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package route
import (
"fmt"
"net/http"
"sync"
"github.com/julienschmidt/httprouter"
"golang.org/x/net/context"
)
var (
mtx = sync.RWMutex{}
ctxts = map[*http.Request]context.Context{}
)
// Context returns the context for the request.
func Context(r *http.Request) context.Context {
mtx.RLock()
defer mtx.RUnlock()
return ctxts[r]
}
type param string
// Param returns param p for the context.
func Param(ctx context.Context, p string) string {
return ctx.Value(param(p)).(string)
}
// WithParam returns a new context with param p set to v.
func WithParam(ctx context.Context, p, v string) context.Context {
return context.WithValue(ctx, param(p), v)
}
type contextFn func(r *http.Request) (context.Context, error)
// Router wraps httprouter.Router and adds support for prefixed sub-routers
// and per-request context injections.
type Router struct {
rtr *httprouter.Router
prefix string
ctxFn contextFn
}
// New returns a new Router.
func New(ctxFn contextFn) *Router {
if ctxFn == nil {
ctxFn = func(r *http.Request) (context.Context, error) {
return context.Background(), nil
}
}
return &Router{
rtr: httprouter.New(),
ctxFn: ctxFn,
}
}
// WithPrefix returns a router that prefixes all registered routes with prefix.
func (r *Router) WithPrefix(prefix string) *Router {
return &Router{rtr: r.rtr, prefix: r.prefix + prefix, ctxFn: r.ctxFn}
}
// handle turns a HandlerFunc into an httprouter.Handle.
func (r *Router) handle(h http.HandlerFunc) httprouter.Handle {
return func(w http.ResponseWriter, req *http.Request, params httprouter.Params) {
reqCtx, err := r.ctxFn(req)
if err != nil {
http.Error(w, fmt.Sprintf("Error creating request context: %v", err), http.StatusBadRequest)
return
}
ctx, cancel := context.WithCancel(reqCtx)
defer cancel()
for _, p := range params {
ctx = context.WithValue(ctx, param(p.Key), p.Value)
}
mtx.Lock()
ctxts[req] = ctx
mtx.Unlock()
h(w, req)
mtx.Lock()
delete(ctxts, req)
mtx.Unlock()
}
}
// Get registers a new GET route.
func (r *Router) Get(path string, h http.HandlerFunc) {
r.rtr.GET(r.prefix+path, r.handle(h))
}
// Options registers a new OPTIONS route.
func (r *Router) Options(path string, h http.HandlerFunc) {
r.rtr.OPTIONS(r.prefix+path, r.handle(h))
}
// Del registers a new DELETE route.
func (r *Router) Del(path string, h http.HandlerFunc) {
r.rtr.DELETE(r.prefix+path, r.handle(h))
}
// Put registers a new PUT route.
func (r *Router) Put(path string, h http.HandlerFunc) {
r.rtr.PUT(r.prefix+path, r.handle(h))
}
// Post registers a new POST route.
func (r *Router) Post(path string, h http.HandlerFunc) {
r.rtr.POST(r.prefix+path, r.handle(h))
}
// Redirect takes an absolute path and sends an internal HTTP redirect for it,
// prefixed by the router's path prefix. Note that this method does not include
// functionality for handling relative paths or full URL redirects.
func (r *Router) Redirect(w http.ResponseWriter, req *http.Request, path string, code int) {
http.Redirect(w, req, r.prefix+path, code)
}
// ServeHTTP implements http.Handler.
func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
r.rtr.ServeHTTP(w, req)
}
// FileServe returns a new http.HandlerFunc that serves files from dir.
// Using routes must provide the *filepath parameter.
func FileServe(dir string) http.HandlerFunc {
fs := http.FileServer(http.Dir(dir))
return func(w http.ResponseWriter, r *http.Request) {
r.URL.Path = Param(Context(r), "filepath")
fs.ServeHTTP(w, r)
}
}
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