fix to disallow invalid characters in filenames

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 All notable changes to the z/OS FTP Plug-in for Zowe CLI will be documented in this file.
 
+## Recent Changes
+- BugFix: Provide new utility function that checks file names for valid characters [143](https://github.com/zowe/zowe-cli-ftp-plugin/issues/143).
+
 ## `2.1.3`
 
 - Update example of `upload file-to-data-set` command.

src/cli/Utilities.ts

@@ -0,0 +1,36 @@
+/*
+ * This program and the accompanying materials are made available under the terms of the
+ * Eclipse Public License v2.0 which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-v20.html
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Copyright Contributors to the Zowe Project.
+ *
+ */
+
+export class Utilities{
+    /**
+     * Check to ensure filename only contains valid characters
+     * @param {fileName} string - filename to be evaluated
+     * @returns {Promise<boolean>} - promise that resolves to true if filename contains valid characters
+     * @memberof Utilities
+     */
+    public static async isValidFileName(fileName: string): Promise<boolean> {
+        // Define valid character ranges for ISO/IEC 8859-1 https://en.wikipedia.org/wiki/ISO/IEC_8859-1
+        const validRanges = [
+            { start: 32, end: 127 },   // First chunk of valid characters
+            { start: 160, end: 255 }  // Second chunk of valid characters
+        ];
+
+        // Check if each character in the filename is within a valid range
+        for (const char of fileName) {
+            const charCode = char.charCodeAt(0);
+            if (!validRanges.some(range => charCode >= range.start && charCode <= range.end)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}

src/cli/download/data-set/DataSet.Handler.ts

@@ -14,33 +14,48 @@ import { FTPBaseHandler } from "../../../FTPBase.Handler";
 import { IFTPHandlerParams } from "../../../IFTPHandlerParams";
 import { FTPProgressHandler } from "../../../FTPProgressHandler";
 import { DataSetUtils, TRANSFER_TYPE_ASCII, TRANSFER_TYPE_ASCII_RDW, TRANSFER_TYPE_BINARY, TRANSFER_TYPE_BINARY_RDW } from "../../../api";
+import { ImperativeError } from "@zowe/imperative";
+import { Utilities } from "../../Utilities";
 
 export default class DownloadDataSetHandler extends FTPBaseHandler {
     public async processFTP(params: IFTPHandlerParams): Promise<void> {
-
         const file = params.arguments.file == null ?
             ZosFilesUtils.getDirsFromDataSet(params.arguments.dataSet) :
             params.arguments.file;
+        try {
+            // Validate the destination file name before proceeding
+            if (!(await Utilities.isValidFileName(file))) {
+                throw new ImperativeError({ msg: "Invalid file name. Please check the file name for typos." });
+            }
+
+            let progress;
+            if (params.response && params.response.progress) {
+                progress = new FTPProgressHandler(params.response.progress, true);
+            }
+            let transferType = params.arguments.binary ? TRANSFER_TYPE_BINARY : TRANSFER_TYPE_ASCII;
+            if (params.arguments.rdw) {
+                transferType = params.arguments.binary ? TRANSFER_TYPE_BINARY_RDW : TRANSFER_TYPE_ASCII_RDW;
+            }
+            const options = {
+                localFile: file,
+                response: params.response,
+                transferType,
+                progress,
+                encoding: params.arguments.encoding
+            };
+            await DataSetUtils.downloadDataSet(params.connection, params.arguments.dataSet, options);
 
-        let progress;
-        if (params.response && params.response.progress) {
-            progress = new FTPProgressHandler(params.response.progress, true);
+            const successMsg = params.response.console.log(ZosFilesMessages.datasetDownloadedSuccessfully.message, file);
+            this.log.info(successMsg);
+            params.response.data.setMessage(successMsg);
         }
-        let transferType = params.arguments.binary ? TRANSFER_TYPE_BINARY : TRANSFER_TYPE_ASCII;
-        if (params.arguments.rdw) {
-            transferType = params.arguments.binary ? TRANSFER_TYPE_BINARY_RDW : TRANSFER_TYPE_ASCII_RDW;
+        catch (e) {
+            if (e instanceof ImperativeError){
+                throw e;
+            }
+            throw new ImperativeError({
+                msg: `An error was encountered while trying to download your dataset '${file}'.\nError details: ${e.message}`
+            });
         }
-        const options = {
-            localFile: file,
-            response: params.response,
-            transferType,
-            progress,
-            encoding: params.arguments.encoding
-        };
-        await DataSetUtils.downloadDataSet(params.connection, params.arguments.dataSet, options);
-
-        const successMsg = params.response.console.log(ZosFilesMessages.datasetDownloadedSuccessfully.message, file);
-        this.log.info(successMsg);
-        params.response.data.setMessage(successMsg);
     }
 }