Firebase-admin不会写入数据库，不会出现任何错误 [英] Firebase-admin won't write to database, gives no errors

问题描述

Firebase管理员未写入数据库.

Firebase admin isn't writing to the database.

我正在实例化数据库:

var db = admin.database();

然后设置对我想要的表的引用:

Then setting up a reference to the table I want:

var systemsRef = db.ref("systems/");

然后我有一个功能来检查系统"(加密的硬件ID)是否存在.

I then have a function to check if the 'system', (an encrypted hardware id), exists.

function isSystemRegistered(id){
  var isTrue;
  systemsRef.once('value', function(snapshot) {
      isTrue = (snapshot.hasChild(id))? true : false;
  });
  return isTrue;
}

截至目前还返回false;这是true，因为它尚不存在.如果系统不存在，它将写入数据.

Which, as of yet returns false; which is true, because it doesn't exist yet. If the system doesn't exist, it writes the data.

const sysID = getSysID();
var sys.info.name = generateUniqueSystemName();

if(isSystemRegistered(sysID){
  console.log("system is already registered!");
} else {
  msystemsRef.set({
      sysID : sys.info.name
    }, function(error){
        console.log('There was an error while attempting to write to database: ' + error);
      });
  });
}

我已经进行了试验，并暂时将我的原型数据库完全公开了几分钟，以确保我的rules不是问题……他们不是:仍然不是布宜诺斯艾利斯.没有写入数据库...，并且没有错误.

I've experimented, and temporarily made my prototype database fully public for a few minutes, just to be sure my rules weren't the issue... They weren't: still no bueno. No writes to the database... and no errors.

我尝试了不同的set，只需确保:

I tried a different set, just be sure:

msystemsRef.set("I'm writing data", function(error) {
  if (error) {
    alert("Data could not be saved." + error);
  } else {
    alert("Data saved successfully.");
  }
});

同样，我使用的是具有public规则的管理员帐户，因此我应该在根目录下看到一个现在的I'm writing data表.没事...

Again, I'm using an admin account, with public rules, so I should see a now I'm writing data table, just below root. Nothing...

因此，我改变了策略，并尝试使用罐装教程将数据库推送到数据库，并且我的数据库 still 完全公开:

So I switched tactics and attempted to push to the database with the canned tutorial, with my database still fully public:

systemsRef.push({sysID : sys.info.name});

什么也没有...我想念吗?

And nothing... Want am I missing?

推荐答案

在isSystemRegistered中，您将返回isTrue的同步值，即undefined.

In isSystemRegistered you're returning the synchronized value of isTrue which is undefined.

您应该返回.once('value')方法的承诺，并在调用方法中附加then()以检查它是否存在.

You should return the promise of the .once('value') method and in the calling method attach a then() to check if it exists.

您还可以使用snapshot.exists()来检查引用是否存在.

You can also use the snapshot.exists() to check on a reference for existence.

建议的修改:

var systemRef = admin.database('system');

function isSystemRegistered(id) {
  return systemRef.child(id).once('value')
    .then(function (snap) {
      return snap.exists();
    });
}

function writeData(aSystem) {
  var sysId = generateUniqueSystemName();
  return systemRef.child(sysId)
    .once('value')
    .then(function (snapshot) {
      if (!snapshot.exists()) {
        return systemRef.child(sysId).update(aSystem);
      }

      // Here `sysId === snapshot.key`
      return systemRef.child(sysId).set(aSystem);
    })
    .catch(function (err) {
       console.error(err);
    });
}

在Raspberry Pi上运行会引发更多问题.

Running on Raspberry Pi raises some more questions.

• 它如何连接到互联网?
• 连接速度有多快?
• 您运行的是哪个NodeJS版本?
• 此操作是否已在您的PC上成功运行?

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