69 lines
1.8 KiB
Go
69 lines
1.8 KiB
Go
package ircv3
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import (
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"context"
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)
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type Handler interface {
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Handle(ctx context.Context, w MessageWriter, m *Message)
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}
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type HandlerFunc func(ctx context.Context, w MessageWriter, m *Message)
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func (h HandlerFunc) Handle(ctx context.Context, w MessageWriter, m *Message) {
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h(ctx, w, m)
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}
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type MessageWriter interface {
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WriteMessage(msg *Message) error
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}
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type Middleware func(next Handler) Handler
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type Middlewares []func(Handler) Handler
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// Chain returns a Middlewares type from a slice of middleware handlers.
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func Chain(middlewares ...func(Handler) Handler) Middlewares {
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return Middlewares(middlewares)
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}
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// Handler builds and returns a http.Handler from the chain of middlewares,
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// with `h http.Handler` as the final handler.
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func (mws Middlewares) Handler(h Handler) Handler {
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return &ChainHandler{h, chain(mws, h), mws}
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}
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// HandlerFunc builds and returns a http.Handler from the chain of middlewares,
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// with `h http.Handler` as the final handler.
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func (mws Middlewares) HandlerFunc(h HandlerFunc) Handler {
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return &ChainHandler{h, chain(mws, h), mws}
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}
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// ChainHandler is a http.Handler with support for handler composition and
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// execution.
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type ChainHandler struct {
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Endpoint Handler
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chain Handler
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Middlewares Middlewares
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}
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func (c *ChainHandler) Handle(ctx context.Context, w MessageWriter, m *Message) {
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c.chain.Handle(ctx, w, m)
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}
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// chain builds a http.Handler composed of an inline middleware stack and endpoint
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// handler in the order they are passed.
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func chain(middlewares []func(Handler) Handler, endpoint Handler) Handler {
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// Return ahead of time if there aren't any middlewares for the chain
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if len(middlewares) == 0 {
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return endpoint
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}
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// Wrap the end handler with the middleware chain
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h := middlewares[len(middlewares)-1](endpoint)
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for i := len(middlewares) - 2; i >= 0; i-- {
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h = middlewares[i](h)
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}
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return h
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}
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