How do you publish bigdatetime data with the C SDK to ESP?
A couple of weeks ago, I was asked how to publish bigdatetime data to ESP using the C SDK. The crux of the problem was that the API used to set the bigdatetime column required an “EspBigDatetime” value as the second parameter:
| ESPAPICALL int32_t esp_relative_rowwriter_set_bigdatetime | ( | EspRelativeRowWriter * | writer, |
| const EspBigDatetime * | bigdatetime_value, | ||
| EspError * | error | ||
| ) |
How does one populate an EspBigDatetime variable?
It turns out that there are two ways to populate an EspBigDatetime variable:
1) The first method works best if your bigdatetime data is coming from a string source (for example, reading from a file):
| ESPAPICALL EspBigDatetime* esp_bigdatetime_create_string | ( | const char * | string_value, |
| EspError * | error | ||
| ) |
// NOTE: The string must be in the standard ESP bigdatetime format which is “yyyy-MM-ddTHH:mm:ss.UUUUUU” where the letter ‘U’ stands for microseconds.
char timestamp[27] = “2013-08-24T09:45:23.543221”;
EspBigDatetime *espDatetime;
// Create and populate the espDatetime variable
espDatetime = esp_bigdatetime_create_string(timestamp, espError);
if(espDatetime == NULL)
{
print_ESP_error_and_exit(espError,__LINE__);
}
// Set the espDatetime value in the current row
rc=esp_relative_rowwriter_set_bigdatetime(row,espDatetime,espError);
if(rc!=0)
{
print_ESP_error(espError,__LINE__);
esp_bigdatetime_free(espDatetime, espError);
exit(1);
}
esp_bigdatetime_free(espDatetime, espError);
2) The second method works best if your bigdatetime data is in a numeric microsecond format (for example, getting the system’s current date and time):
| ESPAPICALL EspBigDatetime* esp_bigdatetime_create_microseconds | ( | const int64_t | microseconds, |
| EspError * | error | ||
| ) |
EspBigDatetime *espDatetime;
time_t tmstamp;
// Get the current date and time in microseconds
tmstamp = getMicroseconds();
// Create and populate the espDatetime variable
espDatetime = esp_bigdatetime_create_microseconds(tmstamp, espError);
if(espDatetime == NULL)
{
print_ESP_error_and_exit(espError,__LINE__);
}
// Set the espDatetime value in the current row
rc=esp_relative_rowwriter_set_bigdatetime(row,espDatetime,espError);
if(rc!=0)
{
print_ESP_error(espError,__LINE__);
esp_bigdatetime_free(espDatetime, espError);
exit(1);
}
esp_bigdatetime_free(espDatetime, espError);