feat(channels): implement binary attachment upload for matrix/signal/mattermost

src/channels/signal/adapter.ts

@@ -388,3 +388,27 @@ function sanitizeFilename(filename?: string): string {
 function escapeRegex(value: string): string {
   return value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
 }
+
+function sanitizeFilename(name?: string): string {
+  if (!name) {
+    return '';
+  }
+  return name.replace(/[^a-zA-Z0-9._-]/g, '_').slice(0, 100);
+}
+
+function extensionFromMimeType(mimeType?: string): string {
+  if (!mimeType) {
+    return '';
+  }
+  const simple = mimeType.split('/')[1]?.trim().toLowerCase();
+  if (!simple) {
+    return '';
+  }
+  if (simple.includes('jpeg')) {
+    return '.jpg';
+  }
+  if (simple.includes('plain')) {
+    return '.txt';
+  }
+  return `.${simple.replace(/[^a-z0-9]/g, '')}`;
+}