Use quote-sats from btcdata instead of local EUR/BTC calculation

Sats value now comes from btcdata's Strike quote endpoint which
includes the actual fee/spread, matching the Strike app.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -36,9 +36,9 @@ btcprice's docker-compose includes btcdata via `include: ../btcdata/docker-compo
 - **Framework:** Kit (Integrant-based)
 - **Server:** Undertow
 - **Routing:** Reitit
-- **Templates:** Hiccup + vanilla JS WebSocket
+- **Templates:** Hiccup + HTMX (WebSocket extension)
 - **Styling:** Tailwind CSS v4
-- **Data backend:** btcdata (separate service at BTCDATA_URL, default http://localhost:4100, WebSocket at ws://localhost:4100)
+- **Data backend:** btcdata (separate service at BTCDATA_URL, default http://localhost:4100)
 - **No database** — all data comes from btcdata
 
 ## Source Layout
@@ -58,6 +58,7 @@ src/clj/pmagnus/btcprice/
     │   └── formats.clj   # Content negotiation
     └── routes/
         ├── api.clj       # /api routes (JSON)
-        ├── ui.clj        # UI routes (HTML + WebSocket)
+        ├── ui.clj        # UI routes (HTML + HTMX WebSocket)
+        ├── ws_proxy.clj  # WebSocket proxy to btcdata
         └── utils.clj     # Route utilities
 ```

Makefile

@@ -1,7 +1,7 @@
 include .env
 export
 
-.PHONY: clean run repl tailwind test uberjar
+.PHONY: clean run run-docker repl tailwind test uberjar
 
 clean:
 	rm -rf target
@@ -9,6 +9,9 @@ clean:
 run:
 	clj -M:dev -e "(dev-prep!) (go)" -r
 
+run-docker:
+	BTCDATA_URL=http://localhost:4101 clj -M:dev -e "(dev-prep!) (go)" -r
+
 repl:
 	clj -M:dev:nrepl
 

README.md

@@ -1,6 +1,6 @@
 # btcprice
 
-Bitcoin price tracker UI. Serves an HTML page with live price updates streamed from [btcdata](../btcdata) via Server-Sent Events.
+Bitcoin price tracker UI. Serves an HTML page with live price updates streamed from [btcdata](../btcdata) via WebSocket using HTMX.
 
 ## Quick Start
 
@@ -21,12 +21,12 @@ docker compose up -d   # btcprice on 4041, btcdata on 4101
 | Variable | Default | Description |
 |---|---|---|
 | `PORT` | `4000` | HTTP server port |
-| `BTCDATA_URL` | `http://localhost:4100` | btcdata service URL (injected into browser JS) |
+| `BTCDATA_URL` | `http://192.168.50.42:4100` | btcdata service URL (browser connects via WebSocket) |
 
 ## How It Works
 
-The server renders an HTML page that includes a vanilla JavaScript `EventSource` connecting directly to btcdata's SSE endpoint (`BTCDATA_URL/api/price/stream`). Price updates are rendered client-side with color-coded changes (green up, red down).
+The server renders an HTML page with HTMX and the WebSocket extension (`hx-ext="ws"`). HTMX connects directly to btcdata's WebSocket endpoint (`BTCDATA_URL/api/price/ws`), which sends HTML fragments. HTMX swaps the received `<div id="price-display">` into the DOM automatically. Price changes are color-coded (green up, red down). Reconnection is handled by HTMX with exponential backoff.
 
 ## Tech Stack
 
-Clojure · Kit · Undertow · Reitit · Hiccup · Tailwind CSS v4
+Clojure · Kit · Undertow · Reitit · Hiccup · HTMX · Tailwind CSS v4

deps.edn

@@ -25,7 +25,8 @@
 
         ;; Serialization
         metosin/muuntaja                     {:mvn/version "0.6.11"}
-        luminus-transit/luminus-transit       {:mvn/version "0.1.6"}}
+        luminus-transit/luminus-transit       {:mvn/version "0.1.6"}
+        org.clojure/data.json                {:mvn/version "2.5.1"}}
 
  :aliases
  {:build {:deps {io.github.clojure/tools.build {:mvn/version "0.10.9"}}

docker-compose.yml

@@ -1,11 +1,15 @@
-include:
-  - path: ../btcdata/docker-compose.yml
+networks:
+  btc-network:
+    name: btc-network
+    external: true
 
 services:
   btcprice:
     build: .
