diff --git a/deps/common/src/logseq/common/missionary_util.cljs b/deps/common/src/logseq/common/missionary_util.cljs
index 52108e208..edd84f803 100644
--- a/deps/common/src/logseq/common/missionary_util.cljs
+++ b/deps/common/src/logseq/common/missionary_util.cljs
@@ -1,7 +1,8 @@
 (ns logseq.common.missionary-util
   "Utils based on missionary."
-  (:import [missionary Cancelled])
-  (:require [missionary.core :as m]))
+  (:require [clojure.core.async :as a]
+            [missionary.core :as m])
+  (:import [missionary Cancelled]))
 
 (def delays (reductions * 1000 (repeat 2)))
 
@@ -55,3 +56,14 @@
   "Return the canceler"
   [task key & {:keys [succ fail]}]
   (task (or succ #(prn key :succ %)) (or fail #(js/console.log key (or (some-> % .-stack) %)))))
+
+(defn >!
+  "Return a task that
+  puts given value on given channel,
+  completing with true when put is accepted, or false if port was closed."
+  [c x] (doto (m/dfv) (->> (a/put! c x))))
+
+(defn <!
+  "Return a task that takes from given channel,
+  completing with value when take is accepted, or nil if port was closed."
+  [c] (doto (m/dfv) (->> (a/take! c))))
diff --git a/src/main/frontend/worker/rtc/core2.cljs b/src/main/frontend/worker/rtc/core2.cljs
index 729ef2a0e..f84a3a023 100644
--- a/src/main/frontend/worker/rtc/core2.cljs
+++ b/src/main/frontend/worker/rtc/core2.cljs
@@ -337,7 +337,4 @@
       (def *rtc-auto-push? *rtc-auto-push?)))
   (cancel)
 
-
-
-
   )
diff --git a/src/main/frontend/worker/rtc/ws2.cljs b/src/main/frontend/worker/rtc/ws2.cljs
index 69b6f5ce0..fcbb9f4c0 100644
--- a/src/main/frontend/worker/rtc/ws2.cljs
+++ b/src/main/frontend/worker/rtc/ws2.cljs
@@ -2,7 +2,8 @@
   "Websocket wrapped by missionary.
   based on
   https://github.com/ReilySiegel/missionary-websocket/blob/master/src/com/reilysiegel/missionary/websocket.cljs"
-  (:require [frontend.worker.rtc.const :as rtc-const]
+  (:require [cljs-http.client :as http]
+            [frontend.worker.rtc.const :as rtc-const]
             [logseq.common.missionary-util :as c.m]
             [missionary.core :as m]))
 
@@ -89,12 +90,12 @@
   (c.m/backoff
    (take retry-count c.m/delays)
    (m/sp
-    (try
-      (m/? (m/timeout (create-mws* url) open-ws-timeout))
-      (catch js/CloseEvent e
-        (throw (ex-info "failed to open websocket conn"
-                        {:missionary/retry true}
-                        e)))))))
+     (try
+       (m/? (m/timeout (create-mws* url) open-ws-timeout))
+       (catch js/CloseEvent e
+         (throw (ex-info "failed to open websocket conn"
+                         {:missionary/retry true}
+                         e)))))))
 (comment
   (defn get-mws-create
     "Returns a task to get a mws(missionary-websocket), creating one if needed.
@@ -171,23 +172,42 @@
    (map rtc-const/data-from-ws-coercer)
    (:recv-flow m-ws)))
 
-(defn send&recv
+(defn- send&recv*
   "Return a task: send message wait to recv its response and return it.
   Throw if timeout"
   [mws message & {:keys [timeout-ms] :or {timeout-ms 10000}}]
-  (assert (pos-int? timeout-ms))
-  (let [req-id (str (random-uuid))
-        message (assoc message :req-id req-id)]
-    (m/sp
-      (let [mws (m/? (send mws message))
-            result (m/?
-                    (m/timeout
-                     (m/reduce
-                      (fn [_ v]
-                        (when (= req-id (:req-id v))
-                          (reduced v)))
-                      (recv-flow mws))
-                     timeout-ms))]
-        (when-not result
-          (throw (ex-info (str "recv timeout (" timeout-ms "ms)") {:missionary/retry true})))
-        result))))
+  {:pre [(pos-int? timeout-ms)
+         (some? (:req-id message))]}
+  (m/sp
+    (let [mws (m/? (send mws message))
+          req-id (:req-id message)
+          result (m/?
+                  (m/timeout
+                   (m/reduce
+                    (fn [_ v]
+                      (when (= req-id (:req-id v))
+                        (reduced v)))
+                    (recv-flow mws))
+                   timeout-ms))]
+      (when-not result
+        (throw (ex-info (str "recv timeout (" timeout-ms "ms)") {:missionary/retry true})))
+      result)))
+
+(defn send&recv
+  "Return a task that send the message then wait to recv its response,
+  if the response has kv `:s3-presign-url`, fetch the response from s3,
+  else just return the response.
+  Throw if timeout"
+  [mws message & {:keys [timeout-ms] :or {timeout-ms 10000}}]
+  (m/sp
+    (let [req-id (str (random-uuid))
+          message (assoc message :req-id req-id)
+          resp (m/? (send&recv* mws message :timeout-ms timeout-ms))]
+      (if-let [s3-presign-url (:s3-presign-url resp)]
+        (let [{:keys [status body]} (m/? (c.m/<! (http/get s3-presign-url {:with-credentials? false})))]
+          (if (http/unexceptional-status? status)
+            (js->clj (js/JSON.parse body) :keywordize-keys true)
+            {:req-id req-id
+             :ex-message "get s3 object failed"
+             :ex-data {:type :get-s3-object-failed :status status :body body}}))
+        resp))))