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// Package auth is an implementation of HTTP Basic and HTTP Digest authentication.
package auth
import (
"net/http"
"golang.org/x/net/context"
)
/*
Request handlers must take AuthenticatedRequest instead of http.Request
*/
type AuthenticatedRequest struct {
http.Request
/*
Authenticated user name. Current API implies that Username is
never empty, which means that authentication is always done
before calling the request handler.
*/
Username string
}
/*
AuthenticatedHandlerFunc is like http.HandlerFunc, but takes
AuthenticatedRequest instead of http.Request
*/
type AuthenticatedHandlerFunc func(http.ResponseWriter, *AuthenticatedRequest)
/*
Authenticator wraps an AuthenticatedHandlerFunc with
authentication-checking code.
Typical Authenticator usage is something like:
authenticator := SomeAuthenticator(...)
http.HandleFunc("/", authenticator(my_handler))
Authenticator wrapper checks the user authentication and calls the
wrapped function only after authentication has succeeded. Otherwise,
it returns a handler which initiates the authentication procedure.
*/
type Authenticator func(AuthenticatedHandlerFunc) http.HandlerFunc
// Info contains authentication information for the request.
type Info struct {
// Authenticated is set to true when request was authenticated
// successfully, i.e. username and password passed in request did
// pass the check.
Authenticated bool
// Username contains a user name passed in the request when
// Authenticated is true. It's value is undefined if Authenticated
// is false.
Username string
// ResponseHeaders contains extra headers that must be set by server
// when sending back HTTP response.
ResponseHeaders http.Header
}
// UpdateHeaders updates headers with this Info's ResponseHeaders. It is
// safe to call this function on nil Info.
func (i *Info) UpdateHeaders(headers http.Header) {
if i == nil {
return
}
for k, values := range i.ResponseHeaders {
for _, v := range values {
headers.Add(k, v)
}
}
}
type key int // used for context keys
var infoKey key = 0
type AuthenticatorInterface interface {
// NewContext returns a new context carrying authentication
// information extracted from the request.
NewContext(ctx context.Context, r *http.Request) context.Context
// Wrap returns an http.HandlerFunc which wraps
// AuthenticatedHandlerFunc with this authenticator's
// authentication checks.
Wrap(AuthenticatedHandlerFunc) http.HandlerFunc
}
// FromContext returns authentication information from the context or
// nil if no such information present.
func FromContext(ctx context.Context) *Info {
info, ok := ctx.Value(infoKey).(*Info)
if !ok {
return nil
}
return info
}
// AuthUsernameHeader is the header set by JustCheck functions. It
// contains an authenticated username (if authentication was
// successful).
const AuthUsernameHeader = "X-Authenticated-Username"
func JustCheck(auth AuthenticatorInterface, wrapped http.HandlerFunc) http.HandlerFunc {
return auth.Wrap(func(w http.ResponseWriter, ar *AuthenticatedRequest) {
ar.Header.Set(AuthUsernameHeader, ar.Username)
wrapped(w, &ar.Request)
})
}
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