嵌入式HTTP获取升级bin包代码

这是一个获取嵌入式HTTP升级bin包的示例代码：

#include <ESPAsyncWebServer.h>
#include <Update.h>

AsyncWebServer server(80);

void handleUpdate(AsyncWebServerRequest *request) {
  if (Update.hasError()) {
    request->send(500, "text/plain", "Update failed: " + String(Update.getError()));
  } else {
    request->send(200, "text/plain", "Update successful");
  }
}

void startUpdate(AsyncWebServerRequest *request, String filename, size_t index, uint8_t *data, size_t len, bool final) {
  if (!index) {
    Update.begin(UPDATE_SIZE_UNKNOWN);
  }
  if (Update.write(data, len) != len) {
    Update.abort();
    request->send(500, "text/plain", "Update failed");
  }
  if (final) {
    Update.end();
  }
}

void setup() {
  server.on("/update", HTTP_POST, [](AsyncWebServerRequest *request) {
    request->send(200, "text/html", "<form method='POST' action='/update' enctype='multipart/form-data'><input type='file' name='update'><button>Update</button></form>");
  });
  server.on("/update", HTTP_POST, [](AsyncWebServerRequest *request) {
    AsyncWebHeader *header = request->getHeader("Content-Length");
    if (!header) {
      request->send(400, "text/plain", "Missing Content-Length header");
      return;
    }
    int contentLength = header->value().toInt();
    if (!Update.begin(contentLength)) {
      request->send(500, "text/plain", "Update failed");
      return;
    }
    if (request->hasParam("MD5", true)) {
      Update.setMD5(request->getParam("MD5", true)->value().c_str());
    }
    request->send(200, "text/plain", "Update started");
  }, startUpdate);
  server.on("/update", HTTP_POST, [](AsyncWebServerRequest *request) {
    AsyncWebHeader *header = request->getHeader("Content-Length");
    if (!header) {
      request->send(400, "text/plain", "Missing Content-Length header");
      return;
    }
    int contentLength = header->value().toInt();
    if (!Update.begin(contentLength, U_FLASH)) {
      request->send(500, "text/plain", "Update failed");
      return;
    }
    if (request->hasParam("MD5", true)) {
      Update.setMD5(request->getParam("MD5", true)->value().c_str());
    }
    request->send(200, "text/plain", "Update started");
  }, startUpdate);
  server.on("/update", HTTP_COMPLETE, handleUpdate);
  server.begin();
}

void loop() {}

这段代码使用了ESPAsyncWebServer库来实现HTTP服务器功能，并使用ESP8266的Update库来进行固件升级。服务器监听端口80，并提供了一个简单的页面，让用户选择需要升级的bin文件并上传。上传完成后，服务器会通过handleUpdate()函数来处理升级结果。如果升级成功，服务器会返回200 OK；如果升级失败，则会返回500 Internal Server Error