Add hash check for file upload

handler/user/user.go

@@ -45,6 +45,8 @@ type ActionUploadNewFile struct {
 	Name      string `json:"name"`
 	Size      uint64 `json:"size"`
 	Chunk     uint64 `json:"chunk"`
+	StartHash string `json:"startHash"`
+	EndHash   string `json:"endHash"`
 	RequestID string `json:"requestID"`
 }
 
@@ -127,7 +129,7 @@ func handlerWS(conn *websocket.Conn, userSession types.User) {
 		err = json.Unmarshal(message, &action)
 		if err != nil {
 			app.Server.Logger.Error("Error unmarshalling WebsocketAction:", err)
-			sendErrorResponse(conn, action.Action)
+			sendErrorResponse(conn, action.Action, "Internal Server Error")
 			continue
 		}
 
@@ -137,7 +139,7 @@ func handlerWS(conn *websocket.Conn, userSession types.User) {
 			err = json.Unmarshal(message, &uploadNewFile)
 			if err != nil {
 				app.Server.Logger.Error("Error unmarshalling ActionUploadNewFile:", err)
-				sendErrorResponse(conn, action.Action)
+				sendErrorResponse(conn, action.Action, "Internal Server Error")
 				continue
 			}
 			var file *models.File
@@ -149,12 +151,14 @@ func handlerWS(conn *websocket.Conn, userSession types.User) {
 						OwnerID:    userSession.UserID,
 						Name:       uploadNewFile.Name,
 						Size:       uploadNewFile.Size,
+						StartHash:  uploadNewFile.StartHash,
+						EndHash:    uploadNewFile.EndHash,
 						TotalChunk: uploadNewFile.Chunk,
 						Downloaded: 0,
 					}
 					err := app.Server.Database.CreateFile(&newFile)
 					if err != nil {
-						sendErrorResponse(conn, action.Action)
+						sendErrorResponse(conn, action.Action, "Error Creating File")
 						continue
 					}
 					fileData := &types.FileWithDetail{
@@ -179,10 +183,14 @@ func handlerWS(conn *websocket.Conn, userSession types.User) {
 					sendSuccessResponseWithID(conn, action.Action, fileData, uploadNewFile.RequestID)
 					continue
 				} else {
-					sendErrorResponse(conn, action.Action)
+					sendErrorResponse(conn, action.Action, "Unknown error")
 					continue
 				}
 			}
+			if uploadNewFile.StartHash != file.StartHash || uploadNewFile.EndHash != file.EndHash {
+				sendErrorResponse(conn, action.Action, "File Is Different")
+				continue
+			}
 			fileData := &types.FileWithDetail{
 				ID:         file.ID,
 				OwnerID:    file.OwnerID,
@@ -213,10 +221,11 @@ func handlerWS(conn *websocket.Conn, userSession types.User) {
 	}
 }
 
-func sendErrorResponse(conn *websocket.Conn, action ActionType) {
+func sendErrorResponse(conn *websocket.Conn, action ActionType, message string) {
 	response := map[string]interface{}{
-		"action": action,
-		"status": "error",
+		"action":  action,
+		"status":  "error",
+		"message": message,
 	}
 	marshal, err := json.Marshal(response)
 	if err != nil {

public/main.js

@@ -9,14 +9,25 @@ if (!window.mySocket) {
     window.mySocket.onmessage = async function(event) {
         try {
             const data = JSON.parse(event.data);
-            if (data.action === "UploadNewFile") {
-                if (data.response.Done === false) {
-                    const file = window.fileIdMap[data.responseID];
-                    addNewUploadElement(file);
-                    const fileChunks = await splitFile(file, file.chunkSize);
-                    await uploadChunks(file.name, file.size, fileChunks, data.response.Chunk, data.response.ID);
+            if (data.status === "error") {
+                if (data.message === "File Is Different") {
+                    ChangeModal("Error", "A file with the same name already exists but has a different hash value. This may indicate that the file is different, despite having the same name. Please verify the file or consider renaming it before proceeding.")
+                    toggleModal();
                 } else {
-                    alert("File already uploaded.");
+                    ChangeModal("Error", "There was an issue with your upload. Please try again later or contact support if the problem persists.")
+                    toggleModal();
+                }
+            } else {
+                if (data.action === "UploadNewFile") {
+                    if (data.response.Done === false) {
+                        const file = window.fileIdMap[data.responseID];
+                        addNewUploadElement(file);
+                        const fileChunks = await splitFile(file, file.chunkSize);
+                        await uploadChunks(file.name, file.size, fileChunks, data.response.Chunk, data.response.ID);
+                    } else {
+                        ChangeModal("Error", "File already uploaded.")
+                        toggleModal();
+                    }
                 }
             }
         } catch (error) {
@@ -44,11 +55,17 @@ async function handleFile(file){
     const chunkSize = 2 * 1024 * 1024;
     const chunks = Math.ceil(file.size / chunkSize);
     const fileId = generateUniqueId();
+    const startChunk = await file.slice(0, chunkSize).arrayBuffer();
+    const endChunk = await file.slice((chunks-1) * chunkSize, file.size).arrayBuffer();
+    const startChunkHash = await hash(startChunk)
+    const endChunkHash = await  hash(endChunk)
     const data = JSON.stringify({
         "action": "UploadNewFile",
         "name": file.name,
         "size": file.size,
         "chunk": chunks,
+        "startHash": startChunkHash,
+        "endHash": endChunkHash,
         "requestID": fileId,
     });
     file.chunkSize = chunkSize;
@@ -133,12 +150,22 @@ async function splitFile(file, chunkSize) {
         const start = i * chunkSize;
         const end = Math.min(fileSize, start + chunkSize);
         const chunk = file.slice(start, end);
+        chunk.hash = "test"
         fileChunks.push(chunk);
     }
 
     return fileChunks;
 }
 
+async function hash(arrayBuffer) {
+    const hashBuffer = await crypto.subtle.digest('SHA-256', arrayBuffer);
+    const hashArray = Array.from(new Uint8Array(hashBuffer));
+    const hashHex = hashArray
+        .map((bytes) => bytes.toString(16).padStart(2, '0'))
+        .join('');
+    return hashHex;
+}
+
 async function uploadChunks(name, size, chunks, chunkArray, FileID) {
     let byteUploaded = 0
     let progress1 = document.getElementById(`progress-${name}-1`);

types/models/models.go

@@ -16,6 +16,8 @@ type File struct {
 	Name       string    `gorm:"type:text;not null"`
 	Size       uint64    `gorm:"not null"`
 	TotalChunk uint64    `gorm:"not null"`
+	StartHash  string    `gorm:"type:text;not null"`
+	EndHash    string    `gorm:"type:text;not null"`
 	Downloaded uint64    `gorm:"not null;default:0"`
 	Owner      *User     `gorm:"foreignKey:OwnerID;constraint:OnDelete:CASCADE;"`
 }