Add fallback option for OpenRouter

public/index.html

@@ -1972,6 +1972,17 @@
                                     <option data-i18n="Connect to the API">-- Connect to the API --</option>
                                 </select>
                             </div>
+                            <div class="marginTopBot5">
+                                <label for="openrouter_use_fallback" class="checkbox_label">
+                                    <input id="openrouter_use_fallback" type="checkbox" />
+                                    <span data-i18n="Allow fallback routes">Allow fallback routes</span>
+                                </label>
+                                <div class="toggle-description justifyLeft">
+                                    <span data-i18n="Allow fallback routes Description">
+                                        Automatically chooses an alternative model if the chosen model can't serve your request.
+                                    </span>
+                                </div>
+                            </div>
                             <h4 data-i18n="OpenRouter API Key">OpenRouter API Key</h4>
                             <div>
                                 <small>

public/scripts/openai.js

@@ -174,6 +174,7 @@ const default_settings = {
     ai21_model: 'j2-ultra',
     windowai_model: '',
     openrouter_model: openrouter_website_model,
+    openrouter_use_fallback: true,
     jailbreak_system: false,
     reverse_proxy: '',
     legacy_streaming: false,
@@ -217,6 +218,7 @@ const oai_settings = {
     ai21_model: 'j2-ultra',
     windowai_model: '',
     openrouter_model: openrouter_website_model,
+    openrouter_use_fallback: true,
     jailbreak_system: false,
     reverse_proxy: '',
     legacy_streaming: false,
@@ -1158,6 +1160,7 @@ async function sendOpenAIRequest(type, openai_msgs_tosend, signal) {
     if (isOpenRouter) {
         generate_data['use_openrouter'] = true;
         generate_data['top_k'] = Number(oai_settings.top_k_openai);
+        generate_data['use_fallback'] = oai_settings.openrouter_use_fallback;
     }
 
     if (isScale) {
@@ -1842,6 +1845,7 @@ function loadOpenAISettings(data, settings) {
     oai_settings.claude_model = settings.claude_model ?? default_settings.claude_model;
     oai_settings.windowai_model = settings.windowai_model ?? default_settings.windowai_model;
     oai_settings.openrouter_model = settings.openrouter_model ?? default_settings.openrouter_model;
+    oai_settings.openrouter_use_fallback = settings.openrouter_use_fallback ?? default_settings.openrouter_use_fallback;
     oai_settings.ai21_model = settings.ai21_model ?? default_settings.ai21_model;
     oai_settings.chat_completion_source = settings.chat_completion_source ?? default_settings.chat_completion_source;
     oai_settings.api_url_scale = settings.api_url_scale ?? default_settings.api_url_scale;
@@ -1891,6 +1895,7 @@ function loadOpenAISettings(data, settings) {
     $('#use_ai21_tokenizer').prop('checked', oai_settings.use_ai21_tokenizer);
     $('#exclude_assistant').prop('checked', oai_settings.exclude_assistant);
     $('#scale-alt').prop('checked', oai_settings.use_alt_scale);
+    $('#openrouter_use_fallback').prop('checked', oai_settings.openrouter_use_fallback);
     if (settings.impersonation_prompt !== undefined) oai_settings.impersonation_prompt = settings.impersonation_prompt;
 
     $('#impersonation_prompt_textarea').val(oai_settings.impersonation_prompt);
@@ -2055,6 +2060,7 @@ async function saveOpenAIPreset(name, settings, triggerUi = true) {
         claude_model: settings.claude_model,
         windowai_model: settings.windowai_model,
         openrouter_model: settings.openrouter_model,
+        openrouter_use_fallback: settings.openrouter_use_fallback,
         ai21_model: settings.ai21_model,
         temperature: settings.temp_openai,
         frequency_penalty: settings.freq_pen_openai,
@@ -2413,6 +2419,7 @@ function onSettingsPresetChange() {
         claude_model: ['#model_claude_select', 'claude_model', false],
         windowai_model: ['#model_windowai_select', 'windowai_model', false],
         openrouter_model: ['#model_openrouter_select', 'openrouter_model', false],
+        openrouter_use_fallback: ['#openrouter_use_fallback', 'openrouter_use_fallback', true],
         ai21_model: ['#model_ai21_select', 'ai21_model', false],
         openai_max_context: ['#openai_max_context', 'openai_max_context', false],
         openai_max_tokens: ['#openai_max_tokens', 'openai_max_tokens', false],
@@ -3125,6 +3132,11 @@ $(document).ready(async function () {
         saveSettingsDebounced();
     });
 
+    $('#openrouter_use_fallback').on('input', function () {
+        oai_settings.openrouter_use_fallback = !!$(this).prop('checked');
+        saveSettingsDebounced();
+    });
+
     $("#api_button_openai").on("click", onConnectButtonClick);
     $("#openai_reverse_proxy").on("input", onReverseProxyInput);
     $("#model_openai_select").on("change", onModelChange);

server.js

@@ -3478,6 +3478,10 @@ app.post("/generate_openai", jsonParser, function (request, response_generate_op
         // OpenRouter needs to pass the referer: https://openrouter.ai/docs
         headers = { 'HTTP-Referer': request.headers.referer };
         bodyParams = { 'transforms': ["middle-out"] };
+
+        if (request.body.use_fallback) {
+            bodyParams['route'] = 'fallback';
+        }
     }
 
     if (!api_key_openai && !request.body.reverse_proxy) {