Router a good

master
Bel LaPointe 2019-03-18 09:27:11 -06:00
commit 32326de6b2
4 changed files with 356 additions and 0 deletions

46
router.go Normal file
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package router
import (
"errors"
"net/http"
)
type Router struct {
t *tree
}
func New() *Router {
return &Router{
t: newTree(),
}
}
func (rt *Router) Add(path string, foo http.HandlerFunc) error {
return rt.t.Insert(path, foo)
}
func (rt *Router) ServeHTTP(w http.ResponseWriter, r *http.Request) {
foo := rt.t.Lookup(r.URL.Path)
if foo == nil {
http.NotFound(w, r)
return
}
foo(w, r)
}
func Params(r *http.Request, toSet ...*string) error {
params := r.Header[WildcardHeader]
if len(params) != len(toSet) {
return errors.New("missing params")
}
for i := range params {
if len(params[i]) < 1 {
return errors.New("empty params")
}
if toSet[i] == nil {
return errors.New("cannot set nil param")
}
*toSet[i] = params[i]
}
return nil
}

118
router_test.go Normal file
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package router
import (
"fmt"
"io/ioutil"
"net/http"
"net/http/httptest"
"strings"
"testing"
)
func TestRouter(t *testing.T) {
rt := New()
paths := []string{
"/not/found",
"/hello",
"/world",
"/hello/world",
"/hello/{}/other",
}
for i, p := range paths {
if i == 0 {
continue
}
if err := rt.Add(p, getHandler(p)); err != nil {
t.Errorf("router cannot add %v: %v", p, err)
}
}
if err := rt.Add(paths[len(paths)-1], getHandler(paths[len(paths)-1])); err == nil {
t.Errorf("router can re-add %v: %v", paths[len(paths)-1], err)
}
for i, p := range paths {
w := httptest.NewRecorder()
gpath := strings.Replace(p, "{}", "seq", -1)
if req, err := http.NewRequest("GET", gpath[1:]+"/", nil); err != nil {
t.Fatalf("cannot make http req: %v", err)
} else {
rt.ServeHTTP(w, req)
b, err := ioutil.ReadAll(w.Body)
if i > 0 && (err != nil || w.Code != 200 || string(b) != p) {
t.Errorf("did not check %v: %v %v %q %q", p, err, w.Code, b, p)
}
}
}
}
func getHandler(s string) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, s)
}
}
func TestParams(t *testing.T) {
var s string
cases := []struct {
actual int
put string
want int
assign *string
err bool
}{
{
put: "a",
assign: &s,
actual: 0,
want: 1,
err: true,
},
{
put: "a",
assign: &s,
actual: 1,
want: 0,
err: true,
},
{
put: "a",
assign: &s,
actual: 1,
want: 1,
err: false,
},
{
put: "i",
assign: nil,
actual: 1,
want: 1,
err: true,
},
{
put: "",
assign: &s,
actual: 1,
want: 1,
err: true,
},
}
for z, c := range cases {
r, _ := http.NewRequest("GET", "localhost:123", nil)
actual := []string{}
for i := 0; i < c.actual; i++ {
actual = append(actual, c.put)
}
r.Header[WildcardHeader] = actual
want := []*string{}
for i := 0; i < c.want; i++ {
want = append(want, c.assign)
}
err := Params(r, want...)
if (err != nil) != c.err {
t.Errorf("[%d] get params didn't find err %v when %v vs %v: %v", z, c.err, c.actual, c.want, err)
}
}
}

