First working version. Just a POC.

11 files changed, 427 insertions, 0 deletions

diff --git a/bilibili/client.go b/bilibili/client.go
new file mode 100644
index 0000000..fcea395
--- /dev/null
+++ b/bilibili/client.go
@@ -0,0 +1,45 @@
+/*
+This file defines the Bilibili client struct.
+This struct is a facade of all necessary Bilibili HTTP API wrappers.
+*/
+package bilibili
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"os"
+)
+
+const (
+	// kUserAgent: the default user-agent header to use when communicating with bilibili.
+	kUserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) " +
+		"AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36"
+)
+
+type Bilibili struct {
+	userAgent string
+	http      *http.Client
+	loggerCommon
+	ctx context.Context
+}
+
+func NewBilibiliWithContext(ctx context.Context) Bilibili {
+	logger := loggerCommon{
+		debug: log.New(os.Stderr, "DEBUG: ", log.Ldate|log.Ltime|log.Lshortfile),
+		info:  log.New(os.Stderr, "INFO: ", log.Ldate|log.Ltime|log.Lshortfile),
+		warn:  log.New(os.Stderr, "WARNING: ", log.Ldate|log.Ltime|log.Lshortfile),
+		error: log.New(os.Stderr, "ERROR: ", log.Ldate|log.Ltime|log.Lshortfile),
+	}
+	return Bilibili{
+		loggerCommon: logger,
+		userAgent:    kUserAgent,
+		http:         http.DefaultClient,
+		ctx:          ctx,
+	}
+}
+
+func NewBilibili() Bilibili {
+	ctx := context.Background()
+	return NewBilibiliWithContext(ctx)
+}
diff --git a/bilibili/danmaku_server_info.go b/bilibili/danmaku_server_info.go
new file mode 100644
index 0000000..dbdf6bb
--- /dev/null
+++ b/bilibili/danmaku_server_info.go
@@ -0,0 +1,28 @@
+package bilibili
+
+import (
+	"bilibili-livestream-archiver/common"
+	"fmt"
+)
+
+type DanmakuServerInfoResponse = BaseResponse[danmakuInfo]
+
+type danmakuInfo struct {
+	Group            string  `json:"group"`
+	BusinessID       int     `json:"business_id"`
+	RefreshRowFactor float64 `json:"refresh_row_factor"`
+	RefreshRate      int     `json:"refresh_rate"`
+	MaxDelay         int     `json:"max_delay"`
+	Token            string  `json:"token"`
+	HostList         []struct {
+		Host    string `json:"host"`
+		Port    int    `json:"port"`
+		WssPort int    `json:"wss_port"`
+		WsPort  int    `json:"ws_port"`
+	} `json:"host_list"`
+}
+
+func (b Bilibili) GetDanmakuServerInfo(roomId common.RoomId) (resp DanmakuServerInfoResponse, err error) {
+	url := fmt.Sprintf("https://api.live.bilibili.com/xlive/web-room/v1/index/getDanmuInfo?id=%d&type=0", roomId)
+	return callGet[DanmakuServerInfoResponse](b, url)
+}
diff --git a/bilibili/errors.go b/bilibili/errors.go
new file mode 100644
index 0000000..3f8ac9b
--- /dev/null
+++ b/bilibili/errors.go
@@ -0,0 +1,7 @@
+package bilibili
+
+import "fmt"
+
+var (
+	ErrRoomIsClosed = fmt.Errorf("living room is closed")
+)
diff --git a/bilibili/logging.go b/bilibili/logging.go
new file mode 100644
index 0000000..a0b9b8e
--- /dev/null
+++ b/bilibili/logging.go
@@ -0,0 +1,13 @@
+/*
+This file defines the common struct of logger pointers used in modules of this package.
