I'm using Azure Mobile Services and I want to clear local database, how can I do that?
I have a problem with my local database. When I logout in app and login with other user, the data of the previous user is loaded for current user and I don't have idea why this occurs. I use debug on server side and the server return correct data, then I believe that the problem is the local Database.
I'm using Azure Mobile Services and I want to clear local database, how can I do that?
For deleting your SQLite file, you could follow Deleting the backing store. Also, you could leverage the capability provided by IMobileServiceSyncTable to purge records under your offline cache, details you could follow Purging Records from the Offline Cache.
When I logout in app and login with other user, the data of the previous user is loaded for current user and I don't have idea why this occurs. I use debug on server side and the server return correct data
Since you did not provide details about your implementations (e.g. user log in/log out, user data management,etc), I would recommend you check whether your server/client side both enable per-user data store. You could use fiddler to capture the network traces when other user logging in, and make sure that the correctly user identifier (e.g. UserId) is returned, then check the query against your local database. Moreover, I would recommend you follow adrian hall's book about Data Projection and Queries.
You can delete all of the local DB files by doing the following.
var dbFiles = Directory.GetFiles(MobileServiceClient.DefaultDatabasePath, "*.db");
foreach (var db in dbFiles)
{
File.Delete(db);
}
However, this would delete all data each time and cause performance issues, as every time after you did this, you'd be getting a fresh copy of the data from your Azure DB, rather than using the cached copy in the device's SQLite DB.
We typically only use this for debugging, and the reason it's in a foreach is to capture all databases created (refer to my last suggestion)
There are a few other things you could try to get around your core issue of data cross-over.
There's another reason you might be seeing this behaviour. With your PullAsync, are you passing it a query ID? Your PullAsync line should look similar to this.
GetAllFoo(string userId)
{
return await fooTable.PullAsync("allFoo"+userId,fooTable.Where(f=>f.userId == userId));
}
Note that the query ID will be unique each time (or at least, for each user). This is used primarilly by the offline sync portion of Azure, but in combination with the Where statement (be sure to import System.Linq), this should ensure only the correct data is brought back.
You can find more information about this here.
Also, some things you may want to consider, store a separate database for each userId. We're doing this for our app (With a company ID) - so that each database is separate. If you do this, and use the correct database on logging in, there's no chance of any data cross over.
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I am working on an fitness app and I am required to make such a data structure such that I can keep the user progress for each program he/she has opted in . I am using MongoDB with Node js. What will be the best solution for this problem ? Should server database or use app's LocalStorage to keep the user progress
It highly depends on if the data is supposed to be accessible on other devices and/or be backed up on the cloud.
If you were to save the data in a database, this would allow the possibility to tie the data to accounts to be accessed on any device that a user is logged into.
Otherwise, if you don't plan on having data accessible on other devices and tying data to an account, you could get away with saving the data on the user's local storage.
I was going through this question: socket.io determine if a user is online or offline.
In the answer I have seen that an object containing the online users is created. In a production app should you store this data in a database like redis? Or is it okay if it stays saved in memory in the server?
I would not store the users in the server's memory, imagine this case:
for some reason you need to restart the server, a crash, a new version update, a new release and the memory of the server gets reset and you loose the users object.
So for this redis looks like a great option to store users data.
I am creating an application in which the user can post information as well as choose as a favorite the publication of someone else, when the user performs any of these actions I keep the necessary information in the in the database, specifically in a document where the information linked to the user is found (name, surname, telephone number, etc.).
so when the user logging in the page I get all that information with a single query and I keep it in the LOCALSTOAGE and reduce the queries in the database, then in a different section you can see the publications you have created as well as the ones you have marked as favorites, very similar to what we commonly see in an online store
I'm using angular 6, noje.js and mongoDB. My question is the following:
Is this a correct and effective way to do it?
Should I save it in the database and then perform the corresponding query to obtain it?
shows a screenshot of local storage for explicit use:
As you can see I also save the token that I use to authenticate the user's queries and obviously I do not show your password I would like your opinions.
You never should consider localStorage as an alternative to the database.
At some point, you might have a huge amount of data and your browser would crash to load them.
Bring the data you required from the server.
For some minimum and temporary amount of data, you can consider localStorage. Don't bring all the data in a single query to save database operation. Databases are built to do that for you.
I am developing a hobby project using Firebase and some Node.JS running on Google App Engine as backend. I am a real newbie in this area, and also just hear about Firebase a month ago.
My question relates to how various "things" can be secured from user actions, even though Firebase is running as JS on client-side.
I am aware that the DB and Storage can be secured using logical rules - that is in place.
My question rather concerns the actions an user can perform with firebase.auth() and similar, such as:
firebase.auth().createUserWithEmailAndPassword()
firebase.auth().currentUser.delete()
firebase.auth().currentUser.link()
As I have understood it from the question linked below, there is no solution - user will always be able to call these functions, and it is considered low-risk since they cannot touch other user accounts. "prevent firebase user from deleting himself"
My concern with not being able to block users from these actions is that I cannot perform the relevant changes to the DB. For some basic use cases I assume it is easy to set up a nightly batch-job to clean up, but I am afraid of future more complex issues.
My current solution for making atomic actions, e.g. delete user account and delete user data in DB, is to send a request to my back-end Node.JS server. That works fine, but a user could, as I understand, by pass this and request e.g. currentUser.delete() by himself/herself. Another case is when a user unlinks a google account. I would like the user to be logged out by, but with the premises the user can unlink with the follow up action.
Question: Have I misunderstood anything? Can this be easily prevented, or is it so that all the available actions are consider harmless and it is up to me to perform clever clean-up etc.? If it cannot be prevented, do you have any more suggestions more clever than nightly batch jobs?
With Cloud functions for firebase you could for example trigger a function on user deletion. That way every time a user is deleted, you can run your code to do the clean up. No matter how the user deletion is invoked.
exports.removeUserFromDatabase = functions.auth.user().onDelete(function(event) {
// Get the uid of the deleted user.
var uid = event.data.uid;
// Remove the user from your Realtime Database's /users node.
return admin.database().ref("/users/" + uid).remove();
});
The same goes for "onCreate". Check out their documentation
https://firebase.google.com/docs/auth/extend-with-functions
I'm using PouchDB + CouchDB to store and sync data in an angular app currently in development. Data is stored per user and contains things such as user authorities/settings, recently viewed content and cart items.
Currently, I have a single CouchDB database that contains a doc for each user. While this structure works well for quickly retrieving user-specific data, it's logically flawed because all user docs are synced to any device that accesses the app. In other words, I ultimately only need the currently logged in user's data to sync.
So, my question is, should I create a Couch database for each user instead of using a single database with a doc for each user? Or is there a better way to go about this?
If you look at the pouchdb-authentication plugin you'll see that you can store metadata for a user in the _user database. That might be all you need.