运行时处理UI5模块时如何检测eval调用及日志功能咨询

Great question! When preparing to enable Asynchronous Module Loading (AML) for FLP and avoiding CSP issues tied to missing unsafe-eval in script-src, tracking which module resolution errors trigger eval calls is critical. UI5 doesn’t have a built-in, dedicated feature to log these specific eval invocations directly, but you can implement several effective workarounds:

1. Leverage UI5’s Debug Mode & Error Handling Hooks #

First, enable UI5’s debug mode to get more detailed error context:

sap.ui.core.Configuration.setDebug(true);

Then, hook into UI5’s message system to capture module-related errors and inspect their call stacks for eval references:

• Use sap.ui.core.MessageManager to subscribe to error events:

  const oMessageManager = sap.ui.getCore().getMessageManager();
  oMessageManager.attachMessageChange(function(oEvent) {
    const aMessages = oEvent.getParameter("messages");
    aMessages.forEach(oMsg => {
      if (oMsg.getType() === sap.ui.core.MessageType.Error && oMsg.getMessage().includes("module")) {
        console.error("Module resolution error:", oMsg);
        // Check if eval appears in the error stack trace
        if (oMsg.getStack().includes("eval")) {
          console.warn("This error triggered an eval call:", oMsg.getStack());
        }
      }
    });
  });
  

2. Wrap UI5’s Module Loading Functions #

You can wrap UI5’s core module loading methods to add custom logging when resolution fails, and detect eval in the call chain:

const originalRequire = sap.ui.require;
sap.ui.require = function(sModules, fnSuccess, fnError) {
  const customErrorHandler = function(oError) {
    console.error("Failed to load module(s):", oError);
    // Inspect the call stack for eval references
    if (new Error().stack.includes("eval")) {
      console.warn("Eval triggered by module resolution failure:", oError.message);
    }
    // Execute original error handler if provided
    if (fnError) fnError(oError);
  };
  return originalRequire(sModules, fnSuccess, customErrorHandler);
};

This wrapper intercepts module loading failures and flags cases where eval is part of the call stack.

3. Use Browser Developer Tools for Runtime Debugging #

Browser dev tools offer a straightforward way to catch eval calls in action:

• Break on eval invocations: In Chrome DevTools (Sources panel), navigate to "Event Listener Breakpoints" > "Script" and check "Eval". This pauses execution every time eval runs, letting you trace the call stack back to the module resolution error.
• Conditional breakpoints: For targeted debugging, set a breakpoint in UI5’s module loader code (look for sap.ui.loader files) when a module lookup fails, then add a condition to check if the error leads to an eval call.

4. Utilize CSP Violation Reports #

If your CSP is already blocking eval, browsers will log detailed violation reports to the console. These reports include the full call stack where eval was triggered, making it easy to pinpoint which module resolution error caused the issue.

内容的提问来源于stack exchange，提问作者Boghyon Hoffmann