Question

我想使用ESP8266解析我站点上的数据并执行LED的开/关。这是一个简单的JSON文件，但是代码仍然无法读取它。我已尽力而为，但仍然无法解决问题。可能是什么问题？

#include "WiFiEsp.h"
#include<ArduinoJson.h>

#ifndef HAVE_HWSERIAL1
#include "SoftwareSerial.h"
SoftwareSerial Serial1(12, 13); // RX, TX
#endif

char ssid[] = "mywifi";            // your network SSID (name)
char pass[] = "12345678";        // your network password
int status = WL_IDLE_STATUS;     // the Wifi radio's status

char server[] = "192.168.1.10";//192.168.1.10/arduino_light/light.json
String path = "/arduino_light/light.json"; //

unsigned long lastConnectionTime = 0;         // last time you connected to the server, in milliseconds
const unsigned long postingInterval = 20000L; // delay between updates, in milliseconds

// Initialize the Ethernet client object
WiFiEspClient client;

void setup()
{
  // initialize serial for debugging
  Serial.begin(9600);
  // initialize serial for ESP module
  Serial1.begin(9600);
  // initialize ESP module
  WiFi.init(&Serial1);

  // check for the presence of the shield
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present");
    // don't continue
    while (true);
  }

  // attempt to connect to WiFi network
  while ( status != WL_CONNECTED) {
    Serial.print("Attempting to connect to WPA SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network
    status = WiFi.begin(ssid, pass);
  }

  Serial.println("You're connected to the network");
}

void loop()
{
  // if there's incoming data from the net connection send it out the serial port
  // this is for debugging purposes only
  while (client.available()) {
    char c = client.read();
    Serial.write(c);
  }

  if (millis() - lastConnectionTime > postingInterval) {
    httpRequest();
  }
}

// this method makes a HTTP connection to the server
void httpRequest()
{
  Serial.println();

  // close any connection before send a new request
  // this will free the socket on the WiFi shield
  client.stop();

  // if there's a successful connection
  if (client.connect(server, 80)) {
    Serial.println("Connecting...");

    client.print(String("GET ") + 
    path + 
    " HTTP/1.1\r\n" + 
    "Host: " + server + "\r\n" + 
    "Connection: keep-alive\r\n\r\n");

    delay(1000); // wait for server to respond

    unsigned long timeout = millis();
    while (client.available() == 0) {
        if (millis() - timeout > 5000) {
            Serial.println(">>> Client Timeout !");
            client.stop();
            return;
        }
    }

    // read response  
    String section="header";
    while(client.available()){
      String line = client.readStringUntil('\r');
      Serial.println("line:"+line);    // we’ll parse the HTML body here
      if (section=="header") { // headers..
        if (line=="\n") { // skips the empty space at the beginning
           section="json";
        }
      } else if (section=="json") {  // print the good stuff
        section="ignore";
        String result = line.substring(1);      // Parse JSON
        int size = result.length() + 1;
        char json[size];
        result.toCharArray(json, size);
        StaticJsonBuffer<200> jsonBuffer;
        JsonObject& json_parsed = jsonBuffer.parseObject(json);
        if (!json_parsed.success())
        {
          Serial.println("parseObject() failed");
          return;
        }
        // Make the decision to turn off or on the LED
        if (strcmp(json_parsed["light"], "on") == 0) {
           Serial.println("LED ON");
        }
        else {
          Serial.println("led off");
        }
      }
      // note the time that the connection was made
      lastConnectionTime = millis();
    }
  } else {
    // if you couldn't make a connection
    Serial.println("Connection failed");
    delay(500);
  }
}

文件路径： 192.168.1.10/arduino_light/light.json

文件内容： {“ light”：“ on”}

结果：

[WiFiEsp] Disconnecting  3
[WiFiEsp] Connecting to 192.168.1.10
Connecting...
line:HTTP/1.1 200 OK
line:
Server: nginx
[WiFiEsp] TIMEOUT: 220
line:

Answer 1

我认为.. 您看一下对HTTP协议的响应：

HTTP/1.1 200 OK\r\n
[header]\r\n
[header]\r\n
[header]\r\n\r\n
[body]...

如果您获得JSON正文使用此代码

String line = client.readStringUntil('}');

或

while (client.connected()) {
    if (client.available()) {
        c = client.read();
        Serial.print(c);
    }
}

并解析响应

Arduino ESP8266无法读取JSON文件

1 个答案: