Add /v1/models endpoint

This is usually used by OpenAI clients, like OpenWebUI for discovery and
health check.

Author: corebonts

llamafile/server/client.cpp

@@ -699,6 +699,8 @@ Client::dispatcher()
         return v1_completions();
     if (p1 == "v1/chat/completions")
         return v1_chat_completions();
+    if (p1 == "v1/models")
+        return v1_models();
     if (p1 == "slotz")
         return slotz();
     if (p1 == "flagz")

llamafile/server/client.h

@@ -117,6 +117,8 @@ struct Client
     bool v1_chat_completions() __wur;
     bool get_v1_chat_completions_params(V1ChatCompletionParams*) __wur;
 
+    bool v1_models() __wur;
+
     bool slotz() __wur;
     bool flagz() __wur;
     bool db_chat(int64_t) __wur;

llamafile/server/v1_models.cpp

@@ -0,0 +1,49 @@
+// -*- mode:c++;indent-tabs-mode:nil;c-basic-offset:4;coding:utf-8 -*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+//
+// Copyright 2024 Mozilla Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "client.h"
+#include "llama.cpp/llama.h"
+#include "llamafile/json.h"
+#include "llamafile/llamafile.h"
+#include "llamafile/string.h"
+#include <ctime>
+
+using jt::Json;
+
+namespace lf {
+namespace server {
+
+// Use it as reported model creation time
+static const time_t model_creation_time = time(0);
+
+bool
+Client::v1_models()
+{
+    jt::Json json;
+    json["object"] = "list";
+    Json& model = json["data"][0];
+    model["id"] = stripext(basename(FLAG_model));
+    model["object"] = "model";
+    model["created"] = model_creation_time;
+    model["owned_by"] = "llamafile";
+    char* p = append_http_response_message(obuf_.p, 200);
+    p = stpcpy(p, "Content-Type: application/json\r\n");
+    return send_response(obuf_.p, p, json.toString());
+}
+    
+} // namespace server
+} // namespace lf