server: added /api/v1/objects/:id that retrieves contents of object given its ID

internal/server/api_object_get.go

@@ -0,0 +1,50 @@
+package server
+
+import (
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/kopia/kopia/repo/object"
+)
+
+func (s *Server) handleObjectGet(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "GET" {
+		http.Error(w, "incompatible HTTP method", http.StatusMethodNotAllowed)
+		return
+	}
+
+	oidstr := r.URL.Path[strings.LastIndex(r.URL.Path, "/")+1:]
+
+	oid, err := object.ParseID(oidstr)
+	if err != nil {
+		http.Error(w, "invalid object id", http.StatusBadRequest)
+		return
+	}
+
+	obj, err := s.rep.Objects.Open(r.Context(), oid)
+	if err == object.ErrObjectNotFound {
+		http.Error(w, "object not found", http.StatusNotFound)
+		return
+	}
+
+	if cid, _, ok := oid.ContentID(); ok && cid.Prefix() == "k" {
+		w.Header().Set("Content-Type", "application/json")
+	}
+
+	fname := oid.String()
+	if p := r.URL.Query().Get("fname"); p != "" {
+		fname = p
+		w.Header().Set("Content-Disposition", "attachment; filename=\""+p+"\"")
+	}
+
+	mtime := time.Now()
+
+	if p := r.URL.Query().Get("mtime"); p != "" {
+		if m, err := time.Parse(time.RFC3339Nano, p); err == nil {
+			mtime = m
+		}
+	}
+
+	http.ServeContent(w, r, fname, mtime, obj)
+}

internal/server/server.go

@@ -41,7 +41,7 @@ func (s *Server) APIHandlers() http.Handler {
 	mux.HandleFunc("/api/v1/sources/resume", s.handleAPI(s.handleResume, "POST"))
 	mux.HandleFunc("/api/v1/sources/upload", s.handleAPI(s.handleUpload, "POST"))
 	mux.HandleFunc("/api/v1/sources/cancel", s.handleAPI(s.handleCancel, "POST"))
-
+	mux.HandleFunc("/api/v1/objects/", s.handleObjectGet)
 	return mux
 }