RIOT exception: Unexpected response code [429]

[lueck]

This issue tracks occurrences of a RIOT exception, that is difficult to understand and to reproduce.

org.apache.jena.riot.RiotException: Unexpected response code [429]

It was first observed on c8eb7d0.

[lueck]

Occured in the gh pipeline run on commit 5a41a41.

Thus it may have been introduced after version 0.3.0 in commits starting at 7068581 and aaa4b6d, which all were on #33. But it did not occur on the large number of local test runs during fixing #33.

Introduction in 5a41a41 seems unlikely, since they only affect the cli.

[lueck]

The stack trace from the test prepared in 438e707 reveals, that the exception already happens during the parsing stage:

org.apache.jena.riot.RiotException: Unexpected response code [429]
        at org.apache.jena.riot.system.ErrorHandlerFactory$ErrorHandlerStd.error(ErrorHandlerFactory.java:148)
        at org.apache.jena.riot.lang.LangJSONLD11.handleJsonLdError(LangJSONLD11.java:96)
        at org.apache.jena.riot.lang.LangJSONLD11.read(LangJSONLD11.java:80)
        at org.apache.jena.riot.RDFParser.read(RDFParser.java:453)
        at org.apache.jena.riot.RDFParser.parseNotUri(RDFParser.java:443)
        at org.apache.jena.riot.RDFParser.parse(RDFParser.java:380)
        at org.apache.jena.riot.RDFParserBuilder.parse(RDFParserBuilder.java:553)
        at org.apache.jena.riot.RDFDataMgr.parseFromInputStream(RDFDataMgr.java:545)
        at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:252)
        at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:219)
        at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:205)
        at de.wwu.scdh.annotation.selection.wadm.NormalizeAnnotation.rewrite(NormalizeAnnotation.java:274)
        at de.wwu.scdh.annotation.selection.wadm.TestRewriteAnnotationHtml.testForwardInImage(TestRewriteAnnotationHtml.java:112)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:701)
        at org.junit.platform.commons.support.ReflectionSupport.invokeMethod(ReflectionSupport.java:502)
        at org.junit.jupiter.engine.support.MethodReflectionUtils.invoke(MethodReflectionUtils.java:45)
        at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:61)
       ...
``'

[lueck]

Trying to parse and convert the same JSON-LD file with the RIOT CLI also fails with the same message:

$ /home/clueck/src/scdh/tei-processing/dts-transformations/target/bin/riot.sh --syntax=jsonld core/src/test/resources/samples/gFwInImage.json 
[main] ERROR org.apache.jena.riot - Unexpected response code [429]

[lueck]

The Web Annotations context file has moved:

$ curl -X GET http://www.w3.org/ns/anno.jsonld -I
HTTP/1.1 301 Moved Permanently
Date: Thu, 27 Aug 2026 14:27:27 GMT
Content-Type: text/html; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Location: https://www.w3.org/ns/anno.jsonld
set-cookie: __cf_bm=st1RpdZlJ1OGBhtNS42VQ.5lCb5TZePO2dmzt7lUllU-1787840847.691405-1.0.1.1-tOCLQ2iWzzrFoTOhHB0oeSUwMS6G5ZHPfTZJ8CbZMp5aw1q34Uls05Wa4fWl67T9Rz0fRYKlcYE47nwitKPG19rICSOwK1jwHZKimG2iQCAC1UOtlecFi_q8J60Yl6VH; HttpOnly; Path=/; Domain=w3.org; Expires=Thu, 27 Aug 2026 14:57:27 GMT
X-Content-Type-Options: nosniff
Server: cloudflare
CF-RAY: a31bc1d21c0c4f92-DUS
alt-svc: h3=":443"; ma=86400

So, this may be an error from side effects. This would mean that the 429 is an HTTP status code and could explain its hardly re-producible nature.

[lueck]

After changing the context URI, the RIOT CLI still fails with 429.

So we have tracked this down.

[lueck]

Measures

1. provide a local version of the Web Annotations context and set up the Titanium Document Loader to use it instead of a web request.
2. Contact W3C to allow a bit more traffic on their cloudflare server when it comes to JSON-LD context files, which are infrastructure relevant.