.Body.Close()
-	}
+	resp, err := get(target)
 	if err != nil {
 		return nil, err
 	}
-	b, err := ioutil.ReadAll(resp.Body)
+	defer resp.Body.Close()
+
+	b, err := io.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("%s: %s", target, resp.Status)
+	}
 	if !utf8.Valid(b) {
 		return nil, errors.New("invalid UTF-8")
 	}
@@ -112,6 +197,36 @@ func resolveM3U8(target string) (out []string, err error) {
 	return out, nil
 }
 
+const resolveURI = "https://lsn.lv/bbcradio.m3u8?station=%s"
+
+var poolRE = regexp.MustCompile(`/pool_([^/]+)/`)
+
+// resolvePool figures out the randomized part of stream URIs.
+func resolvePool(name string) (pool string, err error) {
+	target := fmt.Sprintf(resolveURI, url.QueryEscape(name))
+	resp, err := get(target)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	b, err := io.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("%s: %s", target, resp.Status)
+	}
+	for _, line := range strings.Split(string(b), "\n") {
+		if strings.HasPrefix(line, "#") {
+			continue
+		}
+		if m := poolRE.FindStringSubmatch(line); m == nil {
+			return "", fmt.Errorf("%s: unexpected URI", target)
+		} else {
+			return m[1], nil
+		}
+	}
+	return "", fmt.Errorf("%s: no URI", target)
+}
+
 // metaProc periodically polls the sub-URL given by name for titles and sends
 // them out the given channel. Never returns prematurely.
 func metaProc(ctx context.Context, name string, out chan<- string) {
@@ -125,9 +240,10 @@ func metaProc(ctx context.Context, name string, out chan<- string) {
 	var interval time.Duration
 	for {
 		meta, err := getMeta(name)
-		if err != nil {
-			current = name + " - " + err.Error()
-			interval = maxInterval
+		if err == errNoSong {
+			interval, current = maxInterval, ""
+		} else if err != nil {
+			interval, current = maxInterval, err.Error()
 		} else {
 			current = meta.title
 			interval = time.Duration(meta.timeout) * time.Millisecond
@@ -192,7 +308,7 @@ func dataProc(ctx context.Context, playlistURL string, maxChunk int,
 	go urlProc(ctx, playlistURL, urls)
 
 	for url := range urls {
-		resp, err := http.Get(url)
+		resp, err := get(url)
 		if resp != nil {
 			defer resp.Body.Close()
 		}
@@ -235,10 +351,15 @@ func proxy(w http.ResponseWriter, req *http.Request) {
 	}
 
 	// [ww]/[uk], [48000/96000]/[128000/320000], bbc_radio_one/bbc_1xtra/...
-	region, quality, name := m[1], m[2], m[3]
+	region, quality, name, pool := m[1], m[2], m[3], "904"
+	if p, err := resolvePool(name); err != nil {
+		log.Printf("failed to resolve pool: %s\n", err)
+	} else {
+		pool = p
+	}
 
 	mediaPlaylistURL :=
-		fmt.Sprintf(targetURI, region, region, name, name, name, quality)
+		fmt.Sprintf(targetURI, region, pool, region, name, name, name, quality)
 
 	// This validates the parameters as a side-effect.
 	media, err := resolveM3U8(mediaPlaylistURL)
@@ -264,11 +385,10 @@ func proxy(w http.ResponseWriter, req *http.Request) {
 	}
 	defer conn.Close()
 
-	// TODO: Retrieve some general information from somewhere?
-	// There's nothing interesting in the playlist files.
+	serviceTitle, _ := getServiceTitle(name)
 
 	fmt.Fprintf(bufrw, "ICY 200 OK\r\n")
-	fmt.Fprintf(bufrw, "icy-name:%s\r\n", name)
+	fmt.Fprintf(bufrw, "icy-name:%s\r\n", serviceTitle)
 	// BBC marks this as a video type, maybe just force audio/mpeg.
 	fmt.Fprintf(bufrw, "content-type:%s\r\n", resp.Header["Content-Type"][0])
 	fmt.Fprintf(bufrw, "icy-pub:%d\r\n", 0)
@@ -301,6 +421,9 @@ func proxy(w http.ResponseWriter, req *http.Request) {
 	for {
 		select {
 		case title := <-metaChan:
+			if title == "" {
+				title = serviceTitle
+			}
 			queuedMetaUpdate = []byte(fmt.Sprintf("StreamTitle='%s'",
 				strings.Replace(title, "'", "’", -1)))
 		case chunk, ok := <-chunkChan: