In previous blog I wrote about publishing a message to a AMQ. The documentation says “ActiveMQ implements a RESTful API to messaging which allows any web capable device to publish or consume messages using a regular HTTP POST or GET.”. In this article I want to share an issue that we have not been able to solve. A HTTP POST of a string “blah” to an Apache AMQ in our hands always adds an extra linefeed character i.e. “blahLF”.
We posted a positional flat file to an AMQ as shown below that does not contain any end of line(EOL) character.
We also used fiddler to confirm that the payload did not have a EOL character. The capture is shown below;
POST http://server01d:8161/api/message/MISC.MAX.DATA?type=queue&clientId=misc_data_biztalk&message_type=7228&message_version=1&branch_number=0&message_length=1268 HTTP/1.1
Content-Type: text/plain; charset=utf-8
Authorization: Basic bRlzY19kYXnotRealRhbGs6cUFUMUpLQ2dZUQ==
User-Agent: Microsoft (R) BizTalk (R) Server 2013 R2
T201701160700102017011620001020170116NTheGarbageseEftpos NTWLPalmerstonNorth NPN19.25 N1 Y Y NNZDN483741……28 N0317N0317 NL A/ARAVENA ARAVENA 000000032d028299NTXN100717 N00N00 NAPPROVED Y N0000030170532858N9030200048573514 Y Y Y Y NSCR200 NPXULETSL_LIVE N895038 N89503801N4640 N146XA N4020618221 N0 NUnknown NJY Y YNZN281 Y Y Y N483741 NContactEMV N250 N3028 N755139225 N20170116NBEAEA6171CE0C6FF
When we retrieve the message from the queue using a HTTP GET or programmatically using STOMP we always get a line feed as an EOL character as shown below.
We believe it is the Apache REST API that is adding the additional LF character. Is this normal behaviour for the Apache AMQ REST API? We do not know how the REST API is implemented but if it is using the STOMP protocol it may be normal to add a line feed character. I’m wondering if the STOMP Frame is adding the LF. I don’t know enough about the ActiveMQ to know for sure. See https://svn.apache.org/repos/asf/activemq/stomp/trunk/webgen/src/stomp10/specification.page which says;
We will use the augmented Backus-Naur Form (BNF) used in the HTTP/1.1 (rfc2616) to define a valid stomp frame:
frame-stream = 1*frame
frame = command LF
*( header LF )
[ content ]
*( LF )*( header LF )LF[ content ]NULL*( LF )
In summary we have found that the if we use Apache REST API to POST a message to a AMQ an extra line feed character is appended to the message. Does anyone know whether this is normal behaviour or is there a way to suppress this happening?