Simplifying database access

[JaydenBea]

An class that simplifies access to information needed in the database is quite desirable. It abstracts database access, allowing changes to be done without requiring mass rewrites, and will make things overall easier.

The FirebaseHelper class initializes elements needed for access, including all collection references, but I'm going to make another class between this one and classes responsible for presenting UI to the user. The Snapshots class will contain methods and variables that are needed by various components of the database, and simplify their use.

[JaydenBea]

12:00pm (start)

The first thing the class needs is Future variables for the various Streams and lists needed by different pages. Of note:

• Stream of entries (used by FeederPage)
• List of stations (multiple pages)
• List of users
• List of cats
• Methods interacting with these

Something I need to find is whether lists of QueryDocumentSnapshots (the latter three) will dynamically update like Streams do. It would be important for the Admin page in particular that the lists update after stations/cats are added/removed.

[JaydenBea]

12:25pm (since 12pm)

There is a distinct difference between getting the results of, say, a query that returns a Future with a list of QueryDocumentSnapshots (FirebaseHelper().usersRef.get()) and a Stream (FirebaseHelper.usersRef.snapshots()). Both are asynchronous operations that takes some time to complete. However, where a Future does the operation once and returns an unchanging value, a Stream's values can update over time. Where a Future will return a list of users as they were at the time of Query completion, a Stream will react to changes in the database after data is originally fetched.

For now, I'm going to add variables for both Stream and Future versions of each collection.

[JaydenBea]

1pm (Since 12:25pm)

Added Streams and Futures for all four collections, including initializing functions for the three. The initializers use a common function with a generic typing. The list of stations is sorted by ID.

Working on adding getters that, when given a DocumentReference, returns the DocumentSnapshot of the document referenced by the snapshot. I'm also trying to give this dynamic typing for redundancy's sake.

[JaydenBea]

1:30pm (since 1pm)

Added a generic getter as described above. This was done by introducing Model, an abstract class that the other models (UserDoc, Entry, Station, Cat) all extend. The abstract class itself has no methods. It could include toJson, but not fromJson, as the latter is a constructor.

[JaydenBea]

2pm (since 1:30pm)

Added functions from FeederDataSource and confirmed the functionality of the items in Snapshots.

[JaydenBea]

8:20pm (start)

• Making Snapshots' variables and methods static, as I believe this makes more sense (there's a single point of data access, not multiple).
• Going to start replacing references to FeederDataSource within the feeder files to references to Snapshots
• After that, plan is to start adding methods to Snapshots so that all data access within different feeder files is done through that class.

[JaydenBea]

8:50pm (since 8:20pm)

• Replaced all references to FeederDataSource with references to Snapshots.
• Fixed an error in Snapshots.getDocument where the generic type wasn't checked correctly.
  • Switch case used 'T.runtimeType' when that wasn't necessary (should've just been T)
  • Dart recommended use of typeName _ in place of typeName in switch case, but this caused a bug

[JaydenBea]

9:08pm (since 8:50pm)

• Added equalizeTime to Snapshots, from FirebaseHelper
• Added a runTransaction method to Snapshots, which runs FirebaseFirestore.runTransaction.
• Replaced references to FirebaseHelper in all Feeder Files with to references to Snapshots.