View Source Flamel.Context (flamel v1.10.0)

A Context can be used to in a pipeline to assign data to that future functions can have access to and transform. It also includes a boolean value that signals to other functions in the pipeline whether they should process the context or not.

Example 

alias Flamel.Context

context =
  Context.new()
  |> assign_user(user)
  |> authorize()
  |> perform_action()

if context.assigns[:action_performed?] do
  # something you are allowed to do
end

def assign_user?(%Context{} = context, user) do
  Context.assign(context, :user, user)
end

def authorize(%Context{assigns: %{user: %{type: :admin}} = context) do
  context
end

def authorize(%Context{} = context) do
  Context.halt!(context, "Not permitted")
end

def perform_action(%Context{halt?: true}) do
  # do nothing
  context
end

def perform_action(%Context{assigns: %{user: user}} = context) do
  # Do something
  Context.assign(context, %{action_performed_by: user, action_performed?: true})
end

Summary

Types

t()

Flamel.Context

Functions

assign(context, map)

If given a map it will merge values into the assigns in the context. It does not perform a deep merge.

assign(context, key, value)

Assigns a value to a key in the context.

halt!(context, reason)

Signals to further functions in the pipeline that processing should stop

halted?(context)

Has the context been halted?

resume!(context)

Signals to further functions in the pipeline that processing should resume

Types

Link to this type

t()

View Source 
@type t() :: %Flamel.Context{assigns: map(), halt?: boolean(), reason: binary()}

Flamel.Context

Functions

Link to this function

assign(context, map)

View Source 
@spec assign(term(), map()) :: term()
@spec assign(
  term(),
  keyword()
) :: term()

If given a map it will merge values into the assigns in the context. It does not perform a deep merge.

If given a keyword list it will set values in the assigns. You can also push a value into the key if the value is a list.

Examples 

iex> context = Flamel.Context.assign(%Flamel.Context{}, %{hello: :world})
iex> context.assigns[:hello]
:world


iex> context = Flamel.Context.assign(%Flamel.Context{assigns: %{tags: []}}, set: [hello: :world], push: [tags: "new"])
iex> context.assigns[:hello]
:world
iex> context.assigns[:tags]
["new"]
Link to this function

assign(context, key, value)

View Source 
@spec assign(term(), binary() | atom(), term()) :: term()

Assigns a value to a key in the context.

The assigns is meant to be used to store values in the context so that other functions in your pipeline can access them. The assigns storage is a map.

Examples 

iex> context = %Flamel.Context{}
iex> context.assigns[:hello]
nil
iex> context = Flamel.Context.assign(context, :hello, :world)
iex> context.assigns[:hello]
:world
Link to this function

halt!(context, reason)

View Source 
@spec halt!(term(), binary()) :: term()

Signals to further functions in the pipeline that processing should stop

Examples 

iex> context = %Flamel.Context{}
iex> context.halt?
false
iex> context = Flamel.Context.halt!(context, "no more")
iex> context.halt?
true

iex> context = %Flamel.Context{}
iex> context.halt?
false
iex> context = Flamel.Context.halt!(context, "some error message")
iex> context.halt?
true
iex> context.reason
"some error message"
Link to this function

halted?(context)

View Source 
@spec halted?(term()) :: boolean()

Has the context been halted?

Examples 

iex> context = Flamel.Context.halt!(%Flamel.Context{}, "stop it")
iex> Flamel.Context.halted?(context)
true
Link to this function

resume!(context)

View Source 
@spec resume!(term()) :: term()

Signals to further functions in the pipeline that processing should resume

Examples 

iex> context = %Flamel.Context{halt?: true}
iex> context.halt?
true
iex> context = Flamel.Context.resume!(context)
iex> context.halt?
false