How to pass header information to a custom Jackson JSON deserializer - json

Question

I have a custom Jackson JSON deserializer that converts a user's local timestamp to UTC:
Jackson Config:
#Configuration
public class JacksonConfiguration {
#Bean
public Module javaTimeModule() {
JavaTimeModule module = new JavaTimeModule();
module.addDeserializer(LocalDateTime.class, new JsonDatetimeDeserializer());
module.addSerializer(LocalDateTime.class, new JsonDatetimeSerializer());
return module;
}
}
Deserializer:
public class JsonDatetimeDeserializer extends JsonDeserializer<LocalDateTime> {
#Override
public LocalDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext)
throws IOException {
String timestamp = jsonParser.getText();
DateTimeFormatConstant dateTimeFormat = findDateTimeFormat(timestamp);
LocalDateTime deserializedTime = null;
if (dateTimeFormat != null) {
switch (dateTimeFormat) {
case ISO -> deserializedTime = localTimeToUtc(timestamp, dateTimeFormat.value());
case ISO_WITH_OFFSET -> deserializedTime = zonedTimeWithOffsetToUtc(timestamp, dateTimeFormat.value());
//Add more cases here as more formats are supported and added to DateTimeFormatConstant
}
}
return deserializedTime;
}
private DateTimeFormatConstant findDateTimeFormat(String timestamp) {
DateTimeFormatConstant currentFormat = null;
for (DateTimeFormatConstant format : DateTimeFormatConstant.values()) {
boolean isValidFormat = validateFormat(format.value(), timestamp);
if (isValidFormat) {
currentFormat = format;
break;
}
}
return currentFormat;
}
private boolean validateFormat(String format, String time) {
DateTimeFormatter formatter = DateTimeFormatter.ofPattern(format);
boolean isValid;
try {
try {
LocalDateTime localDateTime = LocalDateTime.parse(time, formatter);
localDateTime.format(formatter);
isValid = true;
} catch (DateTimeException e) {
ZonedDateTime zonedDateTime = ZonedDateTime.parse(time, formatter);
zonedDateTime.format(formatter);
isValid = true;
}
} catch (DateTimeParseException e) {
isValid = false;
}
return isValid;
}
private LocalDateTime zonedTimeWithOffsetToUtc(String time, String format) {
ZonedDateTime zonedDateTime = ZonedDateTime.parse(time, DateTimeFormatter.ofPattern(format));
ZonedDateTime utcTime = zonedDateTime.withZoneSameInstant(ZoneOffset.UTC);
return utcTime.toLocalDateTime();
}
private LocalDateTime localTimeToUtc(String time, String format) {
AuthenticationDetails authDetails = (AuthenticationDetails) SecurityContextHolder.getContext().getAuthentication().getDetails();
ZoneId zoneId = authDetails.getZoneId();
LocalDateTime localDateTime = LocalDateTime.parse(time, DateTimeFormatter.ofPattern(format));
Instant instant = localDateTime.atZone(zoneId).toInstant();
ZonedDateTime zonedDateTimeUTC = ZonedDateTime.ofInstant(instant, ZoneId.of("Etc/UTC"));
return zonedDateTimeUTC.toLocalDateTime();
}
}
I want to add a new case to this method whereby the user provides a time zone offset in the request headers. I'm not sure how I can pass a header from my controller to the custom deserializer. Any thoughts?
So far, I've looked into using ThreadLocal but I fear that may be dangerous in the future when multiple requests are being processed on the same thread.