-
Notifications
You must be signed in to change notification settings - Fork 2
/
router.go
433 lines (395 loc) · 12.1 KB
/
router.go
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
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
package sandwich
import (
"errors"
"fmt"
"net/http"
"strings"
"github.com/augustoroman/sandwich/chain"
)
// Router implements the sandwich middleware chaining and routing functionality.
type Router interface {
// Set a value that will be available to all handlers subsequent referenced.
// This is typically used for concrete values. For interfaces to be correctly
// provided to subsequent middleware, use SetAs.
Set(vals ...any)
// SetAs sets a value as the specified interface that will be available to all
// handlers.
//
// Example:
// type DB interface { ... }
// var db DB = ...
// mux.SetAs(db, (*DB)(nil))
//
// That is functionally equivalent to using a middleware function that returns
// the desired interface instance:
// type DB interface { ... }
// var db DB = ...
// mux.Use(func() DB { return db })
SetAs(val, ifacePtr any)
// Use adds middleware to be invoked for all routes registered by the
// returned Router. The current router is not affected. This is equivalent to
// adding the specified middelwareHandlers to each registered route.
Use(middlewareHandlers ...any)
// On will register a handler for the given method and path.
On(method, path string, handlers ...any)
// Get registers handlers for the specified path for the 'GET' HTTP method.
// Get is shorthand for `On("GET", ...)`.
Get(path string, handlers ...any)
// Put registers handlers for the specified path for the 'PUT' HTTP method.
// Put is shorthand for `On("PUT", ...)`.
Put(path string, handlers ...any)
// Post registers handlers for the specified path for the 'POST' HTTP method.
// Post is shorthand for `On("POST", ...)`.
Post(path string, handlers ...any)
// Patch registers handlers for the specified path for the 'PATCH' HTTP
// method. Patch is shorthand for `On("PATCH", ...)`.
Patch(path string, handlers ...any)
// Delete registers handlers for the specified path for the 'DELETE' HTTP
// method. Delete is shorthand for `On("DELETE", ...)`.
Delete(path string, handlers ...any)
// Any registers a handlers for the specified path for any HTTP method. This
// will always be superceded by dedicated method handlers. For example, if the
// path '/users/:id/' is registered for Get, Put and Any, GET and PUT requests
// will be handled by the Get(...) and Put(...) registrations, but DELETE,
// CONNECT, or HEAD would be handled by the Any(...) registration. Any is a
// shortcut for `On("*", ...)`.
Any(path string, handlers ...any)
// OnErr uses the specified error handler to handle any errors that occur on
// any routes in this router.
OnErr(handler any)
// SubRouter derives a router that will called for all suffixes (and methods)
// for the specified path. For example, `sub := root.SubRouter("/api")` will
// create a router that will handle `/api/`, `/api/foo`.
SubRouter(pathPrefix string) Router
// ServeHTTP implements the http.Handler interface for the router.
ServeHTTP(w http.ResponseWriter, r *http.Request)
}
// BuildYourOwn returns a minimal router that has no initial middleware
// handling.
func BuildYourOwn() Router {
r := &router{}
r.base = r.base.Arg((*http.ResponseWriter)(nil))
r.base = r.base.Arg((*http.Request)(nil))
r.base = r.base.Arg((Params)(nil))
return r
}
// TheUsual returns a router initialized with useful middleware.
