NFC

<NFC/> : DataSource

The NFC Datasource is a custom Data Widget that returns nfc data from the device hardware that can be read or written to. Data read by the NFC widget can be bound to, including serialized url attributes.

Restrictions:

• NFC can only be enabled on devices with an NFC reader.

Attributes

Name	Type	Default	Description	Req
id	string	null	The id of the widget used for databinding.
method	string	read	read or write
enabled	bool	true	If the datasource is enabled.
onsuccess	string/Event	null	events the broker will execute upon a successful read or write
onfail	string/Event	null	events the broker will execute if the read or write operation fails
autoexecute	bool	true	if the NFC read/write operation will happen automatically at startup
received	int		The number of NFC tags read.
serial	string		The last NFC tag serial#
payload	string		The last NFC tag text

Data Point

Name	Type	Description
id		The NFC tag serial#
serial		The NFC tag serial#
payload		The NFC tag text

Attributes (Data Specific)

Name	Type	Default	Description	Req
data	List[?]		If the NFC tag text is encoded as a JSON, XML or URL string, it is deserialized, otherwise it is deserialized as a Data Point. Note: URL's do not neeed to be encoded with their fully qualified domain name. To save space, this can be just a query string (with or without the ?). Only the URL's query parameters are deserialized. The resulting item is addressable using standard DOTNOTATION,
queuetype	string	replace	replace, lifo, fifo, append, prepend. Defines the data aggregation strategy for data returned from initial and subsequent calls. replace (default) replaces all data after each subsequent call. lifo (last in first out), fifo (first in first out), append and prepend are all used in conjunction with the maxrecords attribute
maxrecords	int	10000	The maximum size data can grow to. This works in concert with type
root	string		The root tag that defines the repeatable items in data. This can be a nested field. If not specified, the list is segmented by the first repeatable element found in the data set
ttl	int(s,m,h)	0s	Time to Live caches data in the local persistent HIVE database for the period specified. This saves requerying data that changes infrequently
rowcount	int	0	The number of records in data

Methods (Data Specific)

Name	Type	Description
clear()		Clears data. Invoked in any EVENT string using <id>.clear()
add(jsonOrXml, index)	string, int	Deserializes the jsonOrXml string and adds it to the end of data or at position index if specified. Invoked in any EVENT string using <id>.add(jsonOrXml, index)
remove(index)	int	Removes the last item from data or from position index if specified. Invoked in any EVENT string using <id>.remove(index)
reverse()		Reverses data. Invoked in any EVENT string using <id>.reverse()

Events

Name	Type	Description
start()		If method = "read" (default), the NCF starts listening for NCF taps. If method = "write", the NCF starts the write operation using the NCF body. Invoked in any EVENT string using <id>.start()
read()		If method = "read" (default), the NCF starts listening for NCF taps. If method = "write", this operation is ignored. Invoked in any EVENT string using <id>.read()
write(message)	string	If method = "write", the message passed is written to the tag. If the message is null, the NFC body is used. If method = "read", this operation is ignored. Invoked in any EVENT string using <id>.write('some text to write')
stop()		If method = "read" (default), the NCF stops listening for NCF taps. If method = "write", the NCF cancels the write operation. Invoked in any EVENT string using <id>.stop()
clear()		Clears the data bindable. Invoked in any EVENT string using <id>.clear()

Examples

Example #1 (NFC tag body encoded as json)

<NFC id="DB1"/>

<BOX height="80" />
  <TEXT label="Reads: {DB1.received}"  color="black" size="11"/>
  <TEXT label="Last Tag#: {DB1.serial}"  color="black" size="11"/>
  <TEXT label="Last Tag: {DB1.payload}" color="black" size="11"/>

  <!-- NCF tag body is encoded as a valid json string -->
  <!-- { "book" : { "sku" : "1222345-1", "name" : "Tesla, SpaceX, and the Quest for a Fantastic Future", "author" : "Elon Musk" } } -->
  <TEXT label="Read Result: {DB1.data.book.sku}" color="black" size="11"/>
  <TEXT label="Read Result: {DB1.data.book.name}" color="black" size="11"/>
  <TEXT label="Read Result: {DB1.data.book.author}" color="black" size="11"/>
</BOX>

Example #2 (NFC tag body encoded as a url query string)

<NFC id="DB1"/>

<BOX height="80" />
  <TEXT label="Reads: {DB1.received}"  color="black" size="11"/>
  <TEXT label="Last Tag#: {DB1.serial}"  color="black" size="11"/>
  <TEXT label="Last Tag: {DB1.payload}" color="black" size="11"/>

  <!-- NCF tag body is encoded as a url query string -->
  <!-- sku=1222345-1&name=Tesla, SpaceX, and the Quest for a Fantastic Future&author=Elon Musk -->
  <TEXT label="Read Result: {DB1.data.sku}" color="black" size="11"/>
  <TEXT label="Read Result: {DB1.data.name}" color="black" size="11"/>
  <TEXT label="Read Result: {DB1.data.author}" color="black" size="11"/>
</BOX>

Example #3 (NFC tag body is a simple string)

<NFC id="DB1"/>

<BOX height="80" />
  <TEXT label="Reads: {DB1.received}"  color="black" size="11"/>
  <TEXT label="Last Tag#: {DB1.serial}"  color="black" size="11"/>
  <TEXT label="Last Tag: {DB1.payload}" color="black" size="11"/>

  <!-- NCF tag body is encoded as a simple string -->
  <!-- 1222345-1 Tesla, SpaceX, and the Quest for a Fantastic Future Elon Musk -->
  <TEXT label="Read Result: {DB1.data.serial}" color="black" size="11"/>
  <TEXT label="Read Result: {DB1.data.payload}" color="black" size="11"/>
</BOX>

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