This gist takes json generated by yakovlevga/brickyeditor and a set of templates in an html file, and munges everything together to create a static html (or twig) file. Follows containers down to correctly fill out the container content.

build_page_twig.php

<?php

// method from a CMS object

function build_page_twig(){

    libxml_use_internal_errors(TRUE);  // this avoids errors thrown on HTML5 tags

    //
    //  this section is cms-specific, could just pass in the json file name
    //
    $jsonfile = $this->config->root.'/content/'.$this->config->page.".json";
    if( file_exists( $jsonfile ) ){
        $pageblocks = json_decode( file_get_contents( $jsonfile ) );
    } else {
        $this->push_error( "No page data for ".$this->config->page );
        return;
    }

    $templates = [];

    $doc = new DOMDocument();
    $doc->loadHTML(file_get_contents('ny5/blocks/templateblocks.twig'));

    $divs = $doc->getElementsByTagName('div');

    foreach( $divs as $div ){
        if( $div->getAttribute('class') == 'bre-template' ){
            $templatename = $div->getAttribute('data-name');
            $templates[$templatename] = new DomDocument;
            $templates[$templatename]->appendChild($templates[$templatename]->importNode( $div, true ));
        }
    }

    foreach( $pageblocks as $block ){
        $dom = $templates[ $block->template ];
        $this->expandTemplate( $dom, $templates, $block );
    }
    echo $dom->saveHTML();  // change this line to save munged html off to a static file for the page
}

function generate_nodes( $dom ){
    foreach( $dom->childNodes as $node ){
        yield( $node );
        if( $node->hasChildNodes() ){
            yield from $this->generate_nodes( $node );
        }
    }
}


function expandTemplate( &$root, $templates, $block ){
    foreach( $this->generate_nodes($root) as $node ){
        if( 'DOMElement' != get_class( $node ) ){
            continue;
        }
        $rawfield = str_replace("'",'"',$node->getAttribute('data-bre-field'));
        if( "" !== $rawfield ){
            $templatefield = json_decode( $rawfield );
            foreach( $block->fields as $blockfield ){
                if( $templatefield->name == $blockfield->name ){
                    switch( $templatefield->type ){
                    case 'img':     // img not yet tested
                    case 'html':
                        $node->nodeValue = $blockfield->html;
                        break;
                    case 'container':
                        $contained_blocks = $blockfield->blocks;
                        foreach( $contained_blocks as $cblock ){
                            $contained_dom = $templates[$cblock->template];
                            $this->expandTemplate($contained_dom, $templates, $cblock);

                            $newnode = $root->importNode($contained_dom->getElementsByTagName('div')->item(0), true);
                            $node->appendChild( $newnode );
                        }
                    }
                }
            }
        }
    }
}