How To Build a Todo App With Airsequel and Lowdefy

In this tutorial we will be building a very simple todo app with Lowdefy. It will load the todos via GraphQL from a SQLite database hosted on Airsequel.

This is what the final app will look like. Not pretty, but functional!

If you find any problems in this tutorial, please feel free to leave a comment!

Setting up the Airsequel Database

Things to know:

• As the primary key we use the automatically generated rowid column.

First, let’s create the todo database in Airsequel’s UI. If you’re on Airsequel Enterprise you can alternatively use following steps:

• Alternative way for Airsequel Enterprise: Upload an existing SQLite database <aside> 💡 The next steps describe how to create the database with the sqlite3 cli tool. You can of course also use one of the many graphical database management apps like e.g. DB Browser for SQLite or Beekeeper Studio.</aside>

  1. Create a schema.sql file for creating the SQLite database:

     • schema.sql

       CREATE TABLE todos (
         title TEXT NOT NULL,
         completed BOOLEAN DEFAULT (FALSE) NOT NULL
       );
       
       
       -- Add some example todos
       INSERT INTO todos (title, completed)
       VALUES
         ('Buy milk', 0),
         ('Go hiking', 1);
       

  2. Execute SQL query to create the database:

     sqlite3 todos.sqlite < schema.sql
     

  3. Go to airsequel.com and upload the todos.sqlite file.

Or build it up from scratch:

1. Go to airsequel.com (or your custom Enterprise instance)
2. Click on “Create New SQLite Database”
3. Rename database to “todos”
4. Go to the “Tables” tab
5. Rename “table_1” to “todos”
6. Rename column “name” to “title”
7. Add a new column “completed” with type “Boolean” and activate “Not Null”
8. Create a few todos like “Buy milk” and “Go hiking” to make working with it easier

🎉 Your database and the corresponding GraphQL endpoint are now ready!

It should look something like this:

Creating the Lowdefy app

1. Create the directory and the boilerplate code:

   mkdir lowdefy-todo-app
   cd lowdefy-todo-app
   npx lowdefy@latest init
   

2. Start development server:

   npx lowdefy@latest dev
   

You should now see the welcome screen running at localhost:3000/welcome:

Since Lowdefy does not have a dedicated GraphQL connector yet (https://github.com/lowdefy/lowdefy/issues/298), we simply use the more generic AxiosHttp module to make the necessary HTTP POST request.

Therefore add following block right below the name: … line:

connections:
  - id: graphql_api
    type: AxiosHttp
    properties:
      baseURL: https://<your-company>.airsequel.com

In order to render our todos, replace now the pages: block with following code and replace <database-id>with your database id from database setup step.

pages:
  - id: todos
    type: PageHeaderMenu
    requests:
      - id: todos_request
        type: AxiosHttp
        connectionId: graphql_api
        properties:
          url: /dbs/<database-id>/graphql
          method: post
          data:
            query: "{ todos { title, completed } }"

    events:
      onEnter:
        - id: fetch_todos
          type: Request
          params: todos_request

        - id: set_todos
          type: SetState
          params:
            todo_list:
              _request: todos_request.data.data.todos

    blocks:
      - id: title_main
        type: Title
        properties:
          content: Todos

      - id: todo_list
        type: List
        blocks:
          - id: todo_container_$
            type: Box
            style:
              background: LightGray
              margin: 0.5rem
              padding: 1rem 2rem
            blocks:
              - id: todo_list.$.completed
                type: CheckboxSwitch
                layout:
                  size: 2em
                  align: middle
                properties:
                  label:
                    disabled: true

              - id: todo_title_$
                type: Span
                layout:
                  grow: 1
                  align: middle
                properties:
                  content:
                    _state: todo_list.$.title

Now, the complete file looks like this:

lowdefy.yaml