Class: Lich::Common::DatabaseAdapter

Inherits:
Object
  • Object
show all
Defined in:
documented/common/settings/database_adapter.rb

Overview

Database adapter to separate database concerns Database adapter to separate database concerns

This class handles the interaction with the database, including setting up the database table and saving/loading settings.

Examples:

Creating a new database adapter

adapter = Lich::Common::DatabaseAdapter.new("/path/to/data", "settings_table")

Instance Method Summary collapse

Constructor Details

#initialize(data_dir, table_name) ⇒ DatabaseAdapter

Initializes a new DatabaseAdapter instance.

Parameters:

  • data_dir (String) —

    The directory where the database file is located.

  • table_name (String) —

    The name of the table to use in the database.



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# File 'documented/common/settings/database_adapter.rb', line 16

def initialize(data_dir, table_name)
  @file = File.join(data_dir, "lich.db3")
  @db = Sequel.sqlite(@file)
  @table_name = table_name
  setup!
end

Instance Method Details

#get_settings(script_name, scope = ":") ⇒ Hash

Retrieves settings for a given script and scope.

Parameters:

  • script_name (String) —

    The name of the script to retrieve settings for.

  • scope (String) (defaults to: ":") —

    The scope of the settings (default is “:”).

Returns:

  • (Hash) —

    The settings as a hash, or an empty hash if not found.



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# File 'documented/common/settings/database_adapter.rb', line 47

def get_settings(script_name, scope = ":")
  entry = @table.first(script: script_name, scope: scope)
  entry.nil? ? {} : Marshal.load(entry[:hash])
end

#save_settings(script_name, settings, scope = ":") ⇒ Boolean

Saves settings for a given script and scope.

Examples:

Saving settings

adapter.save_settings("my_script", {"key" => "value"})

Parameters:

  • script_name (String) —

    The name of the script to save settings for.

  • settings (Hash) —

    The settings to save.

  • scope (String) (defaults to: ":") —

    The scope of the settings (default is “:”).

Returns:

  • (Boolean) —

    True if settings were saved successfully, false otherwise.

Raises:

  • (ArgumentError) —

    If settings is not a Hash.

  • (Sequel::DatabaseError) —

    If there is a database error while saving.



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# File 'documented/common/settings/database_adapter.rb', line 62

def save_settings(script_name, settings, scope = ":")
  unless settings.is_a?(Hash)
    Lich::Messaging.msg("error", "--- Error: Report this - settings must be a Hash, got #{settings.class} ---")
    Lich.log("--- Error: settings must be a Hash, got #{settings.class} from call initiated by #{script_name} ---")
    Lich.log(settings.inspect)
    return false
  end

  begin
    blob = Sequel::SQL::Blob.new(Marshal.dump(settings))
  rescue => e
    Lich::Messaging.msg("error", "--- Error: failed to serialize settings ---")
    Lich.log("--- Error: failed to serialize settings ---")
    Lich.log("#{e.message}\n#{e.backtrace.join("\n")}")
    return false
  end

  begin
    @table
      .insert_conflict(target: [:script, :scope], update: { hash: blob })
      .insert(script: script_name, scope: scope, hash: blob)
    return true
  rescue Sequel::DatabaseError => db_err
    Lich::Messaging.msg("error", "--- Database error while saving settings ---")
    Lich.log("--- Database error while saving settings ---")
    Lich.log("#{db_err.message}\n#{db_err.backtrace.join("\n")}")
  rescue => e
    Lich::Messaging.msg("error", "--- Unexpected error while saving settings ---")
    Lich.log("--- Unexpected error while saving settings ---")
    Lich.log("#{e.message}\n#{e.backtrace.join("\n")}")
  end

  false
end

#setup! ⇒ void

This method returns an undefined value.

Sets up the database table if it does not exist.



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# File 'documented/common/settings/database_adapter.rb', line 26

def setup!
  @db.create_table?(@table_name) do
    text :script
    text :scope
    blob :hash
  end
  @table = @db[@table_name]
end

#table ⇒ Sequel::Dataset

Returns the database table object.

Returns:

  • (Sequel::Dataset) —

    The dataset representing the table.



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# File 'documented/common/settings/database_adapter.rb', line 38

def table
  @table
end