refactor: Unified provider loading resources

component/resource/fetcher.go

@@ -0,0 +1,213 @@
+package resource
+
+import (
+	"bytes"
+	"crypto/md5"
+	"os"
+	"path/filepath"
+	"time"
+
+	types "github.com/Dreamacro/clash/constant/provider"
+	"github.com/Dreamacro/clash/log"
+)
+
+var (
+	fileMode os.FileMode = 0o666
+	dirMode  os.FileMode = 0o755
+)
+
+type Parser[V any] func([]byte) (V, error)
+
+type Fetcher[V any] struct {
+	resourceType string
+	name         string
+	vehicle      types.Vehicle
+	UpdatedAt    *time.Time
+	ticker       *time.Ticker
+	done         chan struct{}
+	hash         [16]byte
+	parser       Parser[V]
+	interval     time.Duration
+	OnUpdate     func(V)
+}
+
+func (f *Fetcher[V]) Name() string {
+	return f.name
+}
+
+func (f *Fetcher[V]) VehicleType() types.VehicleType {
+	return f.vehicle.Type()
+}
+
+func (f *Fetcher[V]) Initial() (V, error) {
+	var (
+		buf         []byte
+		err         error
+		isLocal     bool
+		forceUpdate bool
+	)
+
+	if stat, fErr := os.Stat(f.vehicle.Path()); fErr == nil {
+		buf, err = os.ReadFile(f.vehicle.Path())
+		modTime := stat.ModTime()
+		f.UpdatedAt = &modTime
+		isLocal = true
+		if f.interval != 0 && modTime.Add(f.interval).Before(time.Now()) {
+			log.Infoln("[Provider] %s not updated for a long time, force refresh", f.Name())
+			forceUpdate = true
+		}
+	} else {
+		buf, err = f.vehicle.Read()
+	}
+
+	if err != nil {
+		return getZero[V](), err
+	}
+
+	var contents V
+	if forceUpdate {
+		var forceBuf []byte
+		if forceBuf, err = f.vehicle.Read(); err == nil {
+			if contents, err = f.parser(forceBuf); err == nil {
+				isLocal = false
+				buf = forceBuf
+			}
+		}
+	}
+
+	if err != nil || !forceUpdate {
+		contents, err = f.parser(buf)
+	}
+
+	if err != nil {
+		if !isLocal {
+			return getZero[V](), err
+		}
+
+		// parse local file error, fallback to remote
+		buf, err = f.vehicle.Read()
+		if err != nil {
+			return getZero[V](), err
+		}
+
+		contents, err = f.parser(buf)
+		if err != nil {
+			return getZero[V](), err
+		}
+
+		isLocal = false
+	}
+
+	if f.vehicle.Type() != types.File && !isLocal {
+		if err := safeWrite(f.vehicle.Path(), buf); err != nil {
+			return getZero[V](), err
+		}
+	}
+
+	f.hash = md5.Sum(buf)
+
+	// pull contents automatically
+	if f.ticker != nil {
+		go f.pullLoop()
+	}
+
+	return contents, nil
+}
+
+func (f *Fetcher[V]) Update() (V, bool, error) {
+	buf, err := f.vehicle.Read()
+	if err != nil {
+		return getZero[V](), false, err
+	}
+
+	now := time.Now()
+	hash := md5.Sum(buf)
+	if bytes.Equal(f.hash[:], hash[:]) {
+		f.UpdatedAt = &now
+		_ = os.Chtimes(f.vehicle.Path(), now, now)
+		return getZero[V](), true, nil
+	}
+
+	contents, err := f.parser(buf)
+	if err != nil {
+		return getZero[V](), false, err
+	}
+
+	if f.vehicle.Type() != types.File {
+		if err := safeWrite(f.vehicle.Path(), buf); err != nil {
+			return getZero[V](), false, err
+		}
+	}
+
+	f.UpdatedAt = &now
+	f.hash = hash
+
+	return contents, false, nil
+}
+
+func (f *Fetcher[V]) Destroy() error {
+	if f.ticker != nil {
+		f.done <- struct{}{}
+	}
+	return nil
+}
+
+func (f *Fetcher[V]) pullLoop() {
+	for {
+		select {
+		case <-f.ticker.C:
+			elm, same, err := f.Update()
+			if err != nil {
+				log.Warnln("[Provider] %s pull error: %s", f.Name(), err.Error())
+				continue
+			}
+
+			if same {
+				log.Debugln("[Provider] %s's content doesn't change", f.Name())
+				continue
+			}
+
+			log.Infoln("[Provider] %s's content update", f.Name())
+			if f.OnUpdate != nil {
+				f.OnUpdate(elm)
+			}
+		case <-f.done:
+			f.ticker.Stop()
+			return
+		}
+	}
+}
+
+func safeWrite(path string, buf []byte) error {
+	dir := filepath.Dir(path)
+
+	if _, err := os.Stat(dir); os.IsNotExist(err) {
+		if err := os.MkdirAll(dir, dirMode); err != nil {
+			return err
+		}
+	}
+
+	return os.WriteFile(path, buf, fileMode)
+}
+
+func NewFetcher[V any](name string, interval time.Duration, vehicle types.Vehicle, parser Parser[V], onUpdate func(V)) *Fetcher[V] {
+	var ticker *time.Ticker
+	if interval != 0 {
+		ticker = time.NewTicker(interval)
+	}
+
+	return &Fetcher[V]{
+		name:     name,
+		ticker:   ticker,
+		vehicle:  vehicle,
+		parser:   parser,
+		done:     make(chan struct{}, 1),
+		OnUpdate: onUpdate,
+		interval: interval,
+	}
+}
+
+func getZero[V any]() V {
+	var result V
+	return result
+}

component/resource/vehicle.go

@@ -0,0 +1,64 @@
+package resource
+
+import (
+	"context"
+	netHttp "github.com/Dreamacro/clash/component/http"
+	types "github.com/Dreamacro/clash/constant/provider"
+	"io"
+	"net/http"
+	"os"
+	"time"
+)
+
+type FileVehicle struct {
+	path string
+}
+
+func (f *FileVehicle) Type() types.VehicleType {
+	return types.File
+}
+
+func (f *FileVehicle) Path() string {
+	return f.path
+}
+
+func (f *FileVehicle) Read() ([]byte, error) {
+	return os.ReadFile(f.path)
+}
+
+func NewFileVehicle(path string) *FileVehicle {
+	return &FileVehicle{path: path}
+}
+
+type HTTPVehicle struct {
+	url  string
+	path string
+}
+
+func (h *HTTPVehicle) Type() types.VehicleType {
+	return types.HTTP
+}
+
+func (h *HTTPVehicle) Path() string {
+	return h.path
+}
+
+func (h *HTTPVehicle) Read() ([]byte, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*20)
+	defer cancel()
+	resp, err := netHttp.HttpRequest(ctx, h.url, http.MethodGet, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	defer resp.Body.Close()
+	buf, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	return buf, nil
+}
+
+func NewHTTPVehicle(url string, path string) *HTTPVehicle {
+	return &HTTPVehicle{url, path}
+}