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edolstraedolstra
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Add 'nix serve' command
This is a built-in binary cache server, similar to nix-serve. It uses libmicrohttpd.
1 parent 3e9228a commit dad1a4e

3 files changed

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‎src/nix/meson.build‎

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@@ -34,6 +34,9 @@ subdir('nix-meson-build-support/subprojects')
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subdir('nix-meson-build-support/export-all-symbols')
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subdir('nix-meson-build-support/windows-version')
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libmicrohttpd = dependency('libmicrohttpd')
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deps_private += libmicrohttpd
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configdata = configuration_data()
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# The CLI has a more detailed version string than the libraries; see `nixVersion`
@@ -114,6 +117,7 @@ nix_sources = [ config_priv_h ] + files(
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'run.cc',
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'search.cc',
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'self-exe.cc',
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'serve.cc',
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'sigs.cc',
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'store-copy-log.cc',
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'store-delete.cc',

‎src/nix/package.nix‎

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@@ -10,6 +10,8 @@
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nix-cmd,
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sentry-native,
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libmicrohttpd,
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# Configuration Options
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version,
@@ -72,6 +74,7 @@ mkMesonExecutable (finalAttrs: {
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nix-expr
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nix-main
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nix-cmd
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libmicrohttpd
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]
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++ lib.optional (
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stdenv.cc.isClang

