Kdjykuj

Currently Magento 2 is providing JSON and XML response in web REST API
I want to include a custom response format PDF.

So if any third-party will call our API then we can sen them PDF in response.

Just my idea: We shouldn't do this. We can add the download link or generated link to API response.
There are some additional points:

• How about your server resource if serving PDF each time calling. Your server can be stress. We should consider about this case.


• Should consider security in this case as well.

First define your route in etc/webapi.xml

<route url="/V1/invoices/:id/pdf/:template" method="GET">

    <service class="ThousandmonkeysRestpdfApiPDFInterface" method="pdf"/>

    <resources>

        <resource ref="Magento_Sales::sales" />

    </resources>

</route>

Then in your Model class, which you've defined in di.xml as implementing your interface (in my case ThousandmonkeysRestpdfModelPDFMaker) you can return the generated pdf easily. I've used eadesignro/module-pdfgenerator as my pdf engine (it's rather friendlier than than doing it manually).

public function pdf($invoiceId, $templateId){

    $templateModel = $this->pdfGeneratorRepository->getById($templateId);

    if (!$templateModel) {

        throw new MagentoSalesException(

                __('Could not find template.')

        );

    }

    $invoice = $this->invoiceRepository

        ->get($invoiceId);

    if (!$invoice) {

        throw new MagentoSalesException(

                __('Could not find invoice.')

        );

    }

    $helper = $this->helper;

    $helper->setInvoice($invoice);

    $helper->setTemplate($templateModel);

    $pdfFileData = $helper->template2Pdf();

    return new PDFResponse(base64_encode($pdfFileData['filestream']));

}

PDFResponse is just a class with one getter that magento uses to generate json or xml.

It is a bit heavy so consider load, but it's a trade off between that and using the file system, which is not always a great idea (problems with load balancers & clean up). A respectful client wont cause any more issues with this than anything else. A disrespectful client could just request the pdf over and over.

It would be a bit of a problem to open this up to customers however. You can't guarantee that they will be respectful.

Full implementation https://github.com/lingwooc/restpdf-magento2 or just install thousandmonkeys/m2-restpdf-module