4.0 Crossref Websearch fails with "Parser error"

[jonasstein]

JabRef version

JabRef 4.0
Linux 4.12.12-gentoo+ amd64 
Java 1.8.0_152

Steps to reproduce:
search for 10.1103/PhysRevLett.119.177201

14:11:58.427 [JabRef CachedThreadPool] ERROR org.jabref.gui.importer.fetcher.SearchBasedEntryFetcher - Error while fetching from Crossref
org.jabref.logic.importer.FetcherException: An internal parser error occurred
	at org.jabref.logic.importer.SearchBasedParserFetcher.performSearch(SearchBasedParserFetcher.java:72) ~[JabRef-4.0.jar:?]
	at org.jabref.gui.importer.fetcher.SearchBasedEntryFetcher.processQuery(SearchBasedEntryFetcher.java:37) ~[JabRef-4.0.jar:?]
	at org.jabref.gui.importer.fetcher.GeneralFetcher.lambda$actionPerformed$5(GeneralFetcher.java:216) ~[JabRef-4.0.jar:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_152]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_152]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_152]
Caused by: org.jabref.logic.importer.ParseException: CrossRef API JSON format has changed
	at org.jabref.logic.importer.fetcher.CrossRef.jsonItemToBibEntry(CrossRef.java:131) ~[JabRef-4.0.jar:?]
	at org.jabref.logic.importer.fetcher.CrossRef.lambda$getParser$3(CrossRef.java:88) ~[JabRef-4.0.jar:?]
	at org.jabref.logic.importer.SearchBasedParserFetcher.performSearch(SearchBasedParserFetcher.java:60) ~[JabRef-4.0.jar:?]
	... 5 more
Caused by: org.json.JSONException: JSONObject["title"] not found.
	at org.json.JSONObject.get(JSONObject.java:471) ~[JabRef-4.0.jar:?]
	at org.json.JSONObject.getJSONArray(JSONObject.java:618) ~[JabRef-4.0.jar:?]
	at org.jabref.logic.importer.fetcher.CrossRef.jsonItemToBibEntry(CrossRef.java:113) ~[JabRef-4.0.jar:?]
	at org.jabref.logic.importer.fetcher.CrossRef.lambda$getParser$3(CrossRef.java:88) ~[JabRef-4.0.jar:?]
	at org.jabref.logic.importer.SearchBasedParserFetcher.performSearch(SearchBasedParserFetcher.java:60) ~[JabRef-4.0.jar:?]
	... 5 more

[lenhard]

Thanks for bringing this up!

The error message reads CrossRef API JSON format has changed. I wish they would do this less frequently... Anyway, we will have to adapt the code to conform to the new format.

[lenhard]

Appologies to CrossRef, they did not change the format. The error was actually that the search returned a few entries from CrossRef that do have titles and our code wasn't able to handle that.

I submitted a fix as pull request, it should be merged soon.