initial commit for handling extra template kwargs

Author: matteoserva

common/chat.cpp

@@ -24,6 +24,7 @@ struct templates_params {
     std::string grammar;
     bool add_generation_prompt = true;
     bool extract_reasoning     = true;
+    json extra_context;
 };
 
 common_chat_tool_choice common_chat_tool_choice_parse_oaicompat(const std::string & tool_choice) {
@@ -1561,7 +1562,7 @@ static common_chat_msg common_chat_parse_hermes_2_pro(const std::string& input,
 
 static common_chat_params common_chat_params_init_without_tools(const common_chat_template & tmpl, const struct templates_params & inputs) {
     common_chat_params data;
-    data.prompt = apply(tmpl, inputs.messages, inputs.tools.empty() ? json() : inputs.tools, inputs.add_generation_prompt);
+    data.prompt = apply(tmpl, inputs.messages, inputs.tools.empty() ? json() : inputs.tools, inputs.add_generation_prompt,inputs.extra_context);
     data.format = COMMON_CHAT_FORMAT_CONTENT_ONLY;
     data.grammar_lazy = false;
     if (!inputs.json_schema.is_null()) {
@@ -1591,6 +1592,13 @@ static common_chat_params common_chat_templates_apply_jinja(
     params.extract_reasoning = inputs.extract_reasoning;
     params.tool_choice = inputs.tool_choice;
     params.grammar = inputs.grammar;
+
+    for(auto el: inputs.chat_template_kwargs)
+    {
+        params.extra_context[el.first] = json::parse(el.second);
+    }
+    
+
     if (!inputs.json_schema.empty()) {
         params.json_schema = json::parse(inputs.json_schema);
     }

common/chat.h

@@ -5,6 +5,7 @@
 #include "common.h"
 #include <string>
 #include <vector>
+#include <map>
 
 struct common_chat_templates;
 
@@ -71,6 +72,7 @@ struct common_chat_templates_inputs {
     common_chat_tool_choice tool_choice = COMMON_CHAT_TOOL_CHOICE_AUTO;
     bool parallel_tool_calls = false;
     bool extract_reasoning     = true;
+    std::map<std::string,std::string> chat_template_kwargs;
 };
 
 struct common_chat_params {

examples/server/utils.hpp

@@ -638,6 +638,12 @@ static json oaicompat_completion_params_parse(
     inputs.parallel_tool_calls   = json_value(body, "parallel_tool_calls", false);
     inputs.extract_reasoning     = reasoning_format != COMMON_REASONING_FORMAT_NONE;
     inputs.add_generation_prompt = json_value(body, "add_generation_prompt", true);
+
+    auto chat_template_kwargs_object = json_value(body, "chat_template_kwargs", json::object());
+    for (const auto & item : chat_template_kwargs_object.items()) {
+        inputs.chat_template_kwargs[item.key()] = item.value().dump();
+    }
+
     if (!inputs.tools.empty() && inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_NONE && body.contains("grammar")) {
         throw std::runtime_error("Cannot use custom grammar constraints with tools.");
     }