add function getHttpHeader

src/Functions/getHttpHeader.cpp

@@ -0,0 +1,95 @@
+#include <Functions/IFunction.h>
+#include <Functions/FunctionFactory.h>
+#include <Functions/FunctionHelpers.h>
+#include <DataTypes/DataTypeString.h>
+#include <Columns/ColumnString.h>
+#include <Interpreters/Context.h>
+#include "Common/CurrentThread.h"
+#include <Common/Macros.h>
+#include "Interpreters/ClientInfo.h"
+#include "Interpreters/Context_fwd.h"
+#include <Core/Field.h>
+#include <Poco/Net/NameValueCollection.h>
+
+
+namespace DB
+{
+namespace ErrorCodes
+{
+    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
+    extern const int ILLEGAL_COLUMN;
+    extern const int FUNCTION_NOT_ALLOWED;
+}
+
+namespace
+{
+
+/** Get the value of parameter in http headers.
+  * If there no such parameter or the method of request is not
+  * http, the function will return empty string.
+  */
+class FunctionGetHttpHeader : public IFunction
+{
+private:
+
+public:
+    FunctionGetHttpHeader() = default;
+
+    static constexpr auto name = "getHttpHeader";
+
+     static FunctionPtr create(ContextPtr /*context*/)
+    {
+        return std::make_shared<FunctionGetHttpHeader>();
+    }
+
+
+    String getName() const override { return name; }
+
+    bool isDeterministic() const override { return false; }
+
+    bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return false; }
+
+
+    size_t getNumberOfArguments() const override
+    {
+        return 1;
+    }
+
+    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
+    {
+        if (!isString(arguments[0]))
+            throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "The argument of function {} must have String type", getName());
+        return std::make_shared<DataTypeString>();
+    }
+
+    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
+    {
+        const auto & query_context = DB::CurrentThread::getQueryContext();
+        const auto & method = query_context->getClientInfo().http_method; 
+
+        const auto & headers = DB::CurrentThread::getQueryContext()->getClientInfo().headers;
+
+        const IColumn * arg_column = arguments[0].column.get();
+        const ColumnString * arg_string = checkAndGetColumnConstData<ColumnString>(arg_column);
+
+        if (!arg_string)
+            throw Exception(ErrorCodes::ILLEGAL_COLUMN, "The argument of function {} must be constant String", getName());
+
+        if (method != ClientInfo::HTTPMethod::GET && method != ClientInfo::HTTPMethod::POST)
+            return result_type->createColumnConst(input_rows_count, "");
+
+        if (!headers.has(arg_string->getDataAt(0).toString()))
+            return result_type->createColumnConst(input_rows_count, "");
+
+        return result_type->createColumnConst(input_rows_count, headers[arg_string->getDataAt(0).toString()]);
+    }
+};
+
+}
+
+REGISTER_FUNCTION(GetHttpHeader)
+{
+    factory.registerFunction<FunctionGetHttpHeader>();
+}
+
+}

src/Interpreters/ClientInfo.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Core/UUID.h>
+#include <Poco/Net/NameValueCollection.h>
 #include <Poco/Net/SocketAddress.h>
 #include <base/types.h>
 #include <Common/OpenTelemetryTraceContext.h>
@@ -96,6 +97,8 @@ public:
 
     /// For mysql and postgresql
     UInt64 connection_id = 0;
+    Poco::Net::NameValueCollection headers;
+    void setHttpHeaders(const Poco::Net::NameValueCollection & _headers) { headers = _headers; }
 
     /// Comma separated list of forwarded IP addresses (from X-Forwarded-For for HTTP interface).
     /// It's expected that proxy appends the forwarded address to the end of the list.

src/Interpreters/Context.cpp

@@ -2,6 +2,7 @@
 #include <set>
 #include <optional>
 #include <memory>
+#include <Poco/Net/NameValueCollection.h>
 #include <Poco/UUID.h>
 #include <Poco/Util/Application.h>
 #include <Common/Macros.h>
@@ -85,6 +86,7 @@
 #include <Common/logger_useful.h>
 #include <Common/RemoteHostFilter.h>
 #include <Common/HTTPHeaderFilter.h>
+#include "Disks/ObjectStorages/S3/diskSettings.h"
 #include <Interpreters/AsynchronousInsertQueue.h>
 #include <Interpreters/DatabaseCatalog.h>
 #include <Interpreters/JIT/CompiledExpressionCache.h>
@@ -4008,12 +4010,18 @@ void Context::setClientConnectionId(uint32_t connection_id_)
     client_info.connection_id = connection_id_;
 }
 
