trout
trout/route.go
Fix some crashes. When adding a branch, make sure that it has any characters at all before checking if it's a variable. Change the Router methods to be on the *Router pointer. We were having some problems with Router methods not setting properties correctly, but this fixed it. Check that the Endpoint.methods map is set before trying to map methods to Handlers. With these changes, trout is complete enough that it can run the benchmarks.
1 package trout
3 import (
4 "net/http"
5 "strconv"
6 "strings"
7 "time"
8 )
10 var (
11 default404Handler = http.Handler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
12 w.WriteHeader(http.StatusNotFound)
13 w.Write([]byte("404 Not Found"))
14 return
15 }))
16 default405Handler = http.Handler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
17 w.WriteHeader(http.StatusMethodNotAllowed)
18 w.Write([]byte("405 Method Not Allowed"))
19 return
20 }))
21 )
23 // RequestVars returns easy-to-access mappings of parameters to values for URL templates. Any {parameter} in
24 // your URL template will be available in the returned Header as a slice of strings, one for each instance of
25 // the {parameter}. In the case of a parameter name being used more than once in the same URL template, the
26 // values will be in the slice in the order they appeared in the template.
27 //
28 // Values can easily be accessed by using the .Get() method of the returned Header, though to access multiple
29 // values, they must be accessed through the map. All parameters use http.CanonicalHeaderKey for their formatting.
30 // When using .Get(), the parameter name will be transformed automatically. When utilising the Header as a map,
31 // the parameter name needs to have http.CanonicalHeaderKey applied manually.
32 func RequestVars(r *http.Request) http.Header {
33 res := http.Header{}
34 for h, v := range r.Header {
35 stripped := strings.TrimPrefix(h, http.CanonicalHeaderKey("Trout-Param-"))
36 if stripped != h {
37 res[stripped] = v
38 }
39 }
40 return res
41 }
43 // Router defines a set of Endpoints that map requests to the http.Handlers. The http.Handler assigned to
44 // Handle404, if set, will be called when no Endpoint matches the current request. The http.Handler assigned
45 // to Handle405, if set, will be called when an Endpoint matches the current request, but has no http.Handler
46 // set for the HTTP method that the request used. Should either of these properties be unset, a default
47 // http.Handler will be used.
48 //
49 // The Router type is safe for use with empty values, but makes no attempt at concurrency-safety in adding
50 // Endpoints or in setting properties. It should also be noted that the adding Endpoints while simultaneously
51 // routing requests will lead to undefined and (almost certainly) undesirable behaviour. Routers are intended
52 // to be initialised with a set of Endpoints, and then start serving requests. Using them outside of this use
53 // case is unsupported.
54 type Router struct {
55 t *trie
56 Handle404 http.Handler
57 Handle405 http.Handler
58 }
60 func (router *Router) serve404(w http.ResponseWriter, r *http.Request, t time.Time) {
61 h := default404Handler
62 if router.Handle404 != nil {
63 h = router.Handle404
64 }
65 r.Header.Set("Trout-Timer", strconv.FormatInt(time.Now().Sub(t).Nanoseconds(), 10))
66 h.ServeHTTP(w, r)
67 }
69 func (router *Router) serve405(w http.ResponseWriter, r *http.Request, t time.Time) {
70 h := default405Handler
71 if router.Handle405 != nil {
72 h = router.Handle405
73 }
74 r.Header.Set("Trout-Timer", strconv.FormatInt(time.Now().Sub(t).Nanoseconds(), 10))
75 h.ServeHTTP(w, r)
76 }
78 func (router Router) ServeHTTP(w http.ResponseWriter, r *http.Request) {
79 start := time.Now()
80 if router.t == nil {
81 router.serve404(w, r, start)
82 return
83 }
84 pieces := strings.Split(strings.ToLower(strings.Trim(r.URL.Path, "/")), "/")
85 router.t.RLock()
86 defer router.t.RUnlock()
87 branches := make([]*branch, len(pieces))
88 path, ok := router.t.match(pieces)
89 if !ok {
90 router.serve404(w, r, start)
91 return
92 }
93 b := router.t.branch
94 for i, pos := range path {
95 b = b.children[pos]
96 branches[i] = b
97 }
98 v := vars(branches, pieces)
99 for key, vals := range v {
100 r.Header[http.CanonicalHeaderKey("Trout-Param-"+key)] = vals
101 }
102 ms := make([]string, len(b.methods))
103 i := 0
104 for m := range b.methods {
105 ms[i] = m
106 i = i + 1
107 }
108 r.Header[http.CanonicalHeaderKey("Trout-Methods")] = ms
109 h := b.methods[r.Method]
110 if h == nil {
111 router.serve405(w, r, start)
112 return
113 }
114 r.Header.Set("Trout-Timer", strconv.FormatInt(time.Now().Sub(start).Nanoseconds(), 10))
115 h.ServeHTTP(w, r)
116 }
118 // Endpoint defines a new Endpoint on the Router. The Endpoint should be a URL template, using curly braces
119 // to denote parameters that should be filled at runtime. For example, `{id}` denotes a parameter named `id`
120 // that should be filled with whatever the request has in that space.
