viewstl/src/load_stl.js

//1.12
//load STL file info geometry and returns it

importScripts("parser.min.js");

MSG_DATA=0;
MSG_LOAD=1;
MSG_ERROR=2;
MSG_STL_LOADED=3;
MSG_LOAD_IN_PROGRESS=4;

var filename=null;
var local_file=null;
var load_from_blob_or_ab=null; //from ArrayBuffer
var x=0;
var y=0;
var z=0;
var model_id=-1;
var get_progress=false;

self.addEventListener("message", function(e)
{
	switch (e.data.msg_type)
	{
		case MSG_DATA:
			if (!e.data.data) {send_error("no data");break;}
			if ((!e.data.data.filename)&&(!e.data.data.local_file)) {send_error("no file");break;}
			
			if (e.data.data.local_file)
			{
				filename=e.data.data.local_file.name?e.data.data.local_file.name:e.data.data.filename; //filename property is usefull for blob files, 10x Fraser
				local_file=e.data.data.local_file?e.data.data.local_file:null;
			}
			else if (e.data.data.filename)
				filename=e.data.data.filename;
			
			if (e.data.data.x) if (isNumeric(e.data.data.x)) x=e.data.data.x;
			if (e.data.data.y) if (isNumeric(e.data.data.y)) y=e.data.data.y;
			if (e.data.data.y) if (isNumeric(e.data.data.z)) z=e.data.data.z;
			
			load_from_blob_or_ab=null;
			if (e.data.load_from_blob_or_ab)
				load_from_blob_or_ab=e.data.load_from_blob_or_ab;
			
			model_id=e.data.data.id?e.data.data.id:-1;
			get_progress=e.data.get_progress?e.data.get_progress:false;

			break;
			
		case MSG_LOAD:
			if (load_from_blob_or_ab)
			{
				//blob/arraybuffer ready to be parsed
				if (load_from_blob_or_ab instanceof ArrayBuffer) after_file_load(load_from_blob_or_ab); //arraybuffer
				else read_file(load_from_blob_or_ab); //blob
				
			}
			else if (local_file)
				//local server file (not to confuse with local computer file)
				read_file(local_file);
			
			else if (filename)
				//url file (assuming accessible for this domain (if NOT, get help here - https://www.viewstl.com/local_url/)
				download_from_local(filename);
				
			break;
			
		default:
			console.log("invalid msg: "+e.data.msg_type);
			
	}
    
});

function isNumeric(n)
{
	return !isNaN(parseFloat(n)) && isFinite(n);
}

function send_error(s)
{
	postMessage({msg_type:MSG_ERROR, data:s});
}

function download_from_local(filename)
{
	if (fetch)
	{
		download_from_local_fetch(filename);
	}
	else
	{
		download_from_local_xhr(filename);
	}
}

function download_from_local_xhr(filename)
{
	var xhr = new XMLHttpRequest();
	
	if (get_progress)
	{
		xhr.onprogress =
		function(e)
		{
			postMessage({msg_type:MSG_LOAD_IN_PROGRESS, id:model_id, loaded:e.loaded, total:e.total});
		}
	}	

	xhr.onreadystatechange =
	function(e)
	{
		if (xhr.readyState == 4)
		{
			//console.log('status: '+xhr.status);
			if (xhr.status==200)
			{
				//console.log('done');
				after_file_load(xhr.response);
			}
		}
	}
	
	xhr.open("GET", filename, true);
	//xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
	xhr.responseType = "arraybuffer";
	
	xhr.send(null);
}

async function download_from_local_fetch(filename)
{
	const response = await fetch(filename);
	const reader = response.body.getReader();
	const total = Number(response.headers.get('content-length'));
 	const chunksAll = new Uint8Array(total);
  	let position = 0
	while (true)
	{
		const { done, value } = await reader.read()
    	if (done) break;
    	if (!value) continue;
    	chunksAll.set(value, position);
    	position += value.length;
		if (get_progress)
		{
    		postMessage({ msg_type: MSG_LOAD_IN_PROGRESS, id: model_id, loaded: position, total: total });
    	}
  	}
	after_file_load(chunksAll.buffer)
}

function after_file_load(s)
{
	var vf_data;
	
	if (!s)
	{
		send_error("no data");
		return;
	}
	
	try
	{
		vf_data=parse_3d_file(filename, s);
	}
	catch(err)
	{
		vf_data="Error parsing the file";
	}
				
	if (typeof vf_data === 'string')
	{
		send_error(vf_data);
		return;
	}
	
	postMessage({msg_type:MSG_STL_LOADED, vertices:vf_data.vertices, faces:vf_data.faces, colors:vf_data.colors});
}


function read_file(f)
{
	var reader = new FileReader();
				
	reader.onerror = function(e)
	{
		var error_str="";
		switch(e.target.error.code)
		{
			case e.target.error.NOT_FOUND_ERR:
				error_str="File not found";
			break;

			case e.target.error.NOT_READABLE_ERR:
				error_str="Can't read file - too large?";
			break;

			case e.target.error.ABORT_ERR:
				error_str="Read operation aborted";
			break; 
						
			case e.target.error.SECURITY_ERR:
				error_str="File is locked";
			break;

			case e.target.error.ENCODING_ERR:
				error_str="File too large";

			break;

			default:
				error_str="Error reading file";
		}
		send_error(error_str);
	}
	
	reader.onprogress = function(e)
	{
		postMessage({msg_type:MSG_LOAD_IN_PROGRESS, id:model_id, loaded:e.loaded, total:e.total});
	};	
					
	reader.onload = function(e)
	{
		after_file_load(e.target.result);
	};
				
	reader.readAsArrayBuffer(f);
}