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我是 esp32 的新手，现在我正在尝试使用 ArduinoJson 获取数据，在我的 googlesheet “A1”中有一个数字，我想让 esp32 获取它，我将我的 googlesheet 发送到互联网并使用网址：https： //spreadsheets.google.com/feeds/cells/1RICYSv0y0wEEu-PhcCL45jZmh7DlFSAsbW8Bie0inbA/1/public/values?alt=json&range=A1。我的号码在 object > feed > entry > 0 > content > $t。

这里有一个问题：当我使用 esp32 获取这个 json 数据时，我无法获取它，即使我的 esp32 连接到 googlesheet

如果您需要，这是我的完整代码：

#include <ArduinoJson.h>
#include <WiFi.h>
#include <SPI.h>

WiFiClient client;

const char* ssid = "wwwwwwwww";
const char* password = "wwwwwwww";
const char* server = "spreadsheets.google.com";
const char* resource = "/feeds/cells/1RICYSv0y0wEEu-PhcCL45jZmh7DlFSAsbW8Bie0inbA/1/public/values?alt=json&range=A1";


const unsigned long HTTP_TIMEOUT = 10000;  // max respone time from server
const size_t MAX_CONTENT_SIZE = 1024;       // max size of the HTTP response

byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};

struct clientData {
  char item[8];
};


void setup() {
  Serial.begin(9600);
  while (!Serial) {

  }
  Serial.println("Serial ready");
  Serial.print("Connecting to wifi: ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}


void loop() {
  if(connect(server)) {
    if(sendRequest(server, resource) && skipResponseHeaders()) {
      clientData clientData;
      if(readReponseContent(&clientData)) {
        printclientData(&clientData);
      }
    }
  }
  disconnect();
  wait();
}


bool connect(const char* hostName) {
  Serial.print("Connect to ");
  Serial.println(hostName);

  bool ok = client.connect(hostName, 80);

  Serial.println(ok ? "Connected" : "Connection Failed!");
  return ok;
}


bool sendRequest(const char* host, const char* resource) {
  Serial.print("GET ");
  Serial.println(resource);

  client.print("GET ");
  client.print(resource);
  client.println(" HTTP/1.1");
  client.print("Host: ");
  client.println(host);
  client.println("Connection: close");
  client.println();

  return true;
}

bool skipResponseHeaders() {
  // HTTP headers end with an empty line
  char endOfHeaders[] = "\r\n\r\n";

  client.setTimeout(HTTP_TIMEOUT);
  bool ok = client.find(endOfHeaders);

  if (!ok) {
    Serial.println("No response or invalid response!");
  }
  return ok;
}


bool readReponseContent(struct clientData* clientData) {
  const size_t bufferSize = 5*JSON_ARRAY_SIZE(1) + 
  JSON_ARRAY_SIZE(5) + 10*JSON_OBJECT_SIZE(1) + 
  6*JSON_OBJECT_SIZE(2) + 7*JSON_OBJECT_SIZE(3) + 
  JSON_OBJECT_SIZE(4) + JSON_OBJECT_SIZE(7) + JSON_OBJECT_SIZE(15);
  DynamicJsonBuffer jsonBuffer(bufferSize);

  JsonObject& root = jsonBuffer.parseObject(client);

  if (!root.success()) {
    Serial.println("JSON parsing failed!");
    return false;
  }

  strcpy(clientData->item, root["feed"]["entry"][0]["content"]["$t"]);

  return true;
}


void printclientData(const struct clientData* clientData) {
  Serial.print("Time = ");
  Serial.println(clientData->item);

}

void disconnect() {
  Serial.println("Disconnect");
  client.stop();
}

void wait() {
  Serial.println("Wait 20 seconds");
  delay(20000);
}

串行输出：

Connecting to wifi: wwwwwwwwww
..
WiFi connected
IP address: 
xxx.xxx.x.xx
Connect to spreadsheets.google.com
Connected
GET /feeds/cells/1RICYSv0y0wEEu-PhcCL45jZmh7DlFSAsbW8Bie0inbA/1/public/values?alt=json&range=A1
JSON parsing failed!
Disconnect
Wait 20 seconds
4

1 回答 1

0

如果我基于您的 json 输出并使用ArduinoJson Assistant计算 bufferSize ，我会得到：

const size_t capacity = 5*JSON_ARRAY_SIZE(1) + JSON_ARRAY_SIZE(5) + 10*JSON_OBJECT_SIZE(1) + 6*JSON_OBJECT_SIZE(2) + 7*JSON_OBJECT_SIZE(3) + JSON_OBJECT_SIZE(4) + JSON_OBJECT_SIZE(7) + JSON_OBJECT_SIZE(15) + 2270;

注意到+ 2270最后了吗？您的 json 解析失败，因为您在 bufferSize 中缺少 2270 个字节（即您的 bufferSize 太小）。

更新

我没有尝试调试您的代码，但我手边有我的 Web 客户端代码，所以我只是运行它，它对我有用。

我的代码基于 HTTPClient，它是 ESP32 Arduino Core 的一部分，您可以在 ESP-Arduino github进一步了解它。它基于您使用的 Arduino WifiClient，但 API 更简单易用，尤其是用于获取响应负载。我建议你看看。

我将 ArduinoJson 添加到我的代码中，以查看解析接收到的 json 是否有任何问题，但我的是基于 v6 语法，如果您仍然觉得使用 v5 更容易，可以将其转换为 v5 语法。顺便说一句，json 文件包含 Unicode，我必须#define ARDUINOJSON_DECODE_UNICODE 1在程序顶部添加 oder 才能使其工作，否则我会得到一个deserialization error: NotSupported.

#define ARDUINOJSON_DECODE_UNICODE 1
#include <ArduinoJson.h>
#include <WiFi.h>
#include <HTTPClient.h>

HTTPClient http;

const char* ssid = "your_SSID";
const char* password = "your_password";

const char* url = "https://spreadsheets.google.com/feeds/cells/1RICYSv0y0wEEu-PhcCL45jZmh7DlFSAsbW8Bie0inbA/1/public/values?alt=json&range=A1";

void setup() {
  Serial.begin(115200);
  while (!Serial) {}

  Serial.print("Connecting to wifi: "); Serial.print(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(200);
    Serial.print(".");
  }
  Serial.println();
  Serial.print("IP address: "); Serial.println(WiFi.localIP());

  http.begin(url); 
  int httpCode = http.GET();  //send GET request

  if (httpCode != 200) {
    Serial.print("Error on HTTP request: ");
    Serial.println(httpCode);
  } else {
    String payload = http.getString();
    Serial.println(payload);

    // the following is based on ArduinoJson v6 API
    StaticJsonDocument<4000> doc;
    DeserializationError err = deserializeJson(doc, payload);
    if (err) {
      Serial.print("deserialization error ");
      Serial.println(err.c_str());
    }

    JsonObject feed = doc["feed"];
    const char* clientData = feed["entry"][0]["content"]["$t"];
    Serial.println(clientData);
  }

  http.end(); //Free the resources

}


void loop() {

}
于 2020-02-18T01:34:24.423 回答