@section gtint What is generic-table?
Generic-table is a JSON schema and client-side JS file that makes it easy to display live, table structured HTML over a ws link.
An example plugin and index.html using it are provided, but lwsgt itself doesn't have its own plugin, it's just a JSON schema and client-side JS that other plugins can use to simplify displaying live, table-based data without having to reinvent the wheel each time.
The ws protocol sends JSON describing the table, and then JSON updating the table contents when it chooses, the brower table is updated automatically, live.
\image html lwsgt-overview.png
Example protocol plugin (displays directory contents): https://github.com/warmcat/libwebsockets/tree/master/plugins/generic-table/protocol_table_dirlisting.c
Example HTML: https://github.com/warmcat/libwebsockets/tree/master/plugins/generic-table/assets/index.html
lwsgt.js (client-side table rendering / ws link management): https://github.com/warmcat/libwebsockets/tree/master/plugins/generic-table/assets/lwsgt.js
@section gteb Enabling for build
Enable the demo plugin at CMake with -DLWS_WITH_PLUGINS=1
@section gtinth Integrating with your html
<script src="lwsgt.js"></script>
<style>
.lwsgt_title { font-size: 24; text-align:center }
.lwsgt_breadcrumbs { font-size: 18; text-align:left }
.lwsgt_table { font-size: 14; padding:12px; margin: 12px; align:center }
.lwsgt_hdr { font-size: 18; text-align:center;
background-color: rgba(40, 40, 40, 0.8); color: white }
.lwsgt_tr { padding: 10px }
.lwsgt_td { padding: 3px }
</style>
You can skip this but the result will be less beautiful until some CSS is provided.
<tr><td><div id="lwsgt1" class="group1"></div></td></tr>
lwsgt JS will put its content there.
<script>
var v1 = new lwsgt_initial("Dir listing demo",
"protocol-lws-table-dirlisting",
"lwsgt1", "lwsgt_dir_click", "v1");
function lwsgt_dir_click(gt, u, col, row)
{
if (u[0] == '=') { /* change directory */
window[gt].lwsgt_ws.send(u.substring(1, u.length));
return;
}
var win = window.open(u, '_blank');
win.focus();
}
</script>
In the callback, you can recover the ws object by window[gt].lwsgt_ws.
@section gtc Lwsgt constructor
To instantiate the ws link and lwsgt instance, your HTML must call a lwsgt constructor for each region on the page managed by lwsgt.
var myvar = new lwsgt_initial(title, ws_protocol, div_id, click_cb, myvar);
All of the arguments are strings.
| Parameter | Description |
|---|---|
| title | Title string to go above the table |
| ws_protocol | Protocol name string to use when making ws connection |
| div_id | HTML id of div to fill with content |
| click_cb | Callback function name string to handle clickable links |
| myvar | Name of var used to hold this instantiation globally |
Note "myvar" is needed so it can be passed to the click handling callback.
@section gtclick Lwsgt click handling function
When a clickable link produced by lwsgt is clicked, the function named in the click_cb parameter to lwsgt_initial is called.
That function is expected to take four parameters, eg
function lwsgt_dir_click(gt, u, col, row)
| Parameter | Description | |------- ---|-----------------------------------------------------------| | gt | Name of global var holding this lwsgt context (ie, myvar) | | u | Link "url" string | | col | Table column number link is from | | row | Table row number link is from |
@section gtgj Generic-table JSON
When the ws connection is established, the protocol should send a JSON message describing the table columns. For example
"cols": [
{ "name": "Date" },
{ "name": "Size", "align": "right" },
{ "name": "Icon" },
{ "name": "Name", "href": "uri"},
{ "name": "uri", "hide": "1" }
]
}
This describes 5 columns
Only four columns (not "uri") should be visible
"Name" should be presented as a clickable link using "uri" as the destination, when a "uri" field is presented.
"Size" field should be presented aligned to the right
When a view is hierarchical, it's useful to provide a "path" with links back in the "path", known as "breadcrumbs".
Elements before the last one should provide a "url" member as well as the displayable name, which is used to create the link destination.
The last element, being the current displayed page should not have a url member and be displayed without link style.
"breadcrumbs":[{"name":"top", "url": "/" }, {"name":"mydir"}]
The actual file data consists of an array of rows, containing the columns mentioned in the original "cols" section.
"data":[
{
"Icon":" ",
"Date":"2015-Feb-06 03:08:35 +0000",
"Size":"1406",
"uri":"./serve//favicon.ico",
"Name":"favicon.ico"
}
]
@section gtdirl Setting up protocol-lws-table-dirlisting
The example protocol needs two mounts, one to provide the index.html, js and the protocol itself
{
"mountpoint": "/dirtest",
"origin": "file:///usr/share/libwebsockets-test-server/generic-table",
"origin": "callback://protocol-lws-table-dirlisting",
"default": "index.html",
"pmo": [{
"dir": "/usr/share/libwebsockets-test-server"
}]
},
The protocol wants a per-mount option (PMO) to tell it the base directory it is serving from, named "dir".
The other mount is there to simply serve items that get clicked on from the table in a secure way
{
"mountpoint": "/dirtest/serve",
"origin": "file:///usr/share/libwebsockets-test-server",
"default": "index.html"
},
This last bit is not related to using lwsgt itself.