Commands not in sync when no system.describe in builtin RPC

[bilogic]

I have question related to jQuery Terminal

I used fire several exec() from inside onInit() in v0.9.3, it worked correctly.
My output was always:

Output A

prompt1>command1
result1
prompt2>command2
result2
prompt3>command3
result3
prompt4>command4
result4
...

On dev 2.2.1 using exec(), I'm getting

Output B

prompt1>command1
prompt1>command2
result1
prompt1>command3
result2
prompt1>command4
result3
result4
prompt1>

I switch to using execHash and it worked correctly, i.e. output A

My question is, what is the recommended way to use exec() so that the output is correct, i.e. output A? Thank you.

[jcubic]

Is you commands async or they are just echo something?

if you use multiple execs use array:

$.terminal.active().exec(['a', 'b', 'a', 'b'])

if your commands are async (ajax or setTimeout etc.) you need to use pause()/resume() (main reason for those functions is not to hide command line, but to have proper timing with exec).

Example:

$('???').terminal(function(cmd) {
   term.pause();
   setTimeout(() => this.echo('your commands is ' + cmd).resume(), 1000);
}, {
  onInit: function() {
      this.exec(['command1', 'command2', 'command3', 'command4']);
  }
}

this will also work if you call exec one by one:

     onInit: function() {
         this.exec('command1');
         this.exec('command2');
         this.exec('command3');
     },

NOTE: you can't call this.exec('cmd1').exec('cmd2'); because exec return a promise that resolve when you call resume.

Instead of resume you can also return a promise from function, but it need to be resolved to undefined otherwise the value will be echoed to terminal, unless this is something you want.

        .terminal(function(cmd) {
             if (cmd == 'x') {
                 return $.get('exec.html').then((data) => {
                     this.echo(data.split('\n')[0]); // no return so promise will resolve to undefined
                 });
             } else {
                 this.pause();
                 setTimeout(() => this.echo(cmd).resume(), 500);
             }
         }, {
             onInit: function() {
                 this.exec(['x', 'cmd1', 'cmd2']);
             }
         });

The promise is very flexible it only need to be object that have then function, so it work with native Promises or jQuery defereds.

[bilogic]

Hi,

1. I use a URL string, i.e. $('#pjax-main').terminal("{{ url.rpc }}", options);
2. Both the prompt and result are returned via RPC, I suppose that means they are async?

[bilogic]

Actually, execHash() does exactly and correctly what I need, but exec() behaves very differently. Also, I don't see execHash() using any value for setTimeout().

Is there a way to run commands using exec() but have the correct output like execHash()?

[jcubic]

This should work the same, do you the code somewhere online, where I can test this?

[bilogic]

Hi,

I have emailed you the links.

[jcubic]

Not sure what the problem is. Maybe because you don't have system.describe method and different code is executed for rpc interpreter. Will investigate, this seems to be a bug.

[jcubic]

yes, the problem is system.describe if it's not there commands are not in sync. Same happen if you use ignoreSystemDescribe: true (which you should use if you don't have system.describe so no extra request at the beginning will happen).

[bilogic]

Hi,

Thanks! I did add describe: false, in the options earlier, but jquery.terminal.js it threw an exception and I stopped pursuing. https://terminal.jcubic.pl/api_reference.php indicates that ignoreSystemDescribe is replaced since 1.5

[jcubic]

Hm, the original option was not removed to not break existing code (that's why major version was not changed) will need to investigate describe: false then.

[bilogic]

Hi,

2 related questions:

1. Should I open an issue for describe: false throwing exceptions?
2. What is the purpose of enabling system.describe? i.e. benefits of having it etc

Thank you.

[jcubic]

If you have system.describe, terminal know RPC methods and can create completion for you. So you can use completion: true.

[jcubic]

Both errors should be fixed.

[bilogic]

Hi,

If I bring up chrome's developer tools and Disable cache is checked, commands intermittently go out of sync. This is done with describe: false

If the developer tools is closed (implying Disable cache is unchecked), commands are in sync.

[bilogic]

Just to add, it seems very hard to replicate out-of-sync in a normal Chrome tab even with DevTools + Disable cache checked.

If I load the same link in a fancybox's iframe, out-of-sync happens more frequently.
From initial observation, it seems to happen if first few prompt/RPC completes before the iframe is shown on screen.

Any ideas? Thank you.

[jcubic]

Will check. I can also add option to exec only when terminal is visible, but this will be workaround, nevertheless it will be useful option.

[jcubic]

I cannot reproduce, can you provide a demo? the last url/user/passwd don't work:

I was testing using this data uri:

data:text/html,<style>body{margin: 0} iframe { display: none} </style><iframe style="width:100%; height: 100%" src="http://localhost/projects/jcubic/terminal/test/manual/exec.html"></iframe><script>window.onload = () => setTimeout(() => document.querySelector('iframe').style.display = 'block', 3000)</script>

[jcubic]

no reply after almost 2 weeks, it should be fixed not possible to reproduce in iframe for new issue.

[bilogic]

Hi,

Sorry, had other matters on hand. Will update this issue if I find a reliable method to reproduce it. Let's close this for now. Thank you.