Files
cpp-httplib/docs-src/pages/en/llm-app/ch06-desktop-app.md
T
yhirose bef278e0d2 Fix docs pages that no longer match the code
Samples that did not compile or run as shown:
- res.user_data.get<T>() inside a generic lambda needs the `template`
  keyword; use explicit parameter types (tour 09, cookbook s15).
- listen() on a Unix domain socket fails with port 0 (tour 09, s22).
- "*.dev.local" is not a NO_PROXY pattern (c16).
- ssl_backend_error() holds a verify result, not an ERR_get_error()
  value, after a verification failure; decode each with the matching
  OpenSSL function (c18).
- The content provider's `length` is everything that remains, so the
  sample read the whole file in one call (s05).

Statements corrected:
- Client keep-alive is off by default; c14 is rewritten around
  set_keep_alive(true).
- Mounted files are looked up before GET handlers (tour 04, s04).
- Params keep insertion order, and to_string(Error::Connection) reads
  "Could not establish connection" (tour 02).
- A chunked provider ends with sink.done(), and post_routing_handler
  runs before the response is sent (tour 09).
- Timeouts surface as Error::Read; Error::Timeout comes from the stream
  API (c17). The max timeout cuts off the wait for the response only
  (c13). The progress callback needs Content-Length (c11).
- Encoding selection follows q-values, then Brotli, gzip, Zstd (s08),
  and the client compresses with the first of those it was built with
  (c15).
- stop() cuts a provider-driven response short (s19); a rejected
  content_reader already gets 400 or 413 (s07); user_data values must be
  copyable (s12); Client accepts a client certificate too (t04);
  on_message() is the fallback for every unhandled event and 204/403/404
  end reconnection (e04); the pong timeout takes two to three intervals
  and ends a waiting read() (w02).

In the LLM app tutorial, an uncaught exception does not crash the
server, so say what it does instead. Drop the server and client timeout
settings whose stated purpose, covering inference and download time,
they do not serve: those timeouts bound a single socket wait. Update
the llama.cpp server layout in chapter 7.
2026-10-08 20:39:13 -04:00

720 lines
25 KiB
Markdown

---
title: "6. Turning It into a Desktop App with WebView"
order: 6
---
In Chapter 5, we completed a translation app you can use from a browser. But every time, you have to start the server, open the URL in a browser... Wouldn't it be nice to just double-click and start using it, like a normal app?
In this chapter, we'll do two things:
1. **WebView integration** — Use [webview/webview](https://github.com/webview/webview) to turn it into a desktop app that runs without a browser
2. **Single binary packaging** — Use [cpp-embedlib](https://github.com/yhirose/cpp-embedlib) to embed HTML/CSS/JS into the binary, making the distributable a single file
When finished, you'll be able to just run `./translate-app` to open a window and start translating.
![Desktop App](../app.png#large-center)
The model downloads automatically on first launch, so the only thing you need to give users is the single binary.
## 6.1 Introducing webview/webview
[webview/webview](https://github.com/webview/webview) is a library that lets you use the OS's native WebView component (WKWebView on macOS, WebKitGTK on Linux, WebView2 on Windows) from C/C++. Unlike Electron, it doesn't bundle its own browser, so the impact on binary size is negligible.
We'll fetch it with CMake. Add the following to your `CMakeLists.txt`:
```cmake
# webview/webview
FetchContent_Declare(webview
GIT_REPOSITORY https://github.com/webview/webview
GIT_TAG master
)
FetchContent_MakeAvailable(webview)
```
This makes the `webview::core` CMake target available. When you link it with `target_link_libraries`, it automatically sets up include paths and platform-specific frameworks.
> **macOS**: No additional dependencies are needed. WKWebView is built into the system.
>
> **Linux**: WebKitGTK is required. Install it with `sudo apt install libwebkit2gtk-4.1-dev`.
>
> **Windows**: The WebView2 runtime is required. It comes pre-installed on Windows 11. For Windows 10, download it from the [official Microsoft website](https://developer.microsoft.com/en-us/microsoft-edge/webview2/).
## 6.2 Running the Server on a Background Thread
Up through Chapter 5, the server's `listen()` was blocking the main thread. To use WebView, we need to run the server on a separate thread and run the WebView event loop on the main thread.
```cpp
#include "webview/webview.h"
#include <thread>
int main() {
// ... (server setup is the same as Chapter 5) ...
