context.go

// Copyright 2015 Afshin Darian. All rights reserved.
// Use of this source code is governed by The MIT License
// that can be found in the LICENSE file.

package bear

import "net/http"

// Context is state of each request.
type Context struct {
	// Params is a map of string keys with string values that is populated
	// by the dynamic URL parameters (if any).
	// Wildcard params are accessed by using an asterisk: Params["*"]
	Params  map[string]string
	handler int
	mux     *Mux
	// Request is the same as the *http.Request that all handlers receive
	// and is referenced in Context for convenience.
	Request *http.Request
	// ResponseWriter is the same as the http.ResponseWriter that all handlers
	// receive and is referenced in Context for convenience.
	ResponseWriter http.ResponseWriter
	state          map[string]interface{}
	tree           *tree
}

// Get allows retrieving a state value (interface{})
func (ctx *Context) Get(key string) interface{} {
	if nil == ctx.state {
		return nil
	}
	return ctx.state[key]
}

// Next calls the next middleware (if any) that was registered as a handler for
// a particular request pattern.
func (ctx *Context) Next() {
	always := len(ctx.mux.always)
	handlers := len(ctx.tree.handlers)
	ctx.handler++
	if always > 0 && ctx.handler < always {
		index := ctx.handler
		ctx.mux.always[index](ctx.ResponseWriter, ctx.Request, ctx)
		return
	}
	if ctx.handler-always < handlers {
		index := ctx.handler - always
		ctx.tree.handlers[index](ctx.ResponseWriter, ctx.Request, ctx)
	}
}

func (ctx *Context) param(key string, value string, capacity int) {
	if nil == ctx.Params {
		ctx.Params = make(map[string]string, capacity)
	}
	ctx.Params[key] = value[:len(value)-1]
}

// Set allows setting an arbitrary value (interface{}) to a string key
// to allow one middleware to pass information to the next.
// It returns a pointer to the current Context to allow chaining.
func (ctx *Context) Set(key string, value interface{}) *Context {
	if nil == ctx.state {
		ctx.state = make(map[string]interface{})
	}
	ctx.state[key] = value
	return ctx
}