Refactor server certificates

1 files changed, 210 insertions, 0 deletions

diff --git a/mux.go b/mux.go
new file mode 100644
index 0000000..47aa618
--- /dev/null
+++ b/mux.go
@@ -0,0 +1,210 @@
+package gemini
+
+import (
+	"net/url"
+	"path"
+	"sort"
+	"strings"
+	"sync"
+)
+
+// The following code is modified from the net/http package.
+
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// ServeMux is a Gemini request multiplexer.
+// It matches the URL of each incoming request against a list of registered
+// patterns and calls the handler for the pattern that
+// most closely matches the URL.
+//
+// Patterns name fixed, rooted paths, like "/favicon.ico",
+// or rooted subtrees, like "/images/" (note the trailing slash).
+// Longer patterns take precedence over shorter ones, so that
+// if there are handlers registered for both "/images/"
+// and "/images/thumbnails/", the latter handler will be
+// called for paths beginning "/images/thumbnails/" and the
+// former will receive requests for any other paths in the
+// "/images/" subtree.
+//
+// Note that since a pattern ending in a slash names a rooted subtree,
+// the pattern "/" matches all paths not matched by other registered
+// patterns, not just the URL with Path == "/".
+//
+// If a subtree has been registered and a request is received naming the
+// subtree root without its trailing slash, ServeMux redirects that
+// request to the subtree root (adding the trailing slash). This behavior can
+// be overridden with a separate registration for the path without
+// the trailing slash. For example, registering "/images/" causes ServeMux
+// to redirect a request for "/images" to "/images/", unless "/images" has
+// been registered separately.
+//
+// ServeMux also takes care of sanitizing the URL request path and
+// redirecting any request containing . or .. elements or repeated slashes
+// to an equivalent, cleaner URL.
+type ServeMux struct {
+	mu sync.RWMutex
+	m  map[string]muxEntry
+	es []muxEntry // slice of entries sorted from longest to shortest.
+}
+
+type muxEntry struct {
+	r       Responder
+	pattern string
+}
+
+// cleanPath returns the canonical path for p, eliminating . and .. elements.
+func cleanPath(p string) string {
+	if p == "" {
+		return "/"
+	}
+	if p[0] != '/' {
+		p = "/" + p
+	}
+	np := path.Clean(p)
+	// path.Clean removes trailing slash except for root;
+	// put the trailing slash back if necessary.
+	if p[len(p)-1] == '/' && np != "/" {
+		// Fast path for common case of p being the string we want:
+		if len(p) == len(np)+1 && strings.HasPrefix(p, np) {
+			np = p
+		} else {
+			np += "/"
+		}
+	}
+	return np
+}
+
+// Find a handler on a handler map given a path string.
+// Most-specific (longest) pattern wins.
+func (mux *ServeMux) match(path string) Responder {
+	// Check for exact match first.
+	v, ok := mux.m[path]
+	if ok {
+		return v.r
+	}
+
+	// Check for longest valid match.  mux.es contains all patterns
+	// that end in / sorted from longest to shortest.
+	for _, e := range mux.es {
+		if strings.HasPrefix(path, e.pattern) {
+			return e.r
+		}
+	}
+	return nil
+}
+
+// redirectToPathSlash determines if the given path needs appending "/" to it.
+// This occurs when a handler for path + "/" was already registered, but
+// not for path itself. If the path needs appending to, it creates a new
+// URL, setting the path to u.Path + "/" and returning true to indicate so.
+func (mux *ServeMux) redirectToPathSlash(path string, u *url.URL) (*url.URL, bool) {
+	mux.mu.RLock()
+	shouldRedirect := mux.shouldRedirectRLocked(path)
+	mux.mu.RUnlock()
+	if !shouldRedirect {
+		return u, false
+	}
+	path = path + "/"
+	u = &url.URL{Path: path, RawQuery: u.RawQuery}
+	return u, true
+}
+
+// shouldRedirectRLocked reports whether the given path and host should be redirected to
+// path+"/". This should happen if a handler is registered for path+"/" but
+// not path -- see comments at ServeMux.
+func (mux *ServeMux) shouldRedirectRLocked(path string) bool {
+	if _, exist := mux.m[path]; exist {
+		return false
+	}
+
+	n := len(path)
+	if n == 0 {
+		return false
+	}
+	if _, exist := mux.m[path+"/"]; exist {
+		return path[n-1] != '/'
+	}
+
+	return false
+}
+
+// Respond dispatches the request to the responder whose
+// pattern most closely matches the request URL.
+func (mux *ServeMux) Respond(w *ResponseWriter, r *Request) {
+	path := cleanPath(r.URL.Path)
+
+	// If the given path is /tree and its handler is not registered,
+	// redirect for /tree/.
+	if u, ok := mux.redirectToPathSlash(path, r.URL); ok {
+		Redirect(w, u.String())
+		return
+	}
+
+	if path != r.URL.Path {
+		u := *r.URL
+		u.Path = path
+		Redirect(w, u.String())
+		return
+	}
+
+	mux.mu.RLock()
+	defer mux.mu.RUnlock()
+
+	resp := mux.match(path)
+	if resp == nil {
+		w.WriteStatus(StatusNotFound)
+		return
+	}
+	resp.Respond(w, r)
+}
+
+// Handle registers the responder for the given pattern.
+// If a responder already exists for pattern, Handle panics.
+func (mux *ServeMux) Handle(pattern string, responder Responder) {
+	mux.mu.Lock()
+	defer mux.mu.Unlock()
+
+	if pattern == "" {
+		panic("gemini: invalid pattern")
+	}
+	if responder == nil {
+		panic("gemini: nil responder")
+	}
+	if _, exist := mux.m[pattern]; exist {
+		panic("gemini: multiple registrations for " + pattern)
+	}
+
+	if mux.m == nil {
+		mux.m = make(map[string]muxEntry)
+	}
+	e := muxEntry{responder, pattern}
+	mux.m[pattern] = e
+	if pattern[len(pattern)-1] == '/' {
+		mux.es = appendSorted(mux.es, e)
+	}
+}
+
+func appendSorted(es []muxEntry, e muxEntry) []muxEntry {
+	n := len(es)
+	i := sort.Search(n, func(i int) bool {
+		return len(es[i].pattern) < len(e.pattern)
+	})
+	if i == n {
+		return append(es, e)
+	}
+	// we now know that i points at where we want to insert
+	es = append(es, muxEntry{}) // try to grow the slice in place, any entry works.
+	copy(es[i+1:], es[i:])      // move shorter entries down
+	es[i] = e
+	return es
+}
+
+// HandleFunc registers the responder function for the given pattern.
+func (mux *ServeMux) HandleFunc(pattern string, responder func(*ResponseWriter, *Request)) {
+	if responder == nil {
+		panic("gemini: nil responder")
+	}
+	mux.Handle(pattern, ResponderFunc(responder))
+}