redis_client.hpp

// redis_client.hpp
// Created by Greg on 1/30/25.
// Copyright (C) 2025 Presage Security, Inc.
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#pragma once
 
#include <string>
#include <vector>
#include <optional>
#include <chrono>
 
namespace presage::smartspectra::redis_ipc {

class RedisClient {
public:
    RedisClient() = default;
    ~RedisClient();
 
    // No copy
    RedisClient(const RedisClient&) = delete;
    RedisClient& operator=(const RedisClient&) = delete;

    bool Connect(const std::string& host, int port, std::chrono::milliseconds timeout);

    void Close();

    bool Ping();

    bool Publish(const std::string& channel, const std::string& payload);

    bool Set(const std::string& key, const std::string& value);

    bool Del(const std::string& key);

    std::optional<std::string> LPop(const std::string& key, bool* ok);

    const std::string& last_error() const { return last_error_; }

    void SetResponseLimits(size_t max_bulk_string_bytes, size_t max_array_elements);
 
private:
    enum class ReplyType {
        kSimpleString,
        kInteger,
        kBulkString,
        kNull,
        kArray,
        kError
    };
 
    struct Reply {
        ReplyType type = ReplyType::kError;
        std::string string_value;
        int64_t integer_value = 0;
        std::vector<Reply> array_items;
    };
 
    bool Execute(const std::vector<std::string>& command, Reply* reply);
    static std::string Encode(const std::vector<std::string>& command);
    bool EnsureConnected() const;
    bool SendAll(const std::string& data);
    bool ReceiveSome();
    bool EnsureAvailable(size_t bytes);
    bool ReadChar(char* ch);
    bool ReadLine(std::string* line);
    bool ReadBulk(std::string* value, size_t length);
    bool ParseReply(Reply* reply);
    void CompactBuffer();
 
    int fd_ = -1;
    std::chrono::milliseconds timeout_{1000};
    std::string buffer_;
    size_t offset_ = 0;
    mutable std::string last_error_;
 
    size_t max_bulk_string_bytes_ = 134217728;   // 128MB default
    size_t max_array_elements_ = 1000000;        // 1M default
};
 
} // namespace presage::smartspectra::redis_ipc