80 lines
2.2 KiB
Markdown
80 lines
2.2 KiB
Markdown
# Streaming API
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Elstat's Streaming API enables clients to receive realtime
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updates from the server.
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Clients can optionally subscribe to certain channels using the
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Streaming API if they don't want to have a lot of overhead.
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## Common payload format
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Payloads can not exceed 256 bytes in size.
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Payloads are JSON encoded.
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```javascript
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{
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"op": ANY_INTEGER
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}
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```
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Data in packets are stored in specific fields, which are described
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for each OP below. They are not stored inside of a `d` object, like Discord's gateway.
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## Error codes
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| Error code | Name |
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|---:|:---|
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|4200|`INVALID_PAYLOAD`|
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|4420|`TOO_MUCH`|
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## OP Codes
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| OP Int | OP Name | Sent/Received by client |
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|--:|:--|:--:|
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|-1|`UNSUBSCRIBE`|Sent|
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|0|`SUBSCRIBE`|Sent|
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|1|`SUBSCRIBED`|Received|
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|2|`UNSUBSCRIBED`|Received|
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|3|`DATA`|Received|
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## OP Payloads
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- `SUBSCRIBE`
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- field: `channels` (`list[str]`), array of channels you want to subscribe to.
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- reply: `SUBSCRIBED` payload.
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- `UNSUBSCRIBE`
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- field: `channels` (`list[str]`), array of channels you want to **un**subscribe from.
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- reply: `UNSUBSCRIBED` payload.
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- `SUBSCRIBED`
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- field: `channels` (`list[str]`), array of channels you *succesfully* subscribed to.
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- `UNSUBSCRIBED`
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- field: `channels` (`list[str]`), array of channels you *succesfully* **un**subscribed from.
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- `DATA`
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- field: `c` (`str`), the channel the data is coming from.
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- data: `d` (`list[any]`), the data coming in from the channel.
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- The first element of `d` is an integer, encoding an UNIX timestamp with millisecond precision.
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- The second element of `d` is described on *`Channel types`*
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## Channel names
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Clients subscribe to channels to receive specific data. Channel names
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are formatted like: `<type>:<name>`
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e.g `status:elixire` and `graph:elixire`
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### Channel types
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- `status` channel
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- Returns a boolean, representing the status of the service
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- `latency` channel
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- Returns an integer, representing the latency of the service, in *milliseconds*.
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## Connection logic
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- Connect a websocket to `/api/streaming`.
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- Send a `SUBSCRIBE` payload, receive `SUBSCRIBED` back
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- Listen to `DATA` payloads and update local state as needed.
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