stomp.nim
changeset 0 52e9f64937bf
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/stomp.nim	Thu Mar 24 18:56:42 2016 -0700
@@ -0,0 +1,847 @@
+# vim: set et nosta sw=4 ts=4 ft=nim : 
+#
+# Copyright (c) 2016, Mahlon E. Smith <mahlon@martini.nu>
+# All rights reserved.
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+#     * Redistributions of source code must retain the above copyright
+#       notice, this list of conditions and the following disclaimer.
+#
+#     * Redistributions in binary form must reproduce the above copyright
+#       notice, this list of conditions and the following disclaimer in the
+#       documentation and/or other materials provided with the distribution.
+#
+#     * Neither the name of Mahlon E. Smith nor the names of his
+#       contributors may be used to endorse or promote products derived
+#       from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
+# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
+# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+## Overview
+## ============
+##
+## This is a pure-nim client library for interacting with Stomp 1.2
+## compliant messaging brokers.
+##
+## https://stomp.github.io/stomp-specification-1.2.html
+##
+## Stomp is a simple protocol for message passing between clients, using a central
+## broker.  It is a subset of other more elaborate protocols (like AMQP), supporting
+## only the most used features of common brokers.
+##
+## Because this library is pure-nim, there are no external dependencies.  If you
+## can compile a nim binary, you can participate in advanced messaging between processes.
+##
+## A list of broker support for Stomp can be found here:
+## https://stomp.github.io/implementations.html.
+##
+## This library has been tested with recent versions of RabbitMQ.  If it
+## works for you with another broker, please let the author know.
+##
+##
+## Protocol support
+## ----------------
+## 
+## Examples
+## =========
+##
+## Connecting with SSL
+## -------------------
+##
+
+import
+    strutils,
+    nativesockets,
+    net,
+    os,
+    times,
+    uri
+
+const
+    VERSION = "0.1.0" ## The current program version.
+    NULL    = "\x00"  ## The NULL character.
+    CR      = "\r"    ## The carriage return character.
+    CRLF    = "\r\n"  ## Carriage return + Line feed (EOL).
+
+
+# Exceptions
+#
+type
+    StompError* = object of ValueError ## A generic Stomp error state.
+
+    StompClient* = ref object of RootObj ## An object that represents a connection to a Stomp compatible server.
+        socket:         Socket ## The socket object attached to this client.
+        connected*:     bool ## Is the client currently connected?
+        uri*:           Uri ## The URI used to instantiate this client.
+        username:       string ## The Stomp server user, if any.
+        password:       string ## The Stomp server password, if any.
+        host:           string ## The host or IP address to connect to.
+        port:           Port ## Optional, if Stomp is on a non-default port.
+        vhost:          string ## Parsed from the URI path, a Stomp "virtual host".
+        timeout*:       int ## Global socket timeout.
+        last_msgtime*:  Time ## Timestamp of last seen server message.
+        options:        tuple[ heartbeat: int ] ## Any supported client options, derived from the URI query string.
+        subscriptions*: seq[ string ] ## Registered client subscriptions. Array position is the ID.
+        transactions*:  seq[ string ] ## Any currently open transactions.
+        serverinfo:     seq[ tuple[name: string, value: string] ] ## Server metadata, populated upon a successful connection.
+
+        connected_callback*:        proc ( client: StompClient, response: StompResponse ): void
+        error_callback*:            proc ( client: StompClient, response: StompResponse ): void
+        heartbeat_callback*:        proc ( client: StompClient, response: StompResponse ): void
+        message_callback*:          proc ( client: StompClient, response: StompResponse ): void
+        missed_heartbeat_callback*: proc ( client: StompClient ): void
+        receipt_callback*:          proc ( client: StompClient, response: StompResponse ): void
+
+    StompResponse* = ref object of RootObj ## A parsed packet from a Stomp server.
+        headers:  seq[ tuple[name: string, value: string] ] ## Any headers in the response.  Access with the `[]` proc.
+        frame*:   string ## The Stomp frame type.
+        payload*: string ## The message body, if any.
+
+
+# convenience
+proc printf( formatstr: cstring ) {.header: "<stdio.h>", varargs.}
+
+
+#-------------------------------------------------------------------
+# R E S P O N S E
+#-------------------------------------------------------------------
+
+proc is_eol( s: string ): bool =
+    ## Convenience method, returns **true** if string is a Stomp EOF.