func TheUsual() Router {
r := BuildYourOwn()
r.Use(WrapResponseWriter, LogRequests)
r.OnErr(HandleError)
return r
}
type router struct {
base chain.Func
subRouters map[string]*router
byMethod map[string]*mux
anyMethod *mux
notFound http.Handler
}
func (r *router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
params := Params{}
h := r.match(req.Method, req.URL.Path, params)
if h != nil {
h.ServeHTTP(w, req, params)
} else if r.notFound != nil {
r.notFound.ServeHTTP(w, req)
} else {
http.Error(w, "Not found", http.StatusNotFound)
}
}
func (r *router) SubRouter(prefix string) Router {
if r.subRouters == nil {
r.subRouters = map[string]*router{}
}
prefix = strings.TrimRight(prefix, "/") + "/"
for existingPrefix := range r.subRouters {
if existingPrefix == prefix || strings.HasPrefix(existingPrefix, prefix) || strings.HasPrefix(prefix, existingPrefix) {
panic(fmt.Sprintf(
"SubRouter with prefix %#q conflicts with existing SubRouter with prefix %#q",
prefix, existingPrefix,
))
}
}
r.subRouters[prefix] = &router{
base: r.base,
notFound: r.notFound,
}
return r.subRouters[prefix]
}
func (r *router) match(method, uri string, params Params) httpHandlerWithParams {
method = strings.ToUpper(method)
for prefix, sub := range r.subRouters {
if strings.HasPrefix(uri, prefix) {
return sub.match(method, strings.TrimPrefix(uri, prefix), params)
}
}
if h := r.byMethod[method].Match(uri, params); h != nil {
return h
}
if h := r.anyMethod.Match(uri, params); h != nil {
return h
}
return nil
}
func (r *router) Set(vals ...any) {
for _, val := range vals {
r.base = r.base.Set(val)
}
}
func (r *router) SetAs(val, ifacePtr any) {
r.base = r.base.SetAs(val, ifacePtr)
}
func (r *router) Use(middlewareHandlers ...any) {
r.base = apply(r.base, middlewareHandlers...)
}
func (r *router) OnErr(errorHandler any) {
r.base = r.base.OnErr(errorHandler)
}
func (r *router) On(method, path string, handlers ...any) {
method = strings.ToUpper(method)
m := r.getOrAllocateMux(method)
if err := m.Register(path, handler{apply(r.base, handlers...)}); err != nil {
panic(fmt.Errorf("Cannot register route: %v", err))
}
}
func (r *router) Any(path string, handlers ...any) { r.On("*", path, handlers...) }
func (r *router) Get(path string, handlers ...any) { r.On("GET", path, handlers...) }
func (r *router) Put(path string, handlers ...any) { r.On("PUT", path, handlers...) }
func (r *router) Post(path string, handlers ...any) { r.On("POST", path, handlers...) }
func (r *router) Patch(path string, handlers ...any) { r.On("PATCH", path, handlers...) }
func (r *router) Delete(path string, handlers ...any) { r.On("DELETE", path, handlers...) }
func (r *router) getOrAllocateMux(method string) *mux {
if method == "*" {
if r.anyMethod == nil {
r.anyMethod = &mux{}
}
return r.anyMethod
}
if r.byMethod == nil {
r.byMethod = map[string]*mux{}
}
m := r.byMethod[method]
if m == nil {
m = &mux{}
r.byMethod[method] = m
}
return m
}
type handler struct{ chain.Func }
func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request, p Params) {
h.Func.MustRun(w, r, p)
}
type Params map[string]string
type mux struct {
static map[string]*mux
params []muxParam
handler httpHandlerWithParams
}
type muxParam struct {
paramName string
greedy bool
mux *mux
}
type httpHandlerWithParams interface {
ServeHTTP(w http.ResponseWriter, r *http.Request, p Params)
}
func (m *mux) Register(pattern string, h httpHandlerWithParams) error {
if !strings.HasPrefix(pattern, "/") {
return errors.New("patterns must begin with /")
}
segments := strings.Split(pattern[1:], "/")
reg := registerInfo{
seenParams: map[string]bool{},
seenGreedy: false,
}
if m.static == nil {
m.static = map[string]*mux{}
}
if err := reg.registerSegments(m, segments, h); err != nil {
return fmt.Errorf("%#q: bad pattern: %w", pattern, err)
}
return nil
}
type registerInfo struct {
seenParams map[string]bool
seenGreedy bool
}
func (r *registerInfo) registerSegments(m *mux, segments []string, h httpHandlerWithParams) error {
if len(segments) == 0 {
if m.handler != nil {
return fmt.Errorf("repeated entry")
}
m.handler = h
return nil
}
next, remaining := segments[0], segments[1:]
if strings.HasPrefix(next, "::") {
return r.registerStatic(m, next[1:], remaining, h)
