Source and Connector Map Variables

Each connector type automatically populates certain map variables with metadata about the connection and message. These variables are available in transformers, filters, and scripts.

Source connector map variables

TCP Listener

Variable	Description
remoteAddress	IP address of the sending system
remotePort	Port of the sending system
localAddress	Local IP address
localPort	Local listening port

HTTP Listener

Variable	Description
remoteAddress	IP address of the HTTP client
remotePort	Port of the HTTP client
localAddress	Local IP address
localPort	Local listening port
method	HTTP method (GET, POST, PUT, DELETE)
url	Request URL from the scheme through the path, without the query string
uri	Request path with its query string, or the whole URI when the request line carries an absolute URI
protocol	HTTP protocol version
query	Query string
contextPath	Path portion of the request URL
parameters	MessageParameters object wrapping the query and form parameters. getParameter(name) returns the first value, getParameterList(name) every value, getKeys() the parameter names
headers	MessageHeaders object wrapping the request headers, with header names matched case-insensitively. getHeader(name) returns the first value, getHeaderList(name) every value, getKeys() the header names

File Reader

Variable	Description
originalFilename	Original filename of the file being read
fileDirectory	Directory the file was read from
fileSize	Size of the file in bytes
fileLastModified	Last modified time of the file, in milliseconds since the epoch
pollId	ID of the current poll cycle
pollSequenceId	Sequence number within the current poll
pollComplete	true on the last message in the poll cycle, absent on the others

Database Reader

No automatic source map variables.

Channel Reader

Variable	Description
sourceChannelId	Channel ID of the sending channel
sourceChannelIds	List of source channel IDs (when routed through multiple channels)
sourceMessageId	Message ID from the sending channel
sourceMessageIds	List of source message IDs (when routed through multiple channels)

JMS Listener

No automatic source map variables.

DICOM Listener

Variable	Description
localApplicationEntityTitle	Local AE title
remoteApplicationEntityTitle	Remote AE title
localAddress	Local IP address
localPort	Local listening port
remoteAddress	IP address of the sending DICOM node
remotePort	Port of the sending node
associateACProtocolVersion	ASSOCIATE-AC protocol version
associateACImplClassUID	ASSOCIATE-AC implementation class UID
associateACImplVersionName	ASSOCIATE-AC implementation version name
associateACApplicationContext	ASSOCIATE-AC application context
associateACPresentationContexts	Map of ASSOCIATE-AC presentation contexts
associateRQProtocolVersion	ASSOCIATE-RQ protocol version
associateRQImplClassUID	ASSOCIATE-RQ implementation class UID
associateRQImplVersionName	ASSOCIATE-RQ implementation version name
associateRQApplicationContext	ASSOCIATE-RQ application context
associateRQPresentationContexts	Map of ASSOCIATE-RQ presentation contexts
username	User identity username (if provided)
passcode	User identity passcode (if provided)
userIdentityType	User identity type (if provided)

Web Service Listener

No automatic source map variables.

JavaScript Reader

No automatic variables. The script's return value becomes the message: a string, a RawMessage from com.mirth.connect.server.userutil, or a java.util.List of either. A RawMessage built with a source map carries it into the message; a string return has an empty source map. Returning undefined, null, or an empty string produces no message.

Destination connector map variables

A destination connector writes these into its own connectorMap while it sends, after the destination's filter and transformer have run. They are readable in the destination's response transformer. In the destination's filter or transformer they are still null.

HTTP Sender

Variable	Description
responseStatusLine	HTTP response status line
responseStatusCode	HTTP response status code
responseHeaders	MessageHeaders object wrapping the response headers, with the same methods and case-insensitive matching as the HTTP Listener headers entry

TCP Sender (Server mode)

Variable	Description
localAddress	Local IP address of the server socket
localPort	Local port of the server socket
numberOfClients	Total number of connected clients
successfulSends	Count of successful message sends
allResponses	List of Response objects from each connected client

Accessing map variables

Every preprocessor, filter, transformer and response transformer script sees the maps as the scope variables sourceMap, channelMap, connectorMap and responseMap. They are Java Map objects: .get(key) reads a value and .put(key, value) writes one. The shorthand functions $s(key), $c(key), $co(key) and $r(key) call .get() on the same four maps, and with a second argument they call .put(). A key the connector did not populate returns null.

In a filter or transformer

This runs in a source or destination filter or transformer step on a channel whose source connector is a TCP Listener, which populates remoteAddress and remotePort. sourceMap and channelMap come from the script scope. Storing the value in the channel map keeps it with the message, where the Message Browser shows it.

var remoteAddress = sourceMap.get('remoteAddress');
var remotePort = sourceMap.get('remotePort');
channelMap.put('sender', remoteAddress + ':' + remotePort);

In a response transformer

The HTTP Sender writes responseStatusCode, responseStatusLine and responseHeaders into its connector map while it sends, and the send happens after the destination's filter and transformer have run. The destination's response transformer runs after the send and reads the same connectorMap; in the destination's transformer the key is still null. A value the response transformer puts into channelMap is stored with this destination's message. Whether it reaches the next destination in the chain depends on the queue: the next destination's channel map is copied from this one as soon as this destination finishes its turn in the processing thread. With the queue off, or with Send first on and an empty queue, the send and the response transformer run inside that turn, so the value travels down the chain. A destination that queues the message hands its channel map on before the send, and the value then stays on this destination's message only.

var statusCode = connectorMap.get('responseStatusCode');
channelMap.put('httpStatus', statusCode);

In templates (Velocity)

Destination connector fields that accept Velocity, such as the File Writer's file name and template or the HTTP Sender's URL and content, resolve ${key} against the source map, channel map, connector map and response map of the connector message, in that order, so a later map wins when two hold the same key. This template runs in a File Writer on a channel whose source connector is a File Reader, which populates originalFilename and fileSize. ${originalFilename} has a fallback: when no map holds it, the replacer substitutes the current time in milliseconds followed by .dat. A key that no map holds and that has no fallback is left as the literal ${key} text.

Original file: ${originalFilename}
Size: ${fileSize}

In the postprocessor

The postprocessor runs against the merged message rather than one connector, so its scope holds sourceMap, channelMap and responseMap and no connectorMap. sourceMap and channelMap are read-only there: .put() on either, and $c(key, value), throws UnsupportedOperationException. The postprocessor reads what earlier steps stored; it cannot add to those maps.

Custom map variables

A transformer step stores its own values with .put() on the writable maps. channelMap and connectorMap come from the script scope. DateUtil is com.mirth.connect.server.userutil.DateUtil, imported into every script scope; getCurrentDate(pattern) formats the current time with a SimpleDateFormat pattern.

channelMap.put('processedTimestamp', DateUtil.getCurrentDate('yyyy-MM-dd HH:mm:ss'));
connectorMap.put('customFlag', 'URGENT');

The channel map is copied from the source connector to the first destination of each chain, and from each destination to the next one in its chain, so a later step reads processedTimestamp with channelMap.get('processedTimestamp') or $c('processedTimestamp') and a Velocity field resolves it as ${processedTimestamp}. The connector map belongs to one connector: customFlag is visible only within the connector that wrote it.

INFO

The sourceMap is read-only in every script: sourceMap.put() and $s(key, value) throw UnsupportedOperationException. Use channelMap for values every connector in the channel needs, and connectorMap for values scoped to the current connector.