// Start the server on a background thread
auto port = svr.bind_to_any_port("127.0.0.1");
std::thread server_thread([&]() { svr.listen_after_bind(); });
std::cout << "Listening on http://127.0.0.1:" << port << std::endl;
// Display the UI with WebView
webview::webview w(false, nullptr);
w.set_title("Translate App");
w.set_size(1024, 768, WEBVIEW_HINT_NONE);
w.navigate("http://127.0.0.1:" + std::to_string(port));
w.run(); // Block until the window is closed
// Stop the server when the window is closed
svr.stop();
server_thread.join();
}
```
Let's look at the key points:
- **`bind_to_any_port`** — Instead of `listen("127.0.0.1", 8080)`, we let the OS choose an available port. Since desktop apps can be launched multiple times, using a fixed port would cause conflicts
- **`listen_after_bind`** — Starts accepting requests on the port reserved by `bind_to_any_port`. While `listen()` does bind and listen in one call, we need to know the port number first, so we split the operations
- **Shutdown order** — When the WebView window is closed, we stop the server with `svr.stop()` and wait for the thread to finish with `server_thread.join()`. If we reversed the order, WebView would lose access to the server
The `signal_handler` from Chapter 5 is no longer needed. In a desktop app, closing the window means terminating the application.
## 6.3 Embedding Static Files with cpp-embedlib
In Chapter 5, we served files from the `public/` directory, so you'd need to distribute `public/` alongside the binary. With [cpp-embedlib](https://github.com/yhirose/cpp-embedlib), you can embed HTML, CSS, and JavaScript into the binary, packaging the distributable into a single file.
### CMakeLists.txt
Fetch cpp-embedlib and embed `public/`:
```cmake
# cpp-embedlib
FetchContent_Declare(cpp-embedlib
GIT_REPOSITORY https://github.com/yhirose/cpp-embedlib
GIT_TAG main
)
FetchContent_MakeAvailable(cpp-embedlib)
# Embed the public/ directory into the binary
cpp_embedlib_add(WebAssets
FOLDER ${CMAKE_CURRENT_SOURCE_DIR}/public
NAMESPACE Web
)
target_link_libraries(translate-app PRIVATE
WebAssets # Embedded files
cpp-embedlib-httplib # cpp-httplib integration
)
```
`cpp_embedlib_add` converts the files under `public/` into binary data at compile time and creates a static library called `WebAssets`. When linked, you can access the embedded files through a `Web::FS` object. `cpp-embedlib-httplib` is a helper library that provides the `httplib::mount()` function.
### Replacing set_mount_point with httplib::mount
Simply replace Chapter 5's `set_mount_point` with cpp-embedlib's `httplib::mount`:
```cpp
#include <cpp-embedlib-httplib.h>
#include "WebAssets.h"
// Chapter 5:
// svr.set_mount_point("/", "./public");
// Chapter 6:
httplib::mount(svr, Web::FS);
```
`httplib::mount` registers handlers that serve the files embedded in `Web::FS` over HTTP. MIME types are automatically determined from file extensions, so there's no need to manually set `Content-Type`.
The file contents are directly mapped to the binary's data segment, so no memory copies or heap allocations occur.
## 6.4 macOS: Adding the Edit Menu
If you try to paste text into the input field with `Cmd+V`, you'll find it doesn't work. On macOS, keyboard shortcuts like `Cmd+V` (paste) and `Cmd+C` (copy) are routed through the application's menu bar. Since webview/webview doesn't create one, these shortcuts never reach the WebView. We need to add a macOS Edit menu using the Objective-C runtime:
```cpp
#ifdef __APPLE__
#include <objc/objc-runtime.h>
void setup_macos_edit_menu() {
auto cls = [](const char *n) { return (id)objc_getClass(n); };
auto sel = sel_registerName;
auto msg = reinterpret_cast<id (*)(id, SEL)>(objc_msgSend);
auto msg_s = reinterpret_cast<id (*)(id, SEL, const char *)>(objc_msgSend);
auto msg_id = reinterpret_cast<id (*)(id, SEL, id)>(objc_msgSend);
auto msg_v = reinterpret_cast<void (*)(id, SEL, id)>(objc_msgSend);
auto msg_mi = reinterpret_cast<id (*)(id, SEL, id, SEL, id)>(objc_msgSend);
auto str = [&](const char *s) {
return msg_s(cls("NSString"), sel("stringWithUTF8String:"), s);
