Add hints for HTTP handlers

Add hints to HTTP handlers to help users avoid
misspellings. For example, if a user mistakenly writes
`/dashboad` instead of `/dashboard`, they will now get a
hint that /dashboard is the correct handler.

This change will improve the user experience by making it
easier for users to find the correct handlers.

 #47662

programs/keeper/CMakeLists.txt

@@ -57,6 +57,7 @@ if (BUILD_STANDALONE_KEEPER)
 
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/IO/ReadBuffer.cpp
 
+        ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Server/HTTPPathHints.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Server/KeeperTCPHandler.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Server/TCPServer.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Server/NotFoundHandler.cpp

src/Server/HTTPHandlerFactory.cpp

@@ -132,21 +132,25 @@ void addCommonDefaultHandlersFactory(HTTPRequestHandlerFactoryMain & factory, IS
     auto ping_handler = std::make_shared<HandlingRuleHTTPHandlerFactory<StaticRequestHandler>>(server, ping_response_expression);
     ping_handler->attachStrictPath("/ping");
     ping_handler->allowGetAndHeadRequest();
+    factory.addPathToHints("/ping");
     factory.addHandler(ping_handler);
 
     auto replicas_status_handler = std::make_shared<HandlingRuleHTTPHandlerFactory<ReplicasStatusHandler>>(server);
     replicas_status_handler->attachNonStrictPath("/replicas_status");
     replicas_status_handler->allowGetAndHeadRequest();
+    factory.addPathToHints("/replicas_status");
     factory.addHandler(replicas_status_handler);
 
     auto play_handler = std::make_shared<HandlingRuleHTTPHandlerFactory<WebUIRequestHandler>>(server);
     play_handler->attachNonStrictPath("/play");
     play_handler->allowGetAndHeadRequest();
+    factory.addPathToHints("/play");
     factory.addHandler(play_handler);
 
     auto dashboard_handler = std::make_shared<HandlingRuleHTTPHandlerFactory<WebUIRequestHandler>>(server);
     dashboard_handler->attachNonStrictPath("/dashboard");
     dashboard_handler->allowGetAndHeadRequest();
+    factory.addPathToHints("/dashboard");
     factory.addHandler(dashboard_handler);
 
     auto js_handler = std::make_shared<HandlingRuleHTTPHandlerFactory<WebUIRequestHandler>>(server);

src/Server/HTTPPathHints.cpp

@@ -0,0 +1,16 @@
+#include <Server/HTTPPathHints.h>
+
+namespace DB
+{
+
+void HTTPPathHints::add(const String & http_path)
+{
+    http_paths.push_back(http_path);
+}
+
+std::vector<String> HTTPPathHints::getAllRegisteredNames() const
+{
+    return http_paths;
+}
+
+}

src/Server/HTTPPathHints.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <base/types.h>
+
+#include <Common/NamePrompter.h>
+
+namespace DB
+{
+
+class HTTPPathHints : public IHints<1, HTTPPathHints>
+{
+public:
+    std::vector<String> getAllRegisteredNames() const override;
+    void add(const String & http_path);
+
+private:
+    std::vector<String> http_paths;
+};
+
+using HTTPPathHintsPtr = std::shared_ptr<HTTPPathHints>;
+
+}

src/Server/HTTPRequestHandlerFactoryMain.cpp

@@ -29,7 +29,7 @@ std::unique_ptr<HTTPRequestHandler> HTTPRequestHandlerFactoryMain::createRequest
         || request.getMethod() == Poco::Net::HTTPRequest::HTTP_HEAD
         || request.getMethod() == Poco::Net::HTTPRequest::HTTP_POST)
     {
-        return std::unique_ptr<HTTPRequestHandler>(new NotFoundHandler);
+        return std::unique_ptr<HTTPRequestHandler>(new NotFoundHandler(hints.getHints(request.getURI())));
     }
 
     return nullptr;

src/Server/HTTPRequestHandlerFactoryMain.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Server/HTTP/HTTPRequestHandlerFactory.h>
+#include <Server/HTTPPathHints.h>
 
 #include <vector>
 
@@ -15,11 +16,14 @@ public:
 
     void addHandler(HTTPRequestHandlerFactoryPtr child_factory) { child_factories.emplace_back(child_factory); }
 
+    void addPathToHints(const std::string & http_path) { hints.add(http_path); }
+
     std::unique_ptr<HTTPRequestHandler> createRequestHandler(const HTTPServerRequest & request) override;
 
 private:
     Poco::Logger * log;
     std::string name;
+    HTTPPathHints hints;
 
     std::vector<HTTPRequestHandlerFactoryPtr> child_factories;
 };

src/Server/NotFoundHandler.cpp

@@ -10,7 +10,8 @@ void NotFoundHandler::handleRequest(HTTPServerRequest & request, HTTPServerRespo
     try
     {
         response.setStatusAndReason(Poco::Net::HTTPResponse::HTTP_NOT_FOUND);
-        *response.send() << "There is no handle " << request.getURI() << "\n\n"
+        *response.send() << "There is no handle " << request.getURI()
+                         << (!hints.empty() ? fmt::format(". Maybe you meant {}.", hints.front()) : "") << "\n\n"
                          << "Use / or /ping for health checks.\n"
                          << "Or /replicas_status for more sophisticated health checks.\n\n"
                          << "Send queries from your program with POST method or GET /?query=...\n\n"

src/Server/NotFoundHandler.h

@@ -9,7 +9,10 @@ namespace DB
 class NotFoundHandler : public HTTPRequestHandler
 {
 public:
+    NotFoundHandler(std::vector<std::string> hints_) : hints(std::move(hints_)) {}
     void handleRequest(HTTPServerRequest & request, HTTPServerResponse & response) override;
+private:
+    std::vector<std::string> hints;
 };
 
 }

tests/queries/0_stateless/02842_suggest_http_page_in_error_message.reference

@@ -0,0 +1,4 @@
+There is no handle /sashboards. Maybe you meant /dashboard
+There is no handle /sashboard. Maybe you meant /dashboard
+There is no handle /sashboarb. Maybe you meant /dashboard
+There is no handle /sashboaxb. Maybe you meant /dashboard

tests/queries/0_stateless/02842_suggest_http_page_in_error_message.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CURDIR"/../shell_config.sh
+
+export CLICKHOUSE_URL="${CLICKHOUSE_PORT_HTTP_PROTO}://${CLICKHOUSE_HOST}:${CLICKHOUSE_PORT_HTTP}/"
+
+${CLICKHOUSE_CURL} -sS "${CLICKHOUSE_URL}sashboards" | grep -o ".* Maybe you meant /dashboard"
+${CLICKHOUSE_CURL} -sS "${CLICKHOUSE_URL}sashboard"  | grep -o ".* Maybe you meant /dashboard"
+${CLICKHOUSE_CURL} -sS "${CLICKHOUSE_URL}sashboarb"  | grep -o ".* Maybe you meant /dashboard"
+${CLICKHOUSE_CURL} -sS "${CLICKHOUSE_URL}sashboaxb"  | grep -o ".* Maybe you meant /dashboard"