[ENSCORESW-741]. Support Accepts content

We now look at the type of method and will switch to looking at the Accept header.

lib/EnsEMBL/REST/Role/Content.pm

 package EnsEMBL::REST::Role::Content;
 
+###############################################################
+####### HUGE WARNING
+####### I'm not sure the following code will work all the time.
+####### However it's working most of the time. Be aware!
+###############################################################
+
 use Moose::Role;
+use Bio::EnsEMBL::Utils::Scalar qw/check_ref/;
 
 sub is_content_type {
   my ($self, $c, $content_type) = @_;
-  my $request_content_type = $c->request()->params->{'content-type'}; 
-  my $headers_content_type =  $c->request()->headers()->content_type();
-  if( (defined $request_content_type && $request_content_type eq $content_type) || 
-      (defined $headers_content_type && $headers_content_type eq $content_type)) {
-    return 1;
+  my $request = $c->request();
+  my $headers = $request->headers();
+
+  my $param_content_type = $request->parameters()->{'content-type'};
+  my $headers_accept = $headers->header('Accept');
+  my $headers_content_type =  $headers->content_type();
+
+  # If it's a GET then Accepts gets bumped down to the bottom otherwise things go wrong
+  if($request->method() eq 'GET') {
+    if(check_ref($content_type, 'Regexp')) {
+      if( (defined $headers_content_type && $headers_content_type =~ $content_type) || 
+          (defined $param_content_type && $param_content_type =~ $content_type) ||
+          (defined $headers_accept && $headers_accept =~ $content_type) ) {
+        return 1;
+      }
+    }
+    else {
+      if( (defined $headers_content_type && $headers_content_type eq $content_type) || 
+          (defined $param_content_type && $param_content_type eq $content_type) ||
+          (defined $headers_accept && $headers_accept =~ /$content_type/i) ) {
+        return 1;
+      }
+    }
   }
+  # Must be a POST so do the Accepts take precedence thang
+  else {
+     # If it is already a regexp then apply against the values
+    if(check_ref($content_type, 'Regexp')) {
+      if( (defined $headers_accept && $headers_accept =~ $content_type) ||
+          (defined $headers_content_type && $headers_content_type =~ $content_type) || 
+          (defined $param_content_type && $param_content_type =~ $content_type)) {
+        return 1;
+      }
+    }
+    # Otherwise do the old code using eq & regex
+    else {
+      # Accepts ALWAYS WINS
+      if( (defined $headers_accept && $headers_accept =~ /$content_type/i) ||
+          (defined $param_content_type && $param_content_type eq $content_type) || 
+          (defined $headers_content_type && $headers_content_type eq $content_type)) {
+        return 1;
+      }
+    }
+  }
+
   return 0;
 }