# 示例代码|Examples

## 1. 基本Web服务器

```c
#include "netleaf.h"

int main() {
    nl_web_server_t* server = nl_web_create(8080);
    nl_web_add_html(server, "/", "<h1>Hello World</h1>");
    nl_web_start(server);
    
    while (1) sleep(1);
    return 0;
}
```

## 2. 变量硬编码

```c
#include "netleaf.h"

int main() {
    nl_web_server_t* server = nl_web_create(8080);
    
    // 设置UTF-8编码
    nl_web_set_encoding(server, "UTF-8");
    
    // 用户信息
    const char* vars[] = {"name", "user_id", "role"};
    const char* values[] = {"张三", "1001", "管理员"};
    
    nl_web_add_html_with_vars(server, "/user",
        "<!DOCTYPE html>\n"
        "<html>\n"
        "<head><title>用户资料</title></head>\n"
        "<body>\n"
        "  <h1>{{<var>name</var>}}</h1>\n"
        "  <p>ID: {{<var>user_id</var>}}</p>\n"
        "  <p>角色: {{<var>role</var>}}</p>\n"
        "</body></html>",
        vars, values, 3);
    
    nl_web_start(server);
    while (1) sleep(1);
    return 0;
}
```

## 3. Vue页面带变量

```c
#include "netleaf.h"

int main() {
    nl_web_server_t* server = nl_web_create(8080);
    
    const char* vars[] = {"company", "year"};
    const char* values[] = {"NetLeaf科技", "2024"};
    
    nl_web_add_vue_with_vars(server, "/dashboard",
        "<h1>{{<var>company</var>}} - 管理面板</h1>\n"
        "<p>年份: {{<var>year</var>}}</p>\n"
        "<div class=\"counter\">\n"
        "  <button @click=\"count++\">+</button>\n"
        "  <span>{{ count }}</span>\n"
        "  <button @click=\"count--\">-</button>\n"
        "</div>",
        vars, values, 2);
    
    nl_web_start(server);
    while (1) sleep(1);
    return 0;
}
```

## 4. 日志系统

```c
#include "netleaf.h"

int main() {
    // 启用调试模式
    nl_debug_enable(1);
    
    // 输出日志
    nl_log_debug("调试信息 - 服务器启动");
    nl_log_info("一般信息 - 配置加载成功");
    nl_log_warn("警告 - 内存使用率偏高");
    nl_log_error("错误 - 连接失败");
    
    return 0;
}
```

## 5. 快捷函数

```c
#include "netleaf.h"

int main() {
    nl_web_server_t* server = nl_web_create(8080);

    // 一行代码添加首页
    nl_serve_html(0, "<h1>Hello World</h1>");

    nl_web_start(server);
    while (1) sleep(1);
    return 0;
}
```

## 6. 编码动态适配

```c
#include "netleaf.h"

int main() {
    // 创建服务器
    nl_web_server_t* server = nl_web_create(8080);
    
    // 启用自动编码协商（见人说人话，见鬼说鬼话）
    nl_web_enable_auto_encoding(server, 1);
    
    // 设置回退编码（客户端未指定时使用）
    nl_web_set_fallback_encoding(server, "UTF-8");
    
    // 添加页面（内部始终使用UTF-8）
    nl_web_add_html(server, "/", "<h1>你好，世界！</h1>");
    
    // 添加JSON响应（自动转码）
    nl_web_add_json(server, "/api/data", "{\"message\": \"你好世界\"}");
    
    // 服务器会自动根据客户端Accept-Charset头转换编码
    // 例如：GBK客户端会收到GBK编码的响应
    
    while (1) {
#ifdef _WIN32
        Sleep(1000);
#else
        sleep(1);
#endif
    }
    return 0;
}
```

