69 lines
2.4 KiB
Markdown
69 lines
2.4 KiB
Markdown
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This document describes the expected usage of the library. It mixes *go code* and *prose* to expose what is intended. Also it features expected behavior and some library rules and websocket standards (*e.g. RFC*).
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**Warning**
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> This document is not a documentation, it is used by developers to try to find the best interface for an eased usage by other developers using this library.
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### Handshake
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###### 1. Client HTTP Upgrade Request
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This request is sent by clients which want to open a new websocket connection.
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```http
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GET {uri} HTTP/{httpClientVersion}
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Host: {host}
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Upgrade: websocket
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Connection: Upgrade
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Sec-WebSocket-Key: {clientKey}
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Origin: {origin}
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Sec-WebSocket-Protocol: {clientProtocols[]}
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Sec-WebSocket-Extensions: {clientExtensions[]}
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Sec-WebSocket-Version: {wsVersion}
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```
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**Required fields**
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- `httpClientVersion` at least **1.1**
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- `host` ...
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- `Upgrade: websocket` header (not case sensitive)
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- `Connection: Upgrade` header (not case sensitive)
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- `Origin` for security issues only when from browser (to study)
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- `clientKey` because it is not consistent websocket without it. It must be a 16-byte value base64 encoded
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- `wsVersion` is required to be **13**
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**Optional fields**
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- `clientProtocols[]` if not received is an empty list
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- `clientExtensions[]` if not received is an empty list
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###### 2. Server HTTP Response
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```http
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HTTP/{httpServerVersion} {errorCode} Switching Protocols
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Upgrade: websocket
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Connection: Upgrade
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Sec-WebSocket-Accept: {serverKey}
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Sec-WebSocket-Protocol: {serverProtocol}
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```
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**Required fields**
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- `Upgrade: websocket` header because RFC
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- `Connection: Upgrade` header because RFC
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- `errorCode` is 101 on success, other on failure
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- 400 Bad Request on missing or malformed headers
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- 403 Forbidde on invalid `Origin` or `https`/`wss` required, ...
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- 426 Upgrade Required on invalid `wsVersion`
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- 404 Not Found on unserved or invalid `uri`
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- 1002 Protocol Error if received a non-masked frame
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- `serverKey` but can be invalid if server don't want to accept the connection
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**Optional fields**
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- `serverProtocol` if the server has chosen one
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### Clients management
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- It is required that for a same `host` and `port` pair, a client can only have one connection in a `CONNECTING` state. It means that one client can open a 2nd connection only when the 1st succeeded or failed.
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### Frames
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- RFC requires the server to close all connections which sends a non-masked frame
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