};
id app = msg(cls("NSApplication"), sel("sharedApplication"));
id mainMenu = msg(msg(cls("NSMenu"), sel("alloc")), sel("init"));
id editItem = msg(msg(cls("NSMenuItem"), sel("alloc")), sel("init"));
id editMenu = msg_id(msg(cls("NSMenu"), sel("alloc")),
sel("initWithTitle:"), str("Edit"));
struct { const char *title; const char *action; const char *key; } items[] = {
{"Undo", "undo:", "z"},
{"Redo", "redo:", "Z"},
{"Cut", "cut:", "x"},
{"Copy", "copy:", "c"},
{"Paste", "paste:", "v"},
{"Select All", "selectAll:", "a"},
};
for (auto &[title, action, key] : items) {
id mi = msg_mi(msg(cls("NSMenuItem"), sel("alloc")),
sel("initWithTitle:action:keyEquivalent:"),
str(title), sel(action), str(key));
msg_v(editMenu, sel("addItem:"), mi);
}
msg_v(editItem, sel("setSubmenu:"), editMenu);
msg_v(mainMenu, sel("addItem:"), editItem);
msg_v(app, sel("setMainMenu:"), mainMenu);
}
#endif
```
Call this before `w.run()`:
```cpp
#ifdef __APPLE__
setup_macos_edit_menu();
#endif
w.run();
```
On Windows and Linux, keyboard shortcuts are delivered directly to the focused control without going through the menu bar, so this workaround is macOS-specific.
## 6.5 Complete Code
<details>
<summary data-file="CMakeLists.txt">Complete code (CMakeLists.txt)</summary>
```cmake
cmake_minimum_required(VERSION 3.20)
project(translate-app CXX)
set(CMAKE_CXX_STANDARD 20)
include(FetchContent)
# llama.cpp
FetchContent_Declare(llama
GIT_REPOSITORY https://github.com/ggml-org/llama.cpp
GIT_TAG master
GIT_SHALLOW TRUE
)
FetchContent_MakeAvailable(llama)
# cpp-httplib
FetchContent_Declare(httplib
GIT_REPOSITORY https://github.com/yhirose/cpp-httplib
GIT_TAG master
)
FetchContent_MakeAvailable(httplib)
# nlohmann/json
FetchContent_Declare(json
URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz
)
FetchContent_MakeAvailable(json)
# cpp-llamalib
FetchContent_Declare(cpp_llamalib
GIT_REPOSITORY https://github.com/yhirose/cpp-llamalib
GIT_TAG main
)
FetchContent_MakeAvailable(cpp_llamalib)
# webview/webview
FetchContent_Declare(webview
GIT_REPOSITORY https://github.com/webview/webview
GIT_TAG master
)
FetchContent_MakeAvailable(webview)
# cpp-embedlib
FetchContent_Declare(cpp-embedlib
GIT_REPOSITORY https://github.com/yhirose/cpp-embedlib
GIT_TAG main
)
FetchContent_MakeAvailable(cpp-embedlib)
# Embed the public/ directory into the binary
cpp_embedlib_add(WebAssets
FOLDER ${CMAKE_CURRENT_SOURCE_DIR}/public
NAMESPACE Web
)
find_package(OpenSSL REQUIRED)
add_executable(translate-app src/main.cpp)
target_link_libraries(translate-app PRIVATE
httplib::httplib
nlohmann_json::nlohmann_json
cpp-llamalib
OpenSSL::SSL OpenSSL::Crypto
WebAssets
cpp-embedlib-httplib
webview::core
)
if(APPLE)
target_link_libraries(translate-app PRIVATE
"-framework CoreFoundation"
"-framework Security"
)
endif()
target_compile_definitions(translate-app PRIVATE
CPPHTTPLIB_OPENSSL_SUPPORT
)
```
</details>
<details>
<summary data-file="main.cpp">Complete code (main.cpp)</summary>
```cpp
#include <httplib.h>
#include <nlohmann/json.hpp>
#include <cpp-llamalib.h>
#include <cpp-embedlib-httplib.h>
#include "WebAssets.h"
#include "webview/webview.h"
#ifdef __APPLE__
#include <objc/objc-runtime.h>
#endif
#include <algorithm>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <mutex>
#include <thread>
using json = nlohmann::json;
// -------------------------------------------------------------------------
// macOS Edit menu (Cmd+C/V/X/A require an Edit menu on macOS)
// -------------------------------------------------------------------------
#ifdef __APPLE__
void setup_macos_edit_menu() {
auto cls = [](const char *n) { return (id)objc_getClass(n); };
auto sel = sel_registerName;
auto msg = reinterpret_cast<id (*)(id, SEL)>(objc_msgSend);
auto msg_s = reinterpret_cast<id (*)(id, SEL, const char *)>(objc_msgSend);
auto msg_id = reinterpret_cast<id (*)(id, SEL, id)>(objc_msgSend);
auto msg_v = reinterpret_cast<void (*)(id, SEL, id)>(objc_msgSend);
auto msg_mi = reinterpret_cast<id (*)(id, SEL, id, SEL, id)>(objc_msgSend);
auto str = [&](const char *s) {