-void Context::setHttpClientInfo(ClientInfo::HTTPMethod http_method, const String & http_user_agent, const String & http_referer)
+void Context::setHttpClientInfo(ClientInfo::HTTPMethod http_method, const String & http_user_agent, const String & http_referer, const Poco::Net::NameValueCollection & http_headers)
 {
     client_info.http_method = http_method;
     client_info.http_user_agent = http_user_agent;
     client_info.http_referer = http_referer;
     need_recalculate_access = true;
+    
+    if (!http_headers.empty())
+    {
+        for (const auto & http_header : http_headers) 
+            client_info.headers.set(http_header.first, http_header.second);
+    }
 }
 
 void Context::setForwardedFor(const String & forwarded_for)

src/Interpreters/Context.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <Poco/Net/NameValueCollection.h>
+#include "Core/Types.h"
 #ifndef CLICKHOUSE_KEEPER_STANDALONE_BUILD
 
 #include <base/types.h>
@@ -609,7 +611,7 @@ public:
     void setClientInterface(ClientInfo::Interface interface);
     void setClientVersion(UInt64 client_version_major, UInt64 client_version_minor, UInt64 client_version_patch, unsigned client_tcp_protocol_version);
     void setClientConnectionId(uint32_t connection_id);
-    void setHttpClientInfo(ClientInfo::HTTPMethod http_method, const String & http_user_agent, const String & http_referer);
+    void setHttpClientInfo(ClientInfo::HTTPMethod http_method, const String & http_user_agent, const String & http_referer, const Poco::Net::NameValueCollection & http_headers = {});
     void setForwardedFor(const String & forwarded_for);
     void setQueryKind(ClientInfo::QueryKind query_kind);
     void setQueryKindInitial();
@@ -804,6 +806,10 @@ public:
     /// Storage of forbidden HTTP headers from config.xml
     void setHTTPHeaderFilter(const Poco::Util::AbstractConfiguration & config);
     const HTTPHeaderFilter & getHTTPHeaderFilter() const;
+    const Poco::Net::NameValueCollection & getHttpHeaders() const
+    {
+        return client_info.headers; 
+    }
 
     /// The port that the server listens for executing SQL queries.
     UInt16 getTCPPort() const;

src/Interpreters/Session.cpp

@@ -15,6 +15,7 @@
 #include <Interpreters/Cluster.h>
 
 #include <magic_enum.hpp>
+#include <Poco/Net/NameValueCollection.h>
 
 #include <atomic>
 #include <condition_variable>
@@ -428,17 +429,18 @@ void Session::setClientConnectionId(uint32_t connection_id)
         prepared_client_info->connection_id = connection_id;
 }
 
-void Session::setHttpClientInfo(ClientInfo::HTTPMethod http_method, const String & http_user_agent, const String & http_referer)
+void Session::setHttpClientInfo(ClientInfo::HTTPMethod http_method, const String & http_user_agent, const String & http_referer, const Poco::Net::NameValueCollection & http_headers)
 {
     if (session_context)
     {
-        session_context->setHttpClientInfo(http_method, http_user_agent, http_referer);
+        session_context->setHttpClientInfo(http_method, http_user_agent, http_referer, http_headers);
     }
     else
     {
         prepared_client_info->http_method = http_method;
         prepared_client_info->http_user_agent = http_user_agent;
         prepared_client_info->http_referer = http_referer;
+        prepared_client_info->headers = http_headers;
     }
 }
 

src/Interpreters/Session.h

@@ -5,6 +5,7 @@
 #include <Interpreters/ClientInfo.h>
 #include <Interpreters/Context_fwd.h>
 #include <Interpreters/SessionTracker.h>
+#include <Poco/Net/NameValueCollection.h>
 
