// Package auth is an implementation of HTTP Basic and HTTP Digest authentication.
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package auth
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import (
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"context"
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"net/http"
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)
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// AuthenticatedRequest is passed to AuthenticatedHandlerFunc instead
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// of *http.Request.
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type AuthenticatedRequest struct {
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http.Request
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// Username is the authenticated user name. Current API implies that
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// Username is never empty, which means that authentication is
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// always done before calling the request handler.
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Username string
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}
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// AuthenticatedHandlerFunc is like http.HandlerFunc, but takes
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// AuthenticatedRequest instead of http.Request
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type AuthenticatedHandlerFunc func(http.ResponseWriter, *AuthenticatedRequest)
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// Authenticator wraps an AuthenticatedHandlerFunc with
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// authentication-checking code.
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//
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// Typical Authenticator usage is something like:
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//
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// authenticator := SomeAuthenticator(...)
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// http.HandleFunc("/", authenticator(my_handler))
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//
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// Authenticator wrapper checks the user authentication and calls the
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// wrapped function only after authentication has succeeded. Otherwise,
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// it returns a handler which initiates the authentication procedure.
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type Authenticator func(AuthenticatedHandlerFunc) http.HandlerFunc
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// Info contains authentication information for the request.
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type Info struct {
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// Authenticated is set to true when request was authenticated
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// successfully, i.e. username and password passed in request did
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// pass the check.
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Authenticated bool
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// Username contains a user name passed in the request when
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// Authenticated is true. It's value is undefined if Authenticated
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// is false.
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Username string
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// ResponseHeaders contains extra headers that must be set by server
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// when sending back HTTP response.
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ResponseHeaders http.Header
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}
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// UpdateHeaders updates headers with this Info's ResponseHeaders. It is
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// safe to call this function on nil Info.
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func (i *Info) UpdateHeaders(headers http.Header) {
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if i == nil {
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return
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}
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for k, values := range i.ResponseHeaders {
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for _, v := range values {
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headers.Add(k, v)
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}
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}
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}
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type key int // used for context keys
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var infoKey key
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// AuthenticatorInterface is the interface implemented by BasicAuth
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// and DigestAuth authenticators.
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//
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// Deprecated: this interface is not coherent. New code should define
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// and use your own interfaces with a required subset of authenticator
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// methods.
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type AuthenticatorInterface interface {
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// NewContext returns a new context carrying authentication
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// information extracted from the request.
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NewContext(ctx context.Context, r *http.Request) context.Context
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// Wrap returns an http.HandlerFunc which wraps
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// AuthenticatedHandlerFunc with this authenticator's
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// authentication checks.
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Wrap(AuthenticatedHandlerFunc) http.HandlerFunc
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}
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// FromContext returns authentication information from the context or
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// nil if no such information present.
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func FromContext(ctx context.Context) *Info {
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info, ok := ctx.Value(infoKey).(*Info)
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if !ok {
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return nil
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}
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return info
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}
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// AuthUsernameHeader is the header set by JustCheck functions. It
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// contains an authenticated username (if authentication was
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// successful).
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const AuthUsernameHeader = "X-Authenticated-Username"
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// JustCheck returns a new http.HandlerFunc, which requires
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// authenticator to successfully authenticate a user before calling
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// wrapped http.HandlerFunc.
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func JustCheck(auth AuthenticatorInterface, wrapped http.HandlerFunc) http.HandlerFunc {
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return auth.Wrap(func(w http.ResponseWriter, ar *AuthenticatedRequest) {
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ar.Header.Set(AuthUsernameHeader, ar.Username)
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wrapped(w, &ar.Request)
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})
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}
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