Reset state from history
- fails if server changes are made while client is disconnected
This commit is contained in:
Nicholas Kariniemi
parent
763e6f2fc8
commit
a572b9e1eb
5 changed files with 85 additions and 34 deletions
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@ -10,6 +10,24 @@
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(def to-all (chan))
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(def from-all (a/mult to-all))
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(def state-history (atom []))
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(defn save-history-state [history new-state]
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(when-not (= (last history) new-state)
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(println "Adding state to history: " (hasch/uuid new-state))
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(println "History size:" (inc (count history)))
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(conj history new-state)))
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(defn get-history-state [hash]
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(println "Look for history state:" hash)
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(println "History:")
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(doseq [s @state-history]
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(println (hasch/uuid s)))
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(first (filter #(= (hasch/uuid %) hash) @state-history)))
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(add-watch state :history (fn [_ _ _ new-state]
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(swap! state-history save-history-state new-state)))
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(defn initial-state [grubs recipes]
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{:grubs (util/map-by-key :id grubs)
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:recipes (util/map-by-key :id recipes)})
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@ -17,21 +35,49 @@
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(defn sync-new-client! [to from]
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(let [client-id (java.util.UUID/randomUUID)
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server-shadow (atom cs/empty-state)]
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(add-watch state client-id (fn [_ _ _ new-state]
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(when-let [msg (cs/diff-states new-state @server-shadow)]
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(add-watch state client-id (fn [_ _ _ current-state]
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(when-let [msg (cs/diff-states @server-shadow current-state)]
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(a/put! to msg)
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(reset! server-shadow new-state))))
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;; TODO: reset only if send succeeds?
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(reset! server-shadow current-state))))
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(a/go-loop []
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(if-let [{:keys [type diff hash shadow-hash] :as msg} (<! from)]
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(do (condp = type
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:diff (let [new-shadow (swap! server-shadow sync/patch-state diff)]
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(if (= (hasch/uuid new-shadow) hash)
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(let [new-state (swap! state sync/patch-state diff)]
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(>! @to-db diff))
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(do (println "Hash check failed --> complete sync")
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(let [sync-state @state]
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(reset! server-shadow sync-state)
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(a/put! to (cs/complete-sync-response sync-state))))))
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:diff
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(if (= (hasch/uuid @server-shadow) shadow-hash)
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;; we have what they thought we had
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;; apply changes normally
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(let [new-shadow (swap! server-shadow sync/patch-state diff)]
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(println "Hash matched state, apply changes")
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(if (= (hasch/uuid new-shadow) hash)
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(let [new-state (swap! state sync/patch-state diff)]
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(>! @to-db diff))
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(do (println "Applying diff failed --> full sync")
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(let [sync-state @state]
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(reset! server-shadow sync-state)
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(a/put! to (cs/complete-sync-response sync-state))))))
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;; we have something different than they thought
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;; check history
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(if-let [history-state (get-history-state shadow-hash)]
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;; Found what they thought in history,
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;; reset client state to this
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;; and continue as normal
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(do
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(println "Hash check failed --> Reset from history")
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(reset! server-shadow history-state)
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(let [new-shadow (swap! server-shadow sync/patch-state diff)]
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(if (= (hasch/uuid new-shadow) hash)
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(let [new-state (swap! state sync/patch-state diff)]
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(>! @to-db diff))
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(do (println "Applying diff failed --> full sync")
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(let [sync-state @state]
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(reset! server-shadow sync-state)
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(a/put! to (cs/complete-sync-response sync-state)))))))
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;; No history found, do complete sync
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(do (println "Hash check failed, not in history --> full sync")
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(let [sync-state @state]
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(reset! server-shadow sync-state)
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(a/put! to (cs/complete-sync-response sync-state))))))
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:complete (let [new-state (reset! server-shadow @state)]
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(a/put! to (cs/complete-sync-response new-state)))
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(println "Invalid msg:" msg))
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@ -5,11 +5,14 @@
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[cljs.core.async :as a :refer [<! >! chan]])
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(:require-macros [grub.macros :refer [log logs]]))
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(defn init-app []
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(view/render-app state/app-state)
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(defn connect-to-server [reset?]
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(let [to-remote (chan)
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from-remote (chan)]
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(ws/connect-client! to-remote from-remote)
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(state/sync-state! from-remote to-remote)))
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(state/sync-state! from-remote to-remote reset?)))
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(defn init-app []
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(view/render-app state/app-state)
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(connect-to-server true))
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(init-app)
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@ -8,13 +8,13 @@
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(def app-state (atom cs/empty-state))
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(defn sync-state! [to from]
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(defn sync-state! [to from reset?]
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(let [client-shadow (atom cs/empty-state)]
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(add-watch app-state :app-state (fn [_ _ _ new]
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(when-let [msg (cs/diff-states new @client-shadow)]
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(add-watch app-state :app-state (fn [_ _ _ current-state]
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(when-let [msg (cs/diff-states @client-shadow current-state)]
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(a/put! from msg)
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;; TODO: reset shadow only if send succeeds
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(reset! client-shadow new))))
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;; TODO: reset only if send succeeds
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(reset! client-shadow current-state))))
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(go-loop []
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(if-let [{:keys [type diff hash shadow-hash] :as msg} (<! to)]
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(do (condp = type
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@ -28,4 +28,4 @@
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(logs "Invalid msg:" msg))
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(recur))
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(remove-watch app-state :app-state)))
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(a/put! from cs/complete-sync-request)))
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(when reset? (a/put! from cs/complete-sync-request))))
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@ -27,10 +27,13 @@
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(let [msg (cljs.reader/read-string (.-message event))]
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(a/put! from msg)))
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(def ws (atom nil))
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(defn connect-client! [to from]
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(let [handler (goog.events.EventHandler.)
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websocket (goog.net.WebSocket.)
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listen (fn [type fun] (.listen handler websocket type fun false))]
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(reset! ws websocket)
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(listen goog.net.WebSocket.EventType.OPENED (partial on-connected websocket))
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(listen goog.net.WebSocket.EventType.MESSAGE (partial on-message from))
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(listen goog.net.WebSocket.EventType.CLOSED #(log "Closed:" %))
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@ -15,17 +15,16 @@
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:hash hash
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:shadow-hash shadow-hash})
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(defn diff-states [state shadow*]
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(let [shadow shadow*]
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(when (not= state shadow)
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(let [diff (sync/diff-states shadow state)
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hash (hasch/uuid state)
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shadow-hash (hasch/uuid shadow)
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msg (diff-msg diff hash shadow-hash)]
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msg
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;(logs "Sync because:")
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;(logs "Local = " state)
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;(logs "Remote = " shadow)
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;(logs "Diff:" diff)
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;(logs "Send" shadow-hash "->" hash)
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))))
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(defn diff-states [shadow state]
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(when (not= state shadow)
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(let [diff (sync/diff-states shadow state)
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hash (hasch/uuid state)
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shadow-hash (hasch/uuid shadow)
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msg (diff-msg diff hash shadow-hash)]
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msg
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;(logs "Sync because:")
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;(logs "Local = " state)
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;(logs "Remote = " shadow)
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;(logs "Diff:" diff)
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;(logs "Send" shadow-hash "->" hash)
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)))
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