return msg_s(cls("NSString"), sel("stringWithUTF8String:"), s);
};
id app = msg(cls("NSApplication"), sel("sharedApplication"));
id mainMenu = msg(msg(cls("NSMenu"), sel("alloc")), sel("init"));
id editItem = msg(msg(cls("NSMenuItem"), sel("alloc")), sel("init"));
id editMenu = msg_id(msg(cls("NSMenu"), sel("alloc")),
sel("initWithTitle:"), str("Edit"));
struct { const char *title; const char *action; const char *key; } items[] = {
{"Undo", "undo:", "z"},
{"Redo", "redo:", "Z"},
{"Cut", "cut:", "x"},
{"Copy", "copy:", "c"},
{"Paste", "paste:", "v"},
{"Select All", "selectAll:", "a"},
};
for (auto &[title, action, key] : items) {
id mi = msg_mi(msg(cls("NSMenuItem"), sel("alloc")),
sel("initWithTitle:action:keyEquivalent:"),
str(title), sel(action), str(key));
msg_v(editMenu, sel("addItem:"), mi);
}
msg_v(editItem, sel("setSubmenu:"), editMenu);
msg_v(mainMenu, sel("addItem:"), editItem);
msg_v(app, sel("setMainMenu:"), mainMenu);
}
#endif
// -------------------------------------------------------------------------
// Model definitions
// -------------------------------------------------------------------------
struct ModelInfo {
std::string name;
std::string params;
std::string size;
std::string repo;
std::string filename;
};
const std::vector<ModelInfo> MODELS = {
{
.name = "gemma-2-2b-it",
.params = "2B",
.size = "1.6 GB",
.repo = "bartowski/gemma-2-2b-it-GGUF",
.filename = "gemma-2-2b-it-Q4_K_M.gguf",
},
{
.name = "gemma-2-9b-it",
.params = "9B",
.size = "5.8 GB",
.repo = "bartowski/gemma-2-9b-it-GGUF",
.filename = "gemma-2-9b-it-Q4_K_M.gguf",
},
{
.name = "Llama-3.1-8B-Instruct",
.params = "8B",
.size = "4.9 GB",
.repo = "bartowski/Meta-Llama-3.1-8B-Instruct-GGUF",
.filename = "Meta-Llama-3.1-8B-Instruct-Q4_K_M.gguf",
},
};
// -------------------------------------------------------------------------
// Model storage directory
// -------------------------------------------------------------------------
std::filesystem::path get_models_dir() {
#ifdef _WIN32
auto env = std::getenv("APPDATA");
auto base = env ? std::filesystem::path(env) : std::filesystem::path(".");
return base / "translate-app" / "models";
#else
auto env = std::getenv("HOME");
auto base = env ? std::filesystem::path(env) : std::filesystem::path(".");
return base / ".translate-app" / "models";
#endif
}
// -------------------------------------------------------------------------
// Model download
// -------------------------------------------------------------------------
// Abort the download if progress_cb returns false
bool download_model(const ModelInfo &model,
std::function<bool(int)> progress_cb) {
httplib::Client cli("https://huggingface.co");
cli.set_follow_location(true); // Hugging Face redirects to a CDN
auto url = "/" + model.repo + "/resolve/main/" + model.filename;
auto path = get_models_dir() / model.filename;
auto tmp_path = std::filesystem::path(path).concat(".tmp");
std::ofstream ofs(tmp_path, std::ios::binary);
if (!ofs) { return false; }
auto res = cli.Get(url,
// content_receiver: Receive data chunk by chunk and write to file
[&](const char *data, size_t len) {
ofs.write(data, len);
return ofs.good();
},
// progress: Report download progress (return false to abort)
[&, last_pct = -1](size_t current, size_t total) mutable {
int pct = total ? (int)(current * 100 / total) : 0;
if (pct == last_pct) return true; // Skip if the value hasn't changed
last_pct = pct;
return progress_cb(pct);
});
ofs.close();
if (!res || res->status != 200) {
std::filesystem::remove(tmp_path);
return false;
}
// Rename after download completes
std::filesystem::rename(tmp_path, path);
return true;
}
// -------------------------------------------------------------------------
// Server
// -------------------------------------------------------------------------
int main() {
httplib::Server svr;
// Create the model storage directory
auto models_dir = get_models_dir();
std::filesystem::create_directories(models_dir);
// Auto-download the default model if not already present
std::string selected_model = MODELS[0].filename;
auto path = models_dir / selected_model;
