// Efficient favicon handler, mostly a port of node's Connect library implementation
// of the favicon middleware.
// https://github.com/senchalabs/connect
func FaviconHandler(h http.Handler, path string, maxAge time.Duration) http.HandlerFunc {
var buf []byte
var hash string
return func(w http.ResponseWriter, r *http.Request) {
var err error
if r.URL.Path == "/favicon.ico" {
if buf == nil {
// Read from file and cache
ghost.LogFn("ghost.favicon : serving from %s", path)
buf, err = ioutil.ReadFile(path)
if err != nil {
ghost.LogFn("ghost.favicon : error reading file : %s", err)
http.NotFound(w, r)
return
}
hash = hashContent(buf)
}
writeHeaders(w.Header(), buf, maxAge, hash)
writeBody(w, r, buf)
} else {
h.ServeHTTP(w, r)
}
}
}
// Write the content of the favicon, or respond with a 404 not found
// in case of error (hardly a critical error).
func writeBody(w http.ResponseWriter, r *http.Request, buf []byte) {
_, err := w.Write(buf)
if err != nil {
ghost.LogFn("ghost.favicon : error writing response : %s", err)
http.NotFound(w, r)
}
}
// Compute a CRC32 hash of the session's JSON-encoded contents.
func hash(s *Session) uint32 {
data, err := json.Marshal(s)
if err != nil {
ghost.LogFn("ghost.session : error hash : %s", err)
return 0 // 0 is always treated as "modified" session content
}
return crc32.ChecksumIEEE(data)
}
// Compile the specified template file if there is a matching compiler.
func compileTemplate(p, base string) error {
ext := path.Ext(p)
c, ok := compilers[ext]
// Ignore file if no template compiler exist for this extension
if ok {
t, err := c.Compile(p)
if err != nil {
return err
}
key, err := filepath.Rel(base, p)
if err != nil {
return err
}
ghost.LogFn("ghost.templates : storing template for file %s", key)
templaters[key] = t
}
return nil
}
// Compile all templates that have a matching compiler (based on their extension) in the
// specified directory.
func CompileDir(dir string) error {
mu.Lock()
defer mu.Unlock()
return filepath.Walk(dir, func(path string, fi os.FileInfo, err error) error {
if fi == nil {
return ErrDirNotExist
}
if !fi.IsDir() {
err = compileTemplate(path, dir)
if err != nil {
ghost.LogFn("ghost.templates : error compiling template %s : %s", path, err)
return err
}
}
return nil
})
}
// Create a Session handler to offer the Session behaviour to the specified handler.
func SessionHandler(h http.Handler, opts *SessionOptions) http.HandlerFunc {
// Make sure the required cookie fields are set
if opts.CookieTemplate.Name == "" {
opts.CookieTemplate.Name = defaultCookieName
}
if opts.CookieTemplate.Path == "" {
opts.CookieTemplate.Path = "/"
}
// Secret is required
if opts.Secret == "" {
panic(ErrSessionSecretMissing)
}
// Return the actual handler
return func(w http.ResponseWriter, r *http.Request) {
if _, ok := getSessionWriter(w); ok {
// Self-awareness
h.ServeHTTP(w, r)
return
}
if strings.Index(r.URL.Path, opts.CookieTemplate.Path) != 0 {
// Session does not apply to this path
h.ServeHTTP(w, r)
return
}
// Create a new Session or retrieve the existing session based on the
// session cookie received.
var sess *Session
var ckSessId string
exCk, err := r.Cookie(opts.CookieTemplate.Name)
if err != nil {
sess = newSession(opts.CookieTemplate.MaxAge)
ghost.LogFn("ghost.session : error getting session cookie : %s", err)
} else {
ckSessId, err = parseSignedCookie(exCk, opts.Secret)
if err != nil {
sess = newSession(opts.CookieTemplate.MaxAge)
ghost.LogFn("ghost.session : error parsing signed cookie : %s", err)
} else if ckSessId == "" {
sess = newSession(opts.CookieTemplate.MaxAge)
ghost.LogFn("ghost.session : no existing session ID")
} else {
// Get the session
sess, err = opts.Store.Get(ckSessId)
if err != nil {
sess = newSession(opts.CookieTemplate.MaxAge)
ghost.LogFn("ghost.session : error getting session from store : %s", err)
} else if sess == nil {
sess = newSession(opts.CookieTemplate.MaxAge)
ghost.LogFn("ghost.session : nil session")
}
}
}
// Save the original hash of the session, used to compare if the contents
// have changed during the handling of the request, so that it has to be
// saved to the stored.
oriHash := hash(sess)
// Create the augmented ResponseWriter.
srw := &sessResponseWriter{w, sess, opts.Store, false, func() {
// This function is called when the header is about to be written, so that
// the session cookie is correctly set.
// Check if the connection is secure
proto := strings.Trim(strings.ToLower(r.Header.Get("X-Forwarded-Proto")), " ")
tls := r.TLS != nil || (strings.HasPrefix(proto, "https") && opts.TrustProxy)
if opts.CookieTemplate.Secure && !tls {
ghost.LogFn("ghost.session : secure cookie on a non-secure connection, cookie not sent")
return
}
if !sess.IsNew() {
// If this is not a new session, no need to send back the cookie
// TODO : Handle expires?
return
}
// Send the session cookie
ck := opts.CookieTemplate
ck.Value = sess.ID()
err := signCookie(&ck, opts.Secret)
if err != nil {
ghost.LogFn("ghost.session : error signing cookie : %s", err)
return
}
http.SetCookie(w, &ck)
}}
// Call wrapped handler
h.ServeHTTP(srw, r)
// TODO : Expiration management? srw.sess.resetMaxAge()
// Do not save if content is the same, unless session is new (to avoid
// creating a new session and sending a cookie on each successive request).
if newHash := hash(sess); !sess.IsNew() && oriHash == newHash && newHash != 0 {
// No changes to the session, no need to save
ghost.LogFn("ghost.session : no changes to save to store")
return
}
err = opts.Store.Set(sess)
if err != nil {
ghost.LogFn("ghost.session : error saving session to store : %s", err)
}
}
}