+    return s == CR or s == CRLF
+
+
+proc parse_headers( response: StompResponse, c: StompClient ): int =
+    ## Parse response headers from a stream.
+    ## Returns the content length of the response body, or 0.
+    result = 0
+    var line = ""
+
+    c.socket.readline( line, c.timeout )
+    while not line.is_eol:
+        if defined( debug ): printf " <-- %s\n", line
+        var header = line.split( ":" )
+        if header.len < 2: break
+        response.headers.add( (header[0], header[1]) )
+        if cmpIgnoreCase( header[0], "content-length" ) == 0: result = header[1].parse_int
+        c.socket.readline( line, c.timeout )
+
+
+proc parse_payload( response: StompResponse, c: StompClient, bodylength = 0 ): void =
+    ## Parse message payload from a stream.
+    let bufsize = 8192
+    var
+        buf  = ""
+        data = ""
+
+
+    # If we already know the length of the body, just perform a buffered read.
+    #
+    if bodylength > 0:
+        var
+            readtotal = 0
+            readamt   = 0
+            remaining = 0
+
+        while readtotal != bodylength:
+            remaining = bodylength - readtotal
+
+            if remaining < bufsize:
+                readamt = remaining
+            else:
+                readamt = bufsize
+
+            buf = newString( readamt )
+            readtotal = readtotal + c.socket.recv( buf, readamt, c.timeout )
+            data = data & buf
+
+        # Eat the NULL terminator.
+        discard c.socket.recv( buf, 1, c.timeout )
+
+    # Inefficient path.
+    #
+    else:
+        while buf != NULL:
+            discard c.socket.recv( buf, 1, c.timeout )
+            data = data & buf
+
+    response.payload = data
+
+
+proc newStompResponse( c: StompClient ): StompResponse =
+    ## Initialize a response object, which parses and contains
+    ## the Stomp headers and any additional important data from
+    ## the broker socket.
+    new( result )
+    result.headers = @[]
+
+    # Get the frame type, record last seen server activity time.
+    #
+    var line = ""
+    c.socket.readline( line, c.timeout )
+    c.last_msgtime = get_time()
+
+    # Heartbeat packets (empties.)
+    #
+    # This could -also- parse optional EOLs from the prior
+    # message (after the NULL separator), but since it is a no-op,
+    # this seems harmless.
+    #
+    if line.is_eol:
+        result.frame = "HEARTBEAT"
+        return result
+
+    # All other types.
+    #
+    result.frame = line
+    if defined( debug ):
+        printf " <-- %s\n", line
+
+    # Parse headers and body.
+    #
+    var length = result.parse_headers( c )
+    if result.frame == "MESSAGE" or result.frame == "ERROR":
+        result.parse_payload( c, length )
+
+    # If the response -could- have a body, the NULL has already
+    # been removed from the stream while we checked for one.
+    #
+    if result.payload.len > 0:
+        if result.payload == NULL: # We checked for a body, but there was none.
+            result.payload = nil
+            if defined( debug ): printf " <--\n <-- ^@\n\n"
+        else:
+            if defined( debug ): printf " <--\n <-- (payload)^@\n\n"
+
+    # Otherwise, pop off the NULL terminator now.
+    #
+    else:
+        discard c.socket.recv( line, 1, c.timeout )
+        if defined( debug ): printf " <--\n <-- ^@\n\n"
+
+
+proc `$`*( r: StompResponse ): string =
+    ## Represent a Stomp response as a string.
+    result = r.frame & ": " & $r.headers
+
+
+proc `[]`*( response: StompResponse, key: string ): string =
+    ## Get a specific header from a Stomp response.
+    for header in response.headers:
+        if cmpIgnoreCase( key, header.name ) == 0:
+            return header.value
+    return nil
+
+
+#-------------------------------------------------------------------
+# C A L L B A C K S
+#-------------------------------------------------------------------
+
+proc default_error_callback( c: StompClient, response: StompResponse ) =
+    ## Something bad happened.  Disconnect from the server, build an error message,
+    ## and raise an exception.
