Class: FaradayMiddleware::ConvertSdataToHeaders Private

Inherits:
ResponseMiddleware
  • Object
show all
Defined in:
lib/faraday/response/convert_sdata_to_headers.rb

Overview

This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

Middleware to strip out Sage’s pagination SData from the body and place it in a custom response header instead (Using familiar ‘Link’ header syntax). This just leaves the resources in the body which can then be recursively collected later by following the links.

Constant Summary collapse

SDATA_START_INDEX =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

"$startIndex".freeze
SDATA_TOTAL_RESULTS =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

"$totalResults".freeze
SDATA_ITEMS_PER_PAGE =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

"$itemsPerPage".freeze
SDATA_RESOURCES =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

"$resources".freeze
SDATA_HEADER_NAME =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

"X-SData-Pagination-Links".freeze

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ ConvertSdataToHeaders

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of ConvertSdataToHeaders.



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# File 'lib/faraday/response/convert_sdata_to_headers.rb', line 49

def initialize(app)
  @links = []
  super app
end

Instance Method Details

#call(env) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/faraday/response/convert_sdata_to_headers.rb', line 22

def call(env)
  @app.call(env).on_complete do
    @response = env[:response]

    # Only proceed if SData is actually present
    next unless @response.body && @response.body.kind_of?(Hash) && @response.body[SDATA_TOTAL_RESULTS]

    @url  = Addressable::URI::parse(env[:url])
    @url.query_values ||= {}

    # Add 'next' link, if we're not on the last page
    add_link(next_start_index, 'next') if next_start_index < @response.body[SDATA_TOTAL_RESULTS]

    # Add 'prev' link if we're not on the first page
    add_link(prev_start_index, 'prev') if prev_start_index >= 0

    # Special case: If we're halfway through the first page, don't allow negative start indices
    add_link(0, 'prev') if @response.body[SDATA_START_INDEX] != 0 && prev_start_index < 0

    # Add the page links into the header
    @response.headers[SDATA_HEADER_NAME] = @links.join(', ') unless @links.empty?

    # Strip out the SData from the body
    env[:body] = @response.body[SDATA_RESOURCES]
  end
end