ESP32-http server笔记

基于ESP-IDF4.1

#include <esp_wifi.h>
#include <esp_event.h>
#include <esp_log.h>
#include <esp_system.h>
#include <nvs_flash.h>
#include <sys/param.h>
#include "nvs_flash.h"
#include "esp_netif.h"
#include "esp_eth.h"
#include "protocol_examples_common.h"

#include <esp_http_server.h>

/* 
 * 演示服务端创建get和post处理服务
 */

static const char *TAG = "example";

/* HTTP GET 处理程序 */
static esp_err_t hello_get_handler(httpd_req_t *req)
{
    char*  buf;
    size_t buf_len;

    //获取消息头值得长度并且分配内存，而外1个字节存储null终止符
    buf_len = httpd_req_get_hdr_value_len(req, "Host") + 1;
    if (buf_len > 1) {
        buf = malloc(buf_len);
        /* 将null结尾的字符串值复制到缓冲区 */
        if (httpd_req_get_hdr_value_str(req, "Host", buf, buf_len) == ESP_OK) {
            ESP_LOGI(TAG, "Found header => Host: %s", buf);
        }
        free(buf);
    }

    buf_len = httpd_req_get_hdr_value_len(req, "Test-Header-2") + 1;
    if (buf_len > 1) {
        buf = malloc(buf_len);
        if (httpd_req_get_hdr_value_str(req, "Test-Header-2", buf, buf_len) == ESP_OK) {
            ESP_LOGI(TAG, "Found header => Test-Header-2: %s", buf);
        }
        free(buf);
    }

    buf_len = httpd_req_get_hdr_value_len(req, "Test-Header-1") + 1;
    if (buf_len > 1) {
        buf = malloc(buf_len);
        if (httpd_req_get_hdr_value_str(req, "Test-Header-1", buf, buf_len) == ESP_OK) {
            ESP_LOGI(TAG, "Found header => Test-Header-1: %s", buf);
        }
        free(buf);
    }

    // 读取URL查询字符串长度并分配内存空间
    buf_len = httpd_req_get_url_query_len(req) + 1;
    if (buf_len > 1) {
        buf = malloc(buf_len);
        if (httpd_req_get_url_query_str(req, buf, buf_len) == ESP_OK) {
            ESP_LOGI(TAG, "Found URL query => %s", buf);
            char param[32];
            // 从查询字符串获取键值
            if (httpd_query_key_value(buf, "query1", param, sizeof(param)) == ESP_OK) {
                ESP_LOGI(TAG, "Found URL query parameter => query1=%s", param);
            }
            if (httpd_query_key_value(buf, "query3", param, sizeof(param)) == ESP_OK) {
                ESP_LOGI(TAG, "Found URL query parameter => query3=%s", param);
            }
            if (httpd_query_key_value(buf, "query2", param, sizeof(param)) == ESP_OK) {
                ESP_LOGI(TAG, "Found URL query parameter => query2=%s", param);
            }
        }
        free(buf);
    }

    /* 设置自定义消息头 */
    httpd_resp_set_hdr(req, "Custom-Header-1", "Custom-Value-1");
    httpd_resp_set_hdr(req, "Custom-Header-2", "Custom-Value-2");

    //用户上下文通过字符串响应自定义消息头和消息体
    const char* resp_str = (const char*) req->user_ctx;
    httpd_resp_send(req, resp_str, strlen(resp_str));

    //检查http请求消息头是否可以被读取
    if (httpd_req_get_hdr_value_len(req, "Host") == 0) {
        ESP_LOGI(TAG, "Request headers lost");
    }
    return ESP_OK;
}

static const httpd_uri_t hello = {
    .uri       = "/hello",
    .method    = HTTP_GET,
    .handler   = hello_get_handler,
    .user_ctx  = "Hello World!"
};

/* HTTP POST处理 */
static esp_err_t echo_post_handler(httpd_req_t *req)
{
    char buf[100];
    int ret, remaining = req->content_len;

    while (remaining > 0) {
        /* Read the data for the request */
        if ((ret = httpd_req_recv(req, buf,
                        MIN(remaining, sizeof(buf)))) <= 0) {
            if (ret == HTTPD_SOCK_ERR_TIMEOUT) {
                /* Retry receiving if timeout occurred */
                continue;
            }
            return ESP_FAIL;
        }

        /* Send back the same data */
        httpd_resp_send_chunk(req, buf, ret);
        remaining -= ret;

        /* Log data received */
        ESP_LOGI(TAG, "=========== RECEIVED DATA ==========");
        ESP_LOGI(TAG, "%.*s", ret, buf);
        ESP_LOGI(TAG, "====================================");
    }

    // End response
    httpd_resp_send_chunk(req, NULL, 0);
    return ESP_OK;
}

static const httpd_uri_t echo = {
    .uri       = "/echo",
    .method    = HTTP_POST,
    .handler   = echo_post_handler,
    .user_ctx  = NULL
};

