Implement part of the DHT handler

1 files changed, 84 insertions, 11 deletions

diff --git a/server/server.go b/server/server.go
index e84b4e0..11aae25 100644
--- a/server/server.go
+++ b/server/server.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"crypto/ed25519"
 	"crypto/sha256"
 	"encoding/hex"
 	"flag"
@@ -13,20 +14,26 @@ import (
 	"sync"
 )
 
+type user struct {
+	pubkey []byte
+}
+
 var mu sync.Mutex
 var me string
+var myHash string
+var myPos int
 var hashToDomain map[string]string
 var peerHashes []string
 var kvstore map[string]string
 
+// Get the sha256sum of string as a hex string
 func sha256sum(s string) string {
-	// Get the sha256sum of string as a hex string
 	b := sha256.Sum256([]byte(s))
 	return hex.EncodeToString(b[:])
 }
 
+// Try to peer with another server
 func addPeer(peer string) error {
-	// Try to peer with another server
 	peerHash := sha256sum(peer)
 	// Check if already peered
 	mu.Lock()
@@ -52,8 +59,11 @@ func addPeer(peer string) error {
 
 	log.Printf("%s successfully peered with %s", me, peer)
 	mu.Lock()
-	peerHashes = append(peerHashes, peerHash)
-	sort.Sort(sort.StringSlice(peerHashes))
+	i := sort.SearchStrings(peerHashes, peerHash)
+	peerHashes = append(peerHashes, "")
+	copy(peerHashes[i+1:], peerHashes[i:])
+	peerHashes[i] = peerHash
+	myPos = sort.SearchStrings(peerHashes, me)
 	mu.Unlock()
 	// Read response body
 	defer resp.Body.Close()
@@ -69,26 +79,87 @@ func addPeer(peer string) error {
 	return nil
 }
 
+// Handle incoming peer requests
 func peerHandler(w http.ResponseWriter, r *http.Request) {
-	// Handle incoming peer requests
 	r.ParseForm()
 	peer := r.Form.Get("peer")
 	if peer == "" {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
-	go addPeer(peer)
 	for _, p := range hashToDomain {
 		fmt.Fprintf(w, "%s\n", p)
 	}
+	go addPeer(peer)
 }
 
-func getHandler(w http.ResponseWriter, r *http.Request) {
-
+// Handle DHT requests
+func dhtHandler(w http.ResponseWriter, r *http.Request) {
+	key := r.URL.String()[5:]
+	keyHash := sha256sum(key)
+	fmt.Println(key, keyHash)
+	mu.Lock()
+	keyPos := sort.SearchStrings(peerHashes, keyHash)
+	if keyPos < myPos {
+		keyPos += len(peerHashes)
+	}
+	mu.Unlock()
+	if r.Method == "GET" {
+		if keyPos - myPos < 5 {
+			mu.Lock()
+			if val, ok := kvstore[key]; ok {
+				w.Write([]byte(val))
+			} else {
+				w.WriteHeader(http.StatusNotFound)
+			}
+			mu.Unlock()
+		} else {
+			for i := 0; i < 5 && i < len(peerHashes); i++ {
+				j := hashToDomain[peerHashes[(keyPos+i)%len(peerHashes)]]
+				go func() string {
+					resp, err := http.Get(j + r.URL.String())
+					if err != nil {
+						return ""
+					}
+					b, err := io.ReadAll(resp.Body)
+					if err != nil {
+						return ""
+					}
+					return string(b)
+				}()
+
+			}
+
+
+		}
+	} else if r.Method == "PUT" {
+		b, err := io.ReadAll(r.Body)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+		}
+
+
+		if keyPos - myPos < 5 {
+			mu.Lock()
+			kvstore[key] = string(b)
+		}
+	} else {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+	}
 }
 
-func setHandler(w http.ResponseWriter, r *http.Request) {
+// Handle storage requests
+func storageHandler(w http.ResponseWriter, r *http.Request) {
+	filename := r.URL.String()[5:]
+	if r.Method == "GET" {
 
+	} else if r.Method == "PUT" {
+
+	} else if r.Method == "DELETE" {
+
+	} else {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+	}
 }
 
 func main() {
@@ -101,6 +172,8 @@ func main() {
 
 	// Record myself
 	me = *domain
+	myHash = sha256sum(me)
+	myPos = 0
 	peerHashes = append(peerHashes, sha256sum(me))
 	hashToDomain = map[string]string{peerHashes[0]: me}
 
@@ -109,7 +182,7 @@ func main() {
 	}
 
 	http.HandleFunc("/peer", peerHandler)
-	http.HandleFunc("/get", getHandler)
-	http.HandleFunc("/set", setHandler)
+	http.HandleFunc("/dht", dhtHandler)
+	http.HandleFunc("/storage", storageHandler)
 	log.Fatal(http.ListenAndServe(*bindAddr, nil))
 }