feat: Qt client now formats RPC requests in the RPC server's preferred style (#7963)

* feat: Qt client now formats RPC requests in the RPC server's preferred style

* add macro to build TrRpcVersionSemver

Co-authored-by: Yat Ho <lagoho7@gmail.com>

libtransmission/rpcimpl.h

@@ -11,7 +11,13 @@
 struct tr_session;
 struct tr_variant;
 
-auto inline constexpr TrRpcVersionSemver = std::string_view{ "6.0.0" };
+#define RPC_VERSION_VARS(major, minor, patch) \
+    auto inline constexpr TrRpcVersionSemver = std::string_view{ #major "." #minor "." #patch }; \
+    auto inline constexpr TrRpcVersionSemverMajor = major;
+
+RPC_VERSION_VARS(6, 0, 0)
+
+#undef RPC_VERSION_VARS
 
 namespace JsonRpc
 {

qt/RpcClient.cc

@@ -16,6 +16,7 @@
 #include <QNetworkAccessManager>
 #include <QNetworkReply>
 #include <QNetworkRequest>
+#include <QVersionNumber>
 
 #include <libtransmission/api-compat.h>
 #include <libtransmission/rpcimpl.h>
@@ -70,6 +71,7 @@ void RpcClient::stop()
     session_id_.clear();
     url_.clear();
     request_.reset();
+    network_style_ = DefaultNetworkStyle;
 
     if (nam_ != nullptr)
     {
@@ -93,7 +95,6 @@ void RpcClient::start(QUrl const& url)
 RpcResponseFuture RpcClient::exec(tr_quark const method, tr_variant* args)
 {
     auto [req, id] = buildRequest(method, args);
-    req = api_compat::convert_outgoing_data(req);
 
     auto promise = QFutureInterface<RpcResponse>{};
     promise.setExpectedResultCount(1);
@@ -107,6 +108,7 @@ RpcResponseFuture RpcClient::exec(tr_quark const method, tr_variant* args)
     }
     else if (!url_.isEmpty())
     {
+        req = api_compat::convert(req, network_style_);
         auto const json = tr_variant_serde::json().compact().to_string(req);
         auto const body = QByteArray::fromStdString(json);
         sendNetworkRequest(body, promise);
@@ -165,20 +167,20 @@ void RpcClient::sendLocalRequest(tr_variant const& req, QFutureInterface<RpcResp
     tr_rpc_request_exec(
         session_,
         req,
-        [this](tr_session* /*sesson*/, tr_variant&& response)
+        [this](tr_session* /*sesson*/, tr_variant&& response_in)
         {
-            auto converted = std::make_shared<tr_variant>(api_compat::convert_incoming_data(response));
+            auto response = std::make_shared<tr_variant>(std::move(response_in));
+
             if (verbose_)
             {
                 auto serde = tr_variant_serde::json();
                 serde.compact();
-                fmt::print("{:s}:{:d} got raw response:\n{:s}\n", __FILE__, __LINE__, serde.to_string(response));
-                fmt::print("{:s}:{:d} converted response:\n{:s}\n", __FILE__, __LINE__, serde.to_string(*converted));
+                fmt::print("{:s}:{:d} got response:\n{:s}\n", __FILE__, __LINE__, serde.to_string(*response));
             }
 
             // this callback is invoked in the libtransmission thread, so we don't want
             // to process the response here... let's push it over to the Qt thread.
-            QMetaObject::invokeMethod(this, "localRequestFinished", Qt::QueuedConnection, Q_ARG(TrVariantPtr, converted));
+            QMetaObject::invokeMethod(this, "localRequestFinished", Qt::QueuedConnection, Q_ARG(TrVariantPtr, response));
         });
 }
 
@@ -217,6 +219,38 @@ void RpcClient::networkRequestFinished(QNetworkReply* reply)
     {
         // we got a 409 telling us our session id has expired.
         // update it and resubmit the request.
+
+        auto version_str = QString::fromUtf8("unknown");
+
+        if (reply->hasRawHeader(TR_RPC_RPC_VERSION_HEADER))
+        {
+            network_style_ = api_compat::Style::Tr5;
+
+            version_str = QString::fromUtf8(reply->rawHeader(TR_RPC_RPC_VERSION_HEADER));
+            if (QVersionNumber::fromString(version_str).majorVersion() > TrRpcVersionSemverMajor)
+            {
+                fmt::print(
+                    stderr,
+                    "Server '{:s}' RPC version is {:s}, which may be incompatible with our version {:s}.\n",
+                    url_.toDisplayString().toStdString(),
+                    version_str.toStdString(),
+                    TrRpcVersionSemver);
+            }
+        }
+        else
+        {
+            network_style_ = api_compat::Style::Tr4;
+        }
+
+        if (verbose_)
+        {
+            fmt::print(
+                "Server '{:s}' RPC version is {:s}. Using style {:d}\n",
+                url_.toDisplayString().toStdString(),
+                version_str.toStdString(),
+                static_cast<int>(network_style_));
+        }
+
         session_id_ = QString::fromUtf8(reply->rawHeader(TR_RPC_SESSION_ID_HEADER));
         request_.reset();
 
@@ -247,7 +281,7 @@ void RpcClient::networkRequestFinished(QNetworkReply* reply)
 
         if (auto var = tr_variant_serde::json().parse(json))
         {
-            var = api_compat::convert_incoming_data(*var);
+            var = api_compat::convert(*var, api_compat::Style::Tr5);
 
             if (verbose_)
             {

qt/RpcClient.h

@@ -21,6 +21,7 @@
 
 #include <libtransmission/transmission.h>
 
+#include <libtransmission/api-compat.h>
 #include <libtransmission/quark.h>
 #include <libtransmission/variant.h>
 
@@ -92,8 +93,12 @@ private:
     [[nodiscard]] int64_t parseResponseId(tr_variant& response) const;
     [[nodiscard]] RpcResponse parseResponseData(tr_variant& response) const;
 
+    // TODO: change this default in 5.0.0-beta.1
+    static auto constexpr DefaultNetworkStyle = libtransmission::api_compat::Style::Tr4;
+
     std::optional<QNetworkRequest> request_;
 
+    libtransmission::api_compat::Style network_style_ = DefaultNetworkStyle;
     tr_session* session_ = {};
     QString session_id_;
     QUrl url_;