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@aseemk aseemk/app.js forked from laurie71/blocks.js
Created Apr 19, 2011

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Test app for Express blocks middleware
var express = require('express');
var app = express.createServer();
app.configure(function () {
app.use(require('./blocks')(app));
app.use(app.router);
});
app.set('views', __dirname);
app.set('view engine', 'html');
app.register('.html', require('ejs'));
app.get('/', function (req, res) {
res.render('test', { foo: 'bar' });
});
app.listen(8080);
console.log('listening on port 8080...');
var debug = require('util').debug;
// helper prototype for rendering block scripts, stylesheet links, etc
var blocktag = {
toString: function() {
var tag = this.tag,
html = '<'+tag,
that = this;
Object.getOwnPropertyNames(this).forEach(function(prop) {
if (prop !== 'tag') {
html += ' '+prop+'="'+that[prop]+'"';
}
});
if (tag === 'script') {
html += '></script>';
} else {
html += ' />';
}
return html;
}
}
module.exports = function(app) {
return function(req, res, next) {
// request-local hash of named blocks
var blocks = {};
// dynamic helper for defining/rendering blocks
function block(name) {
var block, html;
if (arguments.length === 0) return next(new Error('unnamed block'));
block = blocks[name];
if (arguments.length === 1) {
// render block contents
html = '';
if (block) {
block.forEach(function(item) {
html = String(item) + html;
});
}
debug('block: '+name+': '+JSON.stringify(block));
debug('html: '+html);
return html;
} else {
// define/append block contents
if (! block) block = blocks[name] = [];
block.push(Array.prototype.slice.call(arguments, 1));
debug('block: '+name+': '+JSON.stringify(block));
return '';
}
};
// utility method for adding a script to a block
block.script = function(src) {
return Object.create(blocktag, {
src : { enumerable: true, value: src },
tag : { enumerable: true, value: 'script' },
type: { enumerable: true, value: 'text/javascript' }
});
};
// utility method for adding a stylesheet to a block
block.stylesheet = function(href, media) {
var tag = Object.create(blocktag, {
href: { enumerable: true, value: href },
tag : { enumerable: true, value: 'link' },
type: { enumerable: true, value: 'text/css' },
rel : { enumerable: true, value: 'stylesheet' }
});
if (media) {
tag.media = media;
}
return tag;
};
debug('add helpers');
// res.local('block', block);
// req.app.dynamicHelpers(block);
// req.app.helpers(block);
app.helpers({block:block});
next();
};
};
<!-- use blocks.js to inject content into *parent* layout -->
<!-- use new layout() helper to select parent layout -->
<% layout('layout_site') %>
<% block('head', block.stylesheet('layout.css')) %>
<% block('foot', block.script('layout.js')) %>
<h1>Main Layout</h1>
<p>
This is the main page layout.
It is wrapped by the <t>layout_site</t> layout.
It adds the following blocks to the layout:
</p>
<ul><li>A layout.css stylesheet in the document head</li>
<li>A layout.js script at the document foot</li>
</ul>
<%- body %>
<!doctype html>
<head>
<meta charset=utf-8>
<title>Nested Layouts with Blocks Demo</title>
<!-- pull in the 'head' block content defined by our child layouts/pages -->
<%- block('head') %>
</head>
<body>
<h1>Site Layout</h1>
<p>
This is the master site layout.
It is not wrapped by a layout.
It includes the following dynamic blocks:
</p>
<ul><li><t>head</t>: a block whose content is rendered in the HTML 'head' section</li>
<li><t>foot</t>: a block whose content is rendered just before the closing 'body' tag</li>
</ul>
<%- body %>
<!-- pull in the 'foot' block content defined by our child layouts/pages -->
<%- block('foot') %>
</body>
</html>
<!-- use blocks.js to inject content into layout -->
<!-- use new layout() helper to get nested layouts -->
<% layout('layout_main') %>
<% block('head', block.stylesheet('page.css')) %>
<% block('foot', block.script('page.js')) %>
<h2>Index Page</h2>
<p>
This is the main page content.
It is wrapped by the <t>layout_main</t> layout.
It adds the following blocks to the layout:
</p>
<ul><li>A page.css stylesheet in the document head</li>
<li>A page.js script at the document foot</li>
</ul>
@aseemk

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commented Apr 19, 2011

The three .html files should be in a views directory. Gist doesn't show full pathnames for files.

@aseemk

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commented Apr 19, 2011

As the code is right now, navigating to / hangs. I haven't been able to figure out where the hang is coming from; none of the debug messages get printed.

If I swap the order of the two middlewares, app.router and blocks, requests no longer hang, but it seems to be the wrong order, because I get this error message:

ReferenceError: block is not defined
    at Object.anonymous (eval at <anonymous> (/usr/lib/node/.npm/ejs/0.3.1/package/lib/ejs.js:140:12))
    at Object.<anonymous> (/usr/lib/node/.npm/ejs/0.3.1/package/lib/ejs.js:142:15)
    at ServerResponse._render (/usr/lib/node/.npm/express/2.2.2/package/lib/view.js:377:21)
    at ServerResponse.render (/usr/lib/node/.npm/express/2.2.2/package/lib/view.js:242:17)
    at Object.<anonymous> (/Users/aseemk/Projects/Node/block-test/app.js:14:9)
    at param (/usr/lib/node/.npm/connect/1.3.0/package/lib/middleware/router.js:148:21)
    at pass (/usr/lib/node/.npm/connect/1.3.0/package/lib/middleware/router.js:164:10)
    at Object.router [as handle] (/usr/lib/node/.npm/connect/1.3.0/package/lib/middleware/router.js:170:6)
    at next (/usr/lib/node/.npm/connect/1.3.0/package/lib/http.js:204:15)
    at Object.handle (/usr/lib/node/.npm/express/2.2.2/package/lib/http.js:75:5)
@aseemk

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commented Apr 20, 2011

@laurie71 found the bug: require('blocks') returns a function which needs to be called with app and which returns the actual middleware. Fixed, and now it works. Thanks Laurie!

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