Decoding errror with content-encoding 'gzip'

Describe the bug

When trying to fetch an organization from public GitHub via getOrganization("...") the response body cannot be parsed correctly and the method throws an IOException.

There seems to be an issue with whitespaces in the (assumed) JSON response, indicated by Illegal character ((CTRL-CHAR, code 31)). Some debugging down to GithubResponse::parseBody shows that

responseInfo.headerField("content-encoding")

resolves to "gzip" for some reason.

Here is the full stacktrace:

org.kohsuke.github.HttpException: Server returned HTTP response code: 200, message: 'null' for URL: https://api.github.com/orgs/MovingBlocks
	at org.kohsuke.github.GitHubClient.interpretApiError(GitHubClient.java:443) ~[github-api-1.108.jar:na]
	at org.kohsuke.github.GitHubClient.sendRequest(GitHubClient.java:366) ~[github-api-1.108.jar:na]
	at org.kohsuke.github.GitHubClient.sendRequest(GitHubClient.java:310) ~[github-api-1.108.jar:na]
	at org.kohsuke.github.Requester.fetch(Requester.java:71) ~[github-api-1.108.jar:na]
	at org.kohsuke.github.GitHub.getOrganization(GitHub.java:489) ~[github-api-1.108.jar:na]
	at org.terasology.launcher.updater.LauncherUpdater.updateAvailable(LauncherUpdater.java:91) ~[main/:na]
	at org.terasology.launcher.LauncherInitTask.checkForLauncherUpdates(LauncherInitTask.java:181) [main/:na]
	at org.terasology.launcher.LauncherInitTask.call(LauncherInitTask.java:81) [main/:na]
	at org.terasology.launcher.LauncherInitTask.call(LauncherInitTask.java:44) [main/:na]
	at javafx.concurrent.Task$TaskCallable.call(Task.java:1423) [jfxrt.jar:na]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_232]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_232]
Caused by: com.fasterxml.jackson.core.JsonParseException: Illegal character ((CTRL-CHAR, code 31)): only regular white space (\r, \n, \t) is allowed between tokens
 at [Source: (String)"      ??Mo?0??????n?5?
C??????P?b?6??EC.???}?7;e7??C?z_?s?G?y?????]a~?<??Io??:???>?v????{?z??T?^??+?????;"?Q?X9??$E#?G?*?-s?C4G^\e?A?^??D?A?]M????jz????????H^C???????p\|P??gJ???L??V8a.??6?d?L????>?l?[??
??l?=?
?|???L&?pV?D?j,?K??j?v?6??Sc??O?W*?=g?8Y?_??n(?fHL??fBQj!i.F^?#K	4S?P?�?-?p?|??Y?8??????9?T?"??]q??/?
x?J?Yn???v????_????pP???/?(ZD?"???$?$??5??S?????!?Mnn?M????q?6???XP?  "; line: 1, column: 2]
	at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1840) ~[jackson-core-2.10.2.jar:2.10.2]
	at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:712) ~[jackson-core-2.10.2.jar:2.10.2]
	at com.fasterxml.jackson.core.base.ParserMinimalBase._throwInvalidSpace(ParserMinimalBase.java:690) ~[jackson-core-2.10.2.jar:2.10.2]
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._skipWSOrEnd(ReaderBasedJsonParser.java:2373) ~[jackson-core-2.10.2.jar:2.10.2]
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser.nextToken(ReaderBasedJsonParser.java:672) ~[jackson-core-2.10.2.jar:2.10.2]
	at com.fasterxml.jackson.databind.ObjectReader._initForReading(ObjectReader.java:357) ~[jackson-databind-2.10.2.jar:2.10.2]
	at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:1704) ~[jackson-databind-2.10.2.jar:2.10.2]
	at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1261) ~[jackson-databind-2.10.2.jar:2.10.2]
	at org.kohsuke.github.GitHubResponse.parseBody(GitHubResponse.java:84) ~[github-api-1.108.jar:na]
	at org.kohsuke.github.Requester.lambda$fetch$1(Requester.java:71) ~[github-api-1.108.jar:na]
	at org.kohsuke.github.GitHubClient.createResponse(GitHubClient.java:404) ~[github-api-1.108.jar:na]
	at org.kohsuke.github.GitHubClient.sendRequest(GitHubClient.java:358) ~[github-api-1.108.jar:na]
	... 10 common frames omitted

To Reproduce

This is the MWE from my code to reproduce this error.

try {
	Github github = GitHub.connectAnonymously();
	GHOrganization movingBlocks = github.getOrganization("MovingBlocks");
} catch (IOException e) {
	e.printStacktrace();
}

Expected behavior

I expect that a response with 200 OK is parsed correctly and does not throw an IOException.

Alternatively, is there a way to set custom headers, e.g., setting “accept-encoding” to ensure the lib can parse the response body?

Desktop (please complete the following information):

• OS: macOS / Windows 10
• Java: 1.8.0_232 BellSoft
• Version 1.108

[tomakehurst]

Switching the implementation of GitHubResponse.headerField() to this seems to fix the problem:

public String headerField(String name) {
    return headers.entrySet()
        .stream()
        .filter(entry -> name.equalsIgnoreCase(entry.getKey()))
        .findFirst()
        .map(entry -> entry.getValue().get(0))
        .orElse(null);
}

I’ll raise a PR, but I’m struggling to create a test case at the moment because (the ironies) I can’t persuade WireMock not to capitalise the content-encoding header name.

[tomakehurst]

OK, found the problem: headerField is case-sensitive and GitHub have changed their response headers to be all lower case.