vendor: github.com/abbot/go-http-auth for #1802

vendor/github.com/abbot/go-http-auth/auth.go

@@ -0,0 +1,109 @@
+// 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)
+	})
+}