+    c.socket.close
+    c.connected = false
+
+    var detail = response.payload
+    var msg    = response[ "message" ]
+    if $detail[ ^1 ] == "\n": detail = detail[ 0 .. ^2 ] # chomp
+
+    if detail.len > 0: msg = msg & " (" & detail & ")"
+    raise newException( StompError, "ERROR: " & msg )
+
+
+proc default_missed_heartbeat_callback( c: StompClient ) =
+    ## Timeout while connected to the broker.
+    c.socket.close
+    c.connected = false
+    raise newException( StompError, "Heartbeat timeout.  Last activity: " & $c.last_msgtime )
+
+
+
+#-------------------------------------------------------------------
+# C L I E N T
+#-------------------------------------------------------------------
+
+proc newStompClient*( s: Socket, uri: string ): StompClient =
+    ## Create a new Stomp client object from a preexisting **socket**,
+    ## and a stomp **URI** string.
+    ##
+    ## .. code-block:: nim
+    ##
+    ##    var socket = newSocket()
+    ##    var stomp  = newStompClient( socket, "stomp://test:test@example.com/%2Fvhost" )
+    ##
+    ## or if connecting with SSL, when compiled with -d:ssl:
+    ##
+    ## .. code-block:: nim
+    ##
+    ##    var socket = newSocket()
+    ##    let sslContext = newContext( verifyMode = CVerifyNone )
+    ##    sslContext.wrapSocket(socket)
+    ##    var stomp = newStompClient( socket, "stomp+ssl://test:test@example.com/%2Fvhost" )
+    ##
+    new( result )
+    result.socket        = s
+    result.connected     = false
+    result.uri           = parse_uri( uri )
+    result.username      = result.uri.username
+    result.password      = result.uri.password
+    result.host          = result.uri.hostname
+    result.vhost         = result.uri.path
+    result.timeout       = 500
+    result.subscriptions = @[]
+    result.transactions  = @[]
+
+    # Parse any supported options in the query string.
+    #
+    for pairs in result.uri.query.split( '&' ):
+        let opt = pairs.split( '=' )
+        try:
+            case opt[0]:
+                of "heartbeat":
+                    result.options.heartbeat = opt[1].parse_int
+                else:
+                    discard
+        except IndexError, ValueError:
+            discard
+
+    # Set default STOMP port if otherwise unset.
+    #
+    if not result.uri.scheme.contains( "stomp" ):
+        raise newException( StompError, "Unknown scheme: " & result.uri.scheme  )
+    var port: int
+    if result.uri.port == "":
+        if result.uri.scheme.contains( "+ssl" ):
+            port = 61614
+        else:
+            port = 61613
+    else:
+        port = result.uri.port.parse_int
+
+    result.port = Port( port )
+
+    # Decode URI encoded slashes for vhosts.
+    result.vhost = result.vhost.replace( "%2f", "/" ).replace( "%2F", "/" ).replace( "//", "/" )
+
+
+proc socksend( c: StompClient, data: string ): void =
+    ## Send data on the connected socket with optional debug output.
+    c.socket.send( data )
+    if defined( debug ): printf " --> %s", data
+
+
+proc finmsg( c: StompClient ): void =
+    ## Send data on the connected socket with optional debug output.
+    c.socket.send( CRLF & NULL & CRLF )
+    if defined( debug ): printf " --> \n --> ^@\n\n"
+
+
+proc `[]`*( c: StompClient, key: string ): string =
+    ## Get a specific value from the server metadata, set during the initial connection.
+    if not c.connected: return nil
+    for header in c.serverinfo:
+        if cmpIgnoreCase( key, header.name ) == 0:
+            return header.value
+    return nil
+
+
+proc `$`*( c: StompClient ): string =
+    ## Represent the stomp client as a string, after masking the password.
+    let uri = ( $c.uri ).replace( ":" & c.uri.password & "@", "@" )
+    result = "(NimStomp v" & VERSION & ( if c.connected: " connected" else: " not connected" ) & " to " & uri
+    if not c[ "server" ].is_nil:
+        result.add( " --> " & c["server"] )
+    result.add( ")" )
+
+
+proc connect*( c: StompClient ): void =
+    ## Establish a connection to the Stomp server.
