ESP32-CAM 发送图片到服务器：使用 multipart/form-data 上传

以下是一个示例代码，用于将 ESP32-CAM 拍摄的图像作为 multipart/form-data 发送到服务器：

#include <WiFi.h>
#include <HTTPClient.h>
#include <WiFiClient.h>
#include "esp_camera.h"

// 替换为您的网络凭据
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";

// 服务器详细信息
const char* serverName = "http://your_server_address/upload.php";
const char* serverPort = "80";

// 摄像头引脚
#define PWDN_GPIO_NUM     32
#define RESET_GPIO_NUM    -1
#define XCLK_GPIO_NUM      0
#define SIOD_GPIO_NUM     26
#define SIOC_GPIO_NUM     27
#define Y9_GPIO_NUM       35
#define Y8_GPIO_NUM       34
#define Y7_GPIO_NUM       39
#define Y6_GPIO_NUM       36
#define Y5_GPIO_NUM       21
#define Y4_GPIO_NUM       19
#define Y3_GPIO_NUM       18
#define Y2_GPIO_NUM        5
#define VSYNC_GPIO_NUM    25
#define HREF_GPIO_NUM     23
#define PCLK_GPIO_NUM     22

void setup() {
  Serial.begin(115200);
  delay(10);

  // 连接到 Wi-Fi 网络，使用 SSID 和密码
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");

  // 摄像头配置
  camera_config_t config;
  config.ledc_channel = LEDC_CHANNEL_0;
  config.ledc_timer = LEDC_TIMER_0;
  config.pin_d0 = Y2_GPIO_NUM;
  config.pin_d1 = Y3_GPIO_NUM;
  config.pin_d2 = Y4_GPIO_NUM;
  config.pin_d3 = Y5_GPIO_NUM;
  config.pin_d4 = Y6_GPIO_NUM;
  config.pin_d5 = Y7_GPIO_NUM;
  config.pin_d6 = Y8_GPIO_NUM;
  config.pin_d7 = Y9_GPIO_NUM;
  config.pin_xclk = XCLK_GPIO_NUM;
  config.pin_pclk = PCLK_GPIO_NUM;
  config.pin_vsync = VSYNC_GPIO_NUM;
  config.pin_href = HREF_GPIO_NUM;
  config.pin_sscb_sda = SIOD_GPIO_NUM;
  config.pin_sscb_scl = SIOC_GPIO_NUM;
  config.pin_pwdn = PWDN_GPIO_NUM;
  config.pin_reset = RESET_GPIO_NUM;
  config.xclk_freq_hz = 20000000;
  config.pixel_format = PIXFORMAT_JPEG;
  config.frame_size = FRAMESIZE_QVGA;
  config.jpeg_quality = 12;
  config.fb_count = 1;

  // 初始化摄像头
  esp_err_t err = esp_camera_init(&config);
  if (err != ESP_OK) {
    Serial.printf("Camera init failed with error 0x%x", err);
    return;
  }
}

void loop() {
  // 拍摄照片
  camera_fb_t* fb = esp_camera_fb_get();
  if (!fb) {
    Serial.println("Failed to capture photo");
    return;
  }

  // 创建 HTTP 客户端
  WiFiClient client;
  HTTPClient http;
  http.begin(client, serverName, serverPort);

  // 设置 content-type 头部
  http.addHeader("Content-Type", "multipart/form-data");

  // 创建 multipart/form-data 负载
  WiFiClient stream;
  http.collectHeaders(stream);
  http.beginRequest();
  http.write("--");
  http.print("123456789000");
  http.write("\r\n");
  http.print("Content-Disposition: form-data; name=\"file\"; filename=\"image.jpg\"\r\n");
  http.print("Content-Type: image/jpeg\r\n");
  http.write("\r\n");

  // 发送图片数据
  uint8_t* buf = fb->buf;
  size_t len = fb->len;
  size_t index = 0;
  while (index < len) {
    size_t chunkSize = len - index;
    if (chunkSize > 1024) {
      chunkSize = 1024;
    }
    http.write(buf + index, chunkSize);
    index += chunkSize;
  }

  // 关闭 multipart/form-data 负载
  http.write("\r\n--");
  http.print("123456789000");
  http.write("--\r\n");
  http.endRequest();

  // 发送 HTTP 请求并获取响应
  int httpResponseCode = http.POST();
  String response = http.getString();

  // 打印响应
  Serial.print("HTTP Response code: ");
  Serial.println(httpResponseCode);
  Serial.print("HTTP Response body: ");
  Serial.println(response);

  // 释放摄像头缓冲区
  esp_camera_fb_return(fb);

  // 等待 5 秒，然后拍摄下一张照片
  delay(5000);
}

该代码连接到 Wi-Fi 网络，初始化 ESP32-CAM 摄像头，并在循环中捕获一张照片，将其作为 multipart/form-data 发送到服务器。要使用此代码，请将以下参数替换为您自己的值：

• ssid 和 password：您的 Wi-Fi 网络凭据。
• serverName：您的服务器地址。
• serverPort：您的服务器端口号。

请注意，此代码使用了 HTTPClient 库，因此您需要在 Arduino IDE 中安装该库。您可以通过依次选择“工具”>“管理库”>搜索“HTTPClient”来安装它。