Questions about reprocessing full message attachments and sending attachments between channels

[HScally]

I have a channel where I am storing the entire message as an attachment. Whenever I try to reprocess the message the attachment is gone which causes errors. I have Store Attachments enabled in the channel summary.

• Is it possible to reprocess messages that are fully attached or have attachments?

My second issue is in the same channel the message is sent to another Mirth channel that parses the message. I would like the message to still be attached in the second channel so I set Reattach Attachment to No. This gets send to the downstream channel: ${ATTACH:channel_id:message_id:attachment_id}.

Usually I would use getAttachments(false).get(0).getContentString(); to get the message for parsing, but the array is empty. So I assume I would use the method getAttachment(channelId, messageId, attachmentId, base64Decode).

• Is there a way to easily get all the ids needed from the attachment object ${ATTACH:channel_id:message_id:attachment_id} or do I need convert ${ATTACH:.. to a string and text parse the ids?

[HScally]

I find the cause of the reprocessing issue. In Message storage the field Remove attachment on completion was enabled...

There were three things confusing me about attachments:

1. The attachments were being removed on reprocessing. (See above.)
2. The attachment id, ${ATTACH...}appearing in Raw and Sent. The message will reattach to the next destination or transfer whatever mode is set in the destination if Reattach attachments: is set to Yes. The reattachment will not appear in Mirth, but will happen. The message will asl okeep the attachment on reprocess even though the ids changes.
3. When forwarding a message without reattaching to another channel the attachment will behave the same as 2 and will be reattached in the destination if set to.

I found if you ever need to reattach the message outside the destination you can use the following (for example if it is an ORU with a base64 PDF in the OBX section):

b64 = getAttachments(false).get(0).getContentString();

var raw_msg = connectorMessage.getRawData().replaceAll('\\$\\{ATTACH:.+\\}', b64)

This will return the HL7 with the Base64 again.

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I am not sure how to get Attachment javascript to work right. For example if you have inbound JSON messages and want to attach a key that is Base64. I was able to just do this with RegEx, but I could not parse the JSON message using the javascript attachment mode.