‎src/nix/serve.cc‎

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#include "nix/cmd/command.hh"
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#include "nix/util/file-system.hh"
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#include "nix/util/signals.hh"
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#include "nix/fetchers/git-utils.hh" // for Deleter
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#include "nix/store/nar-info.hh"
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#include <future>
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#include <regex>
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#include <arpa/inet.h>
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#include <microhttpd.h>
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using namespace nix;
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using Response = std::unique_ptr<MHD_Response, Deleter<MHD_destroy_response>>;
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struct CmdServe : StoreCommand
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{
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uint16_t port = 8080;
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std::optional<int> priority;
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std::optional<std::filesystem::path> portFile;
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CmdServe()
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{
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addFlag({
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.longName = "port",
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.shortName = 'p',
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.description = "Port to listen on (default: 8080). Use 0 to dynamically allocate a free port.",
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.labels = {"port"},
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.handler = {&port},
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});
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addFlag({
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.longName = "port-file",
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.description = "Write the bound port number to this file.",
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.labels = {"path"},
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.handler = {[this](std::string s) { portFile = s; }},
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});
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addFlag({
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.longName = "priority",
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.description = "Priority of this cache (overrides the store's default).",
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.labels = {"priority"},
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.handler = {[this](std::string s) { priority = std::stoi(s); }},
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});
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}
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std::string description() override
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{
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return "serve a Nix store over the network";
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}
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MHD_Result
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handleRequest(Store & store, MHD_Connection * connection, const std::string & url, std::string_view method)
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try {
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std::string clientAddr = "unknown";
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if (auto * info = MHD_get_connection_info(connection, MHD_CONNECTION_INFO_CLIENT_ADDRESS)) {
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char buf[INET6_ADDRSTRLEN];
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auto * addr = info->client_addr;
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const void * src = addr->sa_family == AF_INET6 ? (void *) &((sockaddr_in6 *) addr)->sin6_addr
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: (void *) &((sockaddr_in *) addr)->sin_addr;
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if (inet_ntop(addr->sa_family, src, buf, sizeof(buf)))
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clientAddr = buf;
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}
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notice("request: client=%s, method=%s, url=%s", clientAddr, method, url);
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Response response;
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auto notFound = [&] {
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static constexpr std::string_view body = "404 not found\n";
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response.reset(MHD_create_response_from_buffer(body.size(), (void *) body.data(), MHD_RESPMEM_PERSISTENT));
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return MHD_queue_response(connection, MHD_HTTP_NOT_FOUND, response.get());
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};
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static const std::regex narInfoUrlRegex{R"(^/([0-9a-z]+)\.narinfo$)"};
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static const std::regex narUrlRegex{R"(^/nar/([0-9a-z]+)-([0-9a-z]+)\.nar$)"};
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if (method != MHD_HTTP_METHOD_GET && method != MHD_HTTP_METHOD_HEAD) {
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std::string_view body = "405 method not allowed\n";
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response.reset(MHD_create_response_from_buffer(body.size(), (void *) body.data(), MHD_RESPMEM_PERSISTENT));
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MHD_add_response_header(response.get(), "Allow", MHD_HTTP_METHOD_GET);
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return MHD_queue_response(connection, MHD_HTTP_METHOD_NOT_ALLOWED, response.get());
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}
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if (url == "/nix-cache-info") {
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auto body = std::make_unique<std::string>(
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"StoreDir: " + store.storeDir + "\n"
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"WantMassQuery: " + (store.config.wantMassQuery ? "1" : "0") + "\n"
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"Priority: " + std::to_string(priority.value_or(store.config.priority)) + "\n");
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response.reset(MHD_create_response_from_buffer(body->size(), body->data(), MHD_RESPMEM_MUST_COPY));
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MHD_add_response_header(response.get(), "Content-Type", "text/x-nix-cache-info");
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} else if (std::smatch m; std::regex_match(url, m, narInfoUrlRegex)) {
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auto hashPart = m[1].str();
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auto path = store.queryPathFromHashPart(hashPart);
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if (!path)
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return notFound();
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auto info = store.queryPathInfo(*path);
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NarInfo ni(*info);
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ni.compression = "none";
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// FIXME: would be nicer to use just the NAR hash, but we can't look up NARs by NAR hash.
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ni.url = "nar/" + std::string(info->path.hashPart()) + "-"
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+ info->narHash.to_string(HashFormat::Nix32, false) + ".nar";
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ni.fileSize = info->narSize;
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auto body = ni.to_string(store);
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response.reset(MHD_create_response_from_buffer(body.size(), body.data(), MHD_RESPMEM_MUST_COPY));
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MHD_add_response_header(response.get(), "Content-Type", "text/x-nix-narinfo");
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} else if (std::smatch m; std::regex_match(url, m, narUrlRegex)) {
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auto hashPart = m[1].str();
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auto expectedNarHash = m[2].str();
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auto path = store.queryPathFromHashPart(hashPart);
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if (!path)
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return notFound();
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auto info = store.queryPathInfo(*path);
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if (info->narHash.to_string(HashFormat::Nix32, false) != expectedNarHash)
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return notFound();
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StringSink sink;
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store.narFromPath(*path, sink);
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response.reset(MHD_create_response_from_buffer(sink.s.size(), sink.s.data(), MHD_RESPMEM_MUST_COPY));
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MHD_add_response_header(response.get(), "Content-Type", "application/x-nix-nar");
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} else
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return notFound();
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return MHD_queue_response(connection, MHD_HTTP_OK, response.get());
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} catch (const Error & e) {
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auto body = fmt("500 Internal Server Error\n\nError: %s", e.message());
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Response response;
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response.reset(MHD_create_response_from_buffer(body.size(), body.data(), MHD_RESPMEM_MUST_COPY));
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MHD_add_response_header(response.get(), "Content-Type", "text/plain");
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return MHD_queue_response(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, response.get());
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}
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void run(ref<Store> store) override
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{
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struct Ctx
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{
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Store & store;
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CmdServe & cmd;
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};
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Ctx ctx{*store, *this};
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auto handler = [](void * cls,
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MHD_Connection * connection,
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const char * url,
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const char * method,
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const char * version,
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const char * upload_data,
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size_t * upload_data_size,
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void ** con_cls) -> MHD_Result {
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auto & ctx = *static_cast<Ctx *>(cls);
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auto & store = ctx.store;
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auto & cmd = ctx.cmd;
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return cmd.handleRequest(store, connection, std::string(url), method);
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};
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auto * daemon = MHD_start_daemon(
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MHD_USE_INTERNAL_POLLING_THREAD | MHD_USE_DUAL_STACK,
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port,
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nullptr,
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nullptr,
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handler,
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&ctx,
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MHD_OPTION_END);
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if (!daemon)
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throw Error("failed to start HTTP daemon on port %d", port);
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auto * info = MHD_get_daemon_info(daemon, MHD_DAEMON_INFO_BIND_PORT);
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uint16_t boundPort = info ? info->port : port;
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notice("Listening on http://[::]:%d/", boundPort);
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if (portFile)
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writeFile(*portFile, std::to_string(boundPort) + "\n");
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/* Wait for Ctrl-C. */
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std::promise<void> interruptPromise;
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std::future<void> interruptFuture = interruptPromise.get_future();
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auto callback = createInterruptCallback([&]() { interruptPromise.set_value(); });
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interruptFuture.get();
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notice("Shutting down...");
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MHD_stop_daemon(daemon);
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}
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};
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static auto rCmdServe = registerCommand<CmdServe>("serve");

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