     restart: unless-stopped
+    networks:
+      - btc-network
     ports:
       - "4041:4040"
     environment:
-      BTCDATA_URL: "http://localhost:4101"
+      BTCDATA_URL: "http://btcdata:${DOCKER_BTCDATA_PORT:-4102}"

resources/system.edn

@@ -36,5 +36,8 @@
  {:base-path "/api"}
 
  :reitit.routes/ui
+ {:base-path ""}
+
+ :reitit.routes/ws-proxy
  {:base-path   ""
   :btcdata-url #or [#env BTCDATA_URL "http://localhost:4100"]}}

src/clj/pmagnus/btcprice/core.clj

@@ -10,7 +10,8 @@
    [pmagnus.btcprice.web.handler]
    ;; Routes
    [pmagnus.btcprice.web.routes.api]
-   [pmagnus.btcprice.web.routes.ui])
+   [pmagnus.btcprice.web.routes.ui]
+   [pmagnus.btcprice.web.routes.ws-proxy])
   (:gen-class))
 
 (defonce system (atom nil))

src/clj/pmagnus/btcprice/web/htmx.clj

@@ -17,7 +17,9 @@
                    [:meta {:name "apple-mobile-web-app-capable" :content "yes"}]
                    [:meta {:name "apple-mobile-web-app-status-bar-style" :content "black-translucent"}]
                    [:title (or (:title opts#) "BTC Price")]
-                   [:link {:rel "stylesheet" :href "/css/output.css"}]]
+                   [:link {:rel "stylesheet" :href "/css/output.css"}]
+                   [:script {:src "https://unpkg.com/htmx.org@2/dist/htmx.min.js"}]
+                   [:script {:src "https://unpkg.com/htmx-ext-ws@2/ws.js"}]]
                   [:body
                    [:div.mx-auto.max-w-lg.px-4.py-6
                     ~@content]]]))}))

src/clj/pmagnus/btcprice/web/middleware/core.clj

@@ -2,8 +2,18 @@
   (:require
    [ring.middleware.defaults :as defaults]))
 
+(defn- wrap-nil-guard
+  "Discard responses with no :status — these are artifacts of ring-defaults
+   middleware wrapping a nil response (e.g., from a raw WebSocket upgrade).
+   Passes through :undertow/websocket responses for the adapter to handle."
+  [handler]
+  (fn [request]
+    (let [resp (handler request)]
+      (when (or (:status resp) (:undertow/websocket resp)) resp))))
+
 (defn wrap-base [{:keys [site-defaults-config]}]
   (fn [handler]
-    (cond-> handler
-      true (defaults/wrap-defaults
-            (or site-defaults-config defaults/site-defaults)))))
+    (-> handler
+        (defaults/wrap-defaults
+         (or site-defaults-config defaults/site-defaults))
+        (wrap-nil-guard))))

src/clj/pmagnus/btcprice/web/routes/ui.clj

@@ -7,60 +7,25 @@
    [reitit.ring.middleware.muuntaja :as muuntaja]
    [reitit.ring.middleware.parameters :as parameters]))
 
-(defn- home-page [{:keys [btcdata-url]} _req]
+(defn- home-page [_opts _req]
   (page {:title "BTC Price"}
     [:header.text-center.mb-8
      [:h1.text-3xl.font-bold.text-gray-900 "BTC Price"]
      [:p.text-sm.text-gray-500.mt-1 "Bitcoin price tracker"]]
 
-    [:div#price-panel
+    [:div#price-panel {:hx-ext "ws" :ws-connect "/ws/price"}
      [:div#price-display
       [:div.bg-white.rounded-2xl.shadow-sm.border.border-gray-200.p-6
        [:p.text-center.text-gray-400.text-sm "Connecting..."]]]]