+    if c.connected: return
+
+    var headers: seq[ tuple[name: string, value: string] ] = @[]
+    headers.add( ("accept-version", "1.2") )
+
+    # Stomp 1.2 requires the Host: header.  Use the path as a vhost if
+    # supplied, otherwise use the hostname of the server.
+    #
+    if c.vhost != "":
+        headers.add( ("host", c.vhost) )
+    else:
+        headers.add( ("host", c.host) )
+
+    if c.username != "": headers.add( ("login", c.username) )
+    if c.password != "": headers.add( ("passcode", c.password) )
+    if c.options.heartbeat > 0:
+        let heartbeat = c.options.heartbeat * 1000
+        headers.add( ("heart-beat", "0," & $heartbeat) )
+
+    # Connect the socket and send the headers off.
+    #
+    c.socket.connect( c.host, c.port )
+    c.socksend( "CONNECT" & CRLF )
+    for header in headers:
+        c.socksend( header.name & ":" & header.value & CRLF )
+    c.finmsg
+
+    # Retreive and copy server metadata to client object.
+    #
+    var response = newStompResponse( c )
+    c.serverinfo = response.headers
+
+    if response.frame != "CONNECTED":
+        if not isNil( c.error_callback ):
+            c.error_callback( c, response )
+        else:
+            c.default_error_callback( response )
+    else:
+        c.connected = true
+        if not isNil( c.connected_callback ):
+            c.connected_callback( c, response )
+
+
+proc disconnect*( c: StompClient ): void =
+    ## Break down the connection to the Stomp server nicely.
+    if not c.connected: return
+    c.socksend( "DISCONNECT" & CRLF )
+    c.finmsg
+
+    c.socket.close
+    c.connected = false
+
+
+proc add_txn( c: StompClient ): void =
+    ## Add a transaction header if there is only a single open txn.
+    if c.transactions.len != 1: return
+    c.socksend( "transaction:" & c.transactions[0] & CRLF )
+
+
+proc send*( c: StompClient,
+            destination: string,
+            message:     string = nil,
+            contenttype: string = nil,
+            headers:     seq[ tuple[name: string, value: string] ] = @[] ): void =
+    ## Send a **message** to **destination**.
+    ##
+    ## A Content-Length header is automatically and always included.
+    ## A **contenttype** is optional, but strongly recommended.
+    ##
+    ## Additionally, a transaction ID is automatically added if there is only
+    ## one transaction active.  If you need to attach this message to a particular
+    ## transaction ID, you'll need to add it yourself with the user defined
+    ## **headers**.
+
+    if not c.connected: raise newException( StompError, "Client is not connected." )
+    c.socksend( "SEND" & CRLF )
+    c.socksend( "destination:" & destination & CRLF )
+    c.socksend( "content-length:" & $message.len & CRLF )
+    if not contenttype.is_nil: c.socksend( "content-type:" & contenttype & CRLF )
+
+    # Add custom headers.  Add transaction header if one isn't manually
+    # present (and a transaction is open.)
+    #
+    var txn_seen = false
+    for header in headers:
+        if header.name == "transaction": txn_seen = true
+        c.socksend( header.name & ":" & header.value & CRLF )
+    if not txn_seen: c.add_txn
+
+    if message.is_nil:
+        c.finmsg
+    else:
+        c.socket.send( CRLF & message & NULL )
+        if defined( debug ): printf " -->\n --> (payload)^@\n\n"
+
+
+proc subscribe*( c: StompClient,
+            destination: string,
+            ack        = "auto",
+            headers:     seq[ tuple[name: string, value: string] ] = @[] ): void =
+    ## Subscribe to messages at **destination**.
+    ##
+    ## Setting **ack** to "client" or "client-individual" enables client ACK/NACK mode.
+    ## In this mode, incoming messages aren't considered processed by
+    ## the server unless they receive ACK.  By default, the server
+    ## considers the message processed if a client simply accepts it.
+    ##
+    ## You may optionally add any additional **headers** the server may support.
