使用Arduino ESP8266 SparkFun屏蔽的HTTP POST

Question

我正在尝试向运行node.js的本地服务器发送POST HTTP。GET请求运行良好。使用Postman (本地)的帖子工作得很好，我没有任何防火墙。但我不能和Arduino一起运行它。

我使用的代码是一个简单的SparkFun客户端示例，其中我只将GET更改为POST：

void clientDemo() {
  // To use the ESP8266 as a TCP client, use the 
  // ESP8266Client class. First, create an object:
  ESP8266Client client;

  // ESP8266Client connect([server], [port]) is used to 
  // connect to a server (const char * or IPAddress) on
  // a specified port.
  // Returns: 1 on success, 2 on already connected,
  // negative on fail (-1=TIMEOUT, -3=FAIL).
  int retVal = client.connect(destServer, 5000);
  if (retVal == -1) {
    Serial.println(F("Time out"));
    return;
  } else if(retVal == -3) {
    Serial.println(F("Fail connection"));
    return;
  } else if(retVal == 1) {
    Serial.println("Connected with server!");
  }

  // print and write can be used to send data to a connected
  // client connection.
  client.print(httpPost);

  // available() will return the number of characters
  // currently in the receive buffer.
  while (client.available())
    Serial.write(client.read()); // read() gets the FIFO char

  // connected() is a boolean return value - 1 if the 
  // connection is active, 0 if it's closed.
  if (client.connected())
    client.stop(); // stop() closes a TCP connection.
}

httpPost是：

const String httpPost = "POST /meteo HTTP/1.1\n"
                        "Host: 192.168.0.131:5000\n"
                        "User-Agent: Arduino/1.0\n"
                        "Connection: close\n"
                        "Content-Type: application/x-www-form-urlencoded;\n"
                          "windspeedmph=0&winddir=0&humidity=0&temp=0&pressure=0\n";

我在串行监视器上看到的只是“已连接到服务器！”...

我做错了什么？

Answer 1

headers和body之间需要有一个空行：

const String httpPost =   "POST /meteo HTTP/1.1\r\n"
                          "Host: 192.168.0.131:5000\r\n"
                          "User-Agent: Arduino/1.0\r\n"
                          "Connection: close\r\n"
                          "Content-Type: application/x-www-form-urlencoded;\r\n"
                          "\r\n"
                          "windspeedmph=0&winddir=0&humidity=0&temp=0&pressure=0\n";

此外，根据标准，您应该使用\r\n换行符，而不仅仅是\n。

HTTP header line break style

Answer 2

在我的例子中，指定-Length字段也很重要。然后，应用程序开始按其应有的方式工作。如果没有Content-Length字段，在接收端就看不到数据。Content-Length指定有效负载的长度，在本例中为字符串的长度："windspeedmph=0&winddir=0&humidity=0&temp=0&pressure=0\n".