## 8. 编码转换

```c
#include "netleaf.h"
#include <stdio.h>

int main() {
    const char* utf8_str = "你好世界";
    
    // UTF-8转GBK
    char* gbk_str = nl_encoding_convert(utf8_str, strlen(utf8_str), "UTF-8", "GBK");
    printf("GBK: %s\n", gbk_str);
    free(gbk_str);
    
    // 自动检测编码
    const char* detected = nl_encoding_detect(utf8_str, strlen(utf8_str));
    printf("检测到编码: %s\n", detected);
    
    // 获取系统默认编码
    const char* sys_enc = nl_encoding_get_system_default();
    printf("系统默认编码: %s\n", sys_enc);
    
    return 0;
}
```

## 9. TLS 加密通信

```c
#include "netleaf_tls.h"
#include <stdio.h>

int main() {
    // 初始化 TLS
    nl_tls_init();
    
    // 创建 TLS 上下文
    nl_tls_ctx_t* ctx = nl_tls_create();
    if (!ctx) {
        printf("Failed to create TLS context\n");
        return 1;
    }
    
    // 配置 TLS
    nl_tls_config_t cfg = {0};
    cfg.protocol = NL_TLS_PROTOCOL_TLSV1_2;
    cfg.verify_peer = 1;
    
    // 加载 CA 证书
    cfg.ca_chain = "ca.crt";
    
    // 配置密码套件
    cfg.ciphers = "ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256";
    
    int ret = nl_tls_configure(ctx, &cfg);
    if (ret != NL_OK) {
        printf("TLS configure failed: %s\n", nl_tls_strerror(ret));
    }
    
    // 建立连接
    int sock = socket(AF_INET, SOCK_STREAM, 0);
    // ... 连接服务器代码 ...
    
    ret = nl_tls_handshake(ctx, sock);
    if (ret != NL_OK) {
        printf("TLS handshake failed: %s\n", nl_tls_strerror(ret));
    }
    
    // 安全通信
    const char* msg = "Hello, TLS!";
    nl_tls_send(ctx, msg, strlen(msg));
    
    char buf[256];
    nl_tls_recv(ctx, buf, sizeof(buf) - 1);
    buf[sizeof(buf) - 1] = '\0';
    printf("Received: %s\n", buf);
    
    // 获取对端证书信息
    const char* peer_cert = nl_tls_get_peer_cert(ctx);
    if (peer_cert) {
        printf("Peer cert: %s\n", peer_cert);
    }
    
    // 清理
    nl_tls_close(ctx);
    nl_tls_destroy(ctx);
    nl_tls_shutdown();
    
    return 0;
}
```

## 10. MQTT 基础使用

```c
#include "netleaf_mqtt.h"
#include <stdio.h>

// 消息回调函数
void on_message(void* userdata, const nl_mqtt_msg_t* msg) {
    printf("[Received] Topic: %s, Payload: %.*s\n", 
           msg->topic, (int)msg->payload_len, (char*)msg->payload);
}

int main() {
    // 初始化 MQTT
    nl_mqtt_init();
    
    // 创建 MQTT 客户端
    nl_mqtt_client_t* client = nl_mqtt_create();
    if (!client) {
        printf("Failed to create MQTT client\n");
        return 1;
    }
    
    // 设置连接选项
    nl_mqtt_connect_opts_t opts = {0};
    opts.client_id = "netleaf-client-001";
    opts.keep_alive = 60;
    opts.clean_session = 1;
    opts.username = "user";
    opts.password = "password";
    
    // 连接 MQTT 服务器
    int ret = nl_mqtt_connect(client, "tcp://broker.hivemq.com:1883", &opts);
    if (ret != NL_OK) {
        printf("MQTT connect failed\n");
        nl_mqtt_destroy(client);
        return 1;
    }
    
    // 订阅主题
    nl_mqtt_subscribe(client, "test/topic", NL_MQTT_QOS_1, NULL);
    
    // 设置消息回调
    nl_mqtt_set_msg_callback(client, on_message, NULL);
    
    // 发布消息
    nl_mqtt_pub_opts_t pub_opts = {0};
    pub_opts.qos = NL_MQTT_QOS_1;
    pub_opts.retain = 0;
    
    nl_mqtt_publish(client, "test/topic", "Hello MQTT!", 13, &pub_opts);
    
    // 保持运行
    while (1) {
        nl_mqtt_loop(client, 1000);
    }
    
    // 清理
    nl_mqtt_disconnect(client);
    nl_mqtt_destroy(client);
    nl_mqtt_shutdown();
    
    return 0;
}
```