121 //
122 // Parameters are always `/`-separated strings. There is no support for regular expressions or other limitations
123 // on what may be in those strings. A parameter is simply defined as "whatever is between these two / characters".
124 func (router *Router) Endpoint(e string) *Endpoint {
125 e = strings.Trim(e, "/")
126 e = strings.ToLower(e)
127 pieces := strings.Split(e, "/")
128 if router.t == nil {
129 router.t = &trie{}
130 }
131 router.t.Lock()
132 defer router.t.Unlock()
133 if router.t.branch == nil {
134 router.t.branch = &branch{
135 parent: nil,
136 children: []*branch{},
137 key: "",
138 isParam: false,
139 methods: map[string]http.Handler{},
140 }
141 }
142 closest := findClosestLeaf(pieces, router.t.branch)
143 b := router.t.branch
144 for _, pos := range closest {
145 b = b.children[pos]
146 }
147 if len(closest) == len(pieces) {
148 return (*Endpoint)(b)
149 }
150 offset := len(closest)
151 for i := offset; i < len(pieces); i++ {
152 piece := pieces[i]
153 var isParam bool
154 if len(piece) > 0 && piece[0:1] == "{" && piece[len(piece)-1:] == "}" {
155 isParam = true
156 piece = piece[1 : len(piece)-1]
157 }
158 b = b.addChild(piece, isParam)
159 }
160 return (*Endpoint)(b)
161 }
163 func vars(path []*branch, pieces []string) map[string][]string {
164 v := map[string][]string{}
165 for pos, p := range path {
166 if !p.isParam {
167 continue
168 }
169 _, ok := v[p.key]
170 if !ok {
171 v[p.key] = []string{pieces[pos]}
172 continue
173 }
174 v[p.key] = append(v[p.key], pieces[pos])
175 }
176 return v
177 }
179 func findClosestLeaf(pieces []string, b *branch) []int {
180 offset := 0
181 path := []int{}
182 longest := []int{}
183 num := len(pieces)
184 for i := 0; i < num; i++ {
185 piece := pieces[i]
186 var isParam bool
187 if len(piece) > 0 && piece[0:1] == "{" && piece[len(piece)-1:] == "}" {
188 isParam = true
189 piece = piece[1 : len(piece)-1]
190 }
191 offset = pickNextRoute(b, offset, piece, isParam)
192 if offset == -1 {
193 if len(path) == 0 {
194 // exhausted our options, bail
195 break
196 }
197 // no match, maybe save this and backup
198 if len(path) > len(longest) {
199 longest = append([]int{}, path...) // copy them over so they don't get modified
200 }
201 path, offset = backup(path)
202 offset = offset + 1
203 b = b.parent
204 i = i - 2
205 } else {
206 path = append(path, offset)
207 b = b.children[offset]
208 offset = 0
209 }
210 }
211 if len(longest) < len(path) {
212 longest = append([]int{}, path...)
213 }
214 return longest
215 }
217 func pickNextRoute(b *branch, offset int, input string, variable bool) int {
218 count := len(b.children)
219 for i := offset; i < count; i++ {
220 if b.children[i].key == input && b.isParam == variable {
221 return i
222 }
223 }
224 return -1
225 }
227 // Endpoint defines a single URL template that requests can be matched against. It uses
228 // URL parameters to accept variables in the URL structure and make them available to
229 // the Handlers associated with the Endpoint.
230 type Endpoint branch
232 // Handler associates the passed http.Handler with the Endpoint. This http.Handler will be
233 // used for all requests, regardless of the HTTP method they are using, unless overridden by
234 // the Methods method. Endpoints without a http.Handler associated with them will not be
235 // considered matches for requests, unless the request was made using an HTTP method that the
236 // Endpoint has an http.Handler mapped to.
237 func (e *Endpoint) Handler(h http.Handler) {
238 (*branch)(e).setHandler("", h)
239 }
241 // Methods simple returns a Methods object that will enable the mapping of the passed HTTP
242 // request methods to a Methods object. On its own, this function does not modify anything. It
243 // should, instead, be used as a friendly shorthand to get to the Methods.Handler method.
244 func (e *Endpoint) Methods(m ...string) Methods {
245 return Methods{
246 e: e,
247 m: m,
248 }
249 }
251 // Methods defines a pairing of an Endpoint to the HTTP request methods that should be mapped to
252 // specific http.Handlers. Its sole purpose is to enable the Methods.Handler method.
253 type Methods struct {
254 e *Endpoint
255 m []string
256 }
258 // Handler maps a Methods object to a specific http.Handler. This overrides the http.Handler
259 // associated with the Endpoint to only handle specific HTTP method(s).
260 func (m Methods) Handler(h http.Handler) {
261 b := (*branch)(m.e)
262 for _, method := range m.m {
263 b.setHandler(method, h)
264 }
265 }