Initial commit

vendor/github.com/gorilla/sessions/sessions.go

@@ -0,0 +1,218 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sessions
+
+import (
+	"context"
+	"encoding/gob"
+	"fmt"
+	"net/http"
+	"time"
+)
+
+// Default flashes key.
+const flashesKey = "_flash"
+
+// Session --------------------------------------------------------------------
+
+// NewSession is called by session stores to create a new session instance.
+func NewSession(store Store, name string) *Session {
+	return &Session{
+		Values:  make(map[interface{}]interface{}),
+		store:   store,
+		name:    name,
+		Options: new(Options),
+	}
+}
+
+// Session stores the values and optional configuration for a session.
+type Session struct {
+	// The ID of the session, generated by stores. It should not be used for
+	// user data.
+	ID string
+	// Values contains the user-data for the session.
+	Values  map[interface{}]interface{}
+	Options *Options
+	IsNew   bool
+	store   Store
+	name    string
+}
+
+// Flashes returns a slice of flash messages from the session.
+//
+// A single variadic argument is accepted, and it is optional: it defines
+// the flash key. If not defined "_flash" is used by default.
+func (s *Session) Flashes(vars ...string) []interface{} {
+	var flashes []interface{}
+	key := flashesKey
+	if len(vars) > 0 {
+		key = vars[0]
+	}
+	if v, ok := s.Values[key]; ok {
+		// Drop the flashes and return it.
+		delete(s.Values, key)
+		flashes = v.([]interface{})
+	}
+	return flashes
+}
+
+// AddFlash adds a flash message to the session.
+//
+// A single variadic argument is accepted, and it is optional: it defines
+// the flash key. If not defined "_flash" is used by default.
+func (s *Session) AddFlash(value interface{}, vars ...string) {
+	key := flashesKey
+	if len(vars) > 0 {
+		key = vars[0]
+	}
+	var flashes []interface{}
+	if v, ok := s.Values[key]; ok {
+		flashes = v.([]interface{})
+	}
+	s.Values[key] = append(flashes, value)
+}
+
+// Save is a convenience method to save this session. It is the same as calling
+// store.Save(request, response, session). You should call Save before writing to
+// the response or returning from the handler.
+func (s *Session) Save(r *http.Request, w http.ResponseWriter) error {
+	return s.store.Save(r, w, s)
+}
+
+// Name returns the name used to register the session.
+func (s *Session) Name() string {
+	return s.name
+}
+
+// Store returns the session store used to register the session.
+func (s *Session) Store() Store {
+	return s.store
+}
+
+// Registry -------------------------------------------------------------------
+
+// sessionInfo stores a session tracked by the registry.
+type sessionInfo struct {
+	s *Session
+	e error
+}
+
+// contextKey is the type used to store the registry in the context.
+type contextKey int
+
+// registryKey is the key used to store the registry in the context.
+const registryKey contextKey = 0
+
+// GetRegistry returns a registry instance for the current request.
+func GetRegistry(r *http.Request) *Registry {
+	var ctx = r.Context()
+	registry := ctx.Value(registryKey)
+	if registry != nil {
+		return registry.(*Registry)
+	}
+	newRegistry := &Registry{
+		request:  r,
+		sessions: make(map[string]sessionInfo),
+	}
+	*r = *r.WithContext(context.WithValue(ctx, registryKey, newRegistry))
+	return newRegistry
+}
+
+// Registry stores sessions used during a request.
+type Registry struct {
+	request  *http.Request
+	sessions map[string]sessionInfo
+}
+
+// Get registers and returns a session for the given name and session store.
+//
+// It returns a new session if there are no sessions registered for the name.
+func (s *Registry) Get(store Store, name string) (session *Session, err error) {
+	if !isCookieNameValid(name) {
+		return nil, fmt.Errorf("sessions: invalid character in cookie name: %s", name)
+	}
+	if info, ok := s.sessions[name]; ok {
+		session, err = info.s, info.e
+	} else {
+		session, err = store.New(s.request, name)
+		session.name = name
+		s.sessions[name] = sessionInfo{s: session, e: err}
+	}
+	session.store = store
+	return
+}
+
+// Save saves all sessions registered for the current request.
+func (s *Registry) Save(w http.ResponseWriter) error {
+	var errMulti MultiError
+	for name, info := range s.sessions {
+		session := info.s
+		if session.store == nil {
+			errMulti = append(errMulti, fmt.Errorf(
+				"sessions: missing store for session %q", name))
+		} else if err := session.store.Save(s.request, w, session); err != nil {
+			errMulti = append(errMulti, fmt.Errorf(
+				"sessions: error saving session %q -- %v", name, err))
+		}
+	}
+	if errMulti != nil {
+		return errMulti
+	}
+	return nil
+}
+
+// Helpers --------------------------------------------------------------------
+
+func init() {
+	gob.Register([]interface{}{})
+}
+
+// Save saves all sessions used during the current request.
+func Save(r *http.Request, w http.ResponseWriter) error {
+	return GetRegistry(r).Save(w)
+}
+
+// NewCookie returns an http.Cookie with the options set. It also sets
+// the Expires field calculated based on the MaxAge value, for Internet
+// Explorer compatibility.
+func NewCookie(name, value string, options *Options) *http.Cookie {
+	cookie := newCookieFromOptions(name, value, options)
+	if options.MaxAge > 0 {
+		d := time.Duration(options.MaxAge) * time.Second
+		cookie.Expires = time.Now().Add(d)
+	} else if options.MaxAge < 0 {
+		// Set it to the past to expire now.
+		cookie.Expires = time.Unix(1, 0)
+	}
+	return cookie
+}
+
+// Error ----------------------------------------------------------------------
+
+// MultiError stores multiple errors.
+//
+// Borrowed from the App Engine SDK.
+type MultiError []error
+
+func (m MultiError) Error() string {
+	s, n := "", 0
+	for _, e := range m {
+		if e != nil {
+			if n == 0 {
+				s = e.Error()
+			}
+			n++
+		}
+	}
+	switch n {
+	case 0:
+		return "(0 errors)"
+	case 1:
+		return s
+	case 2:
+		return s + " (and 1 other error)"
+	}
+	return fmt.Sprintf("%s (and %d other errors)", s, n-1)
+}