## 11. MQTT 使用 TLS 加密

```c
#include "netleaf_mqtt.h"
#include "netleaf_mqtt_tls.h"
#include <stdio.h>

int main() {
    // 初始化 MQTT 和 TLS
    nl_mqtt_init();
    nl_mqtt_tls_init();
    
    // 创建 MQTT 客户端
    nl_mqtt_client_t* client = nl_mqtt_create();
    
    // 设置连接选项（使用 TLS）
    nl_mqtt_connect_opts_t opts = {0};
    opts.client_id = "netleaf-mqtt-tls";
    opts.keep_alive = 60;
    opts.ssl_enabled = 1;
    
    // 配置 TLS
    nl_mqtt_tls_config_t tls_cfg = {0};
    tls_cfg.ca_chain = "ca.crt";
    tls_cfg.client_cert = "client.crt";
    tls_cfg.client_key = "client.key";
    tls_cfg.verify_peer = 1;
    
    // 连接 TLS 加密的 MQTT 服务器
    int ret = nl_mqtt_connect(client, "ssl://broker.hivemq.com:8883", &opts);
    if (ret != NL_OK) {
        printf("MQTT over TLS connect failed\n");
    }
    
    // 正常订阅和发布...
    nl_mqtt_subscribe(client, "secure/topic", NL_MQTT_QOS_1, NULL);
    
    // 心跳循环
    while (1) {
        nl_mqtt_loop(client, 1000);
    }
    
    nl_mqtt_disconnect(client);
    nl_mqtt_tls_shutdown();
    nl_mqtt_destroy(client);
    nl_mqtt_shutdown();
    
    return 0;
}
```

## 12. MQTT v5.0 属性使用

```c
#include "netleaf_mqtt.h"
#include <stdio.h>

int main() {
    nl_mqtt_init();
    nl_mqtt_client_t* client = nl_mqtt_create();
    
    // 设置 MQTT 5.0 连接属性
    nl_mqtt_connect_opts_t opts = {0};
    opts.client_id = "mqtt5-client";
    opts.session_expiry_interval = 3600;  // 会话保持1小时
    opts.receive_maximum = 100;           // 最大并发包数
    opts.maximum_packet_size = 4096;      // 最大包大小
    opts.topic_alias_maximum = 10;        // 主题别名最大值
    
    // 设置用户属性
    nl_mqtt_user_property_add(&opts.user_properties, "key1", "value1");
    nl_mqtt_user_property_add(&opts.user_properties, "key2", "value2");
    
    nl_mqtt_connect(client, "tcp://broker.hivemq.com:1883", &opts);
    
    // 发布消息带属性
    nl_mqtt_pub_opts_t pub_opts = {0};
    pub_opts.qos = NL_MQTT_QOS_1;
    pub_opts.payload_format_indicator = 1;  // UTF-8 编码
    pub_opts.message_expiry_interval = 86400;  // 消息24小时后过期
    pub_opts.content_type = "application/json";
    pub_opts.response_topic = "response/topic";
    
    nl_mqtt_user_property_add(&pub_opts.user_properties, "author", "netleaf");
    
    nl_mqtt_publish(client, "test/mqtt5", "{\"data\":\"hello\"}", 20, &pub_opts);
    
    nl_mqtt_destroy(client);
    nl_mqtt_shutdown();
    
    return 0;
}
```