Implement dav file preview API like in OC10

changelog/unreleased/preview-api.md

@@ -0,0 +1,5 @@
+Enhancement: implement preview API
+
+Added the API endpoint for file previews.
+
+https://github.com/owncloud/ocis-webdav/pull/13

go.mod

@@ -7,11 +7,12 @@ require (
 	contrib.go.opencensus.io/exporter/ocagent v0.6.0
 	contrib.go.opencensus.io/exporter/zipkin v0.1.1
 	github.com/go-chi/chi v4.0.2+incompatible
-	github.com/gogo/protobuf v1.2.2-0.20190723190241-65acae22fc9d // indirect
 	github.com/micro/cli/v2 v2.1.1
+	github.com/micro/go-micro/v2 v2.0.0
 	github.com/oklog/run v1.0.0
 	github.com/openzipkin/zipkin-go v0.2.2
 	github.com/owncloud/ocis-pkg/v2 v2.0.1
+	github.com/owncloud/ocis-thumbnails v0.0.0-20200318131505-e0ab0b37a5a4
 	github.com/spf13/afero v1.2.2 // indirect
 	github.com/spf13/viper v1.5.0
 	go.opencensus.io v0.22.2

pkg/dav/thumbnails/thumbnail.go

@@ -0,0 +1,72 @@
+package thumbnail
+
+import (
+	"fmt"
+	"net/http"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"github.com/go-chi/chi"
+)
+
+const (
+	// DefaultWidth defines the default width of a thumbnail
+	DefaultWidth = 32
+	// DefaultHeight defines the default height of a thumbnail
+	DefaultHeight = 32
+)
+
+// Request combines all parameters provided when requesting a thumbnail
+type Request struct {
+	Filepath      string
+	Filetype      string
+	Etag          string
+	Width         int
+	Height        int
+	Authorization string
+}
+
+// NewRequest extracts all required parameters from a http request.
+func NewRequest(r *http.Request) (Request, error) {
+	path := extractFilePath(r)
+	query := r.URL.Query()
+	width, err := strconv.Atoi(query.Get("x"))
+	if err != nil {
+		width = DefaultWidth
+	}
+	height, err := strconv.Atoi(query.Get("y"))
+	if err != nil {
+		height = DefaultHeight
+	}
+
+	etag := query.Get("c")
+	if strings.TrimSpace(etag) == "" {
+		return Request{}, fmt.Errorf("c (etag) is missing in query")
+	}
+
+	authorization := r.Header.Get("Authorization")
+
+	tr := Request{
+		Filepath:      path,
+		Filetype:      strings.Replace(filepath.Ext(path), ".", "", 1),
+		Etag:          etag,
+		Width:         width,
+		Height:        height,
+		Authorization: authorization,
+	}
+
+	return tr, nil
+}
+
+// the url looks as followed
+//
+// /remote.php/dav/files/<user>/<filepath>
+//
+// User and filepath are dynamic and filepath can contain slashes
+// So using the URLParam function is not possible.
+func extractFilePath(r *http.Request) string {
+	user := chi.URLParam(r, "user")
+	parts := strings.SplitN(r.URL.Path, user, 2)
+	return parts[1]
+}

pkg/service/v0/instrument.go

@@ -24,7 +24,7 @@ func (i instrument) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	i.next.ServeHTTP(w, r)
 }
 
-// Dummy implements the Service interface.
-func (i instrument) Dummy(w http.ResponseWriter, r *http.Request) {
-	i.next.Dummy(w, r)
+// Thumbnail implements the Service interface.
+func (i instrument) Thumbnail(w http.ResponseWriter, r *http.Request) {
+	i.next.Thumbnail(w, r)
 }

pkg/service/v0/logging.go

@@ -25,6 +25,6 @@ func (l logging) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 // Dummy implements the Service interface.
-func (l logging) Dummy(w http.ResponseWriter, r *http.Request) {
-	l.next.Dummy(w, r)
+func (l logging) Thumbnail(w http.ResponseWriter, r *http.Request) {
+	l.next.Thumbnail(w, r)
 }

pkg/service/v0/service.go

@@ -2,15 +2,19 @@ package svc
 
 import (
 	"net/http"
+	"strings"
 
 	"github.com/go-chi/chi"
+	"github.com/micro/go-micro/v2/client"
+	thumbnails "github.com/owncloud/ocis-thumbnails/pkg/proto/v0"
 	"github.com/owncloud/ocis-webdav/pkg/config"
+	thumbnail "github.com/owncloud/ocis-webdav/pkg/dav/thumbnails"
 )
 
 // Service defines the extension handlers.
 type Service interface {
 	ServeHTTP(http.ResponseWriter, *http.Request)
-	Dummy(http.ResponseWriter, *http.Request)
+	Thumbnail(http.ResponseWriter, *http.Request)
 }
 
 // NewService returns a service implementation for Service.
@@ -26,7 +30,7 @@ func NewService(opts ...Option) Service {
 	}
 
 	m.Route(options.Config.HTTP.Root, func(r chi.Router) {
-		r.Get("/", svc.Dummy)
+		r.Get("/remote.php/dav/files/{user}/*", svc.Thumbnail)
 	})
 
 	return svc
@@ -43,10 +47,39 @@ func (g Webdav) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	g.mux.ServeHTTP(w, r)
 }
 
-// Dummy implements the Service interface.
-func (g Webdav) Dummy(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Content-Type", "text/plain")
+// Thumbnail implements the Service interface.
+func (g Webdav) Thumbnail(w http.ResponseWriter, r *http.Request) {
+	tr, err := thumbnail.NewRequest(r)
+	if err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Write([]byte(err.Error()))
+		return
+	}
+
+	c := thumbnails.NewThumbnailService("com.owncloud.api.thumbnails", client.DefaultClient)
+	rsp, err := c.GetThumbnail(r.Context(), &thumbnails.GetRequest{
+		Filepath:      strings.TrimLeft(tr.Filepath, "/"),
+		Filetype:      extensionToFiletype(tr.Filetype),
+		Etag:          tr.Etag,
+		Width:         int32(tr.Width),
+		Height:        int32(tr.Height),
+		Authorization: tr.Authorization,
+	})
+	if err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Write([]byte(err.Error()))
+		return
+	}
+
+	w.Header().Set("Content-Type", rsp.GetMimetype())
 	w.WriteHeader(http.StatusOK)
+	w.Write(rsp.Thumbnail)
+}
 
-	w.Write([]byte(http.StatusText(http.StatusOK)))
+func extensionToFiletype(ext string) thumbnails.GetRequest_FileType {
+	val, ok := thumbnails.GetRequest_FileType_value[strings.ToUpper(ext)]
+	if !ok {
+		return thumbnails.GetRequest_FileType(-1)
+	}
+	return thumbnails.GetRequest_FileType(val)
 }

pkg/service/v0/tracing.go

@@ -20,7 +20,7 @@ func (t tracing) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	t.next.ServeHTTP(w, r)
 }
 
-// Dummy implements the Service interface.
-func (t tracing) Dummy(w http.ResponseWriter, r *http.Request) {
-	t.next.Dummy(w, r)
+// Thumbnail implements the Service interface.
+func (t tracing) Thumbnail(w http.ResponseWriter, r *http.Request) {
+	t.next.Thumbnail(w, r)
 }