server: improve correctness of request parsing and responses (#2929)

Signed-off-by: Jared Van Bortel <jared@nomic.ai>

gpt4all-chat/CHANGELOG.md

@@ -26,6 +26,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - Fix a typo in Model Settings (by [@3Simplex](https://github.com/3Simplex) in [#2916](https://github.com/nomic-ai/gpt4all/pull/2916))
 - Fix the antenna icon tooltip when using the local server ([#2922](https://github.com/nomic-ai/gpt4all/pull/2922))
 - Fix a few issues with locating files and handling errors when loading remote models on startup ([#2875](https://github.com/nomic-ai/gpt4all/pull/2875))
+- Significantly improve API server request parsing and response correctness ([#2929](https://github.com/nomic-ai/gpt4all/pull/2929))
 
 ## [3.2.1] - 2024-08-13
 

gpt4all-chat/CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.16)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 if(APPLE)
@@ -64,6 +64,12 @@ message(STATUS "Qt 6 root directory: ${Qt6_ROOT_DIR}")
 
 set (CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 
+set(FMT_INSTALL OFF)
+set(BUILD_SHARED_LIBS_SAVED "${BUILD_SHARED_LIBS}")
+set(BUILD_SHARED_LIBS OFF)
+add_subdirectory(deps/fmt)
+set(BUILD_SHARED_LIBS "${BUILD_SHARED_LIBS_SAVED}")
+
 add_subdirectory(../gpt4all-backend llmodel)
 
 set(CHAT_EXE_RESOURCES)
@@ -240,7 +246,7 @@ else()
     PRIVATE Qt6::Quick Qt6::Svg Qt6::HttpServer Qt6::Sql Qt6::Pdf)
 endif()
 target_link_libraries(chat
-    PRIVATE llmodel SingleApplication)
+    PRIVATE llmodel SingleApplication fmt::fmt)
 
 
 # -- install --

gpt4all-chat/src/chat.cpp

@@ -239,16 +239,17 @@ void Chat::newPromptResponsePair(const QString &prompt)
     resetResponseState();
     m_chatModel->updateCurrentResponse(m_chatModel->count() - 1, false);
     m_chatModel->appendPrompt("Prompt: ", prompt);
-    m_chatModel->appendResponse("Response: ", prompt);
+    m_chatModel->appendResponse("Response: ", QString());
     emit resetResponseRequested();
 }
 
+// the server needs to block until response is reset, so it calls resetResponse on its own m_llmThread
 void Chat::serverNewPromptResponsePair(const QString &prompt)
 {
     resetResponseState();
     m_chatModel->updateCurrentResponse(m_chatModel->count() - 1, false);
     m_chatModel->appendPrompt("Prompt: ", prompt);
-    m_chatModel->appendResponse("Response: ", prompt);
+    m_chatModel->appendResponse("Response: ", QString());
 }
 
 bool Chat::restoringFromText() const

gpt4all-chat/src/chatapi.cpp

@@ -93,7 +93,7 @@ void ChatAPI::prompt(const std::string &prompt,
                      bool allowContextShift,
                      PromptContext &promptCtx,
                      bool special,
-                     std::string *fakeReply) {
+                     std::optional<std::string_view> fakeReply) {
 
     Q_UNUSED(promptCallback);
     Q_UNUSED(allowContextShift);
@@ -121,7 +121,7 @@ void ChatAPI::prompt(const std::string &prompt,
     if (fakeReply) {
         promptCtx.n_past += 1;
         m_context.append(formattedPrompt);
-        m_context.append(QString::fromStdString(*fakeReply));
+        m_context.append(QString::fromUtf8(fakeReply->data(), fakeReply->size()));
         return;
     }
 

gpt4all-chat/src/chatapi.h

@@ -12,9 +12,10 @@
 
 #include <cstddef>
 #include <cstdint>
-#include <stdexcept>
 #include <functional>
+#include <stdexcept>
 #include <string>
+#include <string_view>
 #include <vector>
 
 class QNetworkAccessManager;
@@ -72,7 +73,7 @@ public:
                 bool allowContextShift,
                 PromptContext &ctx,
                 bool special,
-                std::string *fakeReply) override;
+                std::optional<std::string_view> fakeReply) override;
 
     void setThreadCount(int32_t n_threads) override;
     int32_t threadCount() const override;
@@ -97,7 +98,7 @@ protected:
     // them as they are only called from the default implementation of 'prompt' which we override and
     // completely replace
 
