nodesi

What is this?

It's a subset of Edge Side Include standard implemented with promise-based interface.

Features

• Support for esi:include tags
• Built-in memory cache (easily replaceable)
• Cache respects Cache-Control server header
• Graceful degradation to custom content upon server error
• Custom logging

...and more, take a look at test cases for complete list.

Installation

npm install nodesi

Usage

Basic:

    var ESI = require('nodesi');

    var esi = new ESI();
    esi.process('<esi:include src="http://full-resource-path/stuff.html" />').then(function(result) {
        // result is a fetched html
    });

With base URL for relative paths:

    var ESI = require('nodesi');

    var esi = new ESI({
        baseUrl: 'http://full-resource-path'
    });
    esi.process('<esi:include src="/stuff.html" />').then(function(result) {
        // result is a fetched html
    });

Error handling

You can provide onError callback to a ESI constructor. It will recieve two arguments: source URL and error object.

It should return a string that will be put in place of errorous content.

Example

    var esi = new ESI({
        onError: function(src, error) {
            if(error.statusCode === 404) {
                return 'Not found';
            }
            return '';
        }
    });

Logging

It's a common anti-pattern that libraries write to stdout w/o users permission.

We want to be nice so you can provide your own logging output with logTo configuration option.

It's expected to be an object with "write" method on it that accepts a single string.

Examples

Logging to a custom object

    var esi = new ESI({
        logTo: {
            write: function(log) {
                // do some stuff with log string here
            }
        }
    });

Logging to a standard output (same as console.log):

    var esi = new ESI({
        logTo: process.stdout
    });

Logging to a file (possible, but please don't do that):

    var logFile = require('fs').createWriteStream('./log.txt');
    var esi = new ESI({
        logTo: logFile
    });

Performance testing

You can run performance tests with npm run perf [args]

This tool assumes you have Siege installed and added to your Path variable.

[args] are list of arguments that will be passed to Siege.