+*/
+package bilibili
+
+import "log"
+
+type loggerCommon struct {
+	debug *log.Logger
+	info  *log.Logger
+	warn  *log.Logger
+	error *log.Logger
+}
diff --git a/bilibili/model.go b/bilibili/model.go
new file mode 100644
index 0000000..ccffef9
--- /dev/null
+++ b/bilibili/model.go
@@ -0,0 +1,8 @@
+package bilibili
+
+type BaseResponse[T any] struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+	TTL     int    `json:"ttl"`
+	Data    T      `json:"data"`
+}
diff --git a/bilibili/play_url.go b/bilibili/play_url.go
new file mode 100644
index 0000000..282d556
--- /dev/null
+++ b/bilibili/play_url.go
@@ -0,0 +1,35 @@
+package bilibili
+
+import (
+	"bilibili-livestream-archiver/common"
+	"fmt"
+)
+
+type RoomUrlInfoResponse = BaseResponse[roomUrlInfo]
+
+type roomUrlInfo struct {
+	CurrentQuality       int                  `json:"current_quality"`
+	AcceptQuality        []string             `json:"accept_quality"`
+	CurrentQualityNumber int                  `json:"current_qn"`
+	QualityDescription   []qualityDescription `json:"quality_description"`
+	URLs                 []StreamingUrlInfo   `json:"durl"`
+}
+
+type qualityDescription struct {
+	QualityNumber int    `json:"qn"`
+	Description   string `json:"desc"`
+}
+
+type StreamingUrlInfo struct {
+	URL        string `json:"url"`
+	Length     int    `json:"length"`
+	Order      int    `json:"order"`
+	StreamType int    `json:"stream_type"`
+	P2pType    int    `json:"p2p_type"`
+}
+
+func (b Bilibili) GetStreamingInfo(roomId common.RoomId) (resp RoomUrlInfoResponse, err error) {
+	url := fmt.Sprintf("https://api.live.bilibili.com/room/v1/Room/playUrl?"+
+		"cid=%d&otype=json&qn=10000&platform=web", roomId)
+	return callGet[RoomUrlInfoResponse](b, url)
+}
diff --git a/bilibili/request.go b/bilibili/request.go
new file mode 100644
index 0000000..cb989a7
--- /dev/null
+++ b/bilibili/request.go
@@ -0,0 +1,68 @@
+package bilibili
+
+import (
+	"encoding/json"
+	"io"
+	"log"
+	"net/http"
+	"strings"
+)
+
+// newRequest create an HTTP request with per-instance User-Agent set.
+func (b Bilibili) newRequest(
+	method string,
+	url string,
+	body io.Reader,
+) (req *http.Request, err error) {
+	req, err = http.NewRequestWithContext(b.ctx, method, url, body)
+	if err != nil {
+		b.error.Printf("Cannot create HTTP request instance: %v. Method: %v, URL: %v", err, method, url)
+		return
+	}
+	req.Header.Set("User-Agent", b.userAgent)
+	return
+}
+
+// newRequest create an HTTP GET request with an empty body and per-instance User-Agent set.
+func (b Bilibili) newGet(url string) (req *http.Request, err error) {
+	return b.newRequest("GET", url, strings.NewReader(""))
+}
+
+// callGet make a GET request and parse response as a JSON document with given model.
+func callGet[T BaseResponse[V], V any](b Bilibili, url string) (resp T, err error) {
+	logger := log.Default()
+	req, err := b.newGet(url)
+	if err != nil {
+		logger.Printf("ERROR: Cannot create HTTP request instance on API %v: %v", url, err)
+		return
+	}
+
+	r, err := b.http.Do(req)
+	defer func() { _ = r.Body.Close() }()
+	if err != nil {
+		logger.Printf("ERROR: HTTP Request failed on API %v: %v", url, err)
+		return
+	}
+
+	err = validateHttpStatus(r)
+	if err != nil {
+		b.error.Printf("%v", err)
+		return
+	}
+
+	data, err := io.ReadAll(r.Body)
+	if err != nil {
+		b.error.Printf("Error when reading HTTP response on API %v: %v", url, err)
+		return
+	}
+
+	err = json.Unmarshal(data, &resp)
+	if err != nil {
+		b.error.Printf("Invalid JSON body of HTTP response on API %v: %v. Text: \"%v\"",
+			url, err, string(data))
+		return
+	}
+
+	b.debug.Printf("HTTP %v, len: %v bytes, url: %v", r.StatusCode, len(data), url)
+	return
+}
diff --git a/bilibili/room_profile.go b/bilibili/room_profile.go