+
+    if not c.connected: raise newException( StompError, "Client is not connected." )
+    c.socksend( "SUBSCRIBE" & CRLF )
+    c.socksend( "destination:" & destination & CRLF )
+    c.socksend( "id:" & $c.subscriptions.len & CRLF )
+    if ack == "client" or ack == "client-individual":
+        c.socksend( "ack:" & ack & CRLF )
+    else:
+        if ack != "auto": raise newException( StompError, "Unknown ack type: " & ack )
+
+    for header in headers:
+        c.socksend( header.name & ":" & header.value & CRLF )
+    c.finmsg
+    c.subscriptions.add( destination )
+
+
+proc unsubscribe*( c: StompClient,
+            destination: string,
+            headers:     seq[ tuple[name: string, value: string] ] = @[] ): void =
+    ## Unsubscribe from messages at **destination**.
+    ## You may optionally add any additional **headers** the server may support.
+
+    if not c.connected: raise newException( StompError, "Client is not connected." )
+    var
+        sub_id: int
+        i = 0
+
+    # Find the ID of the subscription.
+    #
+    for sub in c.subscriptions:
+        if sub == destination:
+            sub_id = i
+            break
+        i = i + 1
+
+    c.socksend( "UNSUBSCRIBE" & CRLF )
+    c.socksend( "id:" & $sub_id & CRLF )
+    for header in headers:
+        c.socksend( header.name & ":" & header.value & CRLF )
+    c.finmsg
+    c.subscriptions[ sub_id ] = ""
+
+
+proc begin*( c: StompClient, txn: string ): void =
+    ## Begin a new transaction on the broker, using **txn** as the identifier.
+    c.socksend( "BEGIN" & CRLF )
+    c.socksend( "transaction:" & txn & CRLF )
+    c.finmsg
+    c.transactions.add( txn )
+
+
+proc commit*( c: StompClient, txn: string = nil ): void =
+    ## Finish a specific transaction **txn**, or the most current if unspecified.
+    var transaction = txn
+    if transaction.is_nil and c.transactions.len > 0: transaction = c.transactions.pop
+    if transaction.is_nil: return
+
+    c.socksend( "COMMIT" & CRLF )
+    c.socksend( "transaction:" & transaction & CRLF )
+    c.finmsg
+
+    # Remove the transaction from the queue.
+    #
+    var new_transactions: seq[ string ] = @[]
+    for txn in c.transactions:
+        if txn != transaction: new_transactions.add( txn )
+    c.transactions = new_transactions
+
+
+proc abort*( c: StompClient, txn: string = nil ): void =
+    ## Cancel a specific transaction **txn**, or the most current if unspecified.
+    var transaction = txn
+    if transaction.is_nil and c.transactions.len > 0: transaction = c.transactions.pop
+    if transaction.is_nil: return
+
+    c.socksend( "ABORT" & CRLF )
+    c.socksend( "transaction:" & transaction & CRLF )
+    c.finmsg
+
+    # Remove the transaction from the queue.
+    #
+    var new_transactions: seq[ string ] = @[]
+    for txn in c.transactions:
+        if txn != transaction: new_transactions.add( txn )
+    c.transactions = new_transactions
+
+
+proc ack*( c: StompClient, id: string, transaction: string = nil ): void =
+    ## Acknowledge message **id**.  Optionally, attach this acknowledgement
+    ## to a specific **transaction** -- if there's only one active, it is
+    ## added automatically.
+    c.socksend( "ACK" & CRLF )
+    c.socksend( "id:" & id & CRLF )
+    if not transaction.is_nil:
+        c.socksend( "transaction:" & transaction & CRLF )
+    else:
+        c.add_txn
+    c.finmsg
+
+
+proc nack*( c: StompClient, id: string, transaction: string = nil ): void =
+    ## Reject message **id**.  Optionally, attach this rejection to a
+    ## specific **transaction** -- if there's only one active, it is
+    ## added automatically.
+    ##
+    ## Subscribe to a queue with ACK mode enabled, and reject the message
+    ## on error:
+    ##
+    ## .. code-block:: nim
+    ##    
+    ##  stomp.subscribe( "/queue/test", "client-individual" )
+    ##  FIXME: attach procs
+    ##  stomp.wait_for_messages
+    ##
+    c.socksend( "NACK" & CRLF )
+    c.socksend( "id:" & id & CRLF )
+    if not transaction.is_nil:
+        c.socksend( "transaction:" & transaction & CRLF )
+    else:
+        c.add_txn
+    c.finmsg
+
+
+proc wait_for_messages*( c: StompClient, loop=true ) =
+    ## Enter a blocking select loop, dispatching to the appropriate proc
+    ## for the received message type.   Return after a single message
+    ## is received if **loop** is set to **false**.
