Initial commit.

2025-08-06 16:58:36 +00:00 · 2025-08-06 16:58:36 +00:00 · 0a9434be1b
commit 0a9434be1b
18 changed files with 1860 additions and 0 deletions
--- a/server/go-http/README.md
+++ b/server/go-http/README.md
@ -0,0 +1,5 @@
+NOJSCAP Go server example with net/http + html/template.
+
+# Running
+
+go run server.go
--- a/server/go-http/server.go
+++ b/server/go-http/server.go
@ -0,0 +1,175 @@
+package main
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"html/template"
+	"log"
+	"net/http"
+	"strconv"
+	"sync"
+	"time"
+)
+
+const (
+	port       = 3000
+	difficulty = 20
+)
+
+var (
+	challengeStore = make(map[string]time.Time)
+	storeMutex     sync.Mutex
+)
+
+func generateChallenge() string {
+	b := make([]byte, 12)
+	_, err := rand.Read(b)
+	if err != nil {
+		panic(err)
+	}
+	return hex.EncodeToString(b)
+}
+
+func checkDifficulty(hash []byte, bits int) bool {
+	i := 0
+	for bits > 0 {
+		b := hash[i]
+		if bits >= 8 {
+			if b != 0 {
+				return false
+			}
+			bits -= 8
+		} else {
+			mask := byte(0xFF << (8 - bits))
+			if b&mask != 0 {
+				return false
+			}
+			bits = 0
+		}
+		i++
+	}
+	return true
+}
+
+func indexHandler(w http.ResponseWriter, r *http.Request) {
+	challenge := generateChallenge()
+
+	storeMutex.Lock()
+	challengeStore[challenge] = time.Now()
+	storeMutex.Unlock()
+
+	tmpl.Execute(w, map[string]string{
+		"Challenge":  challenge,
+		"Difficulty": strconv.Itoa(difficulty),
+	})
+}
+
+func postHandler(w http.ResponseWriter, r *http.Request) {
+	challenge := r.FormValue("challenge")
+	nonce := r.FormValue("nonce")
+
+	storeMutex.Lock()
+	_, ok := challengeStore[challenge]
+	if ok {
+		delete(challengeStore, challenge)
+	}
+	storeMutex.Unlock()
+
+	if !ok {
+		fmt.Fprint(w, "<p>Invalid challenge.</p><a href='/'>Try again</a>")
+		return
+	}
+
+	hash := sha256.Sum256([]byte(challenge + nonce))
+	if checkDifficulty(hash[:], difficulty) {
+		fmt.Fprint(w, "<p>Success! Valid nonce.</p><a href='/'>Try again</a>")
+	} else {
+		fmt.Fprint(w, "<p>Invalid nonce.</p><a href='/'>Try again</a>")
+	}
+}
+
+var tmpl = template.Must(template.New("page").Parse(`
+<!doctype html>
+<html lang="en">
+<head>
+  <title>NOJSCAP demo</title>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <style>
+  body {
+    padding: 20px;
+    margin-bottom: 300px;
+    background: #cacaca;
+    color: black;
+  }
+  code {
+    white-space: break-spaces;
+    background: black;
+    color: white;
+    padding: 10px;
+    display: block;
+    max-width: 500px;
+  }
+  .h {
+    font-size: 21px;
+    font-weight: bolder;
+    width: 100%;
+    float: left;
+  }
+  button {
+    background: #006ed0;
+    color: white;
+    border: 1px solid #006ed0;
+    padding: 10px 20px;
+    margin-top: 10px;
+  }
+  input {
+    background: black;
+    color: white;
+    padding: 10px;
+    display: block;
+    max-width: 500px;
+    width: 100%;
+    border: 0px solid transparent;
+    font-family: monospace;
+    font-size: 12px;
+  }
+  </style>
+</head>
+<body>
+  <h1>NOJSCAP demo</h1>
+  <p><a href="https://git.libroot.org/libroot/NOJSCAP/" target="_blank">https://git.libroot.org/libroot/NOJSCAP/</a></p>
+  <p>If you don't already have the <b><em>NOJSCAP</em></b> client:</p>
+  <code>$ git clone https://git.libroot.org/libroot/NOJSCAP/$ cd NOJSCAP/client/</code>
+  <p><code>$ python3 pow_client.py {{.Challenge}} {{.Difficulty}}</code></p>
+  <p><strong>Go:</strong></p>
+  <p><code>$ go run pow_client.go {{.Challenge}} {{.Difficulty}}</code></p>
+  <p><strong>Node.js:</strong></p>
+  <p><code>$ node pow_client.js {{.Challenge}} {{.Difficulty}}</code></p>
+  <p><strong>Rust:</strong></p>
+  <p><code>$ rustc pow_client.rs -o pow_client_rs$ pow_client_rs {{.Challenge}} {{.Difficulty}}</code></p>
+  <p><strong>C:</strong></p>
+  <p><code>$ gcc -O2 -o pow_client pow_client.c -lssl -lcrypto$ ./pow_client {{.Challenge}} {{.Difficulty}}</code></p>
+  <form method="POST">
+    <input type="hidden" name="challenge" value="{{.Challenge}}">
+    <label class="h">Nonce: <input name="nonce"></label>
+    <button type="submit">Submit</button>
+  </form>
+</body>
+</html>
+`))
+
+func main() {
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodPost {
+			postHandler(w, r)
+		} else {
+			indexHandler(w, r)
+		}
+	})
+	fmt.Printf("Running on http://localhost:%d\n", port)
+	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", port), nil))
+}
+