feat(server): add lora support to sdapi (#1256)

examples/server/main.cpp

@@ -263,6 +263,11 @@ void sd_log_cb(enum sd_log_level_t level, const char* log, void* data) {
     log_print(level, log, svr_params->verbose, svr_params->color);
 }
 
+struct LoraEntry {
+    std::string name;
+    std::string path;
+};
+
 int main(int argc, const char** argv) {
     if (argc > 1 && std::string(argv[1]) == "--version") {
         std::cout << version_string() << "\n";
@@ -293,6 +298,54 @@ int main(int argc, const char** argv) {
 
     std::mutex sd_ctx_mutex;
 
+    std::vector<LoraEntry> lora_cache;
+    std::mutex lora_mutex;
+
+    auto refresh_lora_cache = [&]() {
+        std::vector<LoraEntry> new_cache;
+
+        fs::path lora_dir = ctx_params.lora_model_dir;
+        if (fs::exists(lora_dir) && fs::is_directory(lora_dir)) {
+            auto is_lora_ext = [](const fs::path& p) {
+                auto ext = p.extension().string();
+                std::transform(ext.begin(), ext.end(), ext.begin(), ::tolower);
+                return ext == ".gguf" || ext == ".pt" || ext == ".pth" || ext == ".safetensors";
+            };
+
+            for (auto& entry : fs::recursive_directory_iterator(lora_dir)) {
+                if (!entry.is_regular_file())
+                    continue;
+                const fs::path& p = entry.path();
+                if (!is_lora_ext(p))
+                    continue;
+
+                LoraEntry e;
+                e.name          = p.stem().u8string();
+                std::string rel = fs::relative(p, lora_dir).u8string();
+                std::replace(rel.begin(), rel.end(), '\\', '/');
+                e.path = rel;
+
+                new_cache.push_back(std::move(e));
+            }
+        }
+
+        std::sort(new_cache.begin(), new_cache.end(),
+                  [](const LoraEntry& a, const LoraEntry& b) {
+                      return a.path < b.path;
+                  });
+
+        {
+            std::lock_guard<std::mutex> lock(lora_mutex);
+            lora_cache = std::move(new_cache);
+        }
+    };
+
+    auto is_valid_lora_path = [&](const std::string& path) -> bool {
+        std::lock_guard<std::mutex> lock(lora_mutex);
+        return std::any_of(lora_cache.begin(), lora_cache.end(),
+                           [&](const LoraEntry& e) { return e.path == path; });
+    };
+
     httplib::Server svr;
 
     svr.set_pre_routing_handler([](const httplib::Request& req, httplib::Response& res) {
@@ -312,7 +365,7 @@ int main(int argc, const char** argv) {
         return httplib::Server::HandlerResponse::Unhandled;
     });
 
-    // health
+    // root
     svr.Get("/", [&](const httplib::Request&, httplib::Response& res) {
         if (!svr_params.serve_html_path.empty()) {
             std::ifstream file(svr_params.serve_html_path);
@@ -767,6 +820,37 @@ int main(int argc, const char** argv) {
                 return bad("prompt required");
             }
 
+            std::vector<sd_lora_t> sd_loras;
+            std::vector<std::string> lora_path_storage;
+
+            if (j.contains("lora") && j["lora"].is_array()) {
+                for (const auto& item : j["lora"]) {
+                    if (!item.is_object()) {
+                        continue;
+                    }
+
+                    std::string path   = item.value("path", "");
+                    float multiplier   = item.value("multiplier", 1.0f);
+                    bool is_high_noise = item.value("is_high_noise", false);
+
+                    if (path.empty()) {
+                        return bad("lora.path required");
+                    }
+
+                    if (!is_valid_lora_path(path)) {
+                        return bad("invalid lora path: " + path);
+                    }
+
+                    lora_path_storage.push_back(path);
+                    sd_lora_t l;
+                    l.is_high_noise = is_high_noise;
+                    l.multiplier    = multiplier;
+                    l.path          = lora_path_storage.back().c_str();
+
+                    sd_loras.push_back(l);
+                }
+            }
+
             auto get_sample_method = [](std::string name) -> enum sample_method_t {
                 enum sample_method_t result = str_to_sample_method(name.c_str());
                 if (result != SAMPLE_METHOD_COUNT) return result;
@@ -894,8 +978,8 @@ int main(int argc, const char** argv) {
             }
 
             sd_img_gen_params_t img_gen_params = {
-                gen_params.lora_vec.data(),
+                sd_loras.data(),
-                static_cast<uint32_t>(gen_params.lora_vec.size()),
+                static_cast<uint32_t>(sd_loras.size()),
                 gen_params.prompt.c_str(),
                 gen_params.negative_prompt.c_str(),
                 gen_params.clip_skip,
@@ -987,6 +1071,23 @@ int main(int argc, const char** argv) {
         sdapi_any2img(req, res, true);
     });
 
+    svr.Get("/sdapi/v1/loras", [&](const httplib::Request&, httplib::Response& res) {
+        refresh_lora_cache();
+
+        json result = json::array();
+        {
+            std::lock_guard<std::mutex> lock(lora_mutex);
+            for (const auto& e : lora_cache) {
+                json item;
+                item["name"] = e.name;
+                item["path"] = e.path;
+                result.push_back(item);
+            }
+        }
+
+        res.set_content(result.dump(), "application/json");
+    });
+
     svr.Get("/sdapi/v1/samplers", [&](const httplib::Request&, httplib::Response& res) {
         std::vector<std::string> sampler_names;
         sampler_names.push_back("default");