-    std::vector<Token> tokenize(PromptContext &ctx, const std::string &str, bool special) override
+    std::vector<Token> tokenize(PromptContext &ctx, std::string_view str, bool special) override
     {
         (void)ctx;
         (void)str;

gpt4all-chat/src/chatllm.cpp

@@ -626,16 +626,16 @@ void ChatLLM::regenerateResponse()
     m_ctx.tokens.erase(m_ctx.tokens.end() - m_promptResponseTokens, m_ctx.tokens.end());
     m_promptResponseTokens = 0;
     m_promptTokens = 0;
-    m_response = std::string();
-    emit responseChanged(QString::fromStdString(m_response));
+    m_response = m_trimmedResponse = std::string();
+    emit responseChanged(QString::fromStdString(m_trimmedResponse));
 }
 
 void ChatLLM::resetResponse()
 {
     m_promptTokens = 0;
     m_promptResponseTokens = 0;
-    m_response = std::string();
-    emit responseChanged(QString::fromStdString(m_response));
+    m_response = m_trimmedResponse = std::string();
+    emit responseChanged(QString::fromStdString(m_trimmedResponse));
 }
 
 void ChatLLM::resetContext()
@@ -645,9 +645,12 @@ void ChatLLM::resetContext()
     m_ctx = LLModel::PromptContext();
 }
 
-QString ChatLLM::response() const
+QString ChatLLM::response(bool trim) const
 {
-    return QString::fromStdString(remove_leading_whitespace(m_response));
+    std::string resp = m_response;
+    if (trim)
+        resp = remove_leading_whitespace(resp);
+    return QString::fromStdString(resp);
 }
 
 ModelInfo ChatLLM::modelInfo() const
@@ -705,7 +708,8 @@ bool ChatLLM::handleResponse(int32_t token, const std::string &response)
     // check for error
     if (token < 0) {
         m_response.append(response);
-        emit responseChanged(QString::fromStdString(remove_leading_whitespace(m_response)));
+        m_trimmedResponse = remove_leading_whitespace(m_response);
+        emit responseChanged(QString::fromStdString(m_trimmedResponse));
         return false;
     }
 
@@ -715,7 +719,8 @@ bool ChatLLM::handleResponse(int32_t token, const std::string &response)
     m_timer->inc();
     Q_ASSERT(!response.empty());
     m_response.append(response);
-    emit responseChanged(QString::fromStdString(remove_leading_whitespace(m_response)));
+    m_trimmedResponse = remove_leading_whitespace(m_response);
+    emit responseChanged(QString::fromStdString(m_trimmedResponse));
     return !m_stopGenerating;
 }
 
@@ -741,7 +746,7 @@ bool ChatLLM::prompt(const QList<QString> &collectionList, const QString &prompt
 
 bool ChatLLM::promptInternal(const QList<QString> &collectionList, const QString &prompt, const QString &promptTemplate,
     int32_t n_predict, int32_t top_k, float top_p, float min_p, float temp, int32_t n_batch, float repeat_penalty,
-    int32_t repeat_penalty_tokens)
+    int32_t repeat_penalty_tokens, std::optional<QString> fakeReply)
 {
     if (!isModelLoaded())
         return false;
@@ -751,7 +756,7 @@ bool ChatLLM::promptInternal(const QList<QString> &collectionList, const QString
 
