Add copy file endpoint code

.gitignore

@@ -40,4 +40,5 @@ yarn-error.log*
 **/*.log
 package-lock.json
 **/*.bun
-idea/
+idea/
+

src/app.ts

@@ -6,6 +6,7 @@ import {addGetFileEndpoint} from './endpoints/file/getFile';
 import {addUploadFileEndpoint} from './endpoints/file/uploadFile';
 import {addCheckFileExistsEndpoint} from './endpoints/file/checkFileExists';
 import {addGetFileSizeEndpoint} from './endpoints/file/getFileSize';
+import { addCopyFileEndpoint } from './endpoints/file/copyFile';
 
 export function buildApp() {
   let app = new Elysia();
@@ -20,5 +21,6 @@ export function buildApp() {
   addGetFileSizeEndpoint(app);
   addUploadFileEndpoint(app);
   addCheckFileExistsEndpoint(app);
+  addCopyFileEndpoint(app);
   return app;
 }

src/constants/commonResponses.ts

@@ -13,6 +13,14 @@ export const unsupportedBinaryDataTypeMsg = 'Unsupported binary data type';
 export const invalidFileFormatInFormDataMsg = 'Invalid file format in form data';
 export const noFileFieldInFormDataMsg = 'No file field in form data';
 export const invalidFormDataStructure = 'Invalid structure for multipart/form-data';
+export const invalidOverwriteFlagMsg = 'Parameter "overwrite" must be either "true" or "false"';
+
+// For operations involving a source and a destination
+// such as copy and move
+export const invalidSourcePathMsg = 'Invalid source file path';
+export const invalidDestinationPathMsg = 'Invalid destination file path';
+export const sourceFileDoesNotExistOrIsADirectoryMsg = 'Source file does not exist or is a directory';
+export const destinationFileExistsAndOverwriteIsNotSetMsg = 'Destination file exists and overwrite is not set';
 
 // Internal server errors
 export const dirCreateFailMsg = 'Could not create directory';

src/endpoints/file/copyFile.ts

@@ -0,0 +1,67 @@
+import Elysia from 'elysia';
+import { validateRelativePath } from '../../utils/pathUtils';
+import { copyFile } from '../../utils/fileUtils';
+import {
+  invalidOverwriteFlagMsg,
+  invalidSourcePathMsg,
+  invalidDestinationPathMsg,
+  sourceFileDoesNotExistOrIsADirectoryMsg,
+  destinationFileExistsAndOverwriteIsNotSetMsg
+} from '../../constants/commonResponses'
+
+export function addCopyFileEndpoint(app: Elysia) {
+  return app.post('file/copy', async ({ query, set }) => {
+
+    const sourcePathValidationResult = validateRelativePath(query.source);
+    if (sourcePathValidationResult.isErr()) {
+      set.status = 400;
+      return invalidSourcePathMsg;
+    }
+    const sourcePath = sourcePathValidationResult.value;
+
+    const destinationPathValidationResult = validateRelativePath(query.destination);
+    if (destinationPathValidationResult.isErr()) {
+      set.status = 400;
+      return invalidDestinationPathMsg;
+    }
+    const destinationPath = destinationPathValidationResult.value;
+
+    let overwrite = false;
+    if (query.overwrite) {
+      if (query.overwrite === "true")
+        overwrite = true;
+      else if (query.overwrite === "false")
+        overwrite = false;
+      else {
+        set.status = 400;
+        return invalidOverwriteFlagMsg;
+      }
+    }
+
+    let copyResult = await copyFile(
+      sourcePath.absolutePath,
+      destinationPath.absolutePath,
+      overwrite);
+
+    if (copyResult.isOk()) {
+      return Response("", { status: 204 });
+    }
+    else {
+      switch (copyResult.error) {
+        case sourceFileDoesNotExistOrIsADirectoryMsg: {
+          set.status = 404;
+          break;
+        }
+        case destinationFileExistsAndOverwriteIsNotSetMsg: {
+          set.status = 409;
+          break;
+        }
+        default: {
+          set.status = 500;
+          break;
+        }
+      }
+      return copyResult.error;
+    }
+  });
+}

src/utils/fileUtils.ts

@@ -2,9 +2,11 @@ import {BunFile} from 'bun';
 import Bun from 'bun';
 import {Result, err, ok} from 'neverthrow';
 import {
+  destinationFileExistsAndOverwriteIsNotSetMsg,
   dirCreateFailMsg,
   fileAlreadyExistsMsg,
   fileMustNotEmptyMsg,
+  sourceFileDoesNotExistOrIsADirectoryMsg,
   unknownErrorMsg,
 } from '../constants/commonResponses';
 import {dirname} from 'path';
@@ -62,3 +64,47 @@ export async function writeFile(
     return err(unknownErrorMsg);
   }
 }
+
+/**
+ * Copies the file specified by {@link absoluteSourcePath} 
+ * to the path specified by {@link absoluteDestinationPath}. 
+ * Creates the directories specified by {@link absoluteDestinationPath}
+ * if they do not exist.
+ * @param absoluteSourcePath The absolute path to the source file.
+ * @param absoluteDestinationPath The absolute path to the destination file.
+ * @param overwrite Whether to overwrite the file at the destination
+ *                  path if there is one already.
+ * @returns Returns true if the file was written successfully, 
+ *          or an error message string if there was an error.
+ */
+export async function copyFile(
+  absoluteSourcePath: string,
+  absoluteDestinationPath: string,
+  overwrite: boolean
+) : Promise<Result<boolean, string>> {
+  let sourceFile = null;
+    try {
+
+      // Get source file
+      sourceFile = await getFile(absoluteSourcePath);
+
+      if (sourceFile === null) 
+        return err(sourceFileDoesNotExistOrIsADirectoryMsg);
+
+    } catch (error) {
+      return err(`An error occurred while reading the source file (detail: ${error})`);
+    }
+
+    const fileWriteResult = await writeFile(absoluteDestinationPath, sourceFile, overwrite);
+    if (fileWriteResult.isOk()) {
+      return ok(true);
+    }
+    else {
+      if (fileWriteResult.error == fileAlreadyExistsMsg) {
+        return err(destinationFileExistsAndOverwriteIsNotSetMsg);
+      }
+      else {
+        return err(`An error occurred while copying the file (detail: ${fileWriteResult.error})`);
+      }
+    }
+}