firebase-realtime-database

问题 I want to add a student list to my Firebase realtime database. When a teacher adds a new student, I want the currently logged-in teachers ID to relate to the student they just added. When I compile the following I get my "Student Added" toast on the emulator but nothing shows up on Firebase - no new parent of "students" and no new entries. Can someone see where I'm going wrong? I think using datasnapshot to get thecurrentUserId from Firebase might be long-winded but when I just used the

问题 I want to add a student list to my Firebase realtime database. When a teacher adds a new student, I want the currently logged-in teachers ID to relate to the student they just added. When I compile the following I get my "Student Added" toast on the emulator but nothing shows up on Firebase - no new parent of "students" and no new entries. Can someone see where I'm going wrong? I think using datasnapshot to get thecurrentUserId from Firebase might be long-winded but when I just used the

问题 This question already has an answer here : Firebase - Is auth.uid a shared secret? (1 answer) Closed 2 years ago . I've been reading Firebase Realtime Database Security Rules guides (https://firebase.google.com/docs/database/security), and I'm a bit confused with regards to should I keep the UID generated by the Firebase Auth (lets say if my App users use Facebook to authenticate themselves) secret? I have this kind of data structure: users UID Lots of nodes of personal data to be read

问题 Assuming that I trigger events on the following ref('/users/{userId}/items/{newItem}') I want to get a value from inside the wildcard userId I have tried var token = event.params.userId.token but it return to be undefined Any suggestions? 回答1: Token is not a parameter returned automatically from trigger events. In trigger wild cards only parameters corresponding directly to the wildcard are returned. So You need to do the following if you want to use the var userId = event.params.userId And

问题 Assuming that I trigger events on the following ref('/users/{userId}/items/{newItem}') I want to get a value from inside the wildcard userId I have tried var token = event.params.userId.token but it return to be undefined Any suggestions? 回答1: Token is not a parameter returned automatically from trigger events. In trigger wild cards only parameters corresponding directly to the wildcard are returned. So You need to do the following if you want to use the var userId = event.params.userId And

问题 I want to assign the data I have read in the Firebase database to the values I have given in the code. The data is being read in the code I have given, but the values are not being assigned. I want to assign deviceroom1, deviceRoom2, deviceRoom3, deviceRoom4. var deviceRoom1: String = "" var deviceRoom2: String = "" var deviceRoom3: String = "" var deviceRoom4: String = "" var deviceRoom5: String = "" func fetchDevies(){ let ref = Database.database().reference().child(self.chip1InfoString!)

问题 I'm trying to set timestamp into firebase realtime database but when I retrieve, not ordering by timestamp. I did like so. FirebaseDatabase.instance.reference().child('path').push().set({ 'timestamp': ServerValue.timestamp }); This is the node Then I retrieve like so. FirebaseDatabase.instance.reference().child('path').orderByChild('timestamp').once().then((snap) { print(snap.value); }); but output is this {-LJhyfmrWVDD2ZgJdfMR: {timestamp: 1534074731794}, -LJhyWVi6LddGwVye48K: {timestamp:

问题 I'm trying to set timestamp into firebase realtime database but when I retrieve, not ordering by timestamp. I did like so. FirebaseDatabase.instance.reference().child('path').push().set({ 'timestamp': ServerValue.timestamp }); This is the node Then I retrieve like so. FirebaseDatabase.instance.reference().child('path').orderByChild('timestamp').once().then((snap) { print(snap.value); }); but output is this {-LJhyfmrWVDD2ZgJdfMR: {timestamp: 1534074731794}, -LJhyWVi6LddGwVye48K: {timestamp:

问题 My data structure is like this: firebase-endpoint/updates/<location_id>/<update_id> each location has many updates that firebase adds as "array" elements. How can I index on the "validFrom" property of each update if the location_id is unknown before insertion into the databse? { "rules": { "updates": { "<location_id>": { // WHAT IS THIS NODE SUPPOSED TO BE? ".indexOn": ["validFrom"] } } } } data structure sample { "71a57e17cbfd0f524680221b9896d88c5ab400b3": { "-KBHwULMDZ4EL_B48-if": { "place

问题 My data structure is like this: firebase-endpoint/updates/<location_id>/<update_id> each location has many updates that firebase adds as "array" elements. How can I index on the "validFrom" property of each update if the location_id is unknown before insertion into the databse? { "rules": { "updates": { "<location_id>": { // WHAT IS THIS NODE SUPPOSED TO BE? ".indexOn": ["validFrom"] } } } } data structure sample { "71a57e17cbfd0f524680221b9896d88c5ab400b3": { "-KBHwULMDZ4EL_B48-if": { "place