     QList<ResultInfo> databaseResults;
     const int retrievalSize = MySettings::globalInstance()->localDocsRetrievalSize();
-    if (!collectionList.isEmpty()) {
+    if (!fakeReply && !collectionList.isEmpty()) {
         emit requestRetrieveFromDB(collectionList, prompt, retrievalSize, &databaseResults); // blocks
         emit databaseResultsChanged(databaseResults);
     }
@@ -797,7 +802,8 @@ bool ChatLLM::promptInternal(const QList<QString> &collectionList, const QString
         m_ctx.n_predict = old_n_predict; // now we are ready for a response
     }
     m_llModelInfo.model->prompt(prompt.toStdString(), promptTemplate.toStdString(), promptFunc, responseFunc,
-                                /*allowContextShift*/ true, m_ctx);
+                                /*allowContextShift*/ true, m_ctx, false,
+                                fakeReply.transform(std::mem_fn(&QString::toStdString)));
 #if defined(DEBUG)
     printf("\n");
     fflush(stdout);
@@ -805,9 +811,9 @@ bool ChatLLM::promptInternal(const QList<QString> &collectionList, const QString
     m_timer->stop();
     qint64 elapsed = totalTime.elapsed();
     std::string trimmed = trim_whitespace(m_response);
-    if (trimmed != m_response) {
-        m_response = trimmed;
-        emit responseChanged(QString::fromStdString(m_response));
+    if (trimmed != m_trimmedResponse) {
+        m_trimmedResponse = trimmed;
+        emit responseChanged(QString::fromStdString(m_trimmedResponse));
     }
 
     SuggestionMode mode = MySettings::globalInstance()->suggestionMode();
@@ -1078,6 +1084,7 @@ bool ChatLLM::deserialize(QDataStream &stream, int version, bool deserializeKV,
     QString response;
     stream >> response;
     m_response = response.toStdString();
+    m_trimmedResponse = trim_whitespace(m_response);
     QString nameResponse;
     stream >> nameResponse;
     m_nameResponse = nameResponse.toStdString();
@@ -1306,10 +1313,9 @@ void ChatLLM::processRestoreStateFromText()
 
         auto &response = *it++;
         Q_ASSERT(response.first != "Prompt: ");
-        auto responseText = response.second.toStdString();
 
         m_llModelInfo.model->prompt(prompt.second.toStdString(), promptTemplate.toStdString(), promptFunc, nullptr,
-                                    /*allowContextShift*/ true, m_ctx, false, &responseText);
+                                    /*allowContextShift*/ true, m_ctx, false, response.second.toUtf8().constData());
     }
 
     if (!m_stopGenerating) {

gpt4all-chat/src/chatllm.h

@@ -116,7 +116,7 @@ public:
     void setForceUnloadModel(bool b) { m_forceUnloadModel = b; }
     void setMarkedForDeletion(bool b) { m_markedForDeletion = b; }
 
-    QString response() const;
+    QString response(bool trim = true) const;
 
     ModelInfo modelInfo() const;
     void setModelInfo(const ModelInfo &info);
@@ -198,7 +198,7 @@ Q_SIGNALS:
 protected:
     bool promptInternal(const QList<QString> &collectionList, const QString &prompt, const QString &promptTemplate,
         int32_t n_predict, int32_t top_k, float top_p, float min_p, float temp, int32_t n_batch, float repeat_penalty,
-        int32_t repeat_penalty_tokens);
+        int32_t repeat_penalty_tokens, std::optional<QString> fakeReply = {});
     bool handlePrompt(int32_t token);
     bool handleResponse(int32_t token, const std::string &response);
     bool handleNamePrompt(int32_t token);
@@ -221,6 +221,7 @@ private:
     bool loadNewModel(const ModelInfo &modelInfo, QVariantMap &modelLoadProps);
 