 
-    [:script
-     (hiccup2.core/raw
-      (str
-       "document.addEventListener('DOMContentLoaded', function() {\n"
-       "  var btcdataUrl = '" btcdata-url "';\n"
-       "  var wsUrl = btcdataUrl.replace(/^http/, 'ws');\n"
-       "  var display = document.getElementById('price-display');\n"
-       "\n"
-       "  function connect() {\n"
-       "    var ws = new WebSocket(wsUrl + '/api/price/ws');\n"
-       "\n"
-       "    ws.onmessage = function(e) {\n"
-       "      var d = JSON.parse(e.data);\n"
-       "      if (d.ping) return;\n"
-       "      var price = parseFloat(d.price);\n"
-       "      var prevPrice = d.prev_price ? parseFloat(d.prev_price) : null;\n"
-       "      var color = 'text-gray-900';\n"
-       "      if (prevPrice !== null) {\n"
-       "        if (price > prevPrice) color = 'text-green-600';\n"
-       "        else if (price < prevPrice) color = 'text-red-600';\n"
-       "      }\n"
-       "      var fmt = '$' + price.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});\n"
-       "      var ts = new Date(d.recorded_at);\n"
-       "      var pad = function(n) { return n < 10 ? '0' + n : n; };\n"
-       "      var timeStr = pad(ts.getDate()) + '-' + pad(ts.getMonth()+1) + ' ' + pad(ts.getHours()) + ':' + pad(ts.getMinutes()) + ':' + pad(ts.getSeconds());\n"
-       "      display.innerHTML = '<div class=\"bg-white rounded-2xl shadow-sm border border-gray-200 p-6\">' +\n"
-       "        '<div class=\"text-center\">' +\n"
-       "        '<p class=\"text-4xl font-bold ' + color + '\">' + fmt + '</p>' +\n"
-       "        '<p class=\"text-xs text-gray-400 mt-2\">Updated ' + timeStr + '</p>' +\n"
-       "        '</div></div>';\n"
-       "    };\n"
-       "\n"
-       "    ws.onclose = function() {\n"
-       "      display.innerHTML = '<div class=\"bg-white rounded-2xl shadow-sm border border-gray-200 p-6\">' +\n"
-       "        '<p class=\"text-center text-red-400 text-sm\">Connection lost. Reconnecting...</p></div>';\n"
-       "      setTimeout(connect, 3000);\n"
-       "    };\n"
-       "\n"
-       "    ws.onerror = function() {};\n"
-       "  }\n"
-       "\n"
-       "  connect();\n"
-       "});\n"))]))
+    [:div.mt-4 {:hx-ext "ws" :ws-connect "/ws/strike"}
+     [:div#strike-display
+      [:div.bg-white.rounded-2xl.shadow-sm.border.border-gray-200.p-6
+       [:p.text-center.text-gray-400.text-sm "Loading Strike rates..."]]]]
+
+    ;; Safelist classes used in btcdata HTML fragments
+    [:div {:class "hidden text-4xl text-2xl font-bold text-green-600 text-red-600 text-gray-900 text-xs text-gray-400 mt-2 flex justify-center justify-between items-center gap-4 mt-1 mt-3 text-sm text-gray-600 text-gray-500 mb-3 py-1 grid grid-cols-2 gap-x-6 gap-y-1"
+           :aria-hidden "true"}]))
 
 (defn- ui-routes [opts]
   [["/"

src/clj/pmagnus/btcprice/web/routes/ws_proxy.clj

@@ -0,0 +1,159 @@
+(ns pmagnus.btcprice.web.routes.ws-proxy
+  (:require
+   [clojure.data.json :as json]
+   [clojure.tools.logging :as log]
+   [integrant.core :as ig])
+  (:import
+   [io.undertow.websockets.core WebSockets WebSocketChannel]
+   [java.net URI]
+   [java.net.http HttpClient WebSocket$Builder WebSocket$Listener]
+   [java.time Instant ZoneId]
+   [java.time.format DateTimeFormatter]
+   [java.util Locale]
+   [java.util.concurrent CompletableFuture]))
+
+(defn- close-quietly [^WebSocketChannel ch]
+  (when (and ch (.isOpen ch))
+    (try (.close ch) (catch Exception _))))
+
+(defn- close-upstream-quietly [^java.net.http.WebSocket ws]
+  (when ws
+    (try (.sendClose ws java.net.http.WebSocket/NORMAL_CLOSURE "") (catch Exception _))))
+
+(defn- connect-upstream
+  "Open a Java HttpClient WebSocket to btcdata, transform each text frame
+   with xf, and send the result to the browser channel."
+  [^String btcdata-ws-url ^WebSocketChannel browser-ch xf]
+  (let [client   (HttpClient/newHttpClient)
+        listener (reify java.net.http.WebSocket$Listener
+                   (onOpen [_ ws]
+                     (.request ws 1))
+                   (onText [_ ws data last?]
