本文介绍了如何在开发环境中创建一个 webclient_post 示例工程，并将其编译后在开发板上运行，实现通过 HTTP 或 HTTPS POST 请求 向指定服务器提交数据的功能。旨在帮助读者进一步熟悉开发环境，掌握 HTTP/HTTPS POST 请求的使用方法及其配置要点。

HTTP/HTTPS POST 请求的作用

HTTP POST 请求是 Web 通信中最常用的一种方法，主要作用是向服务器提交数据。区别于 GET 请求，POST 请求会将数据封装在 请求体中 发送，适合传输结构化、敏感、或较大的数据内容。

HTTP POST：明文传输，适合用于本地调试、非敏感数据；

HTTPS POST：基于 TLS/SSL 加密协议，可加密传输数据，保障通信安全，适合在线服务、敏感信息交互。

常见应用包括：表单提交、设备上报信息、物联网云平台对接等。

本示例以演示如何通过 HTTP(S) POST 请求向指定服务器提交数据，并接收服务器响应为实践目标，实现向服务器发送请求，获取服务器返回信息的演示效果。

硬件连接

将开发板网口连接到路由器。

创建工程点击展开

1. 依次点击 “文件” -> “新建” -> "RT-Thread RuiChing App 项目"。

   

2. 在弹出新建向导中选择 开发版 、BSP: 、示例 、 调试器/下载器。选择好之后点击 “完成”。

   

3. 点击 “完成” 后，等待工程创建完成。

   

4. 创建完成。

   

构建工程点击展开

1. 单击工程使工程进入 Active-Debug 模式。

   

2. 点击工具栏上的构建按钮进行工程编译。

   

3. 构建成功后，会显示构建成功的信息。

   

固件下载点击展开

1. 固化设备树

   

2. 固化 APP

   

核心示例代码

webclient post 示例相关 API

• webclient_session_create：创建 WebClient 会话，设置响应头缓冲区大小，若创建失败则返回内存不足错误；
• webclient_request_header_add： 添加 Content-Length 和 Content-Type 请求头；
• webclient_post：发送 POST 请求，若响应状态码不为 200，则打印错误信息并返回错误；
• webclient_read： 循环读取响应数据，直到读取完所有数据，并将其逐个字符打印出来；

applications/webclient_post_example.c

#define POST_LOCAL_URI    "http://www.rt-thread.com/service/echo"

const char *post_data =
    "RT-Thread is an open source IoT operating system from China!";

/* send HTTP POST request by common request interface, it used to receive longer data */
static int webclient_post_comm(
    const char *uri, const void *post_data, size_t data_len)
{
    struct webclient_session *session = RT_NULL;
    unsigned char *buffer = RT_NULL;
    int index, ret = 0;
    int bytes_read, resp_status;

    buffer = (unsigned char *)web_malloc(POST_RESP_BUFSZ);
    if (buffer == RT_NULL)
    {
        rt_kprintf("no memory for receive response buffer.\n");
        ret = (-RT_ENOMEM);
        goto __exit;
    }

    /* create webclient session and set header response size */
    session = webclient_session_create(POST_HEADER_BUFSZ);
    if (session == RT_NULL)
    {
        ret = (-RT_ENOMEM);
        goto __exit;
    }

    /* build header for upload */
    webclient_header_fields_add(
        session, "Content-Length: %d\r\n", strlen(post_data));
    webclient_header_fields_add(session,
        "Content-Type: application/octet-stream \
        \r\n");

    /* send POST request by default header */
    if ((resp_status = webclient_post(session, uri, post_data, data_len)) !=
        200)
    {
        rt_kprintf("webclient POST request failed, response(%d) error.\n",
            resp_status);
        ret = -RT_ERROR;
        goto __exit;
    }

    rt_kprintf("webclient post response data: \n");

    do
    {
        bytes_read = webclient_read(session, buffer, POST_RESP_BUFSZ);
        if (bytes_read <= 0)
        {
            break;
        }

        for (index = 0; index < bytes_read; index++)
        {
            rt_kprintf("%c", buffer[index]);
        }
    } while (1);

    rt_kprintf("\n");

