Configurable connection and advertising parameters

[Uvis-Acurable]

1. Currently Bless server does not allow configuring advertising packet data such as manufacturer data or data service data, however Core Bluetooth allows it.

2. Allow changing minimum and maximum connection interval values

[oclyke]

Anyone working on this? I am interested in helping out.

[kevincar]

@oclyke Please do! Pull requests are very helpful to tackle some of the issues.

[rwkeane]

I have an in-progress change to support adding manufacturer_data - though it would be pretty easy for someone to add a follow-up to make service_data work as well (it would be pretty much copy-paste of my code), it's just not needed for my use case. Planning to put up a PR once I solve an ongoing issue related to my machine's Bluetooth adapter.

Will be Linux only for the moment (I don't have an Apple device to test with, but the code to make it work is only a few lines. Windows is too crazy for me to figure out), but I hope to circle back and add other OSs soon to expand support for the app I am writing.

[cangiant]

@Uvis-Acurable where did you see that Core Bluetooth supports changing of manufacturer data? From their API,

advertisementData

    An optional dictionary containing the data you want to advertise. The peripheral manager only supports two keys: [CBAdvertisementDataLocalNameKey](https://developer.apple.com/documentation/corebluetooth/cbadvertisementdatalocalnamekey) and [CBAdvertisementDataServiceUUIDsKey](https://developer.apple.com/documentation/corebluetooth/cbadvertisementdataserviceuuidskey).

It's not possible to change the manufacturer data in macOS.

[Uvis-Acurable]

It's under CBPeripheralManager class. You get the following:

CBAdvertisementDataLocalNameKey -	A string containing the local name of the peripheral
CBAdvertisementDataServiceUUIDsKey - An array of service UUIDs to advertise.
CBAdvertisementDataManufacturerDataKey - Manufacturer-specific data.
CBAdvertisementDataServiceDataKey - Service-specific data.
CBAdvertisementDataOverflowServiceUUIDsKey - UUIDs that do not fit in the main advertising packet.
CBAdvertisementDataTxPowerLevelKey - The transmit power level.
CBAdvertisementDataIsConnectable - Indicates if the advertising device is connectable.

[Uvis-Acurable]

It should still be possible to update this. As an example:

let newAdvertisementData: [String: Any] = [
    CBAdvertisementDataLocalNameKey: "NewName",
    CBAdvertisementDataServiceUUIDsKey: [CBUUID(string: "180A")]
]

peripheralManager.startAdvertising(newAdvertisementData)

[cangiant]

I guess the fact that it's there does not mean it can both be written and read. I think you can only access what's already there. I tried to set it and it was not doing anything.
And, as I pasted above, "the peripheral manager only supports two keys" (name and service uuidskey).
It makes sense from apple's perspective, not to allow change of manufacturer data done from one of their devices.

[Uvis-Acurable]

OK, Apple has locked it, so no writes can be done. With BlueZ would work I suppose that would require rewriting the driver as it's based on Apples CoreBluetooth