+                     (let [text (str data)]
+                       (try
+                         (when (and (.isOpen browser-ch) (seq text))
+                           (WebSockets/sendTextBlocking (xf text) browser-ch))
+                         (catch Exception e
+                           (log/debug e "Error forwarding to browser")
+                           (close-upstream-quietly ws))))
+                     (.request ws 1)
+                     (CompletableFuture/completedFuture nil))
+                   (onClose [_ _ws status-code _reason]
+                     (log/debug "Upstream closed" status-code)
+                     (close-quietly browser-ch))
+                   (onError [_ _ws error]
+                     (log/debug error "Upstream error")
+                     (close-quietly browser-ch)))]
+    (-> (.newWebSocketBuilder client)
+        ^WebSocket$Builder identity
+        (.buildAsync (URI. btcdata-ws-url) listener)
+        (.join))))
+
+(defn- ws-handler [btcdata-ws-url xf _req]
+  (let [upstream-atom (atom nil)]
+    {:undertow/websocket
+     {:on-open
+      (fn [{:keys [^WebSocketChannel channel]}]
+        (log/info "Browser connected, proxying to" btcdata-ws-url)
+        (reset! upstream-atom (connect-upstream btcdata-ws-url channel xf)))
+      :on-close-message
+      (fn [_]
+        (log/debug "Browser closed")
+        (close-upstream-quietly @upstream-atom))}}))
+
+;; --- Price rendering ---
+
+(def ^:private ts-fmt (DateTimeFormatter/ofPattern "dd-MM HH:mm:ss"))
+(def ^:private da-locale (Locale. "da" "DK"))
+
+(defn- da-fmt [fmt val]
+  (String/format da-locale fmt (into-array Object [val])))
+
+(defn- price-json->html [text]
+  (let [{:strs [price prev_price recorded_at
+                price_eur price_dkk]} (json/read-str text)
+        p     (double (bigdec price))
+        pp    (when prev_price (double (bigdec prev_price)))
+        color (cond
+                (nil? pp) "text-gray-900"
+                (> p pp)  "text-green-600"
+                (< p pp)  "text-red-600"
+                :else     "text-gray-900")
+        ts    (.format (.atZone (Instant/parse recorded_at) (ZoneId/systemDefault)) ts-fmt)]
+    (str "<div id=\"price-display\">"
+         "<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 "\">$" (da-fmt "%,.2f" p) "</p>"
+         (when price_eur
+           (let [p-eur (double (bigdec price_eur))
+                 p-dkk (double (bigdec price_dkk))
+                 eur   (/ p-eur p)
+                 dkk   (/ p-dkk p)]
+             (str "<div class=\"flex justify-center gap-4 mt-3\">"
+                  "<span class=\"text-2xl font-bold text-gray-600\">\u20AC" (da-fmt "%,.0f" p-eur) "</span>"
+                  "<span class=\"text-2xl font-bold text-gray-600\">" (da-fmt "%,.0f" p-dkk) " kr</span>"
+                  "</div>"
+                  "<div class=\"flex justify-center gap-4 mt-1\">"
+                  "<span class=\"text-xs text-gray-400\">EUR/USD " (da-fmt "%.4f" eur) "</span>"
+                  "<span class=\"text-xs text-gray-400\">DKK/USD " (da-fmt "%.4f" dkk) "</span>"
+                  "</div>")))
+         "<p class=\"text-xs text-gray-400 mt-2\">Updated " ts "</p>"
+         "</div></div></div>")))
+
+;; --- Strike rendering ---
+
+(def ^:private strike-pairs
+  [["BTC/USDT" "$"]
+   ["BTC/EUR"  "\u20AC"]
+   ["USDT/EUR" ""]
+   ["EUR/BTC"  ""]])
+
+(defn- format-strike-amount [prefix amount]
+  (if amount
+    (let [v (double (bigdec amount))]
+      (case prefix
+        "$"      (str prefix (da-fmt "%,.2f" v))
+        "\u20AC" (str prefix (da-fmt "%,.2f" v))
+        amount))
+    "\u2014"))
+
+(defn- strike-json->html [text]
+  (let [rates (json/read-str text)
+        sats  (get rates "quote-sats")]
+    (str "<div id=\"strike-display\">"
+         "<div class=\"rounded-2xl shadow-sm border border-gray-200 p-6\" style=\"background:#f3f4f6;\">"
+         (if sats
+           (str "<p class=\"text-center text-2xl font-bold mb-3\" style=\"color:#1e3a5f;\">"
+                (da-fmt "%,d" sats) " <span style=\"color:#1e3a5f;\">sats</span></p>")
+           "")
+         "<div style=\"display:grid;grid-template-columns:1fr;row-gap:0.25rem;\">"
+         (apply str
+           (for [[pair prefix] strike-pairs
+                 :let [amount (get rates pair)]]
+             (str "<div style=\"display:flex;justify-content:space-between;align-items:center;padding:0.25rem 0;\">"
+                  "<span class=\"text-sm text-gray-500\">" pair "</span>"
+                  "<span class=\"text-sm font-bold text-gray-900\">"
+                  (format-strike-amount prefix amount)
+                  "</span></div>")))
+         "</div></div></div>")))
+
+;; --- Routes ---
+
+(defn- ws-proxy-routes [{:keys [btcdata-url]}]
+  (let [ws-base (str (.replaceFirst ^String btcdata-url "^http" "ws"))]
+    [["/ws/price"
+      {:get        (fn [req] (ws-handler (str ws-base "/api/price/ws") price-json->html req))
+       :no-doc     true
+       :middleware []}]
+     ["/ws/strike"
+      {:get        (fn [req] (ws-handler (str ws-base "/api/strike/ws") strike-json->html req))
+       :no-doc     true
+       :middleware []}]]))
+
+(derive :reitit.routes/ws-proxy :reitit/routes)
+
+(defmethod ig/init-key :reitit.routes/ws-proxy
+  [_ {:keys [base-path]
+      :or   {base-path ""}
+      :as   opts}]
+  [base-path {} (ws-proxy-routes opts)])