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Add Frankfurter EUR/DKK rate polling and include rates in WebSocket stream

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Polls self-hosted Frankfurter API hourly for USD-based EUR and DKK exchange
rates. Both the WebSocket HTML fragments and the /api/price/latest JSON
endpoint now include the currency rates alongside BTC price.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
magnus
2026-02-27 14:22:24 +01:00
co-authored by Claude Opus 4.6
parent 39ec47b5e1
commit 7d6ca3911f
5 changed files with 113 additions and 22 deletions
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src/clj/pmagnus/btcdata/web/routes/api.clj
+32 -16
View File
@@ -18,15 +18,17 @@
[java.time.format DateTimeFormatter]
[java.util.concurrent LinkedBlockingQueue TimeUnit]))
(defn- price->json [{:keys [price prev-price recorded-at]}]
(defn- price->json [{:keys [price prev-price recorded-at]} rates]
(json/write-str
{:price (str price)
:prev_price (when prev-price (str prev-price))
:recorded_at (str recorded-at)}))
(cond-> {:price (str price)
:prev_price (when prev-price (str prev-price))
:recorded_at (str recorded-at)}
rates (assoc :eur (str (:eur rates))
:dkk (str (:dkk rates))))))
(def ^:private ts-fmt (DateTimeFormatter/ofPattern "dd-MM HH:mm:ss"))
(defn- price->html [{:keys [price prev-price recorded-at]}]
(defn- price->html [{:keys [price prev-price recorded-at]} rates]
(let [p (double (bigdec price))
pp (when prev-price (double (bigdec prev-price)))
color (cond
@@ -39,50 +41,64 @@
"<div class=\"bg-white rounded-2xl shadow-sm border border-gray-200 p-6\">"
"<div class=\"text-center\">"
"<p class=\"text-4xl font-bold " color "\">$" (format "%,.2f" p) "</p>"
(when rates
(let [eur (double (:eur rates))
dkk (double (:dkk rates))]
(str "<div class=\"flex justify-center gap-4 mt-3\">"
"<span class=\"text-sm text-gray-600\">EUR " (format "%.4f" eur) "</span>"
"<span class=\"text-sm text-gray-600\">DKK " (format "%.4f" dkk) "</span>"
"</div>")))
"<p class=\"text-xs text-gray-400 mt-2\">Updated " ts "</p>"
"</div></div></div>")))
(defn- start-ws-send-loop! [^WebSocketChannel channel price-atom]
(defn- start-ws-send-loop! [^WebSocketChannel channel price-atom rates-atom]
(let [queue (LinkedBlockingQueue.)
wkey (keyword (gensym "ws-"))]
wkey (keyword (gensym "ws-"))
rkey (keyword (gensym "ws-r-"))]
(.set (.getReceiveSetter channel)
(proxy [AbstractReceiveListener] []))
(.resumeReceives channel)
(add-watch price-atom wkey
(fn [_ _ _ v] (.offer queue v)))
(when-let [v @price-atom]
(.offer queue v))
(fn [_ _ _ _] (.offer queue :update)))
(add-watch rates-atom rkey
(fn [_ _ _ _] (.offer queue :update)))
(when @price-atom
(.offer queue :update))
(future
(try
(loop []
(when (.isOpen channel)
(if-let [v (.poll queue 15 TimeUnit/SECONDS)]
(WebSockets/sendTextBlocking (price->html v) channel)
(if (.poll queue 15 TimeUnit/SECONDS)
(when-let [v @price-atom]
(WebSockets/sendTextBlocking (price->html v @rates-atom) channel))
(WebSockets/sendTextBlocking "" channel))
(recur)))
(catch Exception _)
(finally
(remove-watch price-atom wkey)
(remove-watch rates-atom rkey)
(when (.isOpen channel)
(try (.close channel) (catch Exception _))))))))
(defn- ws-price-handler [{:keys [binance]} req]
(defn- ws-price-handler [{:keys [binance frankfurter]} req]
(let [^HttpServerExchange exchange (:server-exchange req)
price-atom (:latest-price binance)
rates-atom (:rates frankfurter)
callback (proxy [WebSocketConnectionCallback] []
(onConnect [_ws-exchange channel]
(start-ws-send-loop! channel price-atom)))
(start-ws-send-loop! channel price-atom rates-atom)))
handler (WebSocketProtocolHandshakeHandler. callback)]
(.handleRequest handler exchange)
nil))
(defn- latest-price-handler [{:keys [binance]} _req]
(defn- latest-price-handler [{:keys [binance frankfurter]} _req]
(let [price-atom (:latest-price binance)
rates-atom (:rates frankfurter)
v @price-atom]
(if v
{:status 200
:headers {"Content-Type" "application/json"}
:body (price->json v)}
:body (price->json v @rates-atom)}
{:status 503
:headers {"Content-Type" "application/json"}
:body (json/write-str {:error "No price data yet"})})))