67
tree.go Normal file
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package router
import (
"errors"
"net/http"
"path"
"strings"
)
var Wildcard = "{}"
var WildcardHeader = "__wildcard_value__"
type tree struct {
next map[string]*tree
handler http.HandlerFunc
}
func newTree() *tree {
return &tree{
next: make(map[string]*tree),
handler: nil,
}
}
func (t *tree) Lookup(path string) http.HandlerFunc {
if path == "/" || path == "" {
return t.handler
}
key, following := nextPathSegment(path)
if n, ok := t.next[key]; ok {
return n.Lookup(following)
} else if n, ok := t.next[Wildcard]; ok {
foo := n.Lookup(following)
if foo != nil {
return func(w http.ResponseWriter, r *http.Request) {
r.Header.Add(WildcardHeader, key)
foo(w, r)
}
}
}
return nil
}
func (t *tree) Insert(path string, foo http.HandlerFunc) error {
if path == "/" {
if t.handler != nil {
return errors.New("occupied path")
}
t.handler = foo
return nil
}
key, following := nextPathSegment(path)
_, ok := t.next[key]
if !ok {
t.next[key] = newTree()
}
return t.next[key].Insert(following, foo)
}
func nextPathSegment(p string) (string, string) {
p = path.Clean("/" + p)
i := strings.Index(p[1:], "/") + 1
if i <= 0 {
return p[1:], "/"
}
return p[1:i], p[i:]
}

125
tree_test.go Normal file
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package router
import (
"fmt"
"io/ioutil"
"net/http"
"net/http/httptest"
"strings"
"testing"
)
var nilHandle = func(w http.ResponseWriter, r *http.Request) {}
func TestNewTree(t *testing.T) {
newTree()
}
func TestTreeInsert(t *testing.T) {
tree := newTree()
if err := tree.Insert("/hello/world", nilHandle); err != nil {
t.Errorf("failed to insert first path: %v", err)
}
if err := tree.Insert("/hello/world", nilHandle); err == nil {
t.Errorf("succeeded to insert dupe path: %v", err)
}
if err := tree.Insert("/hello/", nilHandle); err != nil {
t.Errorf("failed to insert sub path: %v", err)
}
if err := tree.Insert("/world/", nilHandle); err != nil {
t.Errorf("failed to insert new path: %v", err)
}
}
func TestTreeLookup(t *testing.T) {
tree := newTree()
subtree := newTree()
checked := false
subtree.handler = func(w http.ResponseWriter, r *http.Request) {
checked = true
}
tree.next["hi"] = subtree
foo := tree.Lookup("/hi/")
if foo == nil {
t.Errorf("cannot lookup path: %v", "/hi/")
} else {
foo(nil, nil)
}
if !checked {
t.Errorf("lookup returned wrong function")
}
}
func TestTreeInsertLookup(t *testing.T) {
tree := newTree()
checked := false
foo := func(_ http.ResponseWriter, _ *http.Request) {
checked = true
}
paths := []string{
"/hello",
"/hello/world",
"/world",
}
for _, p := range paths {
if err := tree.Insert(p, foo); err != nil {
t.Fatalf("cannot insert: %v", err)
}
}
for _, p := range paths {
if bar := tree.Lookup(p[1:] + "/"); bar == nil {
t.Fatalf("cannot lookup: %v", p)
} else {
checked = false
bar(nil, nil)
if !checked {
t.Errorf("failed to call %v: %v", p, checked)
}
}
}
}
func TestTreeWildcard(t *testing.T) {
tree := newTree()
checked := false
foo := func(w http.ResponseWriter, r *http.Request) {
checked = true
fmt.Fprintf(w, "%v", r.Header[WildcardHeader])
}
paths := []string{
"/hello/{}",
"/hello/{}/{}/world",
}
for _, p := range paths {
if err := tree.Insert(p, foo); err != nil {
t.Fatalf("cannot insert: %v", err)
}
}
for _, p := range paths {
dpath := strings.Replace(p, "{}", "seq", -1)
if bar := tree.Lookup(dpath[1:] + "/"); bar == nil {
t.Fatalf("cannot lookup: %v", p)
} else {
checked = false
w := httptest.NewRecorder()
r, _ := http.NewRequest("GET", dpath, nil)
bar(w, r)
if !checked {
t.Errorf("failed to call %v: %v", p, checked)
}
b, err := ioutil.ReadAll(w.Body)
if err != nil {
t.Errorf("failed to read all: %v", err)
}
if strings.Count(string(b), "seq") != strings.Count(p, "{}") {
t.Errorf("failed to decode wildcards: %s", b)
}
}
}
}