new file mode 100644
index 0000000..d75d447
--- /dev/null
+++ b/bilibili/room_profile.go
@@ -0,0 +1,86 @@
+package bilibili
+
+import (
+	"bilibili-livestream-archiver/common"
+	"fmt"
+)
+
+type roomProfile struct {
+	UID              int      `json:"uid"`
+	RoomID           int      `json:"room_id"`
+	ShortID          int      `json:"short_id"`
+	Attention        int      `json:"attention"`
+	Online           int      `json:"online"`
+	IsPortrait       bool     `json:"is_portrait"`
+	Description      string   `json:"description"`
+	LiveStatus       int      `json:"live_status"`
+	AreaID           int      `json:"area_id"`
+	ParentAreaID     int      `json:"parent_area_id"`
+	ParentAreaName   string   `json:"parent_area_name"`
+	OldAreaID        int      `json:"old_area_id"`
+	Background       string   `json:"background"`
+	Title            string   `json:"title"`
+	UserCover        string   `json:"user_cover"`
+	Keyframe         string   `json:"keyframe"`
+	IsStrictRoom     bool     `json:"is_strict_room"`
+	LiveTime         string   `json:"live_time"`
+	Tags             string   `json:"tags"`
+	IsAnchor         int      `json:"is_anchor"`
+	RoomSilentType   string   `json:"room_silent_type"`
+	RoomSilentLevel  int      `json:"room_silent_level"`
+	RoomSilentSecond int      `json:"room_silent_second"`
+	AreaName         string   `json:"area_name"`
+	Pendants         string   `json:"pendants"`
+	AreaPendants     string   `json:"area_pendants"`
+	HotWords         []string `json:"hot_words"`
+	HotWordsStatus   int      `json:"hot_words_status"`
+	Verify           string   `json:"verify"`
+	NewPendants      struct {
+		Frame struct {
+			Name       string `json:"name"`
+			Value      string `json:"value"`
+			Position   int    `json:"position"`
+			Desc       string `json:"desc"`
+			Area       int    `json:"area"`
+			AreaOld    int    `json:"area_old"`
+			BgColor    string `json:"bg_color"`
+			BgPic      string `json:"bg_pic"`
+			UseOldArea bool   `json:"use_old_area"`
+		} `json:"frame"`
+		Badge struct {
+			Name     string `json:"name"`
+			Position int    `json:"position"`
+			Value    string `json:"value"`
+			Desc     string `json:"desc"`
+		} `json:"badge"`
+		MobileFrame struct {
+			Name       string `json:"name"`
+			Value      string `json:"value"`
+			Position   int    `json:"position"`
+			Desc       string `json:"desc"`
+			Area       int    `json:"area"`
+			AreaOld    int    `json:"area_old"`
+			BgColor    string `json:"bg_color"`
+			BgPic      string `json:"bg_pic"`
+			UseOldArea bool   `json:"use_old_area"`
+		} `json:"mobile_frame"`
+		MobileBadge interface{} `json:"mobile_badge"`
+	} `json:"new_pendants"`
+	UpSession            string `json:"up_session"`
+	PkStatus             int    `json:"pk_status"`
+	PkID                 int    `json:"pk_id"`
+	BattleID             int    `json:"battle_id"`
+	AllowChangeAreaTime  int    `json:"allow_change_area_time"`
+	AllowUploadCoverTime int    `json:"allow_upload_cover_time"`
+	StudioInfo           struct {
+		Status     int           `json:"status"`
+		MasterList []interface{} `json:"master_list"`
+	} `json:"studio_info"`
+}
+
+type RoomProfileResponse = BaseResponse[roomProfile]
+
+func (b Bilibili) GetRoomProfile(roomId common.RoomId) (resp RoomProfileResponse, err error) {
+	url := fmt.Sprintf("https://api.live.bilibili.com/room/v1/Room/get_info?room_id=%d", roomId)
+	return callGet[RoomProfileResponse](b, url)
+}
diff --git a/bilibili/room_status.go b/bilibili/room_status.go
new file mode 100644
index 0000000..6b6495b
--- /dev/null
+++ b/bilibili/room_status.go
@@ -0,0 +1,58 @@
+/*
+Get live room basic status.
+This is used to check initially if it is streaming or not.
