fix: Prevent server from crashing if requested data can't be handled

src/ldp/AuthenticatedLdpHandler.ts

@@ -98,7 +98,7 @@ export class AuthenticatedLdpHandler extends HttpHandler {
 
     const writeData = { response: input.response, description, error: err };
 
-    return this.responseWriter.handleSafe(writeData);
+    await this.responseWriter.handleSafe(writeData);
   }
 
   /**

src/ldp/http/SimpleResponseWriter.ts

@@ -12,6 +12,11 @@ export class SimpleResponseWriter extends ResponseWriter {
     if (!input.description && !input.error) {
       throw new UnsupportedHttpError('Either a description or an error is required for output.');
     }
+    if (input.description && input.description.body) {
+      if (input.description.body.dataType !== 'binary' && input.description.body.dataType !== 'string') {
+        throw new UnsupportedHttpError('Only string or binary results are supported.');
+      }
+    }
   }
 
   public async handle(input: { response: HttpResponse; description?: ResponseDescription; error?: Error }): Promise<void> {

src/server/ExpressHttpServer.ts

@@ -21,7 +21,13 @@ export class ExpressHttpServer {
     }));
 
     app.use(async(request, response): Promise<void> => {
-      await this.handler.handleSafe({ request, response });
+      try {
+        await this.handler.handleSafe({ request, response });
+      } catch (error) {
+        const errMsg = `${error.name}: ${error.message}\n${error.stack}`;
+        process.stderr.write(errMsg);
+        response.status(500).send(errMsg);
+      }
     });
     return app.listen(port);
   }