feature (watcher): can now receive change events

server/pkg/files/handler_mkdir.go

@@ -1,6 +1,7 @@
 package files
 
 import (
+	"strings"
 	"net/http"
 
 	. "github.com/mickael-kerjean/filestash/server/pkg/core"
@@ -38,4 +39,5 @@ func FileMkdir(ctx *App, res http.ResponseWriter, req *http.Request) {
 		return
 	}
 	SendSuccessResult(res, nil)
+	markDirty(ctx, req, strings.TrimSuffix(path, "/"))
 }

server/pkg/files/handler_mv.go

@@ -49,4 +49,6 @@ func FileMv(ctx *App, res http.ResponseWriter, req *http.Request) {
 		return
 	}
 	SendSuccessResult(res, nil)
+	markDirty(ctx, req, from)
+	markDirty(ctx, req, to)
 }

server/pkg/files/handler_rm.go

@@ -38,4 +38,5 @@ func FileRm(ctx *App, res http.ResponseWriter, req *http.Request) {
 		return
 	}
 	SendSuccessResult(res, nil)
+	markDirty(ctx, req, path)
 }

server/pkg/files/handler_save.go

@@ -86,7 +86,9 @@ func FileSave(ctx *App, res http.ResponseWriter, req *http.Request) {
 		handlerRDIFF(ctx, res, req, path, h)
 	default:
 		SendErrorResult(res, ErrNotImplemented)
+		return
 	}
+	markDirty(ctx, req, path)
 }
 
 func handlerClassic(ctx *App, res http.ResponseWriter, req *http.Request, path string, h http.Header) {

server/pkg/files/handler_touch.go

@@ -38,4 +38,5 @@ func FileTouch(ctx *App, res http.ResponseWriter, req *http.Request) {
 		return
 	}
 	SendSuccessResult(res, nil)
+	markDirty(ctx, req, path)
 }

server/pkg/files/handler_watch.go

@@ -0,0 +1,115 @@
+package files
+
+import (
+	"container/ring"
+	"strings"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	. "github.com/mickael-kerjean/filestash/server/pkg/core"
+	. "github.com/mickael-kerjean/filestash/server/pkg/kernel"
+	. "github.com/mickael-kerjean/filestash/server/pkg/utils"
+)
+
+var (
+	feed = ring.New(1000)
+	flock = sync.Mutex{}
+	fdrop = atomic.Uint64{}
+)
+
+func init() {
+	t := time.Now().UTC()
+	for i := 0; i < feed.Len(); i++ {
+  		feed.Value = change{Time: t}
+  		feed = feed.Next()
+  	}
+}
+
+type change struct {
+	Echo      bool      `json:"echo"`
+	Path      string    `json:"path"`
+	StorageID string    `json:"-"`
+	Time      time.Time `json:"-"`
+	UserAgent string    `json:"-"`
+}
+
+func FileWatch(ctx *App, res http.ResponseWriter, req *http.Request) {
+	flusher, ok := res.(http.Flusher)
+	if !ok {
+		SendErrorResult(res, NewError("streaming not supported", 500))
+		return
+	}
+	since, err := time.Parse(time.RFC3339, req.Header.Get("Last-Event-ID"))
+	if err != nil {
+		since = time.Now()
+	}
+	currentDrop := uint64(0)
+	ticker := time.NewTimer(0)
+	defer ticker.Stop()
+	storageID := GenerateID(ctx.Session)
+	userAgent := req.Header.Get("User-Agent")
+	res.Header().Set("Content-Type", "text/event-stream")
+	res.Header().Set("Cache-Control", "no-cache")
+	res.Header().Set("Connection", "keep-alive")
+
+	for {
+		select {
+		case <-req.Context().Done():
+			return
+		case <-ticker.C:
+			flock.Lock()
+			t := feed.Value.(change).Time
+			if nDrop := fdrop.Load(); currentDrop != nDrop {
+				t = time.Now().UTC()
+				fmt.Fprintf(res, "id: %s\nevent: purge\ndata: {}\n\n", t.Format(time.RFC3339Nano))
+				since = t
+				currentDrop = nDrop
+			} else if since.Before(t) {
+				fmt.Fprintf(res, "id: %s\nevent: purge\ndata: {}\n\n", t.Format(time.RFC3339Nano))
+				since = t
+			}
+			feed.Do(func(p any) {
+				el := p.(change)
+				el.Echo = el.UserAgent == userAgent
+				el.Path = strings.TrimPrefix(el.Path, ctx.Session["path"])
+				if el.StorageID != storageID {
+					return
+				} else if since.Equal(el.Time) || since.After(el.Time) {
+					return
+				}
+				data, _ := json.Marshal(el)
+				fmt.Fprintf(res, "id: %s\nevent: dirty\ndata: %s\n\n", el.Time.Format(time.RFC3339Nano), data)
+				since = el.Time
+			})
+			flock.Unlock()
+			flusher.Flush()
+			ticker.Reset(5 * time.Second)
+		}
+	}
+}
+
+func markDirty(ctx *App, req *http.Request, fullpath string) {
+	if !flock.TryLock() {
+		Log.Debug("ls::watch message=cannot_lock_feed", )
+		fdrop.Add(1)
+		return
+	}
+	path, _ := SplitPath(fullpath)
+	cVal := change{
+		Path:      path,
+		StorageID: GenerateID(ctx.Session),
+		Time:      time.Now().UTC(),
+		UserAgent: req.Header.Get("User-Agent"),
+	}
+	pVal := feed.Prev().Value.(change)
+	if pVal.StorageID == cVal.StorageID && pVal.Path == cVal.Path && pVal.UserAgent == cVal.UserAgent {
+		feed = feed.Prev()
+	}
+	feed.Value = cVal
+	feed = feed.Next()
+	flock.Unlock()
+}

server/routes.go

@@ -71,6 +71,7 @@ func Build(r *mux.Router) {
 	router.HandleFunc("/rm", NewMiddlewareChain(files.FileRm, middlewares)).Methods("POST")
 	router.HandleFunc("/mkdir", NewMiddlewareChain(files.FileMkdir, middlewares)).Methods("POST")
 	router.HandleFunc("/touch", NewMiddlewareChain(files.FileTouch, middlewares)).Methods("POST")
+	router.HandleFunc("/watch", NewMiddlewareChain(files.FileWatch, middlewares)).Methods("GET")
 	middlewares = []Middleware{ApiHeaders, SecureHeaders, SecureOrigin, SessionStart, LoggedInOnly, PluginInjector}
 	router.HandleFunc("/search", NewMiddlewareChain(files.FileSearch, middlewares)).Methods("GET")