Question

我正在使用Azure Mobile服务-NodeJS后端，在编程时，我总是面对这个疑问 - 让我解释一下使用下面的代码片段

//--------------------------------------------------------------------------
function addUserToDB(request, response){
  ///some code here
  var	theUser = request.user;

  ///get the user's entity object
  try {
    objAppUser = buildAppUserEntityObj(theUser, request); //for simplicity sake, lets say this is not asynchronous function
  }
  catch (err) {
    console.log ('error in addUserToDB when calling buildAppUserEntityObj');  //****????****
    request.respond(statusCodes.BAD_REQUEST, err);
    return; // ##????## is a 'return' needed here to avoid the execution of the code below,  or should I assume that the function will return once request is responded (request.respond) in above line.
  }

  ....code to add userEntity to DB
  //some more code in case of successful try above, can I assume there is no way this code will be reached in case of error in the above try-catch
  //       ofcourse I can move this code in the 'try' block above, but I am just trying to understand what happens if above try ends in catch block for some reason and there is no 'return' at the end that catch block.
}

//--------------------------------------------------------------------------
function buildAppUserEntityObj(user, request) {
  if ( user.level === 'anonymous' ) { //ideally this would be called in above function, but I am putting this here just to throw an example.
    console.error('Anonymous User' );
    request.respond(statusCodes.BAD_REQUEST, message);  //will this request.respond will send the response to client immediately, or will it be passed on as error the try-catch of above 'addUserToDB' function 
    return; // ##????## also, is 'return' needed here to avoid the execution of the code below, 
  }

  ....code to build a User entity object based on some business logic
}

//--------------------------------------------------------------------------

我猜，这一切归结为三个问题：
1.两个地方是否需要“返回”（在上述两个功能中用## ???? ##标记？） 2.如果user.level ==='匿名'，则会记录消息（标记为// **** ???? ****） 3. request.respond vs response.send，这是什么区别？

我相信这些怀疑是因为我缺乏完整的expressJS知识，所以当我再次通过azure / express.js文档时，我想我会向专家社区提出疑问以获得更清楚的解释。

非常感谢。

Answer 1

第一

在第二个return（buildAppUserEntityObj函数的insode中，我相信你希望它是：

throw new Error("Anonymous user is not allowed")

否则，即使用户是匿名用户，您的catch代码也永远不会执行。

您需要第一个return;，否则它将继续执行以下代码。

第二

如果您修复了 First 段落中描述的代码，则会记录消息。

第三

标准Node.js http module中没有request.respond。你能澄清一下，你在用什么模块？无论如何，该模块的API将回答您的问题。

azure node.js请求，响应 - 寻求一些澄清

1 个答案:

第一

第二

第三