Colorized output from docker to websocket

Question

This might be a little bit of a complex question but I am open to try any and all suggestions thrown at me.

I am running a docker instance which clones a git repository, it is a php 7 apache docker instance:

FROM php:7.0-apache

With the Symfony Process Component I am booting up my container and pass my environment variables.

"docker run -e REPOSITORY=\"{$url}\" 
-e COMPOSER_ALLOW_SUPERUSER=1 
-e TERM='xterm-256color' arbiter bash -l"

I have added the xterm-256-color environment to make sure I am getting colored output(correct me if this is wrong).

To display the output of the container I am using the Symfony Process Component to send it to a websocket.

$process->run(function ($type, $buffer) use ($socket) {
    socket_write($socket, $buffer, strlen($buffer));
});

At this point I can use something like socket.io to display it on a webpage in realtime.

The problem is that I want to display the docker output with proper coloring as you would normally see it with a terminal. All formatting and coloring seems to be lost at this point though.

Is there any web I can pass the docker output to a websocket and still maintain my coloring to display on a webpage?

Any hints or tips to guide me in the right direction are welcome since I am asking a lot here.

Thanks for readings, cheers.

Edit

To be clear I am not yet getting any colored output so far the output given to me from the docker container looks simply like this(composer example):

[2017-02-12 01:02:56] local.INFO: remote: Counting objects: 69, done.        
remote: Compressing objects:   2% (1/47)           
remote: Compressing objects:   4% (2/47)

Answer 1

In this case I simply had to add a -t flag to my docker run command. I was trying to add -it which led to an error. Obviously that my bad and not necessary since there is nothing interactive about this process.

After adding the -t flag like in the example below the ANSI symbols started showing up:

docker run -t 
-e REPOSITORY=\"{$url}\" 
-e COMPOSER_ALLOW_SUPERUSER=1 
-e TERM='xterm' arbiter

I am formatting the ANSI symbols with the provided library from @Robert everything works perfectly fine now. When executing:

socket_write($socket, $buffer, strlen($buffer));

I just had to remember to also pass the generated HTML's string length and it all renders perfect.