if (!std::filesystem::exists(path)) {
std::cout << "Downloading " << selected_model << "..." << std::endl;
if (!download_model(MODELS[0], [](int pct) {
std::cout << "\r" << pct << "%" << std::flush;
return true;
})) {
std::cerr << "\nFailed to download model." << std::endl;
return 1;
}
std::cout << std::endl;
}
auto llm = llamalib::Llama{path};
std::mutex llm_mutex; // Protect access during model switching
svr.set_logger([](const auto &req, const auto &res) {
std::cout << req.method << " " << req.path << " -> " << res.status
<< std::endl;
});
svr.Get("/health", [](const httplib::Request &, httplib::Response &res) {
res.set_content(json{{"status", "ok"}}.dump(), "application/json");
});
// --- Translation endpoint (Chapter 2) ------------------------------------
svr.Post("/translate",
[&](const httplib::Request &req, httplib::Response &res) {
auto input = json::parse(req.body, nullptr, false);
if (input.is_discarded()) {
res.status = 400;
res.set_content(json{{"error", "Invalid JSON"}}.dump(),
"application/json");
return;
}
if (!input.contains("text") || !input["text"].is_string() ||
input["text"].get<std::string>().empty()) {
res.status = 400;
res.set_content(json{{"error", "'text' is required"}}.dump(),
"application/json");
return;
}
auto text = input["text"].get<std::string>();
auto target_lang = input.value("target_lang", "ja");
auto prompt = "Translate the following text to " + target_lang +
". Output only the translation, nothing else.\n\n" + text;
try {
std::lock_guard<std::mutex> lock(llm_mutex);
auto translation = llm.chat(prompt);
res.set_content(json{{"translation", translation}}.dump(),
"application/json");
} catch (const std::exception &e) {
res.status = 500;
res.set_content(json{{"error", e.what()}}.dump(), "application/json");
}
});
// --- SSE streaming translation (Chapter 3) -------------------------------
svr.Post("/translate/stream",
[&](const httplib::Request &req, httplib::Response &res) {
auto input = json::parse(req.body, nullptr, false);
if (input.is_discarded()) {
res.status = 400;
res.set_content(json{{"error", "Invalid JSON"}}.dump(),
"application/json");
return;
}
if (!input.contains("text") || !input["text"].is_string() ||
input["text"].get<std::string>().empty()) {
res.status = 400;
res.set_content(json{{"error", "'text' is required"}}.dump(),
"application/json");
return;
}
auto text = input["text"].get<std::string>();
auto target_lang = input.value("target_lang", "ja");
auto prompt = "Translate the following text to " + target_lang +
". Output only the translation, nothing else.\n\n" + text;
res.set_chunked_content_provider(
"text/event-stream",
[&, prompt](size_t, httplib::DataSink &sink) {
std::lock_guard<std::mutex> lock(llm_mutex);
try {
llm.chat(prompt, [&](std::string_view token) {
sink.os << "data: "
<< json(std::string(token)).dump(
-1, ' ', false, json::error_handler_t::replace)
<< "\n\n";
return sink.os.good(); // Abort inference on disconnect
});
sink.os << "data: [DONE]\n\n";
} catch (const std::exception &e) {
sink.os << "data: " << json({{"error", e.what()}}).dump() << "\n\n";
}
sink.done();
return true;
});
});
// --- Model list (Chapter 4) ----------------------------------------------
svr.Get("/models",
[&](const httplib::Request &, httplib::Response &res) {
auto models_dir = get_models_dir();
auto arr = json::array();
for (const auto &m : MODELS) {
auto path = models_dir / m.filename;
arr.push_back({
{"name", m.name},
{"params", m.params},
{"size", m.size},
{"downloaded", std::filesystem::exists(path)},
{"selected", m.filename == selected_model},
});
}
res.set_content(json{{"models", arr}}.dump(), "application/json");
});
// --- Model selection (Chapter 4) -----------------------------------------
svr.Post("/models/select",
[&](const httplib::Request &req, httplib::Response &res) {
auto input = json::parse(req.body, nullptr, false);
if (input.is_discarded() || !input.contains("model")) {
res.status = 400;
res.set_content(json{{"error", "'model' is required"}}.dump(),
"application/json");
return;
}
auto name = input["model"].get<std::string>();
