The Store Forward Plugin is an implementation of a Store and Forward system to enable resilient messaging in the event that a client device is disconnected from the main network.
Because of the increased network traffic for this overhead, it's not advised to use this if you are duty cycle limited for your airtime usage nor is it advised to use this for SF12 (Long range but Slow).
* To use / test this you will want at least 3 devices
* * One device will (currently) need be a tbeam v1.0 and tbeamv1.1 configured as a meshtastic router. Other devices with built in PSRAM will be supported at some point.
* * Two others will be regular clients. Nothing special required.
Don't use this on the "Very long range (but slow)" or "Long range (but slower)" channel settings. You're welcome to try and report back, but those channels have a very low bitrate.
* * * store_forward_plugin_enabled - Set this to true to enable the plugin. False to disable the plugin.
* * Optional configuration
* * * store_forward_plugin_records - Set this to the maximum number of records to save. Best to leave this at the default (0) where the plugin will use 2/3 of your device's available PSRAM. This is about 11,000 records.
Currently, no special configuration is required. To request your history sent to you, send the command into the message field "SF". That's it. This will eventually change to make it easier. At the moment, that message will be sent to everyone on the mesh but we'll (eventually) make it easier to use where there'll be a button (or maybe it'll be transparent) and the command isn't sent as a text message to the mesh.
| SF | Send the last few messages I may have missed |
| SFm | Send a 240 byte payload (Used for testing) |
The Store and Forward plugin will only service one client at a time. If a second client requests messages while the S&F is busy, the S&F will send a private message to the second client that they will need to wait.
Story: Carol has been away from the mesh with device turned off. She would like to get a replay of what she has missed. The router will return the messages.
* Carol
* * Packet (Port: STORE_FORWARD_APP)
* * * To: Broadcast (Optionally, direct to router)
* * * StoreAndForward.rr.CLIENT_HISTORY
* Router
* * Packet (Port: STORE_FORWARD_APP)
* * * To: Carol
* * * StoreAndForward.rr.ROUTER_HISTORY
* * * StoreAndForward.history.HistoryMessages = 42 // Router has 42 messages that will be sent to Carol
* * * StoreAndForward.history.Window = 120 // Router searched for messages over the last two hours.
* * * StoreAndForward.history.LastRequest = 0 // Carol has never asked for the history.
* * Packet (Port: TEXT_MESSAGE_APP)
* * * ... a series of 42 text messages
### Request History (No history available)
Story: Carol has been away from the mesh with device turned off. She would like to get a replay of what she has missed but the router indicates there are no messages available.
* Carol
* * Packet (Port: STORE_FORWARD_APP)
* * * To: Broadcast (Optionally, direct to router)
* * * StoreAndForward.rr.CLIENT_HISTORY
* Router
* * Packet (Port: STORE_FORWARD_APP)
* * * To: Carol
* * * StoreAndForward.rr.ROUTER_HISTORY
* * * StoreAndForward.history.HistoryMessages = 0 // Router has no messages to be sent to carol
* * * StoreAndForward.history.Window = 120 // Router searched for messages over the last two hours.
* * * StoreAndForward.history.LastRequest = (timestamp) // Last time carol requested the history
### Store & Forward Router Heartbeat
Story: The Store & Forward Router sends a periodic message onto the network. This allows connected devices to know that a router is in range and listening to received messages. Client will not respond to network but (optionally) indicate to the user that a S&F router is available or not available.
* * * StoreAndForward.heartbeat.Period = 120 // Expect a heartbeat every 2 minutes
* * * StoreAndForward.heartbeat.Secondary = false // If true, this is a secondary "backup" S&F node. Will be (eventually) used for router election in the event there are multiple S&F Routers.
When a message is 'real time', time a message is sent is the same as the time the message was received. In the case the message is delayed, there is no timestamp available for the message.
Where the message is a delayed broadcast, the "To" is *not* a broadcast address but rather the address of the device that requested the messages to be replayed. This is to allow the message to be routed over the mesh network and not displayed in the message screen of other devices.
* Client Interface (Web, Android, Python or iOS when that happens) to request packets be resent.
* Router sends a heartbeat so the client knows there is a router in range.
* support for a mesh to have multiple routers that have the store & forward functionality (for redundancy)
* Add a default channel at about 1.5kbit / sec
* Eventually we could add a "want_store_and_forward" bit to MeshPacket and that could be nicer than whitelists in this plugin. Initially we'd only set that bit in text messages (and any other plugin messages that can cope with this). This change would be backward wire compatible so can add easily later.
* Have a "cool down" period to disallow a client to request the history too often.
* Currently the way we allocate messages in the device code is super inefficient. It always allocates the worst case message size. Really we should dynamically allocate just the # of bytes we need. This would allow many more MeshPackets to be kept in RAM.
