embedded/004SendData/server-src/server.c

#include <arpa/inet.h>
#include <cjson/cJSON.h>
#include <sqlite3.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define PORT 9000
#define BUFFER_SIZE 1024

typedef struct ESPData {
  double celsius;
  double fahrenheit;
  double humidity;
} ESPData;

int parseJSON(char buffer[BUFFER_SIZE], ESPData *espData);
sqlite3 *initDB();
int storeData(sqlite3 *db, ESPData espData);

int main(int argc, char **argv) {

  sqlite3 *db = initDB();
  if (!db) {
    exit(EXIT_FAILURE);
  }

  int serverSocket;
  struct sockaddr_in serverAddr;

  if ((serverSocket = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
    perror("socket failed");
    exit(EXIT_FAILURE);
  }

  serverAddr.sin_family = AF_INET;
  serverAddr.sin_addr.s_addr = INADDR_ANY;
  serverAddr.sin_port = htons(PORT);

  if (bind(serverSocket, (struct sockaddr *)&serverAddr, sizeof serverAddr) <
      0) {
    perror("bind failed");
    exit(EXIT_FAILURE);
  }

  if (listen(serverSocket, 5) < 0) {
    perror("listen failed");
    exit(EXIT_FAILURE);
  }

  printf("Server listening on port %d\n", PORT);
  while (1) {

    struct sockaddr_in clientAddr;
    socklen_t clientAddr_len = sizeof clientAddr;
    int *clientSocket = malloc(sizeof(int));

    if ((*clientSocket = accept(serverSocket, (struct sockaddr *)&clientAddr,
                                &clientAddr_len)) < 0) {
      perror("accept failed");
      continue;
    }

    printf("Connected\n");

    // Receive from Client
    char buf[BUFFER_SIZE];
    int bytes = recv(*clientSocket, buf, sizeof buf, 0);
    if (bytes <= 0) {
      perror("failed to recv from client");
      continue;
    }
    printf("raw data: %s\n", buf);

    // Parse JSON
    ESPData espData;
    if (parseJSON(buf, &espData) == 0) {
      printf("Fahrenheit: %.2f, Celsius: %.2f, Humidity: %.2f\n",
             espData.fahrenheit, espData.celsius, espData.humidity);

      storeData(db, espData);
    }

    close(*clientSocket);
    printf("disconnected client.\n");
  }

  close(serverSocket);
  return 0;
}

int parseJSON(char buffer[BUFFER_SIZE], ESPData *espData) {

  // char *data = strstr(buffer, "\r\n\r\n");
  // if (data) {
  //   data += 4;
  // } else {
  //   return -1;
  // }

  const cJSON *fahr;
  const cJSON *cel;
  const cJSON *hum;
  cJSON *jsonData = cJSON_Parse(buffer);

  fahr = cJSON_GetObjectItem(jsonData, "fahrenheit");
  if (!fahr || !cJSON_IsNumber(fahr)) {
    printf("Error: failed to parse fahrenheit\n");
    cJSON_Delete(jsonData);
    return -1;
  }

  cel = cJSON_GetObjectItem(jsonData, "celsius");
  if (!cel || !cJSON_IsNumber(cel)) {
    printf("Error: failed to parse celsius\n");
    cJSON_Delete(jsonData);
    return -1;
  }

  hum = cJSON_GetObjectItem(jsonData, "humidity");
  if (!hum || !cJSON_IsNumber(hum)) {
    printf("Error: failed to parse humidity\n");
    cJSON_Delete(jsonData);
    return -1;
  }

  espData->fahrenheit = fahr->valuedouble;
  espData->celsius = cel->valuedouble;
  espData->humidity = hum->valuedouble;

  cJSON_Delete(jsonData);
  return 0;
}

sqlite3 *initDB() {
  sqlite3 *db = NULL;
  int res = sqlite3_open("stats.db", &db);
  if (res != SQLITE_OK) {
    fprintf(stderr, "Failed to open the db: %s", sqlite3_errmsg(db));
  }

  return db;
}
int storeData(sqlite3 *db, ESPData espData) {

  char sql[256];
  sprintf(sql,
          "insert into Stats(Id, Fahrenheit, Celsius, Humidity) values(NULL, "
          "'%f', '%f', '%f');",
          espData.fahrenheit, espData.celsius, espData.humidity);

  char *errMsg;
  int res = sqlite3_exec(db, sql, 0, 0, &errMsg);
  if (res != SQLITE_OK) {
    fprintf(stderr, "Could not insert into DB: %s", errMsg);
    sqlite3_free(errMsg);
    return -1;
  }
  return 0;
}