refactor file handling in WASM wrapper

js/index.html

@@ -11,17 +11,91 @@
   <h1>dcm2niix WASM Demo</h1>
   <input type="file" id="fileInput" webkitdirectory multiple>
   <button id="processButton">Process Image</button>
+  <div id="dropTarget" style="margin: 2rem; color: white; width: 100px; height: 100px; background-color: red;">
+    Drop files here
+  </div>
   <p id="status">Please select a dicom folder to process.</p>
   <a id="downloadLink" style="display: none;">Download Processed Image(s)</a>
 
   <script type="module">
     import { Dcm2niix } from './dist/index.js';
-    const dcm2niix = new Dcm2niix();
+
     const fileInput = document.getElementById('fileInput');
     const processButton = document.getElementById('processButton');
     const status = document.getElementById('status');
     const downloadLink = document.getElementById('downloadLink');
 
+    const dropTarget = document.getElementById('dropTarget');
+    dropTarget.addEventListener('dragover', (event) => {
+      event.preventDefault();
+      dropTarget.style.backgroundColor = 'green';
+    });
+
+    dropTarget.addEventListener('dragleave', (event) => {
+      event.preventDefault();
+      dropTarget.style.backgroundColor = 'red';
+    });
+
+    dropTarget.ondrop = handleDrop;
+
+    async function handleDrop(e) {
+      e.preventDefault(); // prevent navigation to open file
+      const items = e.dataTransfer.items;
+      const files = [];
+      for (let i = 0; i < items.length; i++) {
+        const item = items[i].webkitGetAsEntry();
+        if (item) {
+          await traverseFileTree(item, '', files);
+        }
+      }
+      const dcm2niix = new Dcm2niix();
+      await dcm2niix.init()
+      const resultFileList = await dcm2niix.inputFromDropItems(files).run()
+
+      resultFileList.forEach((resultFile, index) => {
+          let url = URL.createObjectURL(resultFile);
+          const downloadLink = document.createElement('a');
+          downloadLink.href = url;
+          downloadLink.download = resultFile.name;
+          downloadLink.textContent = `Download ${resultFile.name}`;
+          downloadLink.style.display = 'block';
+          document.body.appendChild(downloadLink);
+        });
+        status.textContent = 'Processing complete!';
+    }
+
+    async function traverseFileTree(item, path = '', fileArray) {
+      return new Promise((resolve) => {
+        if (item.isFile) {
+          item.file(file => {
+            file.fullPath = path + file.name; 
+            // IMPORTANT: _webkitRelativePath is required for dcm2niix to work.
+            // We need to add this property so we can parse multiple directories correctly.
+            // the "webkitRelativePath" property on File objects is read-only, so we can't set it directly, hence the underscore.
+            file._webkitRelativePath = path + file.name;
+            fileArray.push(file);
+            resolve();
+          });
+        } else if (item.isDirectory) {
+          const dirReader = item.createReader();
+          const readAllEntries = () => {
+            dirReader.readEntries(entries => {
+              if (entries.length > 0) {
+                const promises = [];
+                for (const entry of entries) {
+                  promises.push(traverseFileTree(entry, path + item.name + '/', fileArray));
+                }
+                Promise.all(promises).then(readAllEntries);
+              } else {
+                resolve();
+              }
+            });
+          };
+          readAllEntries();
+        }
+      });
+    }
+
     let selectedFiles = null;
 
     fileInput.addEventListener('change', async (event) => {
@@ -30,26 +104,22 @@ <h1>dcm2niix WASM Demo</h1>
     });
 
     processButton.addEventListener('click', async () => {
-      // if (!selectedFile) return;
-
       status.textContent = 'Processing...';
-      // processButton.disabled = true;
-
       try {
         console.log('Initializing dcm2niix wasm...');
+        const dcm2niix = new Dcm2niix();
         await dcm2niix.init();
         console.log('dcm2niix wasm initialized.');
 
         const t0 = performance.now();
 
         const inputFileList = selectedFiles
-        const resultFileList = await dcm2niix.input(inputFileList).run()        
+        const resultFileList = await dcm2niix.input(inputFileList).run()
         console.log(resultFileList);
 
         const t1 = performance.now();
         console.log("dcm2niix wasm took " + (t1 - t0) + " milliseconds.")
 
-        // Create a download link for each file in resultFileList
         resultFileList.forEach((resultFile, index) => {
           let url = URL.createObjectURL(resultFile);
           const downloadLink = document.createElement('a');

js/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@niivue/dcm2niix",
-  "version": "0.1.1",
+  "version": "0.1.1-dev.2",
   "main": "dist/index.js",
   "module": "dist/index.js",
   "exports": {

js/src/index.js

@@ -23,13 +23,40 @@ export class Dcm2niix {
     });
   }
 
-  input(fileList) {
-    return new Processor({ worker: this.worker, fileList });
+  conformFileList(fileObjectOrArray) {
+    // prepare files with their relative paths.
+      // annoyingly, safari strips the webkitRelativePath property when sending files to the worker.
+      // fileList is a FileList object, not an array, so we need to convert it to an array.
+      // filesWithRelativePaths is an array of objects with the file and webkitRelativePath properties.
+      // Now we can use the webkitRelativePath property in the worker.
+      // This is important for dcm2niix to work with nested dicom directories in safari.
+      const filesWithRelativePaths = Array.from(fileObjectOrArray).map((file) => ({
+        file,
+        // need to check for both webkitRelativePath and _webkitRelativePath.
+        // _webkitRelativePath is used in case the file was not from a webkitdirectory file input element (e.g. from a drop event).
+        // IMPORTANT: it is up to other developers to ensure that the special _webkitRelativePath property is set correctly when using drop events.
+        webkitRelativePath: file.webkitRelativePath || file._webkitRelativePath || ''
+      }));
+      return filesWithRelativePaths
+    }
+
+  input(fileListObject) {
+    const conformedFileList = this.conformFileList(fileListObject);
+    return new Processor({ worker: this.worker, fileList: conformedFileList });
+  }
+
+  inputFromWebkitDirectory(fileListObject) {
+    const conformedFileList = this.conformFileList(fileListObject);
+    return new Processor({ worker: this.worker, fileList: conformedFileList });
+  }
+
+  inputFromDropItems(dataTransferItemArray) {
+    const conformedFileList = this.conformFileList(dataTransferItemArray);
+    return new Processor({ worker: this.worker, fileList: conformedFileList });
   }
 }
 
 class Processor {
-
   constructor({ worker, fileList }) {
     this.worker = worker;
     this.fileList = fileList;
@@ -281,19 +308,8 @@ class Processor {
       if (this.worker === null) {
         reject(new Error('Worker not initialized. Did you await the init() method?'));
       }
-      // prepare files with their relative paths.
-      // annoyingly, safari strips the webkitRelativePath property when sending files to the worker.
-      // fileList is a FileList object, not an array, so we need to convert it to an array.
-      // filesWithRelativePaths is an array of objects with the file and webkitRelativePath properties.
-      // Now we can use the webkitRelativePath property in the worker.
-      // This is important for dcm2niix to work with nested dicom directories in safari.
-      const filesWithRelativePaths = Array.from(this.fileList).map((file) => ({
-        file,
-        webkitRelativePath: file.webkitRelativePath || ''
-      }));
-
       // send files and commands to the worker
-      this.worker.postMessage({ fileList: filesWithRelativePaths, cmd: args });
+      this.worker.postMessage({ fileList: this.fileList, cmd: args });
     });
   }
 }