Strings have double quotes the first time

[kwboi]

Hello.
I have a FB field set as a string. When my device first initializes FB, it receives the string within double quotes '"'. For instance, if the value of the string is '1.30', the value received is '"1.30"'. Any subsequent changes made to the field in FB, causes the string to be received without the double quotes. Does anyone know why it's doing this?

Thanks.

[mobizt]

Follow the example how to get the value correctly.

If your value in database is string, the double quotes will be trimmed from first position and last position of the server response payload when process the value.

In your case, string may contain double quotes in the form of escape sequence \" for allowing string processor to read it back correctly which will be seen from the database console like this.
"\"1.30\""

And when it reads out from library, it will show the remaining double quotes in string.
"1.30"

There is nothing mysterious about this.

[kwboi]

Upon further investigation, I've noticed that I handle the read in from FB differently if it's a json (first time) vs. individual changes. Here is a snippet of the code:
switch (oRdStreamFBDO.dataTypeEnum())
{
case fb_esp_rtdb_data_type_json:
{
oJsonFB = oRdStreamFBDO.to();
size_t count = oJsonFB.iteratorBegin();
for (size_t i = 0; i < count; i++)
{
FirebaseJson::IteratorValue value = oJsonFB.valueAt(i);
bValidRead = bReadKeyValue ("/" + value.key, value.value, pstUserChanges);
}
oJsonFB.iteratorEnd(); // required to free the used memory in iteration (node data collection)
}
return bValidRead;

  default:
     return bReadKeyValue (oRdStreamFBDO.dataPath(), oRdStreamFBDO.stringData(), pstUserChanges);
  }

The bReadKeyValue funciton looks like this:
bool bReadKeyValue (String cpKey, String sValue, FB_UserSt *pstUserChanges)
{
if (cpKey == USER_LATEST_FW)
{
Serial.printf ("Version Val: %sA\n", sValue.c_str()); // This comes w/ the double quotes when it's called from a json change
return true;
}

[kwboi]

BTW, I've tried the following change but it didn't work either (i.e., it still had the double quote):
Original: bValidRead = bReadKeyValue ("/" + value.key, value.value, pstUserChanges);
Change: bValidRead = bReadKeyValue ("/" + value.key, value.value.c_str(), pstUserChanges);

[mobizt]

When you iterate through the JSON object, the value is always raw string because it does not parse but list all keys and its value which can be any type which you need to treat it to string by trim the double quotes, cast to number, float, double and Boolean or deserialize it as JSON object and JSON Array later.

That's why you get doble quotes from iterator as it is raw.

See also #458

[kwboi]

The value of value.type is always 1 (FirebaseJson::OBJECT). I'd expect that for the string above it should be 3 (FirebaseJson::STRING). What am I missing?

[mobizt]

The iterator types reported are always JSON object and JSON Array which it's not the type of iterator result (key/value) but the type of object (parent) that its children needed to be iterated.

These objects contain child members that still can iterate values from them.

In case of JSON Array, the iterator result 'value is the array value while result' key will be empty.

As I said the iterator result consist of value and/or key that stores in String variable.

Please remember that the JSON and JSON Array iterations are not parsing or de-serializing, it just extracts the element contents from it as a list of raw string.

For example, the iterator result' of this JSON object will be a single key/value pair that the key is user and value is "bob".

{"user":'bob')

And the iterator result' key is count and the result' value is 789 of this JSON object.

{"count":789)

The iterator result' value can be any type and it is the raw string which you should determine its type yourself.

You may see the double quotes at the first and last characters which means that value type is string.

if you see the curly bracket {} at the first and last characters. It means the iterator result' value type is JSON object and it will continue to iterate into its child members.

If the square bracket [] is at the first and last characters, your value type is JSON Array, and all remaining siblings will be iterated.

If the iterator result' value is true or false, it is Boolean type value.

If it doesn't match all above cases, the iterator result' value type is number.

Let's focus only the content of iterator result' value and parse it for type yourself if you want to process the value from it.