How to make a correct POST with http client request on ESP32 (error: "DNS Failed for sitename")

Question

我正在尝试向我设置的网站发送一个 POST 请求，使用 ESP32，其中包含 2 条数据。我曾尝试使用站点 "reqbin.com" 发送包含相同数据的 POST 请求，因此我认为数据本身不是问题。

下面是我的代码：

char ssid[] = "{{name}}";
char pass[] = "{{pass}}";
int port = 8080;
WiFiClient wifi;

void setup()
{
delay(1000);
    WiFi.mode(WIFI_OFF); //Prevents reconnection issue (taking too long to connect)
    delay(1000);
    WiFi.mode(WIFI_STA); //This line hides the viewing of ESP as wifi hotspot

    WiFi.begin(ssid, pass); //Connect to your WiFi router
    Serial.println("");

    Serial.print("Connecting");
    // Wait for connection
    while (WiFi.status() != WL_CONNECTED)
    {
        delay(500);
        Serial.print(".");
    }

    //If connection successful show IP address in serial monitor
    Serial.println("");
    Serial.print("Connected to ");
    Serial.println(ssid);
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
}

void loop()
{
String serverAddress = "sitename.com/data.php";
    String contentType = "text/plain"
    String postData = "t=26.1 h=25.6";
    HttpClient http = HttpClient(wifi, serverAddress, port);
    http.beginRequest(); //Specify request destination
    int httpCode = http.post("/", contentType, postData);
    Serial.println("httpCode = " + httpCode);
    if (httpCode > 0)
    {
        String response = http.responseBody();
        Serial.println("httpCode === " + httpCode);
        Serial.println(response);
    }
    else
    {
        Serial.println("Error on POST request");
        Serial.println(httpCode);
    }
    http.endRequest();
}

使用 reqbin 时，我得到状态 200 和站点 returns。但是，在 ESP32 上，它 returns 错误：

[E][WiFiGeneric.cpp:654] hostByName(): DNS Failed for sitename.com/data.php

我不确定我请求的语法是否不正确。

更新：更改了我的循环并将服务器地址更改为：

String serverAddress = "sitename.com";
    String contentType = "text/plain";
    String postData = "t=26.1 h=25.6";
    HttpClient http = HttpClient(wifi, serverAddress, port);
    http.beginRequest(); //Specify request destination
    int httpCode = http.post("/data.php", contentType, postData);
    Serial.println("httpCode = " + httpCode);

现在出现错误：

socket error on fd 57, errno: 104, "Connection reset by peer"

为 Codebreaker 编辑：

String serverAddress = "sitename.com";
HttpClient http = HttpClient(wifi, serverAddress, port);
String response;
int statusCode = 0;

Setup has stayed the same.

void loop()
{
String contentType = "application/x-www-form-urlencoded";
    // String postData = temp + " " + humid;
    String postData = "?t=26.1&h=25.6";
    http.post("/data.php", contentType, postData);
    // read the status code and body of the response
    statusCode = http.responseStatusCode();
    response = http.responseBody();

    Serial.print("Status code: ");
    Serial.println(statusCode);
    Serial.print("Response: ");
    Serial.println(response);
}

Answer 1

我猜服务器需要 url 编码数据而不是纯文本。所以试试在 setup()

之前定义以下内容

 int port = 80;
 String response;
int statusCode = 0;

String serverAddress = "sitename.com";
HttpClient http = HttpClient(wifi, serverAddress, port);

并且在你的循环中你构建 post 如下

String contentType = "application/x-www-form-urlencoded";
String postData = "?t=26.1&h=25.6";
http.post("/data.php", contentType, postData);

然后阅读回复

  // read the status code and body of the response
  statusCode = http.responseStatusCode();
  response = http.responseBody();

  Serial.print("Status code: ");
  Serial.println(statusCode);
  Serial.print("Response: ");
  Serial.println(response);

如果可行，请将字符串 class 替换为这样的字符数组

char serverAddress[] = "www.test.com";  // server address

How to make a correct POST with http client request on ESP32 (error: "DNS Failed for sitename")

How to make a correct POST with http client request on ESP32 (error: "DNS Failed for sitename")

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