__exit:
    if (session)
    {
        webclient_close(session);
        session = RT_NULL;
    }

    if (buffer)
    {
        web_free(buffer);
    }

    return ret;
}

static int webclient_post_smpl(
    const char *uri, const char *post_data, size_t data_len)
{
    char *response = RT_NULL;
    char *header = RT_NULL;
    size_t resp_len = 0;
    int index = 0;

    webclient_request_header_add(
        &header, "Content-Length: %d\r\n", strlen(post_data));
    webclient_request_header_add(&header,
        "Content-Type: application/octet-stream \
        \r\n");

    if (webclient_request(uri, header, post_data, data_len, (void **)&response,
            &resp_len) < 0)
    {
        rt_kprintf("webclient send post request failed.");
        web_free(header);
        return (-RT_ERROR);
    }

    rt_kprintf("webclient send post request by simplify request interface.\n");
    rt_kprintf("webclient post response data: \n");

    for (index = 0; index < resp_len; index++)
    {
        rt_kprintf("%c", response[index]);
    }
    rt_kprintf("\n");

    if (header)
    {
        web_free(header);
    }

    if (response)
    {
        web_free(response);
    }

    return 0;
}

int webclient_post_test(int argc, char **argv)
{
    char *uri = RT_NULL;

    if (argc == 1)
    {
        uri = web_strdup(POST_LOCAL_URI);
        if (uri == RT_NULL)
        {
            rt_kprintf("no memory for create post request uri buffer.\n");
            return (-RT_ENOMEM);
        }

        webclient_post_comm(uri, (void *)post_data, strlen(post_data));
    }
    else if (argc == 2)
    {
        if (strcmp(argv[1], "-s") == 0)
        {
            uri = web_strdup(POST_LOCAL_URI);
            if (uri == RT_NULL)
            {
                rt_kprintf("no memory for create post request uri buffer.\n");
                return (-RT_ENOMEM);
            }

            webclient_post_smpl(uri, (void *)post_data, strlen(post_data));
        }
        else
        {
            uri = web_strdup(argv[1]);
            if (uri == RT_NULL)
            {
                rt_kprintf("no memory for create post request uri buffer.\n");
                return (-RT_ENOMEM);
            }
            webclient_post_comm(uri, (void *)post_data, strlen(post_data));
        }
    }
    else if (argc == 3 && strcmp(argv[1], "-s") == 0)
    {
        uri = web_strdup(argv[2]);
        if (uri == RT_NULL)
        {
            rt_kprintf("no memory for create post request uri buffer.\n");
            return (-RT_ENOMEM);
        }

        webclient_post_smpl(uri, (void *)post_data, strlen(post_data));
    }
    else
    {
        rt_kprintf("web_post_test [uri]     - webclient post request test.\n");
        rt_kprintf(
            "web_post_test -s [uri]  - webclient simplify post request test.\n");
        return (-RT_ERROR);
    }

    if (uri)
    {
        web_free(uri);
    }

    return RT_EOK;
}

如需体验 https 将webclient_post_example.c 文件中的 GET_LOCAL_URI 宏修改为 "https://www.rt-thread.com/service/echo"

webclient_post_example.c

#define GET_LOCAL_URI "http://www.rt-thread.com/service/echo"
#define GET_LOCAL_URI "https://www.rt-thread.com/service/echo"

运行示例

操作步骤

• 设置 IP 地址：将 IP 地址替换为自己网络的实际 IP 地址。

msh />ifconfig e0 10.23.8.38 10.23.8.254 255.255.255.0
config : e0
IP addr: 10.23.8.38
Gateway: 10.23.8.254
netmask: 255.255.255.0

• 设置 DNS 服务器：将 DNS 服务器替换为自己网络的实际 DNS 服务器地址。

msh />dns e0 0 223.5.5.5
set network interface device(e0) dns server #0: 223.5.5.5

• 执行 POST 请求测试

msh />web_post_test
method 2
webclient post response data:
RT-Thread is an open source IoT operating system from China!