+*/
+package bilibili
+
+import (
+	"bilibili-livestream-archiver/common"
+	"fmt"
+)
+
+type LiveStatus int
+
+const (
+	Inactive  LiveStatus = 0
+	Streaming LiveStatus = 1
+	Playback  LiveStatus = 2
+)
+
+var liveStatusStringMap = map[LiveStatus]string{
+	Inactive:  "inactive",
+	Streaming: "streaming",
+	Playback:  "inactive (playback)",
+}
+
+type roomPlayInfo struct {
+	RoomID          uint64        `json:"room_id"`
+	ShortID         uint          `json:"short_id"`
+	UID             uint          `json:"uid"`
+	IsHidden        bool          `json:"is_hidden"`
+	IsLocked        bool          `json:"is_locked"`
+	IsPortrait      bool          `json:"is_portrait"`
+	LiveStatus      LiveStatus    `json:"live_status"` // 0: inactive 1: streaming 2: playback
+	HiddenTill      int           `json:"hidden_till"`
+	LockTill        int           `json:"lock_till"`
+	Encrypted       bool          `json:"encrypted"`
+	PwdVerified     bool          `json:"pwd_verified"`
+	LiveTime        int           `json:"live_time"`
+	RoomShield      int           `json:"room_shield"`
+	AllSpecialTypes []interface{} `json:"all_special_types"`
+	PlayurlInfo     interface{}   `json:"playurl_info"`
+}
+
+type RoomPlayInfoResponse = BaseResponse[roomPlayInfo]
+
+func (s LiveStatus) IsStreaming() bool {
+	return s == Streaming
+}
+
+func (s LiveStatus) String() string {
+	return liveStatusStringMap[s]
+}
+
+func (b Bilibili) GetRoomPlayInfo(roomId common.RoomId) (resp RoomPlayInfoResponse, err error) {
+	url := fmt.Sprintf("https://api.live.bilibili.com/xlive/web-room/v2/index/getRoomPlayInfo"+
+		"?room_id=%d&protocol=0,1&format=0,1,2&codec=0,1&qn=0&platform=web&ptype=8&dolby=5&panorama=1", roomId)
+	return callGet[RoomPlayInfoResponse](b, url)
+}
diff --git a/bilibili/streaming.go b/bilibili/streaming.go
new file mode 100644
index 0000000..cc915a3
--- /dev/null
+++ b/bilibili/streaming.go
@@ -0,0 +1,66 @@
+package bilibili
+
+import (
+	"bilibili-livestream-archiver/common"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+)
+
+// CopyLiveStream read data from a livestream video stream, copy them to a writer.
+func (b Bilibili) CopyLiveStream(
+	ctx context.Context,
+	roomId common.RoomId,
+	stream StreamingUrlInfo,
+	out io.Writer,
+) (err error) {
+	url := stream.URL
+	if !strings.HasPrefix(url, "https://") &&
+		!strings.HasPrefix(url, "http://") {
+		return fmt.Errorf("invalid URL: %v", url)
+	}
+
+	r, err := b.newGet(url)
+	if err != nil {
+		b.error.Printf("Cannot create HTTP GET instance on %v: %v", url, err)
+		return err
+	}
+
+	r.Header.Set("Referer",
+		fmt.Sprintf("https://live.bilibili.com/blanc/%d?liteVersion=true", roomId))
+
+	resp, err := b.http.Do(r)
+	if err != nil {
+		b.error.Printf("Cannot make HTTP GET request on %v: %v\n", url, err)
+		return
+	}
+
+	// 404 when not streaming
+	if resp.StatusCode == http.StatusNotFound {
+		return ErrRoomIsClosed
+	}
+
+	err = validateHttpStatus(resp)
+	if err != nil {
+		return
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	// guard the following copy loop
+	// if the context is cancelled, stop it by closing the reader
+	guardianCtx, cancelGuardian := context.WithCancel(ctx)
+	go func() {
+		<-guardianCtx.Done()
+		_ = resp.Body.Close()
+	}()
+	defer cancelGuardian()
+
+	// blocking copy
+	n, err := io.Copy(out, resp.Body)
+
+	b.info.Printf("Bytes copied: %v", n)
+	return
+}
diff --git a/bilibili/util.go b/bilibili/util.go
new file mode 100644
index 0000000..1267a39
--- /dev/null
+++ b/bilibili/util.go
@@ -0,0 +1,13 @@
+package bilibili
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func validateHttpStatus(r *http.Response) (err error) {
+	if code := r.StatusCode; code != http.StatusOK {
+		err = fmt.Errorf("unsuccessful HTTP status on API %v: %v", r.Request.URL, code)
+	}
+	return
+}