Generate Dart Types from Database Schema

[atreeon]

Are there any current ways or future plans to generate Dart types from Supabase tables?

for example, currently I do this where I use strings inside the methods and the output is a dynamic map that I manually convert

  var result = await supabase //
      .from('TestTable')
      .select()
      .eq('id', 1)
      .execute();

  var dataFirst = result.data[0];
  var data = TestTable(id: dataFirst["id"], name: dataFirst["name"]);

and I would like to do this; with the type generated automatically for me (a bit more like c#'s entity framework or dart's Conduit), where the type returned is a specific type that matches the database.

  var testTable = await supabase //
      .TestTable
      .select()
      .eq((x) => x.id, 1)
      .execute();

  print(testTable.name);

[DanMossa]

What I've been doing until a better solution comes up is to make an enum of my tables, and then create a method that takes in the table enum and uses that to call Supabase.

I then only interact with Supabase using my wrapper method.

[bdlukaa]

Maybe you're looking for withConverter.

final User user = await postgrest
  .from('users')
  .select()
  .withConverter<User>((data) => User.fromJson(data));

[atreeon]

Thanks @bdlukaa, so is the data variable json? Do you use the json_serializable package to create your fromJson code?

[bdlukaa]

is the data variable json?

data is the result given from the server. It can be either a Map or a List, depending on your query

Do you use the json_serializable package to create your fromJson code?

There are a lot of options to generate the fromJson/toJson code

• https://pub.dev/packages/json_serializable
• https://pub.dev/packages/freezed (I like this better)

Or you can do it by hand.

[atreeon]

thanks @bdlukaa, that is very helpful and gets me a bit further. It would still be helpful if it were more type safe of course and the models were generated from the db automatically (I'm used to .net's Entity Framework which does everything for you). For example if the table name or a field name changed in the database there would be a runtime error. Also you have to manually write the table name and the withConverter doesn't know what type it should be.

Thanks again though, much better than doing the mappings manually.

[bdlukaa]

It would still be helpful if it were more type safe of course and the models were generated from the db automatically

@dshukertjr we could create a tool that would convert schemas into dart classes. What do you think?

[dshukertjr]

@bdlukaa That sounds amazing! We could possibly add it to the Supabase cli? https://github.com/supabase/cli

[DanMossa]

This is something that exists. I haven't personally used it but it's definitely worth looking into as a starting point
https://pub.dev/packages/schema_dart

[kkalisz]

It's possible to generate models using swagger-codegen and exposed API definition.

swagger-codegen generate -i https://yourproject.supabase.co/rest/v1/?apikey=your_api_key -l dart -o ./test -Dmodels

To generate only required types it's possible to add a filter to -Dmodels argument

swagger-codegen generate -i https://yourproject.supabase.co/rest/v1/?apikey=your_api_key -l dart -o ./test -Dmodels=type1,type2

All of the generated types contain convert methods.
Type.fromJson(Map<String, dynamic> json)
and
List<Type> listFromJson(List<dynamic> json)

[atreeon]

So, I've tried some of these solutions out.

1. swagger-codegen generate version 2 isn't compatible with null safety so I couldn't use that

2. there is a package called swagger_dart_code_generator
   It generates CRUD operations ok. I can sort and order and do some basic filtering but then it seems to fail and get tricky when trying to combine multiple logical operators (or / and).
   myService.employeesGet(employeeId: "lt.4")
   as you can see, it still uses raw text for operators so it isn't very safe.

3. what I'm going to do for now is use the supabase package and use the withConverter using the toJson from the swagger dart code generator.

However, this still doesn't get me what I want, ie I can't do this .eq((x) => x.id, 1) in a safe way because the column name and the value still need to be text.

I think it is possible to build something, possibly using postgrest as that is what supabase uses; I'll think about giving it a go.

(apologies for the delay in responding until now)