HTTP Server and Request Routing

The server handles HTTP requests and routes them to the appropriate nodes based on the hash ring.

Implementation

// shreder/server.go
type CacheServer struct {
    cache    *Cache
    peers    []string
    mu       sync.Mutex
    selfID   string
    hashRing *hash_ring.HashRing
}

func (cs *CacheServer) SetHandler(w http.ResponseWriter, r *http.Request) {
    bodyBytes, err := io.ReadAll(r.Body)
    if err != nil {
        w.WriteHeader(http.StatusBadRequest)
        return
    }

    var request setRequest
    if err := json.Unmarshal(bodyBytes, &request); err != nil {
        w.WriteHeader(http.StatusBadRequest)
        return
    }

    isReplication := r.Header.Get(replicationHeader) == "true"
    targetNode := cs.hashRing.GetNode(request.Key)

    if targetNode.Address == cs.selfID {
        cs.cache.Set(request.Key, request.Value, 10*time.Minute)
        if !isReplication {
            cs.replicaset(request.Key, request.Value)
        }
        w.WriteHeader(http.StatusOK)
    } else {
        r.Body = io.NopCloser(bytes.NewReader(bodyBytes))
        cs.forwardRequest(targetNode, r, w)
    }
}

Request Flow

1. Client sends request to any node
2. Node uses hash ring to determine responsible node
3. If current node is responsible, it processes the request locally
4. Otherwise, it forwards the request to the responsible node
5. Data changes are replicated to peer nodes