+
+    if not c.connected: raise newException( StompError, "Client is not connected." )
+
+    while true:
+        var
+            timeout: int
+            fds = @[ c.socket.get_fd ]
+
+        # Check for missed heartbeats, with an additional second
+        # of wiggle-room.
+        #
+        if c.options.heartbeat > 0:
+             timeout = ( c.options.heartbeat + 1 ) * 1000
+        else:
+            timeout = -1
+
+        if select( fds, timeout ) == 0: # timeout, only happens if heartbeating missed
+            if not isNil( c.missed_heartbeat_callback ):
+                c.missed_heartbeat_callback( c )
+            else:
+                c.default_missed_heartbeat_callback
+            if loop: continue else: break
+
+        let response = newStompResponse( c )
+        case response.frame:
+
+            of "HEARTBEAT":
+                if not isNil( c.heartbeat_callback ):
+                    c.heartbeat_callback( c, response )
+                continue
+
+            of "RECEIPT":
+                if not isNil( c.receipt_callback ):
+                    c.receipt_callback( c, response )
+
+            of "MESSAGE":
+                if not isNil( c.message_callback ):
+                    c.message_callback( c, response )
+
+            of "ERROR":
+                if not isNil( c.error_callback ):
+                    c.error_callback( c, response )
+                else:
+                    c.default_error_callback( response )
+
+            else:
+                if defined( debug ):
+                    echo "Strange broker frame: " & response.repr
+
+        if not loop: break
+
+
+
+#-------------------------------------------------------------------
+# T E S T S
+#-------------------------------------------------------------------
+
+# Functional (rather than unit) tests.  Requires a Stomp compatible broker.
+# This was tested against RabbitMQ 3.5.3 and 3.6.0.
+# 3.6.0 was -so- much faster.
+#
+# First start up a message receiver:
+#   ./stomp receiver [stomp-uri] [subscription-destination]
+#
+# then run another process, to publish stuff:
+#   ./stomp publisher [stomp-uri] [publish-destination]
+#
+# An example with an AMQP "direct" exchange, and an exclusive queue:
+#   ./stomp publisher stomp://test:test@localhost/?heartbeat=10 /exchange/test
+#   ./stomp receiver  stomp://test:test@localhost/?heartbeat=10 /exchange/test
+#
+# Then just let 'er run.
+#
+# You can also run a nieve benchmark (deliveries/sec):
+#
+#   ./stomp benchmark stomp://test:test@localhost/ /exchange/test
+#
+# It will set messages to require acknowledgement, and nack everything, causing
+# a delivery loop for 10 seconds.
+#
+when isMainModule:
+    let expected = 8
+    var
+        socket   = newSocket()
+        messages: seq[ StompResponse ] = @[]
+
+    if paramCount() != 3: quit "See source comments for how to run functional tests."
+
+    var stomp = newStompClient( socket, paramStr(2) )
+    stomp.connect
+    echo stomp
+
+    case paramStr(1):
+
+        of "benchmark":
+            echo "* Running for 10 seconds.  Compile with -d:debug to see the Stomp conversation."
+            var count = 0
+            var start = get_time()
+
+            proc incr( c: StompClient, r: StompResponse ) =
+                let id = r["ack"]
+                count = count + 1
+                c.nack( id )
+
+            stomp.message_callback = incr
+            stomp.subscribe( paramStr(3), "client" )
+            stomp.send( paramStr(3), "hi." )
+            while get_time() - start < 10:
+                stomp.wait_for_messages( false )
+
+            printf "* Processed %d messages in 10 seconds.\n", count
+            stomp.disconnect
+
+
+        # Store incoming messages, ensure their contents match our expected behavior.
+        #
+        of "receiver":
+            var heartbeats = 0
+            echo "* Waiting on messages from publisher.  Compile with -d:debug to see the Stomp conversation."
