I am working with Firebase database for my application. I have one scenario where I need to display list of Call detail screen where each user's call history should be display. In firebase database I have two main node
Here is the image of the both node.
1) Users - user node have user related data with basic details of name,email and other stuff
2) Calls - user's call history each call have user_id which is related to in Users node for his/her basic details.
Now I want to details (first_name,last_name,email) of user_id from Calls node each entry or each object. So is there any solution for getting details via passing a comma seprated user_id list and getting its details from Firebase. Or is there a any other solution to fetching basic details.
Thank you in advanced if any one have faced this and provide a solution on this.
Related
I've created form in google sheet, so that multiple users can add data, modify & delete.
However, it is not working properly when multiple users are working on it simultaneously.
For an example, two people are working on the sheet. User A and User B. If user A is typing something user B is also able to see and user B will be able to enter the detail, but it will change the details which are being entered by user A. Technically same sheet is opened for both the users and details keeps on changing what users are changing.
Ideally, if user A is entering some details user B should not be able to see it and form should be blank or unique for user B, so that both the data won't clash. I want it to be like the way google form is there wherein form will be blank when any user is opening it. (I have tried google form for my work, but as there are too many drop downs google form takes time to load and work gets slow that the reason I am trying to find the option in google sheet).
google sheet link
Above is the google sheet which you can open and check the form and coding. Also, please test it with a different id to test for multiple users.
Let me know if there is any workaround for this. Also, let me know if you need any other details.
Answer:
This just isn't possible. Sheets is meant to be a collaborative tool; what's edited by one person will always show up for others. You need to use a different tool, for example like a Google form for data entry, but having data not being edited in other open versions is just not workaroundable.
I am building out an iOS app that requires getting lists of users at different parts of the app(finding users nearby, find users that have similar interest etc) I'm displaying the list of users in collection views/table views.
I have a user structure that contains all of the user data(name, photo, list of interest, location, preferences..etc)
My question is, when I'm getting the list of users from the database, is it more cost effective to use the query function or to use the observe functions? In the list I only need to display the users photo and username. If the user wants to find out more then clicking on the cell will get more data from the larger user data table.
My options
using a query to get the users that meet the criteria for that list(say all users nearby). Then when the user clicks on the cell that interests them, get a snapshot from the database for that specific users.
My thought process is its less costly than pulling back the whole snapshot using the observe functions.
using the observe functions, getting all users snapshot data and only displaying the photo and username. If the user selects a cell send the data to the detail view.
creating a special display structure that contains only items necessary for the collection view/ table view and if the user clicks on a cell call the database again getting all of that users data.
If anyone has a point of view they could share that would be great!
Thanks
Observing in Firebase needed for making instant update, like in chats, when new message appear you need to update message list. So here, for getting list of users that fit your request, better to use queries
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Firebase is configured in APPDelegate.
Read is set to .true in rules.
But, before I have a user sign into my application, I am checking for usernames, within a separate table of my Firebase DB. It would skip the observation block entirely, until I forced signed-in into another already created account of mine. And then when I would re-build the application the block is no longer skipped and actually accesses the table.
How do I "Wake Up" Firebase when I run the app on a fresh device, so I can check for usernames without having to log onto the app with an existing account before hand?
You may want to reconsider how the app is structured.
If you are checking for usernames before being authenticated that means the node is exposed and anyone can grab a copy of all the usernames. Obviously that in itself may not be a huge issue but if your users decide to use an email, whoever grabs the list has a instant list they can spam to.
When you add any observer to a node, that node is read once as soon as the observer is added. When you app starts you can use .childAdded to iterate over an existing node to pre-load some data, a grocery list for example, and then any new grociees added after that will be sent your your app via an event.
Likewise a .value event will read in an entire node and leave an observer attached for any future events.
The username issue is tricky and the way you are doing is now is probably going to get you in trouble in the long run.
A better way is to leverage Firebase Authentication.
Firebase handles all of the usernames and passwords for you. It's very powerful and flexible and avoids the issues you are encountering. It will let you know if user names exist or not, it will do password reset emails and you can manage users from the Firebase Console. It's the way to go.
If you want to add username functionality it can be pretty easily done by adding a username or nickname node to the /users node
/users
uid_0
email: "bill#email.com"
username: "bill_the_cat"
uid_1
email: "clark#email.com"
username: "superman"
Once the user authenticates using Firebase Authentication, from there forward any time the user info needs to be displayed in the app, simply look up the uid that you need (uid_1) and grab the username node (superman) for display.
I read some Firebase database structure guides on how to structure your data properly (without data nesting) but I have one question.
So, I have an iOS app that uses Firebase database. The users need to login/register.
In terms of data structure, my database looks like this:
-Database
---Users
-----User1
--------username: johndoe
---------email: johndoe#test.com
---------display_name: John Doe
-----User2 {....}
-----User3 {....}
Now, let's imagine I have 100K users in there. Every time a new user is being registered, I check if the username & the email already exist in the database, if they don't then create the new user account.
My question is - Do I need to create a new object that contains only the usernames and another that contains only the emails? I'm asking this because I'm concerned that if I iterate through the Users objects I will potentially be downloading hundreds of megabytes just to check if the username and the email already exist.
Firebase will not allow duplicate users (authentication names). So when you call createUser, firebase will return an error if the user already exists.
Secondly, if you are performing a query for a specific item in Firebase, you are not downloading anything unless that item is found. So whether its 10 or 100k user nodes, nothing is downloaded when performing a query other than the nodes that match the query, which would only be one if there was a duplicate user. again though, this is not needed since Firebase rejects duplicate authentication names.
And to clarify; there is nothing wrong with nesting nodes. However, keeping them flat is usually better depending on your use case. So don't go overcomplicating your structure if you don't need to.
Oh, and your Firebase structure is spot on. Keep going with that.
I am writing an app, where a signed up user should be able to see which of his contacts have signed up, too. What is the most elegant way to do this?
I was planning to create an array of all locally saved email addresses extracted from the user's local iOS addressbook and create a query for those. Is there any better way to do this?
Edit: Is this actually possible without downloading the whole user list? I could use a for loop with queryStartingAtValue(emailAddress) and queryEndingAtValue(emailAddress). But this could possibly lead to hundreds of queries at the same time.
In NoSQL databases you'll often end up modeling the data in ways that your application wants to consume it.
In this case it seems your app needs to look up whether a user exists, based on their email address. For that purpose I'd add a list of email-to-uid data:
emailToUid
"test#mail,com": "P0...wklsh1"
"MJQZ1347": "Aj1278a..."
This is essentially a self-created index that allows you to check whether an email address is used without having to run a query.
Now you can loop over the contact and look whether there is a user for that email address with a:
ref.child("emailToUid").child(email).observeSingleEventOfType(.Value
This is going to be very fast. Because of the way Firebase communicates with the back-end, there's going to be very little difference between a single request with 100 email addresses or 100 requests with a single email address. See my answer here for more on that: Speed up fetching posts for my social network app by using query instead of observing a single event repeatedly
You could have something like this
user
-$user_id
-email
-username
-contacts
-contact_uid1:email1,
-contact_uid2:email2,
-contact_uid3:email3,
And then do:
Download the contact child from firebase and save it to a var
Create the loop to check every contact in the address book
If the email is in the contact child don't do anything (it means you already verified the user once)
If the email is not in the contact child launch a single event query to find the uid of an specific email
in the callback of the query if it is nsnull the user is not in the app
if the user exist, add the user to your contacts child node in firebase
This way you only launch the queries of the contacts you haven't checked