     std::string m_response;
+    std::string m_trimmedResponse;
     std::string m_nameResponse;
     QString m_questionResponse;
     LLModelInfo m_llModelInfo;

gpt4all-chat/src/localdocsmodel.h

@@ -20,24 +20,25 @@ class LocalDocsCollectionsModel : public QSortFilterProxyModel
     Q_OBJECT
     Q_PROPERTY(int count READ count NOTIFY countChanged)
     Q_PROPERTY(int updatingCount READ updatingCount NOTIFY updatingCountChanged)
+
 public:
     explicit LocalDocsCollectionsModel(QObject *parent);
+    int count() const { return rowCount(); }
+    int updatingCount() const;
 
 public Q_SLOTS:
-    int count() const { return rowCount(); }
     void setCollections(const QList<QString> &collections);
-    int updatingCount() const;
 
 Q_SIGNALS:
     void countChanged();
     void updatingCountChanged();
 
-private Q_SLOT:
-    void maybeTriggerUpdatingCountChanged();
-
 protected:
     bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const override;
 
+private Q_SLOTS:
+    void maybeTriggerUpdatingCountChanged();
+
 private:
     QList<QString> m_collections;
     int m_updatingCount = 0;

gpt4all-chat/src/modellist.h

@@ -18,10 +18,12 @@
 #include <QVector>
 #include <Qt>
 #include <QtGlobal>
-#include <QtQml>
+
+#include <utility>
 
 using namespace Qt::Literals::StringLiterals;
 
+
 struct ModelInfo {
     Q_GADGET
     Q_PROPERTY(QString id READ id WRITE setId)
@@ -523,7 +525,7 @@ private:
 
 protected:
     explicit ModelList();
-    ~ModelList() { for (auto *model: m_models) { delete model; } }
+    ~ModelList() override { for (auto *model: std::as_const(m_models)) { delete model; } }
     friend class MyModelList;
 };
 

gpt4all-chat/src/mysettings.h

@@ -8,6 +8,7 @@
 #include <QSettings>
 #include <QString>
 #include <QStringList>
+#include <QTranslator>
 #include <QVector>
 
 #include <cstdint>

gpt4all-chat/src/server.h

@@ -4,22 +4,29 @@
 #include "chatllm.h"
 #include "database.h"
 
-#include <QHttpServerRequest>
+#include <QHttpServer>
 #include <QHttpServerResponse>
-#include <QObject>
+#include <QJsonObject>
 #include <QList>
+#include <QObject>
 #include <QString>
 
+#include <memory>
+#include <optional>
+#include <utility>
+
 class Chat;
-class QHttpServer;
+class ChatRequest;
+class CompletionRequest;
+
 
 class Server : public ChatLLM
 {
     Q_OBJECT
 
 public:
-    Server(Chat *parent);
-    virtual ~Server();
+    explicit Server(Chat *chat);
+    ~Server() override = default;
 
 public Q_SLOTS:
     void start();
@@ -27,14 +34,17 @@ public Q_SLOTS:
 Q_SIGNALS:
     void requestServerNewPromptResponsePair(const QString &prompt);
 
+private:
+    auto handleCompletionRequest(const CompletionRequest &request) -> std::pair<QHttpServerResponse, std::optional<QJsonObject>>;
+    auto handleChatRequest(const ChatRequest &request) -> std::pair<QHttpServerResponse, std::optional<QJsonObject>>;
+
 private Q_SLOTS:
-    QHttpServerResponse handleCompletionRequest(const QHttpServerRequest &request, bool isChat);
     void handleDatabaseResultsChanged(const QList<ResultInfo> &results) { m_databaseResults = results; }
     void handleCollectionListChanged(const QList<QString> &collectionList) { m_collections = collectionList; }
 
 private:
     Chat *m_chat;
-    QHttpServer *m_server;
+    std::unique_ptr<QHttpServer> m_server;
     QList<ResultInfo> m_databaseResults;
     QList<QString> m_collections;
 };