/* 
 * 自定义错误处理
 */
esp_err_t http_404_error_handler(httpd_req_t *req, httpd_err_code_t err)
{
    if (strcmp("/hello", req->uri) == 0) {
        httpd_resp_send_err(req, HTTPD_404_NOT_FOUND, "/hello URI is not available");
        /* Return ESP_OK to keep underlying socket open */
        return ESP_OK;
    } else if (strcmp("/echo", req->uri) == 0) {
        httpd_resp_send_err(req, HTTPD_404_NOT_FOUND, "/echo URI is not available");
        /* Return ESP_FAIL to close underlying socket */
        return ESP_FAIL;
    }
    /* For any other URI send 404 and close socket */
    httpd_resp_send_err(req, HTTPD_404_NOT_FOUND, "Some 404 error message");
    return ESP_FAIL;
}

/* 
 * HTTP POST处理程序
 */
static esp_err_t ctrl_put_handler(httpd_req_t *req)
{
    char buf;
    int ret;

    if ((ret = httpd_req_recv(req, &buf, 1)) <= 0) {
        if (ret == HTTPD_SOCK_ERR_TIMEOUT) {
            httpd_resp_send_408(req);
        }
        return ESP_FAIL;
    }

    if (buf == '0') {
        /* URI handlers can be unregistered using the uri string */
        ESP_LOGI(TAG, "Unregistering /hello and /echo URIs");
        httpd_unregister_uri(req->handle, "/hello");
        httpd_unregister_uri(req->handle, "/echo");
        /* Register the custom error handler */
        httpd_register_err_handler(req->handle, HTTPD_404_NOT_FOUND, http_404_error_handler);
    }
    else {
        ESP_LOGI(TAG, "Registering /hello and /echo URIs");
        httpd_register_uri_handler(req->handle, &hello);
        httpd_register_uri_handler(req->handle, &echo);
        /* Unregister custom error handler */
        httpd_register_err_handler(req->handle, HTTPD_404_NOT_FOUND, NULL);
    }

    /* Respond with empty body */
    httpd_resp_send(req, NULL, 0);
    return ESP_OK;
}

static const httpd_uri_t ctrl = {
    .uri       = "/ctrl",
    .method    = HTTP_PUT,
    .handler   = ctrl_put_handler,
    .user_ctx  = NULL
};

//启动web服务
static httpd_handle_t start_webserver(void)
{
    httpd_handle_t server = NULL;
    httpd_config_t config = HTTPD_DEFAULT_CONFIG();

    // 启动httpd服务
    ESP_LOGI(TAG, "Starting server on port: '%d'", config.server_port);
    if (httpd_start(&server, &config) == ESP_OK) {
        // 设置URI处理程序
        ESP_LOGI(TAG, "Registering URI handlers");
        httpd_register_uri_handler(server, &hello);
        httpd_register_uri_handler(server, &echo);
        httpd_register_uri_handler(server, &ctrl);
        return server;
    }

    ESP_LOGI(TAG, "Error starting server!");
    return NULL;
}

//停止web服务
static void stop_webserver(httpd_handle_t server)
{
    // 停止httpd服务
    httpd_stop(server);
}

//断网处理程序
static void disconnect_handler(void* arg, esp_event_base_t event_base, 
                               int32_t event_id, void* event_data)
{
    httpd_handle_t* server = (httpd_handle_t*) arg;
    if (*server) {
        ESP_LOGI(TAG, "Stopping webserver");
        stop_webserver(*server);
        *server = NULL;
    }
}

//联网处理程序
static void connect_handler(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data)
{
    httpd_handle_t* server = (httpd_handle_t*) arg;
    if (*server == NULL) {
        ESP_LOGI(TAG, "Starting webserver");
        *server = start_webserver();
    }
}

//入口
void app_main(void)
{
    static httpd_handle_t server = NULL;

    ESP_ERROR_CHECK(nvs_flash_init());
    ESP_ERROR_CHECK(esp_netif_init());
    ESP_ERROR_CHECK(esp_event_loop_create_default());


    ESP_ERROR_CHECK(example_connect());

    /* 
     * 注册事件处理服务，当断开网络时停止服务，当连接网络时重启
     */
#ifdef CONFIG_EXAMPLE_CONNECT_WIFI
    //连接wifi
    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &connect_handler, &server));
    ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, WIFI_EVENT_STA_DISCONNECTED, &disconnect_handler, &server));
#endif 

#ifdef CONFIG_EXAMPLE_CONNECT_ETHERNET
    //连接以太网
    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_ETH_GOT_IP, &connect_handler, &server));
    ESP_ERROR_CHECK(esp_event_handler_register(ETH_EVENT, ETHERNET_EVENT_DISCONNECTED, &disconnect_handler, &server));
#endif 

    //启动服务
    server = start_webserver();
}

需要包含的文件：https://gitee.com/EspressifSystems/esp-idf/tree/master/examples/common_components/protocol_examples_common

原文：https://gitee.com/EspressifSystems/esp-idf