Loading xml data with response mimetype 'application/fhir+xml' fails #315

pherk · 2025-08-11T07:08:38Z

pherk
Aug 11, 2025

my challenge: loading xml data from an external FHIR server.
Despite I'm requesting with mimetype 'application/xml', the server insists on responding with 'application/fhir+xml'.
The request completes with '200', the response data are ok. It is followed(?) by an OPTIONS request '200' (CORS).
The submission completes with 'submit-done', but I cannot access the data.
Tried to set responsemediatype attribute and fx-headers
If I use ?inspect, errors pop up
Uncaught TypeError: can't access property "length", root.childNodes is undefined
drawDOM http://localhost:8080/exist/apps/iCalSE/resources/scripts/fore-dev.js:29009

Wrong submission parameters, bug?

regards
Peter

mwe

<html lang="en">
<head>
    <meta charset="utf-8"/>
    <meta content="width=device-width, minimum-scale=1, initial-scale=1, user-scalable=yes" name="viewport"/>
    <title>MWE</title>
    <link rel="shortcut icon" type="image/png" href="../resources/images/icon.png" sizes="16x16"/>
    <link rel="stylesheet" href="../resources/css/fore.css" media="screen"/>
    <script type="module" src="../resources/scripts/fore-dev.js"/>
</head>
<body>
<div class="wrapper">
    <!-- for accessability adding a 'role' and 'title' to make it a landmark -->
    <fx-fore xmlns:fhir="http://hl7.org/fhir" id="ical" title="ical app" role="form">
      <fx-model> 
        <fx-action event="model-construct-done" target="#document">
            <fx-send submission="s-hapi"/>
        </fx-action>
        <fx-instance id="default">
            <data user="">
            </data>
        </fx-instance>
            <fx-submission id="s-hapi" url="http://hapi.fhir.org/baseR4/Patient?family=y7s" method="get" replace="instance" instance="default" responsemediatype="application/fhir+xml">
            <!--
                <fx-header name="Accept">application/xml</fx-header>
                <fx-header name="Content-Type">application/xml</fx-header>
            -->
                <fx-action event="submit-error">
                    <fx-message>failed</fx-message>
                </fx-action>
                <fx-action event="submit-done">
                    <fx-message>stored</fx-message>
                </fx-action>
            </fx-submission>
      </fx-model>
        <h3>
            <fx-output ref="instance()//fhir:total/@value">
                <label>HAPI total</label>
            </fx-output>
        </h3>
    </fx-fore>
</div>
</body>
</html>

Answered by pherk

Sep 3, 2025

works in my actual setup.
additional header still needed for announcing the 'correct' mimetype with 'get' submissions to the external server

<fx-header name="Accept">application/fhir+xml</fx-header>

found by try and error, element is not documented,
mimetype attr does nothing for 'get' submissions
... however, no show stopper for me
regards
Peter

View full answer

DrRataplan · 2025-08-12T07:08:34Z

DrRataplan
Aug 12, 2025
Maintainer

Hello!

That looks like a bug. If the thing is whatever/whatever+xml, it's XML. The code is around https://github.com/Jinntec/Fore/blob/dev/src/fx-submission.js#L253. There is similar handling happening around https://github.com/Jinntec/Fore/blob/dev/src/fx-instance.js#L11. Both should either use the predefined mimetype expectation or just check whether the mimetype ends with +xml or /xml, and handle it as XML.

I'll see if I can pick it up somewhere soon. Do you have a work-around? You might be able to proxy the external request to some other server, and expose it as application/xml.

Martin

1 reply

pherk Aug 12, 2025
Author

my interim workaround is a partial setup in eXistDB which delivers the FHIR data as application/xml (about 10 times slower than the HAPI server). No problem for the next few months, but the eXistDB performance is too limited for production use in our case.
Apart from the work developing a decent API in eXistDB/Roaster which comes free with the HAPI FHIR Server.
Regrettably the FHIR API is very complex and cannot easily emulated in eXistDB.

many thanks in advance
Peter

JoernT · 2025-09-01T10:11:15Z

JoernT
Sep 1, 2025
Maintainer

changed the code on 'dev' to handle all XML mimetypes by simply checking of contentType ends with 'xml'. This should do it.

7 replies

JoernT Sep 2, 2025
Maintainer

sorry - my bad - will work it out tomorrow - lack of proper test ;)

pherk Sep 2, 2025
Author

don't worry, I know ...
correct parsing of content-type isn't trivial
for my part simple splitting off the parameter after the semicolon and taking the subtype or the suffix after the '+' is sufficient, but parsing the full spec is definitely a challenge ;-)

btw I stumbled over line 246 fx-instance.js

const contentType = Fore.getContentType(this, 'get');

'get' as contentType
especially because there is a private function in fx-instance.js, which does the same job.
regards
Peter

JoernT Sep 3, 2025
Maintainer

just pushed modified version - hope this does the trick now.

pherk Sep 3, 2025
Author

works in my actual setup.
additional header still needed for announcing the 'correct' mimetype with 'get' submissions to the external server

<fx-header name="Accept">application/fhir+xml</fx-header>

found by try and error, element is not documented,
mimetype attr does nothing for 'get' submissions
... however, no show stopper for me
regards
Peter

Answer selected by pherk

JoernT Sep 3, 2025
Maintainer

oh, yes - missing docs. Thanks for letting me know.

Plus - it should use the responseMediatype as an accept header but it doesn't. Will put that on my list.

JoernT Sep 16, 2025
Maintainer

Added a section on fx-header to fx-submission element

Loading xml data with response mimetype 'application/fhir+xml' fails #315

Uh oh!

pherk Aug 11, 2025

Replies: 2 comments · 8 replies

Uh oh!

Uh oh!

DrRataplan Aug 12, 2025 Maintainer

Uh oh!

pherk Aug 12, 2025 Author

Uh oh!

JoernT Sep 1, 2025 Maintainer

Uh oh!

Uh oh!

JoernT Sep 2, 2025 Maintainer

Uh oh!

pherk Sep 2, 2025 Author

Uh oh!

JoernT Sep 3, 2025 Maintainer

Uh oh!

pherk Sep 3, 2025 Author

Uh oh!

JoernT Sep 3, 2025 Maintainer

Uh oh!

JoernT Sep 16, 2025 Maintainer

pherk
Aug 11, 2025

Replies: 2 comments 8 replies

DrRataplan
Aug 12, 2025
Maintainer

pherk Aug 12, 2025
Author

JoernT
Sep 1, 2025
Maintainer

JoernT Sep 2, 2025
Maintainer

pherk Sep 2, 2025
Author

JoernT Sep 3, 2025
Maintainer

pherk Sep 3, 2025
Author

JoernT Sep 3, 2025
Maintainer

JoernT Sep 16, 2025
Maintainer