} else if strings.HasPrefix(next, ":") {
return r.registerParam(m, next[1:], remaining, h)
} else {
return r.registerStatic(m, next, remaining, h)
}
}
func (r *registerInfo) registerStatic(m *mux, path string, remaining []string, h httpHandlerWithParams) error {
sub := m.static[path]
if sub == nil {
sub = &mux{
static: map[string]*mux{},
}
}
err := r.registerSegments(sub, remaining, h)
if err == nil {
m.static[path] = sub
}
return err
}
func (r *registerInfo) registerParam(m *mux, param string, remaining []string, h httpHandlerWithParams) error {
greedy := strings.HasSuffix(param, "*")
name := strings.TrimSuffix(param, "*")
if greedy && r.seenGreedy {
return fmt.Errorf("only one greedy param allowed per pattern: %#q", name)
} else if r.seenParams[name] {
return fmt.Errorf("param used twice: %#q", name)
}
// Check to see if the param already exists. E.g. we've already registered
// param at this level via:
// /root/:param/path1 --> h1
// and now we're registering:
// /root/:param/path2 --> h2
for _, p := range m.params {
if p.paramName == name {
if p.greedy != greedy {
return fmt.Errorf("param %#q is sometimes greedy and sometimes not", name)
}
return r.registerSegments(p.mux, remaining, h)
}
// If we haven't registered this one yet, then we need to avoid ambiguous
// path registrations. For example:
// /root/:p1/path
// /root/:p2/path
// should not be allowed, nor should:
// /root/:p1/:x/:y
// /root/:p2/:a/:b
if err := p.mux.checkAmbiguous(remaining); err != nil {
return fmt.Errorf("ambiguous route: %w", err)
}
}
sub := &mux{
static: map[string]*mux{},
}
r.seenParams[name] = true
r.seenGreedy = r.seenGreedy || greedy
err := r.registerSegments(sub, remaining, h)
if err == nil {
m.params = append(m.params, muxParam{
paramName: name,
greedy: greedy,
mux: sub,
})
}
return err
}
func (m *mux) checkAmbiguous(segments []string) error {
if len(segments) == 0 {
if m.handler != nil {
return fmt.Errorf("ambiguous route")
}
return nil
}
static, isStatic, _, _ := entryToInfo(segments[0])
if isStatic {
if child := m.static[static]; child != nil {
return child.checkAmbiguous(segments[1:])
}
return nil
}
for _, p := range m.params {
if err := p.mux.checkAmbiguous(segments[1:]); err != nil {
return err
}
}
return nil
}
func entryToInfo(entry string) (static string, isStatic bool, paramName string, greedy bool) {
if strings.HasPrefix(entry, "::") {
// double colon prefix escapes to single colon static path name.
return entry[1:], true, "", false
} else if !strings.HasPrefix(entry, ":") {
return entry, true, "", false
}
paramName = strings.TrimSuffix(entry[1:], "*")
greedy = strings.HasSuffix(entry, "*")
return "", false, paramName, greedy
}
func (m *mux) Match(uri string, params Params) httpHandlerWithParams {
uri = strings.TrimPrefix(uri, "/")
segments := strings.Split(uri, "/")
matched := m.matchPrefix(segments, params)
if matched == nil {
return nil
}
return matched
}
func (m *mux) matchPrefix(segments []string, params Params) httpHandlerWithParams {
if m == nil {
return nil
}
if len(segments) == 0 {
return m.handler
}
path, remaining := segments[0], segments[1:]
if sub := m.static[path]; sub != nil {
match := sub.matchPrefix(remaining, params)
if match != nil {
return match
}
}
for _, param := range m.params {
if !param.greedy {
matched := param.mux.matchPrefix(remaining, params)
if matched != nil {
params[param.paramName] = path
return matched
}
} else {
matched, used := param.mux.matchSuffix(remaining, params)
if matched != nil {
N := len(segments)
params[param.paramName] = strings.Join(segments[:N-used], "/")
return matched
}
}
}
return nil
}
func (m *mux) matchSuffix(segments []string, params Params) (h httpHandlerWithParams, depth int) {
N := len(segments)
if N == 0 {
return m.handler, 0
}
for staticPath, sub := range m.static {
match, d := sub.matchSuffix(segments, params)
if match == nil {
continue
}
depth = d + 1
actualPath := segments[N-depth]
if actualPath != staticPath {
continue
}
return match, depth
}
for _, param := range m.params {
match, d := param.mux.matchSuffix(segments, params)
if match == nil {
continue
}
depth = d + 1
actualPath := segments[N-depth]
params[param.paramName] = actualPath // TODO: might be rejected, might spam params
return match, depth
}
return m.handler, 0
}