/usr/share/gocode/src/github.com/bmizerany/pat/mux.go is in golang-github-bmizerany-pat-dev 0.0~git20140625-5.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 | // Package pat implements a simple URL pattern muxer
package pat
import (
"net/http"
"net/url"
"strings"
)
// PatternServeMux is an HTTP request multiplexer. It matches the URL of each
// incoming request against a list of registered patterns with their associated
// methods and calls the handler for the pattern that most closely matches the
// URL.
//
// Pattern matching attempts each pattern in the order in which they were
// registered.
//
// Patterns may contain literals or captures. Capture names start with a colon
// and consist of letters A-Z, a-z, _, and 0-9. The rest of the pattern
// matches literally. The portion of the URL matching each name ends with an
// occurrence of the character in the pattern immediately following the name,
// or a /, whichever comes first. It is possible for a name to match the empty
// string.
//
// Example pattern with one capture:
// /hello/:name
// Will match:
// /hello/blake
// /hello/keith
// Will not match:
// /hello/blake/
// /hello/blake/foo
// /foo
// /foo/bar
//
// Example 2:
// /hello/:name/
// Will match:
// /hello/blake/
// /hello/keith/foo
// /hello/blake
// /hello/keith
// Will not match:
// /foo
// /foo/bar
//
// A pattern ending with a slash will get an implicit redirect to it's
// non-slash version. For example: Get("/foo/", handler) will implicitly
// register Get("/foo", handler). You may override it by registering
// Get("/foo", anotherhandler) before the slash version.
//
// Retrieve the capture from the r.URL.Query().Get(":name") in a handler (note
// the colon). If a capture name appears more than once, the additional values
// are appended to the previous values (see
// http://golang.org/pkg/net/url/#Values)
//
// A trivial example server is:
//
// package main
//
// import (
// "io"
// "net/http"
// "github.com/bmizerany/pat"
// "log"
// )
//
// // hello world, the web server
// func HelloServer(w http.ResponseWriter, req *http.Request) {
// io.WriteString(w, "hello, "+req.URL.Query().Get(":name")+"!\n")
// }
//
// func main() {
// m := pat.New()
// m.Get("/hello/:name", http.HandlerFunc(HelloServer))
//
// // Register this pat with the default serve mux so that other packages
// // may also be exported. (i.e. /debug/pprof/*)
// http.Handle("/", m)
// err := http.ListenAndServe(":12345", nil)
// if err != nil {
// log.Fatal("ListenAndServe: ", err)
// }
// }
//
// When "Method Not Allowed":
//
// Pat knows what methods are allowed given a pattern and a URI. For
// convenience, PatternServeMux will add the Allow header for requests that
// match a pattern for a method other than the method requested and set the
// Status to "405 Method Not Allowed".
type PatternServeMux struct {
handlers map[string][]*patHandler
}
// New returns a new PatternServeMux.
func New() *PatternServeMux {
return &PatternServeMux{make(map[string][]*patHandler)}
}
// ServeHTTP matches r.URL.Path against its routing table using the rules
// described above.
func (p *PatternServeMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
for _, ph := range p.handlers[r.Method] {
if params, ok := ph.try(r.URL.Path); ok {
if len(params) > 0 {
r.URL.RawQuery = url.Values(params).Encode() + "&" + r.URL.RawQuery
}
ph.ServeHTTP(w, r)
return
}
}
allowed := make([]string, 0, len(p.handlers))
for meth, handlers := range p.handlers {
if meth == r.Method {
continue
}
for _, ph := range handlers {
if _, ok := ph.try(r.URL.Path); ok {
allowed = append(allowed, meth)
}
}
}
if len(allowed) == 0 {
http.NotFound(w, r)
return
}
w.Header().Add("Allow", strings.Join(allowed, ", "))
http.Error(w, "Method Not Allowed", 405)
}
// Head will register a pattern with a handler for HEAD requests.
func (p *PatternServeMux) Head(pat string, h http.Handler) {
p.Add("HEAD", pat, h)
}
// Get will register a pattern with a handler for GET requests.
// It also registers pat for HEAD requests. If this needs to be overridden, use
// Head before Get with pat.
func (p *PatternServeMux) Get(pat string, h http.Handler) {
p.Add("HEAD", pat, h)
p.Add("GET", pat, h)
}
// Post will register a pattern with a handler for POST requests.
func (p *PatternServeMux) Post(pat string, h http.Handler) {
p.Add("POST", pat, h)
}
// Put will register a pattern with a handler for PUT requests.
func (p *PatternServeMux) Put(pat string, h http.Handler) {
p.Add("PUT", pat, h)
}
// Del will register a pattern with a handler for DELETE requests.
func (p *PatternServeMux) Del(pat string, h http.Handler) {
p.Add("DELETE", pat, h)
}
// Options will register a pattern with a handler for OPTIONS requests.
func (p *PatternServeMux) Options(pat string, h http.Handler) {
p.Add("OPTIONS", pat, h)
}
// Add will register a pattern with a handler for meth requests.
func (p *PatternServeMux) Add(meth, pat string, h http.Handler) {
p.handlers[meth] = append(p.handlers[meth], &patHandler{pat, h})
n := len(pat)
if n > 0 && pat[n-1] == '/' {
p.Add(meth, pat[:n-1], http.RedirectHandler(pat, http.StatusMovedPermanently))
}
}
// Tail returns the trailing string in path after the final slash for a pat ending with a slash.
//
// Examples:
//
// Tail("/hello/:title/", "/hello/mr/mizerany") == "mizerany"
// Tail("/:a/", "/x/y/z") == "y/z"
//
func Tail(pat, path string) string {
var i, j int
for i < len(path) {
switch {
case j >= len(pat):
if pat[len(pat)-1] == '/' {
return path[i:]
}
return ""
case pat[j] == ':':
var nextc byte
_, nextc, j = match(pat, isAlnum, j+1)
_, _, i = match(path, matchPart(nextc), i)
case path[i] == pat[j]:
i++
j++
default:
return ""
}
}
return ""
}
type patHandler struct {
pat string
http.Handler
}
func (ph *patHandler) try(path string) (url.Values, bool) {
p := make(url.Values)
var i, j int
for i < len(path) {
switch {
case j >= len(ph.pat):
if ph.pat != "/" && len(ph.pat) > 0 && ph.pat[len(ph.pat)-1] == '/' {
return p, true
}
return nil, false
case ph.pat[j] == ':':
var name, val string
var nextc byte
name, nextc, j = match(ph.pat, isAlnum, j+1)
val, _, i = match(path, matchPart(nextc), i)
p.Add(":"+name, val)
case path[i] == ph.pat[j]:
i++
j++
default:
return nil, false
}
}
if j != len(ph.pat) {
return nil, false
}
return p, true
}
func matchPart(b byte) func(byte) bool {
return func(c byte) bool {
return c != b && c != '/'
}
}
func match(s string, f func(byte) bool, i int) (matched string, next byte, j int) {
j = i
for j < len(s) && f(s[j]) {
j++
}
if j < len(s) {
next = s[j]
}
return s[i:j], next, j
}
func isAlpha(ch byte) bool {
return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_'
}
func isDigit(ch byte) bool {
return '0' <= ch && ch <= '9'
}
func isAlnum(ch byte) bool {
return isAlpha(ch) || isDigit(ch)
}
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