Update generating-a-json-web-token-jwt-for-a-github-app.md

[mark-mxwl]

Why:

Closes: #33324
Closes: #33989

What's being changed (if available, include any code snippets, screenshots, or gifs):

Updated formatting for payload JSON to return top-level JSON when decoded, as the previous version was throwing an error for some users. Header JSON moved to single line to match payload. Also removed "JWT: " from print line to avoid scripting conflicts.

Check off the following:

• I have reviewed my changes in staging, available via the View deployment link in this PR's timeline (this link will be available after opening the PR).

  • For content changes, you will also see an automatically generated comment with links directly to pages you've modified. The comment won't appear if your PR only edits files in the data directory.

• For content changes, I have completed the self-review checklist.

[github-actions]

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Source	Preview	Production	What Changed
apps/creating-github-apps/authenticating-with-a-github-app/generating-a-json-web-token-jwt-for-a-github-app.md	fpt ghec ghes@ 3.13 3.12 3.11 3.10	fpt ghec ghes@ 3.13 3.12 3.11 3.10

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fpt: Free, Pro, Team
ghec: GitHub Enterprise Cloud
ghes: GitHub Enterprise Server

[lindhe]

Thanks for fixing this! Great job!

There seem to be some shellcheck warnings left:

$ shellcheck bash.sh

In bash.sh line 5:
pem=$( cat $2 ) # file path of the private key as second argument
           ^-- SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
pem=$( cat "$2" ) # file path of the private key as second argument


In bash.sh line 8:
iat=$((${now} - 60)) # Issues 60 seconds in the past
       ^----^ SC2004 (style): $/${} is unnecessary on arithmetic variables.


In bash.sh line 9:
exp=$((${now} + 600)) # Expires 10 minutes in the future
       ^----^ SC2004 (style): $/${} is unnecessary on arithmetic variables.


In bash.sh line 30:
printf '%s\n' $JWT
              ^--^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
printf '%s\n' "$JWT"

For more information:
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2004 -- $/${} is unnecessary on arithmeti...

Maybe let's fix them also.

[nguyenalex836]

@mark-mxwl Thanks so much for opening a PR! I'll get this triaged for review ✨

[mark-mxwl]

Thx for the ShellCheck output @lindhe! While those are all valid warnings, we don't really have to worry about globbing (wildcards)/splitting (tab, space, newline) on our positional parameters, due to the type of data we're passing through. The curly braces on the expressions are optional--I kept them there for the sake of consistency and readability.

[brakel]

Hi, thanks for the update. I ran the updated script, removing the templating, and there still seems to be an issue with the iat claim being a string:

{
  "message": "'Issued at' claim ('iat') must be an Integer representing the time that the assertion was issued",
  "documentation_url": "https://docs.github.com/rest",
  "status": "401"
}

Removing the quotes in the script solves the issue for me.

Interestingly, the same validation is not applied to the exp claim and will work as either a string or int.

[mark-mxwl]

Thanks for catching that @brakel. Interesting re: the behavior with exp. I adjusted the script so that iat and exp values are both integers, which hopefully will resolve this.

[github-actions]

Thanks for opening a pull request! We've triaged this issue for technical review by a subject matter expert 👀

[nguyenalex836]

@mark-mxwl Apologies for the delay! We recently merged a PR that I believe resolves the issue this PR is attempting to fix. Many apologies for not being able to get to this sooner 💛

I'll go ahead and close out this PR, but please feel free to reopen / ping if needed!

[mark-mxwl]

Np @nguyenalex836! Glad it got sorted. Appreciate the heads-up! 🙏