+
+            proc receive_message( c: StompClient, r: StompResponse ) =
+                messages.add( r )
+                case r.frame:
+                    of "RECEIPT":
+                        discard
+                    of "MESSAGE":
+                        let body = r.payload
+                        let id   = r[ "ack" ]
+
+            proc seen_heartbeat( c: StompClient, r: StompResponse ) =
+                heartbeats = heartbeats + 1
+
+            stomp.message_callback   = receive_message
+            stomp.receipt_callback   = receive_message
+            stomp.heartbeat_callback = seen_heartbeat
+            stomp.subscribe( paramStr(3) )
+
+            # Populate the messages sequence with the count of expected messages.
+            for i in 1..expected: stomp.wait_for_messages( false )
+
+            # Assertions on the results!
+            #
+            doAssert( messages.len == expected )
+            doAssert( messages[0].payload == nil )
+
+            doAssert( messages[1].payload == "Hello world!" )
+
+            doAssert( messages[2].payload == "Dumb.\n\n" )
+
+            doAssert( messages[3].payload == "Hello again." )
+            doAssert( messages[3][ "content-type" ] == "text/plain" )
+            doAssert( messages[3][ "Content-Type" ] == "text/plain" )
+
+            doAssert( messages[4][ "x-custom" ] == "yum" )
+
+            doAssert( messages[5][ "receipt" ] == "42" )
+
+            doAssert( messages[6].payload == "transaction!" )
+            doAssert( messages[7].payload == "transaction 2" )
+
+            stomp.disconnect
+
+            if heartbeats > 0:
+                printf "* Tests passed! %d heartbeats seen.", heartbeats
+            else:
+                echo "* Tests passed!"
+
+
+        # Publish a variety of messages with various options.
+        # Pause momentarily between sends(), as brokers -might- impose
+        # rate limits and/or message dropping.
+        #
+        of "publisher":
+            echo "* Publishing to receiver.  Compile with -d:debug to see the Stomp conversation."
+
+            # Simple, no frills event.
+            stomp.send( paramStr(3) )
+            sleep 500
+
+            # Event with a body.
+            stomp.send( paramStr(3), "Hello world!" )
+            sleep 500
+
+            # Event that doesn't contain a content-length.
+            # (Note, the broker may elect to add one on your behalf, which is a good thing...
+            # but invalidates this test.)
+            stomp.socksend( "SEND" & CRLF )
+            stomp.socksend( "destination:" & paramStr(3) & CRLF & CRLF )
+            stomp.socksend( "Dumb.\n\n" & NULL )
+            sleep 500
+
+            # Content-Type
+            stomp.send( paramStr(3), "Hello again.", "text/plain" )
+            sleep 500
+
+            # Custom headers.
+            var headers: seq[ tuple[ name: string, value: string ] ] = @[]
+            headers.add( ("x-custom", "yum") )
+            stomp.send( paramStr(3), "Hello again.", "text/plain", headers )
+            sleep 500
+
+            # Receipt requests.
+            proc receive_receipt( c: StompClient, r: StompResponse ) =
+                messages.add( r )
+            headers = @[]
+            headers.add( ("receipt", "42") )
+            stomp.send( paramStr(3), "Hello again.", "text/plain", headers )
+            stomp.receipt_callback = receive_receipt
+            stomp.wait_for_messages( false )
+            doAssert( messages[0]["receipt-id"] == "42" )
+
+            # Aborted transaction.
+            stomp.begin( "test-abort" )
+            for i in 1..3:
+                stomp.send( paramStr(3), "Message: " & $i )
+            stomp.abort
+
+            # Committed transaction.
+            stomp.begin( "test-commit" )
+            stomp.send( paramStr(3), "transaction!" )
+            stomp.commit
+
+            # Mixed transactions.
+            for i in 1..3:
+                headers = @[]
+                headers.add( ("transaction", "test-" & $i ) )
+                stomp.begin( "test-" & $i )
+                stomp.send( paramStr(3), "transaction " & $i, nil, headers )
+                sleep 500
+            stomp.abort( "test-1" )
+            sleep 500
+            stomp.commit( "test-2" )
+            sleep 500
+            stomp.abort( "test-3" )
+            sleep 500
+
+            stomp.disconnect
+            echo "* Tests passed!"
+
+        else:
+            quit "See source comments for how to run functional tests."
+
+