Problem (BaseX 12) serializing a map with json:serialize() in combination with the http-client module
Hi everyone,
I have found a problem when serializing a map to JSON.
I use the following map as request body for the http-client:
map {
'username' : "aaa",
'password' : "bbb",
'grant_type' : 'password'
} => json:serialize()
In 10.4 everything works fine. In 12.0 this now leads to an error when I send the request. (Response from service: <code type="number">400</code><message>Invalid json message received</message>)
It seems that the request body is being escaped twice when interacting with the http client. If I omit json:serialize(), it works fine in BaseX 12.
I would expect json:serialize() to recognize the map(*) data type and serialize it correctly.
Best regards Andreas
btw: I found out that this leads directly to an exception.
map {
'username' : "aaa",
'password' : "bbb",
'grant_type' : 'password'
} => inspect:type()
Hello, it's me again.
I can't actually find a way to transport a JSON as a request body except with a map, which obviously always has a json representation as well.
My current workaround for my code base is to convert the serialized form back into a map using xquery:eval.
let $requestBody := element { 'json' } {
attribute { 'type' } { 'object' },
element { 'the' } {
attribute { 'type' } { 'object' },
element { 'shit' } {
attribute { 'type' } { 'object' },
element { 'is' } {
attribute { 'type' } { 'array' },
element { '_' } {
attribute { 'type' } { 'object' },
element { 'on' } {
attribute { 'type' } { 'object' },
element { 'the' } {
"steam"
}
}
},
element { '_' } {
attribute { 'type' } { 'object' },
element { 'what' } {
attribute { 'type' } { 'object' },
element { 'the' } {
"f..."
}
}
}
}
}
}
}
return $requestBody => json:serialize() => xquery:eval()Hi Andreas,
Thanks for your observations. A new snapshot is available, containing the fix for the copy expression [1]; an updated version for inspect:type will follow soon (this bug is only due to the generatation of the output for the InfoView panel).
With regard to your third question: In a previous 11.x version of BaseX, the behavior of http:send-request was changed, making th explicite json:serialize call obsolete (it should have been better documented).
Here’s one way to send XML JSON representations to the server with the current version:
(: Query :)
http:send-request(
<http:request method='post'><http:body media-type='application/json'/></http:request>,
'http://localhost...',
<json>a</json>
)
(: RESTXQ endpoint :)
declare %rest:path('test') %rest:POST('{$x}') function local:f($x) { };Best, Christian
Quoted text · Andreas Hengsbach · 38 lines
Von: Andreas Hengsbach <andreas.hengsbach at nexoma.de> Gesendet: Dienstag, 8. Juli 2025 14:52 An: basex-talk at mailman.uni-konstanz.de <basex-talk at mailman.uni-konstanz.de> Betreff: [basex-talk] Re: Problem (BaseX 12) serializing a map with json:serialize() in combination with the http-client module Hello, it's me again. I can't actually find a way to transport a JSON as a request body except with a map, which obviously always has a json representation as well. My current workaround for my code base is to convert the serialized form back into a map using xquery:eval. let $requestBody := element { 'json' } { attribute { 'type' } { 'object' }, element { 'the' } { attribute { 'type' } { 'object' }, element { 'shit' } { attribute { 'type' } { 'object' }, element { 'is' } { attribute { 'type' } { 'array' }, element { '_' } { attribute { 'type' } { 'object' }, element { 'on' } { attribute { 'type' } { 'object' }, element { 'the' } { "steam" } } }, element { '_' } { attribute { 'type' } { 'object' }, element { 'what' } { attribute { 'type' } { 'object' }, element { 'the' } { "f..." } } } } } } } return $requestBody => json:serialize() => xquery:eval()
Hi Andreas,
thank you for reporting this, too. It is now being handled by https://github.com/BaseXdb/basex/pull/2456
Best regards, Gunther
Quoted text · Andreas Hengsbach · 13 lines
> Gesendet: Dienstag, 8. Juli 2025 um 12:32 > Von: "Andreas Hengsbach" <andreas.hengsbach at nexoma.de> > An: basex-talk at mailman.uni-konstanz.de > Betreff: [basex-talk] Re: Problem (BaseX 12) serializing a map with json:serialize() in combination with the http-client module > > btw: I found out that this leads directly to an exception. > > map { > 'username' : "aaa", > 'password' : "bbb", > 'grant_type' : 'password' > } => inspect:type() >
Oh boy...
I could have had that quicker. I never tried to put it non-serialized in the request-body and was convinced that it had something to do with the new construction of maps.
But I would actually consider that a groundbreaking change, because if the request-body receives already serialized data, it arrives incorrectly at the endpoint.
You wrote that it could have been better documented. I have just searched in vain for a reference to these changes.
I would like to suggest that this be included in the changelogs or displayed more prominently there.
Anyway, thanks Christian for the clarification. It saves me a lot of trouble.
Beste regards, Andreas
Written for BaseX 12.0. BaseX may have changed since: please check the current documentation.