如何修复bookshelfjs事务中的嵌套结构 [英] How to fix nested structure in bookshelfjs transaction

问题描述

我想在一个bookhelf事务中更新许多数据库表。我可以使用一些帮助重构我的代码。我是节点的新手并且对Promises没有很好的理解，但是下面的嵌套结构不是很漂亮，我希望有一种更清洁的方式。任何帮助将不胜感激。

I want to update a number of database tables in a single bookshelf transaction. I could use some help refactoring my code. I'm new to node and don't have a good understanding of promises, but the nested structure below is not very pretty, and I'm hoping there is a cleaner way. Any help would be appreciated.

function insertUser(user, cb) {
  bookshelf.transaction(function(t) {
  var key = user.key;
  Developer.forge({key: key})
  .fetch({require: true, transacting: t})
  .then(function(developerModel) {
    var devID = developerModel.get('id');
    Address.forge(user.address)
    .save(null, {transacting: t})
    .then(function(addressModel) {
      var addressID = addressModel.get('addressId');
      Financial.forge(user.financial)
      .save(null, {transacting: t})
      .then(function(financialModel) {
        var financialID = financialModel.get('financialId');
        var userEntity = user.personal;
        userEntity.addressId = addressID;
        userEntity.developerId = devID;
        userEntity.financialId = financialId;
        User.forge(userEntity)
        .save(null, {transacting: t})
        .then(function(userModel) {
          logger.info('saved user: ', userModel);
          logger.info('commiting transaction');
          t.commit(userModel);
        })
        .catch(function(err) {
          logger.error('Error saving user: ', err);
          t.rollback(err);
        });
      })
      .catch(function(err) {
        logger.error('Error saving financial data: ', err);
        t.rollback(err);
      })
    })
    .catch(function(err) {
      logger.error('Error saving address: ', err);
      t.rollback(err);
    })
  })
  .catch(function(err) {
    logger.error('Error saving business : ', err);
    t.rollback(err);
  })
})
.then(function(model) {
  logger.info(model, ' successfully saved');
  return Promise.resolve(respond.success({userId: model.get('userId')}));
})
.catch(function(err) {
  logger.error(err, ' occurred');
  return Promise.reject(new DatabaseError('Unable to write user to database due to error ', err.message));
})};

推荐答案

将promises-for-results保存到变量和你可以在最后一次使用它们，然后保证它们被完成，因此它们的值可以用 .value（）同步检索

Save the promises-for-results to variables and you can use them later in the final then where it's guaranteed that they are fulfilled and thus their value can be retrieved with .value() synchronously

function insertUser(user, cb) {
  return bookshelf.transaction(function(t) {
    var key = user.key;

    var devID = Developer.forge({key: key})
      .fetch({require: true, transacting: t})
      .call("get", "id");

    var addressID = devID.then(function() {
      return Address.forge(user.address).fetch({require: true, transacting: t})
    }).call("get", "addressId");

    var financialID = addressModel.then(function() {
      return Financial.forge(user.financial).save(null, {transacting: t})
    }).call("get", "financialId");

    var userModel = financialID.then(function() {
      var userEntity = user.personal;
      userEntity.addressId = addressID.value();
      userEntity.developerId = devID.value();
      userEntity.financialId = financialID.value();
      return User.forge(userEntity).save(null, {transacting: t});
    });

    return userModel.then(function(userModel) {
      logger.info('saved user: ', userModel);
      logger.info('commiting transaction');
      t.commit(userModel);
    }).catch(function(e) {
      t.rollback(e);
      throw e;
    });
  });
}
.then(function(model) {
  logger.info(model, ' successfully saved');
  return Promise.resolve(respond.success({userId: model.get('userId')}));
})
.catch(function(err) {
  logger.error(err, ' occurred');
  return Promise.reject(new DatabaseError('Unable to write user to database due to error ', err.message));
})};

---

另一种方法是使用 Promise.join ：

function insertUser(user, cb) {
  return bookshelf.transaction(function(t) {
    var key = user.key;

    var devID = Developer.forge({key: key})
      .fetch({require: true, transacting: t})
      .call("get", "id");

    var addressID = devID.then(function() {
      return Address.forge(user.address).fetch({require: true, transacting: t})
    }).call("get", "addressId");

    var financialID = addressModel.then(function() {
      return Financial.forge(user.financial).save(null, {transacting: t})
    }).call("get", "financialId");

    var userModel = Promise.join(devID, addressID, financialID,
     function(devID, addressID, financialID) {
      var userEntity = user.personal;
      userEntity.addressId = addressID;
      userEntity.developerId = devID;
      userEntity.financialId = financialID;
      return User.forge(userEntity).save(null, {transacting: t});
    });

    return userModel.then(function(userModel) {
      logger.info('saved user: ', userModel);
      logger.info('commiting transaction');
      t.commit(userModel);
    }).catch(function(e) {
      t.rollback(e);
      throw e;
    });
  });
}
.then(function(model) {
  logger.info(model, ' successfully saved');
  return Promise.resolve(respond.success({userId: model.get('userId')}));
})
.catch(function(err) {
  logger.error(err, ' occurred');
  return Promise.reject(new DatabaseError('Unable to write user to database due to error ', err.message));
})};

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