modified: app.py

modified:   templates/base.html
	modified:   templates/index.html

app.py

@@ -29,6 +29,14 @@ def _set_language():
     g.lang = lang
     g.T = TRANSLATIONS[lang]
 
+@app.after_request
+def _persist_language_cookie(response):
+    """If ?lang= was in the URL, save it as a cookie so it survives navigation."""
+    url_lang = request.args.get("lang")
+    if url_lang in TRANSLATIONS:
+        response.set_cookie("lang", url_lang, max_age=60*60*24*365, samesite="Lax")
+    return response
+
 @app.context_processor
 def _inject_i18n():
     return {"T": g.get("T", TRANSLATIONS["de"]), "lang": g.get("lang", "de")}

templates/base.html

@@ -15,6 +15,7 @@
   <form class="nav-search" action="/wetter" method="get" autocomplete="off">
     <div class="nav-search-wrap">
       <svg class="nav-search-icon" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><circle cx="11" cy="11" r="8"/><path d="m21 21-4.35-4.35"/></svg>
+      <input type="hidden" name="lang" value="{{ lang }}">
       <input type="text" name="ort" id="nav-ort" placeholder="{{ T.nav_placeholder }}" value="{{ request.args.get('ort','') }}"/>
       <ul class="ac-list" id="nav-ac"></ul>
     </div>

templates/index.html

@@ -14,6 +14,7 @@
         <svg class="home-search-icon" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
           <circle cx="11" cy="11" r="8"/><path d="m21 21-4.35-4.35"/>
         </svg>
+        <input type="hidden" name="lang" value="{{ lang }}">
         <input type="text" name="ort" id="home-ort" placeholder="{{ T.home_placeholder }}" required autofocus/>
         <ul class="ac-list" id="home-ac"></ul>
       </div>
@@ -61,7 +62,7 @@ document.getElementById("btn-location").addEventListener("click", function() {
   this.textContent = _i18n.locating;
   this.disabled = true;
   navigator.geolocation.getCurrentPosition(
-    pos => { window.location = `/wetter?lat=${pos.coords.latitude}&lon=${pos.coords.longitude}&ort=Mein+Standort`; },
+    pos => { window.location = `/wetter?lat=${pos.coords.latitude}&lon=${pos.coords.longitude}&ort=Mein+Standort&lang={{ lang }}`; },
     () => { this.textContent = _i18n.locationUnavailable; this.disabled = false; }
   );
 });