Collapse directory structure for VFS resources

_extensions/live/templates/pyodide-setup.ojs

@@ -5,6 +5,7 @@ pyodideOjs = {
     setupPython,
     startPyodideWorker,
     b64Decode,
+    collapsePath,
   } = window._exercise_ojs_runtime;
 
   const statusContainer = document.getElementById("exercise-loading-status");
@@ -59,19 +60,22 @@ pyodideOjs = {
         file = name;
       }
 
-      // Create directory tree, swallowing any `dir exists` errors
-      let path = file;
-      while (path = path.substr(0, path.lastIndexOf('/'))) {
-        try {
+      // Create directory tree, collapsing higher directory structure
+      let path = file = collapsePath(file);
+      try {
+        while (path = path.substr(0, path.lastIndexOf('/'))) {
           await pyodide.FS.mkdir(path);
-        } catch (e) {
-          if (!(e.name == "ErrnoError" && e.errno == 20)) {
-            throw e;
-          }
+        }
+        return await pyodide.FS.writeFile(file, new Uint8Array(data));
+      } catch (e) {
+        if (e.name !== "ErrnoError") throw e;
+        // Ignore "dir exists" filesystem error
+        if (e.errno !== 20) {
+          const errorTextPtr = await pyodide._module._strerror(e.errno);
+          const errorText = await pyodide._module.UTF8ToString(errorTextPtr);
+          throw new Error(`Filesystem Error ${e.errno} "${errorText}".`);
         }
       }
-
-      return await pyodide.FS.writeFile(file, new Uint8Array(data));
     }).reduce((cur, next) => cur.then(next), Promise.resolve());
 
     statusText.textContent = `Pyodide environment setup`;

_extensions/live/templates/webr-setup.ojs

@@ -1,6 +1,12 @@
 webROjs = {
   const { WebR } = window._exercise_ojs_runtime.WebR;
-  const { WebREvaluator, WebREnvironmentManager, setupR, b64Decode } = window._exercise_ojs_runtime;
+  const {
+    WebREvaluator,
+    WebREnvironmentManager,
+    setupR,
+    b64Decode,
+    collapsePath
+  } = window._exercise_ojs_runtime;
 
   const statusContainer = document.getElementById("exercise-loading-status");
   const indicatorContainer = document.getElementById("exercise-loading-indicator");
@@ -60,12 +66,13 @@ webROjs = {
         file = name;
       }
 
-      // Create directory tree, swallowing any `dir exists` errors
-      let path = file;
+      // Create directory tree, collapsing higher directory structure
+      let path = file = collapsePath(file);
       while (path = path.substr(0, path.lastIndexOf('/'))) {
         try {
           await webR.FS.mkdir(path);
         } catch (e) {
+          // Ignore "dir exists" filesystem error
           if (!e.message.includes("FS error")) {
             throw e;
           }

docs/other/resources.qmd

@@ -60,13 +60,14 @@ summary(mod)
 ## Python
 
 ### Source
+
+````{.markdown filename="resources.qmd"}
 ---
 format: live-html
 resources:
   - data
 ---
 
-````{.markdown filename="resources.qmd"}
 ```{{pyodide}}
 from os import listdir
 import pandas as pd

live-runtime/src/live-runtime.ts

@@ -9,7 +9,7 @@ import { WebREnvironment, PyodideEnvironment } from './environment';
 import { WebRGrader } from './grader-webr';
 import { PyodideGrader } from './grader-pyodide';
 import { comlinkTransfer, imageBitmapTransfer, mapTransfer, proxyTransfer } from './pyodide-proxy';
-import { b64Encode, b64Decode } from './utils';
+import { b64Encode, b64Decode, collapsePath } from './utils';
 import './css/live-runtime.css';
 import './css/highlighting.css';
 
@@ -68,6 +68,7 @@ declare global {
       startPyodideWorker: typeof startPyodideWorker;
       b64Decode: typeof b64Decode;
       b64Encode: typeof b64Encode;
+      collapsePath: typeof collapsePath;
     };
   }
 }
@@ -90,6 +91,7 @@ window._exercise_ojs_runtime = {
   startPyodideWorker,
   b64Encode,
   b64Decode,
+  collapsePath,
 };
 
 export {
@@ -110,4 +112,5 @@ export {
   startPyodideWorker,
   b64Encode,
   b64Decode,
+  collapsePath,
 }

live-runtime/src/utils.ts

@@ -83,3 +83,18 @@ export function loadScriptAsync(url: string): Promise<any> {
     document.getElementsByTagName("head")[0].appendChild(script);
   });
 }
+
+export function collapsePath(path: string) {
+  const parts = path.replace(/\/+/g, '/').split('/');
+  const stack = [];
+  for (const part of parts) {
+    if (part === '.' || part === '') {
+      continue;
+    } else if (part === '..') {
+      stack.pop();
+    } else {
+      stack.push(part);
+    }
+  }
+  return stack.join('/');
+}