auto it = std::find_if(MODELS.begin(), MODELS.end(),
[&](const ModelInfo &m) { return m.name == name; });
if (it == MODELS.end()) {
res.status = 404;
res.set_content(json{{"error", "Unknown model"}}.dump(),
"application/json");
return;
}
const auto &model = *it;
// Always respond with SSE (same format whether downloaded or not)
res.set_chunked_content_provider(
"text/event-stream",
[&, model](size_t, httplib::DataSink &sink) {
// SSE event sending helper
auto send = [&](const json &event) {
sink.os << "data: " << event.dump() << "\n\n";
};
// Download if not yet downloaded (report progress via SSE)
auto path = get_models_dir() / model.filename;
if (!std::filesystem::exists(path)) {
bool ok = download_model(model, [&](int pct) {
send({{"status", "downloading"}, {"progress", pct}});
return sink.os.good(); // Abort download on client disconnect
});
if (!ok) {
send({{"status", "error"}, {"message", "Download failed"}});
sink.done();
return true;
}
}
// Load and switch to the model
send({{"status", "loading"}});
{
std::lock_guard<std::mutex> lock(llm_mutex);
llm = llamalib::Llama{path};
selected_model = model.filename;
}
send({{"status", "ready"}});
sink.done();
return true;
});
});
// --- Embedded file serving (Chapter 6) ------------------------------------
// Chapter 5: svr.set_mount_point("/", "./public");
httplib::mount(svr, Web::FS);
// Start the server on a background thread
auto port = svr.bind_to_any_port("127.0.0.1");
std::thread server_thread([&]() { svr.listen_after_bind(); });
std::cout << "Listening on http://127.0.0.1:" << port << std::endl;
// Display the UI with WebView
webview::webview w(false, nullptr);
w.set_title("Translate App");
w.set_size(1024, 768, WEBVIEW_HINT_NONE);
w.navigate("http://127.0.0.1:" + std::to_string(port));
#ifdef __APPLE__
setup_macos_edit_menu();
#endif
w.run(); // Block until the window is closed
// Stop the server when the window is closed
svr.stop();
server_thread.join();
}
```
</details>
To summarize the changes from Chapter 5:
- `#include <csignal>` replaced with `#include <thread>`, `<cpp-embedlib-httplib.h>`, `"WebAssets.h"`, `"webview/webview.h"`
- Removed the `signal_handler` function
- `svr.set_mount_point("/", "./public")` replaced with `httplib::mount(svr, Web::FS)`
- `svr.listen("127.0.0.1", 8080)` replaced with `bind_to_any_port` + `listen_after_bind` + WebView event loop
Not a single line of handler code has changed. The REST API, SSE streaming, and model management built through Chapter 5 all work as-is.
## 6.6 Building and Testing
```bash
cmake -B build
cmake --build build -j
```
Launch the app:
```bash
./build/translate-app
```
No browser is needed. A window opens automatically. The same UI from Chapter 5 appears as-is, and translation and model switching all work just the same.
When you close the window, the server shuts down automatically. There's no need for `Ctrl+C`.
### What Needs to Be Distributed
You only need to distribute:
- The single `translate-app` binary
That's it. You don't need the `public/` directory. HTML, CSS, and JavaScript are embedded in the binary. Model files download automatically on first launch, so there's no need to ask users to prepare anything in advance.
## Next Chapter
Congratulations! 🎉
In Chapter 1, `/health` just returned `{"status":"ok"}`. Now we have a desktop app where you type text and translations stream in real time, pick a different model from a dropdown and it downloads automatically, and closing the window cleanly shuts everything down — all in a single distributable binary.
What we changed in this chapter was just the static file serving and the server startup. Not a single line of handler code changed. The REST API, SSE streaming, and model management we built through Chapter 5 all work as a desktop app, as-is.
In the next chapter, we'll shift perspective and read through the code of llama.cpp's own `llama-server`. Let's compare our simple server with a production-quality one and see what design decisions differ and why.
**Next:** [Reading the llama.cpp Server Source Code](../ch07-code-reading)