mirror of
https://github.com/diamondburned/arikawa.git
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54cadd2f45
This commit refactors the whole package gateway as well as utils/ws
(formerly utils/wsutil) and voice/voicegateway. The new refactor
utilizes a design pattern involving a concurrent loop and an arriving
event channel.
An additional change was made to the way gateway events are typed.
Before, pretty much any type will satisfy a gateway event type, since
the actual type was just interface{}. The new refactor defines a
concrete interface that events can implement:
type Event interface {
Op() OpCode
EventType() EventType
}
Using this interface, the user can easily add custom gateway events
independently of the library without relying on string maps. This adds a
lot of type safety into the library and makes type-switching on Event
types much more reasonable.
Gateway error callbacks are also almost entirely removed in favor of
custom gateway events. A catch-all can easily be added like this:
s.AddHandler(func(err error) {
log.Println("gateway error:, err")
})
102 lines
2.1 KiB
Go
102 lines
2.1 KiB
Go
package ws
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import (
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"io"
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"net/http"
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"github.com/diamondburned/arikawa/v3/utils/json"
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"github.com/pkg/errors"
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)
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// Codec holds the codec states for Websocket implementations to share with the
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// manager. It is used internally in the Websocket and the Connection
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// implementation.
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type Codec struct {
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Unmarshalers OpUnmarshalers
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Headers http.Header
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}
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// NewCodec creates a new default Codec instance.
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func NewCodec(unmarshalers OpUnmarshalers) Codec {
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return Codec{
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Unmarshalers: unmarshalers,
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Headers: http.Header{
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"Accept-Encoding": {"zlib"},
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},
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}
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}
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type codecOp struct {
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Op
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Data json.Raw `json:"d,omitempty"`
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}
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const maxSharedBufferSize = 1 << 15 // 32KB
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// DecodeBuffer boxes a byte slice to provide a shared and thread-unsafe buffer.
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// It is used internally and should only be handled around as an opaque thing.
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type DecodeBuffer struct {
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buf []byte
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}
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// NewDecodeBuffer creates a new preallocated DecodeBuffer.
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func NewDecodeBuffer(cap int) DecodeBuffer {
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if cap > maxSharedBufferSize {
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cap = maxSharedBufferSize
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}
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return DecodeBuffer{
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buf: make([]byte, 0, cap),
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}
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}
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// DecodeFrom reads the given reader and decodes it into an Op.
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//
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// buf is optional.
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func (c Codec) DecodeFrom(r io.Reader, buf *DecodeBuffer) Op {
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var op codecOp
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op.Data = json.Raw(buf.buf)
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if err := json.DecodeStream(r, &op); err != nil {
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return newErrOp(err, "cannot read JSON stream")
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}
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// buf isn't grown from here out. Set it back right now. If Data hasn't been
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// grown, then this will just set buf back to what it was.
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if cap(op.Data) < maxSharedBufferSize {
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buf.buf = op.Data[:0]
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}
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fn := c.Unmarshalers.Lookup(op.Code, op.Type)
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if fn == nil {
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err := UnknownEventError{
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Op: op.Code,
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Type: op.Type,
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}
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return newErrOp(err, "")
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}
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op.Op.Data = fn()
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if err := op.Data.UnmarshalTo(op.Op.Data); err != nil {
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return newErrOp(err, "cannot unmarshal JSON data from gateway")
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}
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return op.Op
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}
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func newErrOp(err error, wrap string) Op {
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if wrap != "" {
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err = errors.Wrap(err, wrap)
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}
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ev := &BackgroundErrorEvent{
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Err: err,
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}
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return Op{
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Code: ev.Op(),
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Type: ev.EventType(),
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Data: ev,
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}
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}
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