Не могу понять, как делать запросы на «доступ», «часы» и «аудит» с необходимыми параметрами.Не могли бы вы дать мне несколько советов о том, как сделать эти запросы?
package main
import (
"crypto/sha256"
"crypto/subtle"
"encoding/base64"
"encoding/json"
"fmt"
"log"
"net/http"
"os"
"sync"
"time"
)
const secret = "galumphing"
// Required parameters for the request
type params struct {
Act string
Nonce string
Signature string
Timeout int64
Offset int
}
var (
auditLock sync.Mutex
auditBase int
auditLog []string
)
var (
seenLock sync.Mutex
seenMap = map[string]bool{}
)
var (
clockAsk = make(chan bool)
clockTime = make(chan int64, 1)
)
func main() {
// Endpoints available
http.HandleFunc("/903/access", handleAccess)
http.HandleFunc("/903/clock", handleClock)
http.HandleFunc("/903/audit", handleAudit)
err := http.ListenAndServe(os.Args[1], nil)
if err != nil {
log.Fatal(err)
}
}
func checkCapacity(w http.ResponseWriter) (ok bool) {
auditLock.Lock()
defer auditLock.Unlock()
if len(auditLog) > 10 {
w.WriteHeader(http.StatusServiceUnavailable)
return
}
ok = true
return
}
func audit(r *http.Request, params params, ok bool) {
auditLock.Lock()
defer auditLock.Unlock()
auditLog = append(auditLog, fmt.Sprintf("%v %q %q", ok, r.URL.Path, params.Act))
}
func parse(w http.ResponseWriter, r *http.Request) (params params, ok bool) {
defer func() {
if !ok {
audit(r, params, false)
}
}()
w.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS")
w.Header().Set("Access-Control-Allow-Origin", "*")
w.Header().Set("Access-Control-Max-Age", "3600")
if r.Method != "POST" {
w.Header().Set("Allow", "POST, OPTIONS")
if r.Method == "OPTIONS" {
w.WriteHeader(http.StatusOK)
} else {
w.WriteHeader(http.StatusMethodNotAllowed)
}
return
}
err := json.NewDecoder(r.Body).Decode(¶ms)
if err != nil {
w.WriteHeader(http.StatusBadRequest)
log.Printf("%s: %v", r.URL.Path, err)
return
}
h := sha256.New()
fmt.Fprintf(h, "%s\r\n%s\r\n%s\r\n%s", r.URL.Path, params.Act, params.Nonce, secret)
sig := base64.StdEncoding.EncodeToString(h.Sum(nil))
if subtle.ConstantTimeCompare([]byte(sig), []byte(params.Signature)) != 1 {
w.WriteHeader(http.StatusForbidden)
return
}
seenLock.Lock()
seen := seenMap[params.Signature]
if !seen {
seenMap[params.Signature] = true
}
seenLock.Unlock()
if seen {
w.WriteHeader(http.StatusForbidden)
return
}
ok = true
return
}
func handleAccess(w http.ResponseWriter, r *http.Request) {
if !checkCapacity(w) {
return
}
params, ok := parse(w, r)
if !ok {
return
}
switch params.Act {
case "begin":
if params.Timeout < 0 || params.Timeout > 250000 {
w.WriteHeader(http.StatusBadRequest)
audit(r, params, false)
return
}
timer := time.NewTimer(time.Duration(params.Timeout) * time.Microsecond)
select {
case clockAsk <- true: // https://golang.org/ref/spec#Send_statements
w.WriteHeader(http.StatusNoContent)
audit(r, params, true)
case <-timer.C:
w.WriteHeader(http.StatusConflict)
audit(r, params, false)
return
}
go func() {
<-timer.C
select {
case <-clockTime:
default:
}
}()
case "end":
if params.Timeout < 0 {
w.WriteHeader(http.StatusBadRequest)
audit(r, params, false)
return
}
timer := time.NewTimer(time.Duration(params.Timeout) * time.Microsecond)
select {
case value := <-clockTime: // https://golang.org/ref/spec#Receive_operator
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(http.StatusOK)
fmt.Fprintln(w, value)
audit(r, params, true)
case <-timer.C:
w.WriteHeader(http.StatusConflict)
audit(r, params, false)
}
default:
w.WriteHeader(http.StatusBadRequest)
audit(r, params, false)
}
}
func handleClock(w http.ResponseWriter, r *http.Request) {
if !checkCapacity(w) {
return
}
params, ok := parse(w, r)
if !ok {
return
}
switch params.Act {
case "observe":
if params.Timeout != 0 {
w.WriteHeader(http.StatusBadRequest)
audit(r, params, false)
return
}
select {
case <-clockAsk: // https://golang.org/ref/spec#Receive_operator
select {
case clockTime <- time.Now().Unix(): // https://golang.org/ref/spec#Send_statements
default:
}
default:
}
w.WriteHeader(http.StatusNoContent)
audit(r, params, true)
default:
w.WriteHeader(http.StatusBadRequest)
audit(r, params, false)
}
}
func handleAudit(w http.ResponseWriter, r *http.Request) {
params, ok := parse(w, r)
if !ok {
return
}
ok = false
func() {
auditLock.Lock()
defer auditLock.Unlock()
switch params.Act {
case "":
if params.Offset != 0 {
w.WriteHeader(http.StatusBadRequest)
return
}
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(http.StatusOK)
fmt.Fprintln(w, auditBase)
case "burble":
if params.Offset < auditBase || params.Offset > auditBase+len(auditLog) {
w.WriteHeader(http.StatusBadRequest)
return
}
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(http.StatusOK)
for i := params.Offset - auditBase; i < len(auditLog); i++ {
fmt.Fprintf(w, "%d %s\n", auditBase+i, auditLog[i])
}
case "chortle":
if params.Offset > auditBase+len(auditLog) {
w.WriteHeader(http.StatusBadRequest)
return
}
if params.Offset > auditBase {
auditLog = auditLog[params.Offset-auditBase:] // https://golang.org/ref/spec#Slice_expressions
auditBase = params.Offset
}
w.WriteHeader(http.StatusNoContent)
default:
w.WriteHeader(http.StatusBadRequest)
return
}
ok = true
}()
audit(r, params, ok)
}