Supporting Formatted Text: Gateway Responsibilities

To handle Rich Text Format for outgoing messages, gateways

1. Retrieve only a message's PR_RTF_COMPRESSED property from the message store. The main advantage in retrieving only the PR_RTF_COMPRESSED property is that the message text does not need to be sent between machines if the gateway and the message store exist on different machines.
2. Generate the message text from the formatted text either by calling the RTF library function HrTextFromCompressedRTFStream or, if the message is stored locally, RTFSync. The RTF_SYNC_RTF_CHANGED flag should be set in the call to RTFSync.
3. Make any irreversible modifications to the message text, such as dropping unsupported characters.
4. Ensure that both PR_RTF_IN_SYNC and all of the RTF auxilliary properties are either set or absent.
5. If any modifications were made, call RTFSync with both the RTF_SYNC_RTF_CHANGED and RTF_SYNC_BODY_CHANGED flags set. RTFSync will recalculate the RTF auxilliary properties from the modified text.
6. Make any reversable modifications to the message text, such as inserting attachment placeholders and performing nondestructive code page conversions.
7. Send the message.

To handle Rich Text Format for incoming messages, gateways

1. Reverse any message text modifications that were made directly before the message was sent.
2. Call RTFSync if the message contains both the PR_RTF_COMPRESSED and PR_BODY properties.
3. Update the message in the message store with the PR_RTF_COMPRESSED property if the message contains it; update with the PR_BODY property only if PR_RTF_COMPRESSED is absent.
4. Discard PR_BODY if the message contains both this property and PR_RTF_COMPRESSED.

Gateways call RTFSync to avoid transmitting both the message text and formatted text if the message store is on a different machine. If the gateway is local, it can set both properties and allow the message store to perform the synchronization.