Replace all of webwork2's direct JSON usage with Mojo::JSON.

PG still uses `JSON` for now, so this doesn't quite remove the
dependency on the module.  But PG can be switched also.

Note that the module uses `Cpanel::JSON::XS` (if that module is
installed) which is the recommended perl JSON encoding and decoding
module. `Mojo::JSON` falls back to their own pure perl implementation if
`Cpanel::JSON::XS` is not installed.

Note that the `Mojo::JSON::encode_json` method UTF-8 encodes the output
and is canonical (sorts object keys). The `Mojo::JSON::to_json` method
does not UTF-8 encode the output, but is still canonical.  The
corresponding `Mojo::JSON::decode_json` decodes UTF-8 encoded JSON and
`Mojo::JSON::from_json` method decodes non UTF-8 encoded json.

Author: drgrice1

bin/OPL-update-legacy

@@ -539,8 +539,6 @@ if($canopenfile) {
 }
 #### End of taxonomy/taxonomy2
 
-use JSON;
-
 #### Save the official taxonomy in json format
 my $webwork_htdocs = $ce->{webworkDirs}{htdocs};
 my $file = "$webwork_htdocs/DATA/tagging-taxonomy.json";

bin/OPLUtils.pm

@@ -17,7 +17,7 @@ use warnings;
 use File::Find::Rule;
 use File::Basename;
 use open qw/:std :utf8/;
-use JSON;
+use Mojo::JSON qw(encode_json);
 
 our @EXPORT = ();
 our @EXPORT_OK =
@@ -373,7 +373,7 @@ sub build_library_textbook_tree {
 sub writeJSONtoFile {
 	my ($data, $filename) = @_;
 
-	my $json = JSON->new->utf8->encode($data);
+	my $json = encode_json($data);
 	open my $fh, ">", $filename or die "Cannot open $filename";
 	print $fh $json;
 	close $fh;

bin/check_modules.pl

@@ -108,7 +108,6 @@ =head1 DESCRIPTION
 	Iterator
 	Iterator::Util
 	JSON
-	JSON::MaybeXS
 	Locale::Maketext::Lexicon
 	Locale::Maketext::Simple
 	LWP::Protocol::https

bin/download-OPL-metadata-release.pl

@@ -11,7 +11,7 @@
 use File::Path;
 use Archive::Tar;
 use Mojo::File;
-use JSON;
+use Mojo::JSON qw(decode_json);
 
 BEGIN {
 	use Mojo::File qw(curfile);
@@ -36,7 +36,7 @@ BEGIN
 	File::Fetch->new(uri => 'https://api.github.com/repos/openwebwork/webwork-open-problem-library/releases/latest');
 my $file        = $releaseDataFF->fetch(to => $ce->{webworkDirs}{tmp}) or die $releaseDataFF->error;
 my $path        = Mojo::File->new($file);
-my $releaseData = JSON->new->utf8->decode($path->slurp);
+my $releaseData = decode_json($path->slurp);
 $path->remove;
 
 my $releaseTag = $releaseData->{tag_name};

lib/Caliper/Sensor.pm

@@ -7,7 +7,7 @@ use WeBWorK::CourseEnvironment;
 use WeBWorK::DB;
 use WeBWorK::Debug;
 use Data::Dumper;
-use JSON;
+use Mojo::JSON  qw(encode_json);
 use Time::HiRes qw/gettimeofday/;
 use Date::Format;
 
@@ -67,7 +67,7 @@ sub sendEvents {
 			'data'        => $event_chunk,
 		};
 
-		my $json_payload = JSON->new->canonical->encode($envelope);
+		my $json_payload = encode_json($envelope);
 		# debug("Caliper event json_payload: " . $json_payload);
 
 		my $HTTPRequest = HTTP::Request->new(

lib/WeBWorK/ContentGenerator/InstructorRPCHandler.pm

@@ -39,8 +39,6 @@ error occurs, then the response will contain an "error" key.
 # was "instructor" only.  Usage of all commands is based on permissions, and there have always been non-instructor users
 # that have some of these permissions. So this module and the corresponding route should really be renamed.
 
-use JSON;
-
 use WebworkWebservice;
 
 sub initializeRoute ($c, $routeCaptures) {

lib/WeBWorK/Controller.pm

@@ -25,7 +25,6 @@ fields.
 =cut
 
 use Encode;
-use JSON::MaybeXS;
 
 use WeBWorK::Localize;
 

lib/WeBWorK/Utils/Instructor.pm

@@ -26,6 +26,7 @@ use strict;
 use warnings;
 
 use File::Find;
+use Mojo::JSON qw(decode_json);
 
 use WeBWorK::DB::Utils qw(initializeUserProblem);
 use WeBWorK::Debug;
@@ -642,7 +643,7 @@ sub loadSetDefListFile {
 			$contents;
 		};
 
-		return @{ JSON->new->decode($data) };
+		return @{ decode_json($data) };
 	}
 
 	return;

lib/WebworkWebservice/SetActions.pm

@@ -20,7 +20,6 @@ use strict;
 use warnings;
 
 use Carp;
-use JSON;
 use Data::Structure::Util qw(unbless);
 
 use WeBWorK::Utils             qw(max);