View Source RecordList (record_list v0.1.3)

A struct that builds a list of records defined by a query by initialising with a set of parameters and passing the struct through a sequence of steps. A pagination struct RecordList.Pagination is built to capture the paging information.

The libary is built to be open-ended but a typical pipeline could look something like:

params -> base query -> apply sorting -> search against some criteria
  -> apply filtering -> calculate paging values -> retrieve the records.

A RecordList can be created by calling

  use RecordList,
    steps: [
      base: [impl: MyBaseStep],
      sort: [impl: MySortStep, default_sort: "name", default_order: "asc"],
      paginate: [impl: MyPaginationStep, per_page: 20, count_by: :id, repo: MyApp.Repo]
      retrieve: [impl: MyRetrieveStep]
    ]

steps
Steps

Steps implement the RecordList.StepBehaviour behaviour. The execute/3 function takes the record list in the making, the step name as an atom and any options that were passed in, for example, the default_sort and default_order options above.

Steps are executed in the order in which they are defined in the :steps option to the RecordList.__using__/1 macro. Calling a step will execute all the steps higher in the list of steps.

  %RecordList{params: ^params, query: _base_query, steps: [:base]}
    = MyRecordList.base(params)
  %RecordList{loaded: true, records: _populated_with_results_of_query, params: ^params, query: _, steps: [:retrieve, :paginate, :sort, :base]}
    = MyRecordList.retrieve(params)

Notice that calling retrieve/1 returns a record list with the prior steps executed as well. Calling paginate/1 will build the pagination struct, but not retrieve the records.

  %RecordList{loaded: false, records: [], pagination: %RecordList.Pagination{records_count: _, records_offset: _}, steps: [:retrieve, :paginate, :sort, :base]}
    = MyRecordList.paginate(params)

See __struct__/0 for details about the attributes.

Link to this section Summary

Types

t()

The RecordList struct collects meta data along with the list of records.

Link to this section Types

t()

@type t() :: %RecordList{
  extra: term(),
  loaded: term(),
  pagination: term(),
  params: term(),
  query: term(),
  records: term(),
  steps: term()
}

The RecordList struct collects meta data along with the list of records.

attributes
Attributes

:query- the variable where the query is built up. In the case of Ecto this will be an Ecto.Query struct.
:params- Queries to create a record list are typically driven by parameters. These can be captured in the params attribute to be referenced in subsequent steps.
:pagination- paginating a list of data is common. RecordList comes with a %RecordList.Pagination{} struct that can be used to capture information describing the pages in the list.
:loaded- a boolean value indiciating whether the records have been loaded. An empty list of records does not capture the same information since the result of a query can be an empty list.
:records- a list of records retrieved by executing the query.
:steps- a list of the steps that have been executed. This makes it possible to not have to run a step.
:extra- a map of any extra information that might be needed along the way.

Settings View Source RecordList (record_list v0.1.3)

steps Steps