Invoices loaded with pagination needlessly load line items separately

[pinfieldharm]

When Invoices are loaded with a page specified, e.g. client.Invoice.all(page: 1) Xero returns line items inline with the invoices:

<Response xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Id>558b39e7-c7dc-451f-883e-e52934a8ea0a</Id>
  <Status>OK</Status>
  <ProviderName>Funding Gates (privatedev)</ProviderName>
  <DateTimeUTC>2014-09-24T16:27:01.3399614Z</DateTimeUTC>
  <Invoices>
    <Invoice>
      <Contact>
        <ContactID>018355fc-c67e-4352-b443-ef3873031983</ContactID>
        <Name>Truxton Property Management</Name>
      </Contact>
      <Date>2014-08-25T00:00:00</Date>
      <DueDate>2014-08-25T00:00:00</DueDate>
      <Status>PAID</Status>
      <LineAmountTypes>Inclusive</LineAmountTypes>
      <LineItems>
        <LineItem>
          <Description>Monthly rent in advance</Description>
          <UnitAmount>1181.25</UnitAmount>
          <TaxType>NONE</TaxType>
          <TaxAmount>0.00</TaxAmount>
          <LineAmount>1181.25</LineAmount>
          <AccountCode>660</AccountCode>
          <Quantity>1.0000</Quantity>
        </LineItem>
      </LineItems>
      <SubTotal>1181.25</SubTotal>
      <TotalTax>0.00</TotalTax>
      <Total>1181.25</Total>
      <UpdatedDateUTC>2012-05-19T00:30:56.483</UpdatedDateUTC>
      <CurrencyCode>USD</CurrencyCode>
      <FullyPaidOnDate>2014-09-05T00:00:00</FullyPaidOnDate>
      <Type>ACCPAY</Type>
      <InvoiceID>2d106259-ee44-45da-8030-fec35dd1af43</InvoiceID>
      <InvoiceNumber>RPT660-1</InvoiceNumber>
      <Payments>
        <Payment>
          <PaymentID>8f9aa345-c2b0-4dc5-b868-0402c86ced79</PaymentID>
          <Date>2014-09-05T00:00:00</Date>
          <Amount>1181.25</Amount>
          <CurrencyRate>1.000000</CurrencyRate>
        </Payment>
      </Payments>
      <AmountDue>0.00</AmountDue>
      <AmountPaid>1181.25</AmountPaid>
      <AmountCredited>0.00</AmountCredited>
      <HasAttachments>false</HasAttachments>
    </Invoice>
    ...
  </Invoices>
</Response>

However, if line_items is accessed either directly or indirectly (e.g. through Invoice#total_tax) a new request is made to Xero for the invoice details. The line_items are in fact already accessible within the invoice model, but ignored.

[waynerobinson]

The Xeroizer library doesn't currently support pagination.

Happy to receive a PR for this issue to implement pagination. It should happen at a lower level in the API and have a way to configure which endpoints support pagination.

This should still be optional (with potentially a global configuration default) as many existing users may expect calls to these endpoints to contain all records.

When using pagination, you should return the correct result for Xeroizer::Record::Base#complete_record_downloaded? for the configured models.

[umairsiddique]

#169

[pinfieldharm]

#171 is my take on a partial solution to this problem.