# Nearby Connection

Nearby Connections is a high level protocol on top of Bluetooth/Wi-Fi that acts
as a medium-agnostic socket. Devices are able to advertise, scan, and connect
with one another over any shared medium (eg. BT <-> BT).
Once connected, the two devices share a list of all supported mediums and
attempt to upgrade to the one with the highest bandwidth (eg. BT -> Wi-Fi).
The connection is encrypted, reliable, and fully duplex. BYTE, FILE, and STREAM
payloads are all supported and will be chunked & transferred internally and
recombined on the receiving device.
See [Nearby Connections Overview](https://developers.google.com/nearby/connections/overview)
for more information.

# Checkout the source tree

```shell
git clone https://github.com/google/nearby
cd nearby
git submodule update --init --recursive
```

# Building Nearby, Unit Testing and Sample Apps

We support multiple platforms including Linux, iOS & Windows.

## Building for Linux

> **NOTE:** Linux has no mediums implemented.

Currently we support building from source using [bazel](https://bazel.build). Other BUILD system such as cmake may be added later.

### Prerequisites:

1. Bazel
2. clang with support for c++ 17+
3. Openssl libcrypto.so (-lssl;-lcrypto).


To build the Nearby Connection Core library:

```shell
CC=clang CXX=clang++ bazel build -s --check_visibility=false //connections:core  --spawn_strategy=standalone --verbose_failures
```


## Building for macOS and iOS

> **NOTE:** The only medium supported is Wi-Fi LAN.

Currently we support building with [Swift Package Manager](https://www.swift.org/package-manager).

### Prerequisites:

1. Xcode. Available from Apple Store.
2. Google Protobuf Compiler (protoc). If you have [homebrew](https://brew.sh/) installed, you can do `brew install protobuf`.

To build the Nearby Connection library:

```shell
swift build
```

# Supported Mediums

<table>
  <thead>
    <tr>
      <th align="left" colspan="2">Legend</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><ul><li>[x] </li></ul></td>
      <td>Supported.</td>
    </tr>
    <tr>
      <td><ul><li>[ ] </li></ul></td>
      <td>Support is possible, but not implemented.</td>
    </tr>
    <tr>
      <td></td>
      <td>Support is not possible or does not make sense.</td>
    </tr>
  </tbody>
</table>


## Android
| Mediums           | Advertising            | Scanning               | Data                   |
| :---------------- | :--------------------: | :--------------------: | :--------------------: |
| Bluetooth Classic | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| BLE (Fast)        | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |                        |
| BLE (GATT)        | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| BLE (Extended)    | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |                        |
| BLE (L2CAP)       |                        |                        | <ul><li>[x] </li></ul> |
| Wi-Fi LAN         | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| Wi-Fi Hotspot     |                        |                        | <ul><li>[x] </li></ul> |
| Wi-Fi Direct      |                        |                        | <ul><li>[x] </li></ul> |
| Wi-Fi Aware       | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| WebRTC            |                        |                        | <ul><li>[x] </li></ul> |
| NFC               | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| USB               | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| AWDL              |                        |                        |                        |

## ChromeOS
| Mediums           | Advertising            | Scanning               | Data                   |
| :---------------- | :--------------------: | :--------------------: | :--------------------: |
| Bluetooth Classic | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| BLE (Fast)        | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |                        |
| BLE (GATT)        | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> |
| BLE (Extended)    | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> |                        |
| BLE (L2CAP)       |                        |                        |                        |
| Wi-Fi LAN         | <ul><li>[ ] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| Wi-Fi Hotspot     |                        |                        | <ul><li>[ ] </li></ul> |
| Wi-Fi Direct      |                        |                        | <ul><li>[ ] </li></ul> |
| Wi-Fi Aware       |                        |                        |                        |
| WebRTC            |                        |                        | <ul><li>[x] </li></ul> |
| NFC               |                        |                        |                        |
| USB               | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> |
| AWDL              |                        |                        |                        |

## Windows
| Mediums           | Advertising            | Scanning               | Data                   |
| :---------------- | :--------------------: | :--------------------: | :--------------------: |
| Bluetooth Classic |                        | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| BLE (Fast)        | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |                        |
| BLE (GATT)        | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[ ] </li></ul> |
| BLE (Extended)    | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |                        |
| BLE (L2CAP)       |                        |                        |                        |
| Wi-Fi LAN         | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| Wi-Fi Hotspot     |                        |                        | <ul><li>[x] </li></ul> |
| Wi-Fi Direct      |                        |                        | <ul><li>[ ] </li></ul> |
| Wi-Fi Aware       |                        |                        |                        |
| WebRTC            |                        |                        | <ul><li>[ ] </li></ul> |
| NFC               |                        |                        |                        |
| USB               | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> |
| AWDL              |                        |                        |                        |

## iOS/macOS
| Mediums           | Advertising            | Scanning               | Data                   |
| :---------------- | :--------------------: | :--------------------: | :--------------------: |
| Bluetooth Classic |                        | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> |
| BLE (Fast)        | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> |                        |
| BLE (GATT)        | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> |
| BLE (Extended)    |                        | <ul><li>[ ] </li></ul> |                        |
| BLE (L2CAP)       |                        |                        | <ul><li>[ ] </li></ul> |
| Wi-Fi LAN         | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> | <ul><li>[x] </li></ul> |
| Wi-Fi Hotspot     |                        |                        | <ul><li>[ ] </li></ul> |
| Wi-Fi Direct      |                        |                        |                        |
| Wi-Fi Aware       |                        |                        |                        |
| WebRTC            |                        |                        | <ul><li>[ ] </li></ul> |
| NFC               |                        | <ul><li>[ ] </li></ul> |                        |
| USB               |                        |                        |                        |
| AWDL              | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> | <ul><li>[ ] </li></ul> |