今天需要对 Firebase 增加删除功能,代码精简如下:
1 var admin = require('firebase-admin'); 2 var config = require('./config.json'); 3 4 var defaultAppConfig = { 5 credential: admin.credential.cert(config.firebase.cert), 6 databaseURL: config.firebase.databaseURL 7 }; 8 9 10 var defaultAppName = 'GoPeople-NodeJS-Admin'; 11 var defaultApp = admin.initializeApp(defaultAppConfig, defaultAppName); 12 13 var signaturesRef = defaultApp.database().ref('signatures'); 14 15 signaturesRef.orderByChild("isChecked").equalTo(true).limitToLast(10).once("value") 16 .then(function(snapshot) { 17 18 snapshot.forEach(function(childSnapshot) { 19 var key = childSnapshot.key; 20 var childData = childSnapshot.val(); 21 22 var now = new Date(); 23 var date = new Date(childData.date); 24 var dayDiff = parseInt((now - date) / (1000 * 60 * 60 * 24)); // day diff 25 26 if(dayDiff >30){ 27 signaturesRef.child(key).remove(function(error) { 28 console.log(key); 29 console.log(dayDiff); 30 console.log(error ? ("Uh oh! " + error) : "Success!"); 31 }); 32 }else{ 33 console.log(key); 34 console.log(dayDiff); 35 } 36 }); 37 38 });
Firebase 修改节点:
function finishJobSync(jobGuid) { var signaturesRef = defaultApp.database().ref('signatures').child(jobGuid); signaturesRef.update({isChecked: true},function(error) { if (error) { logger.error(error); } else { logger.info('Job ' + jobGuid + ' signature has been synced.'); } }); }
Firebase 监听:
var signaturesRef = defaultApp.database().ref('signatures'); signaturesRef.orderByChild("isChecked").equalTo(false).on("child_added", function(snapshot, prevChildKey) { // TODO: });
>> key
// Assume we have the following data in the Database: { "name": { "first": "Ada", "last": "Lovelace" } } var ref = admin.database().ref("users/ada"); ref.once("value") .then(function(snapshot) { var key = snapshot.key; // "ada" var childKey = snapshot.child("name/last").key; // "last" });
>> child
var rootRef = admin.database().ref(); rootRef.once("value") .then(function(snapshot) { var key = snapshot.key; // null var childKey = snapshot.child("users/ada").key; // "ada" });
>> exists
// Assume we have the following data in the Database: { "name": { "first": "Ada", "last": "Lovelace" } } // Test for the existence of certain keys within a DataSnapshot var ref = admin.database().ref("users/ada"); ref.once("value") .then(function(snapshot) { var a = snapshot.exists(); // true var b = snapshot.child("name").exists(); // true var c = snapshot.child("name/first").exists(); // true var d = snapshot.child("name/middle").exists(); // false });
>> foreach
// Assume we have the following data in the Database: { "users": { "ada": { "first": "Ada", "last": "Lovelace" }, "alan": { "first": "Alan", "last": "Turing" } } } // Loop through users in order with the forEach() method. The callback // provided to forEach() will be called synchronously with a DataSnapshot // for each child: var query = admin.database().ref("users").orderByKey(); query.once("value") .then(function(snapshot) { snapshot.forEach(function(childSnapshot) { // key will be "ada" the first time and "alan" the second time var key = childSnapshot.key; // childData will be the actual contents of the child var childData = childSnapshot.val(); }); });
>> hasChildren
// Assume we have the following data in the Database: { "name": { "first": "Ada", "last": "Lovelace" } } var ref = admin.database().ref("users/ada"); ref.once("value") .then(function(snapshot) { var a = snapshot.hasChildren(); // true var b = snapshot.child("name").hasChildren(); // true var c = snapshot.child("name/first").hasChildren(); // false });
>> numChildren
// Assume we have the following data in the Database: { "name": { "first": "Ada", "last": "Lovelace" } } var ref = admin.database().ref("users/ada"); ref.once("value") .then(function(snapshot) { var a = snapshot.numChildren(); // 1 ("name") var b = snapshot.child("name").numChildren(); // 2 ("first", "last") var c = snapshot.child("name/first").numChildren(); // 0 });
>> orderByChild
var ref = admin.database().ref("dinosaurs"); ref.orderByChild("height").on("child_added", function(snapshot) { console.log(snapshot.key + " was " + snapshot.val().height + " m tall"); });
>> orderByKey
var ref = admin.database().ref("dinosaurs"); ref.orderByKey().on("child_added", function(snapshot) { console.log(snapshot.key); });
>> orderByValue
var scoresRef = admin.database().ref("scores"); scoresRef.orderByValue().limitToLast(3).on("value", function(snapshot) { snapshot.forEach(function(data) { console.log("The " + data.key + " score is " + data.val()); }); });
>> startAt, endAt
// Find all dinosaurs that are at least three meters tall. var ref = admin.database().ref("dinosaurs"); ref.orderByChild("height").startAt(3).on("child_added", function(snapshot) { console.log(snapshot.key) }); // Find all dinosaurs whose names come before Pterodactyl lexicographically. var ref = admin.database().ref("dinosaurs"); ref.orderByKey().endAt("pterodactyl").on("child_added", function(snapshot) { console.log(snapshot.key); });
>> limitToFirst, limitToLast
// Find the two shortest dinosaurs. var ref = admin.database().ref("dinosaurs"); ref.orderByChild("height").limitToFirst(2).on("child_added", function(snapshot) { // This will be called exactly two times (unless there are less than two // dinosaurs in the Database). // It will also get fired again if one of the first two dinosaurs is // removed from the data set, as a new dinosaur will now be the second // shortest. console.log(snapshot.key); }); // Find the two heaviest dinosaurs. var ref = admin.database().ref("dinosaurs"); ref.orderByChild("weight").limitToLast(2).on("child_added", function(snapshot) { // This callback will be triggered exactly two times, unless there are // fewer than two dinosaurs stored in the Database. It will also get fired // for every new, heavier dinosaur that gets added to the data set. console.log(snapshot.key); });
>> equalTo
// Find all dinosaurs whose height is exactly 25 meters. var ref = admin.database().ref("dinosaurs"); ref.orderByChild("height").equalTo(25).on("child_added", function(snapshot) { console.log(snapshot.key); });
>> isEqual
var rootRef = admin.database().ref(); var usersRef = rootRef.child("users"); usersRef.isEqual(rootRef); // false usersRef.isEqual(rootRef.child("users")); // true usersRef.parent.isEqual(rootRef); // true
var rootRef = admin.database().ref(); var usersRef = rootRef.child("users"); var usersQuery = usersRef.limitToLast(10); usersQuery.isEqual(usersRef); // false usersQuery.isEqual(usersRef.limitToLast(10)); // true usersQuery.isEqual(rootRef.limitToLast(10)); // false usersQuery.isEqual(usersRef.orderByKey().limitToLast(10)); // false
>> toString
// Calling toString() on a root Firebase reference returns the URL where its // data is stored within the Database: var rootRef = admin.database().ref(); var rootUrl = rootRef.toString(); // rootUrl === "https://sample-app.firebaseio.com/". // Calling toString() at a deeper Firebase reference returns the URL of that // deep path within the Database: var adaRef = rootRef.child('users/ada'); var adaURL = adaRef.toString(); // adaURL === "https://sample-app.firebaseio.com/users/ada".
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