 #include <chrono>
 #include <memory>
@@ -64,7 +65,7 @@ public:
     void setClientInterface(ClientInfo::Interface interface);
     void setClientVersion(UInt64 client_version_major, UInt64 client_version_minor, UInt64 client_version_patch, unsigned client_tcp_protocol_version);
     void setClientConnectionId(uint32_t connection_id);
-    void setHttpClientInfo(ClientInfo::HTTPMethod http_method, const String & http_user_agent, const String & http_referer);
+    void setHttpClientInfo(ClientInfo::HTTPMethod http_method, const String & http_user_agent, const String & http_referer, const Poco::Net::NameValueCollection & http_headers = {});
     void setForwardedFor(const String & forwarded_for);
     void setQuotaClientKey(const String & quota_key);
     void setConnectionClientVersion(UInt64 client_version_major, UInt64 client_version_minor, UInt64 client_version_patch, unsigned client_tcp_protocol_version);

src/Server/HTTPHandler.cpp

@@ -40,6 +40,7 @@
 #include <Poco/Net/HTTPBasicCredentials.h>
 #include <Poco/Net/HTTPStream.h>
 #include <Poco/MemoryStream.h>
+#include <Poco/Net/NameValueCollection.h>
 #include <Poco/StreamCopier.h>
 #include <Poco/String.h>
 #include <Poco/Net/SocketAddress.h>
@@ -500,7 +501,11 @@ bool HTTPHandler::authenticateUser(
     else if (request.getMethod() == HTTPServerRequest::HTTP_POST)
         http_method = ClientInfo::HTTPMethod::POST;
 
-    session->setHttpClientInfo(http_method, request.get("User-Agent", ""), request.get("Referer", ""));
+    NameValueCollection http_headers; 
+    for (const auto & it : request)
+        http_headers.set(it.first, it.second);
+
+    session->setHttpClientInfo(http_method, request.get("User-Agent", ""), request.get("Referer", ""), http_headers);
     session->setForwardedFor(request.get("X-Forwarded-For", ""));
     session->setQuotaClientKey(quota_key);
 
@@ -580,6 +585,10 @@ void HTTPHandler::processQuery(
         session->makeSessionContext();
     }
 
+    NameValueCollection headers;
+    for (auto it = request.begin(); it != request.end(); ++it)
+        headers.set(it->first, it->second);
+
     auto context = session->makeQueryContext();
 
     /// This parameter is used to tune the behavior of output formats (such as Native) for compatibility.

tests/queries/0_stateless/02884_getHttpHeaderFunction.reference

@@ -0,0 +1,2 @@
+Code: 81. DB::Exception: Database `02884_getHttpHeaderFunction` does not exist. (UNKNOWN_DATABASE) (version 23.9.1.1)
+default

tests/queries/0_stateless/02884_getHttpHeaderFunction.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+CUR_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CUR_DIR"/../shell_config.sh
+db="02884_getHttpHeaderFunction"
+
+$CLICKHOUSE_CLIENT -q "CREATE DATABASE IF NOT EXISTS ${db}"
+$CLICKHOUSE_CLIENT -q "CREATE TABLE IF NOT EXISTS ${db}.get_http_header (id UInt32, header_value String DEFAULT getHttpHeader('X-Clickhouse-User')) Engine=Memory()" 
+
+#Insert data via tcp client
+$CLICKHOUSE_CLIENT -q "INSERT INTO ${db}.get_http_header (id) values (1), (2)" 
+
+#Insert data via http request
+echo "INSERT INTO ${db}.get_http_header (id) values (3), (4)" | curl -H 'X-ClickHouse-User: default' -H 'X-ClickHouse-Key: ' 'http://localhost:8123/' -d @-  
+
+$CLICKHOUSE_CLIENT -q "SELECT * FROM ${db}.get_http_header ORDER BY id;" 
+$CLICKHOUSE_CLIENT -q "DROP DATABASE ${db}" 
+
+echo "SELECT getHttpHeader('X-Clickhouse-User')" | curl -H 'X-ClickHouse-User: default' -H 'X-ClickHouse-Key: ' 'http://localhost:8123/' -d @-  
+