ESP8266 - 来自服务器的响应被切断 [英] ESP8266 - Response from server gets cut

问题描述

我正在使用通过 SoftwareSerial 连接到 Arduino 的 ESP8266 向节点 Web 服务器发出发布请求.ESP8266 向服务器发送一些数据，它应该返回其他数据.数据正确到达服务器，但来自服务器的响应不完整(每次都以不同的方式被截断)并且我无法从我的 Arduino 草图访问响应正文.服务器正确发送响应，因为我已经检查过 hurl.

I'm using an ESP8266 connected to an Arduino one via SoftwareSerial to make a post request to a node web server. The ESP8266 sends some data to the server and it should get back other data. The data arrives at the server correctly, but the response from the server is incomplete (it gets cut each time in a different way) and I can't access the body of the response from my Arduino sketch. The server sends the response correctly, as i've checked with hurl.

这是我的代码:

#include "SoftwareSerial.h"

String ssid ="ssid";
String password="pwd";
SoftwareSerial esp(3, 2);// RX, TX

ESP8266_Simple wifi(3,2);

String data;
String server = "server"; 
String uri = "uri";

String token = "token";

float temp_set = 15; //standard values
float temp_rec = 15;
String temp_set_s;
String temp_rec_s;

int activate = LED_BUILTIN; //pin for relay
int button_up = 4;
int button_down = 5;

unsigned long time;

//LCD
#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

// DHT11
#include <Adafruit_Sensor.h>
#include <DHT.h>
#include <DHT_U.h>
#define DHTPIN 6
#define DHTTYPE DHT22    
DHT_Unified dht(DHTPIN, DHTTYPE);

void setup() {
  esp.begin(9600);
  Serial.begin(9600);
  delay(10);

  reset();
  connectWifi();

  pinMode(activate, OUTPUT);
  pinMode(button_up, INPUT);
  pinMode(button_down, INPUT);

  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);

  //DHT setup
  dht.begin();
  sensor_t sensor;

  delay(500);
}

//reset the esp8266 module
void reset() {
    esp.println("AT+RST");
    delay(1000);
    if(esp.find("OK") ) Serial.println("Module Reset");

}

//connect to your wifi network
void connectWifi() {
    String cmd = "AT+CWJAP="" +ssid+"","" + password + """;

    esp.println(cmd);

    delay(4000);

    if(esp.find("OK")) {
        Serial.println("Connected!");
        time = millis();
    } else {
        connectWifi();
        Serial.println("Cannot connect to wifi"); 
    }
} 


void loop () {

  //temp_rec_s = String(temp_rec);
  //temp_set_s = String(temp_set);
  //data = "tempRec=" + temp_rec_s + "&tempSet=" + temp_set_s;
  //httppost();

  // dht data
  sensors_event_t event;  
  dht.temperature().getEvent(&event);
  temp_rec = event.temperature; 

  //temp_rec_s = String(temp_rec);
  //temp_set_s = String(temp_set);
  //data = "tempRec=" + temp_rec_s + "&tempSet" + temp_set_s;


  // to activate
  if(temp_set < temp_rec){
    digitalWrite(activate, LOW);
  } else{
    digitalWrite(activate, HIGH);
  }

  //function for physical buttons
  if((digitalRead(button_up)) == HIGH){
    temp_set = temp_set + 0.5;
    delay(100);
  }
  if((digitalRead(button_down)) == HIGH){
    temp_set = temp_set - 0.5;
    delay(100);
  }

  //shows temperature on display
  lcd.setCursor(0, 0);
  lcd.print("T rec " + String(temp_rec));

  //shows temperature on display
  lcd.setCursor(0, 1);
  lcd.print("T set " + String(temp_set));

  temp_rec_s = String(temp_rec);
  temp_set_s = String(temp_set);
  data = "tempRec=" + temp_rec_s + "&tempSet=" + temp_set_s + "&token=" + token;
  //Serial.println(data);
  if((millis() - time) >= 10000){
    httppost();
  }


  delay(200);
}

void httppost () {
    esp.println("AT+CIPSTART="TCP","" + server + "",80");//start a TCP connection.

    if(esp.find("OK")) {
        Serial.println("TCP connection ready");
    } 
    delay(1000);

    String postRequest =
    "POST " + uri + " HTTP/1.0
" +
    "Host: " + server + "
" +
    "Accept: *" + "/" + "*
" +
    "Content-Length: " + data.length() + "
" +
    "Content-Type: application/x-www-form-urlencoded
" +
    "
" + data;

    String sendCmd = "AT+CIPSEND="; //determine the number of caracters to be sent.

    esp.print(sendCmd);
    esp.println(postRequest.length());

    Serial.println(postRequest);

    delay(500);

    if(esp.find(">")) {
        Serial.println("Sending.."); 
        esp.print(postRequest);

        String tmpResp = esp.readString();
        Serial.println(tmpResp);

        if(esp.find("SEND OK")) { 
            Serial.println("Packet sent");

            while(esp.available()) {
                String line = esp.readString();
                Serial.print(line);
            }

            // close the connection
            esp.println("AT+CIPCLOSE");

        }
    }
} 

推荐答案

在 esp.readString() 下放置一个 delay(1) 并使用 .read() 而不是 char 像这样:

Put a delay(1) under the esp.readString() and use .read() instead with char like this:

while(esp.available())
{
    char line = esp.read();        // read one char at a time
    delay(1);                      // prevent freezing
    Serial.print(line);
    if (line == '') continue;    // terminate the `while` when end of the data
}

@gre_gor 指出的 .readString() 方法读取直到 1 秒内没有传入数据.

The .readString() method as pointed out by @gre_gor reads until there is no incoming data for 1 second.

所以更好的方法是使用 read() 和 char 因为您可以测试字符以查看是否已到达数据字符的末尾 .

So the better method is to use read() and char since you can test the char to see if you have reached the end of data character .

使用 .read() 时，请考虑使用自定义超时，因为数据可能会延迟交付，因此如果您尚未达到数据结束符，像这样:

When using .read() consider using a custom timeout, because data can be delivered with delays so you might want to keep trying for a certain period of time if you haven't yet reached the end of data character , like this:

long int time = millis();       // current time
long int wait = 1000 * 10;      // wait 10 seconds before terminating the read process

while ((time + wait) > millis())
{
    while (esp.available())
    {
        char line = esp.read();
        delay(1);
        Serial.print(line);
        if (line == '') continue;
    }
}    

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