fnx_config

Transformer which helps you manage different configurations for different builds of your web app. Usually you need different configuration for different environments:

String apiRoot = "http://localhost:8080/api/v1
// Use in production!!!!!
// String apiRoot = "http://this-is-very-important.qwerty/api/v1/"

... and that's just terrible. Let's try something else.

Usage

Add transformer to your pubspec.yaml:

dependencies:
  fnx_config: ^1.0.0

transformers:
- fnx_config

Then create configuration profiles (YAML files). Usually you will need two of them.

  • lib/conf/config_debug.yaml - for pub serve
  • lib/conf/config_release.yaml - for pub build

Content of those files is completely up to you, it's probably going to be something like this:

ourSecretApiKey: qwertyuiop
ourSecretApiUrl: http://this-is-very-secret.qwerty/api/v1/

Then add <script type="pub/fnx_config"></script> into the <head> of your HTML files and run pub serve.

Result

Transformer searches for HTML files with this instruction, and replaces it with encoded content of your YAML file:

var fnx_config = "eyJjb25maWciOnsiYWhvai  ... tMjlUMTg6NDE6MjAuMTkwIn19";

The reason why we encode the configuration, is that we don't want to tempt the user with too much knowledge. We don't need any bored teenager to play with our API endpoints and API keys.

Please don't mistake this feature for any kind of security, it's just simple BASE64 and the configuration will be accessible to any skilled user. But a little bit of obfuscation cannot do any harm.

See example.

Reading

Import

import 'package:fnx_config/fnx_config_read.dart';

and access your configuration via global function:

String apiKey = fnxConfig()["ourSecretApiKey"];

fnx_config also adds few metadata you might find useful:

fnxConfigMeta()["mode"]; // pub build mode (--mode=qwerty)
fnxConfigMeta()["timestamp"]; // timestamp of build    
    

Multiple configuration profiles

Simply add more configuration files:

lib/conf/config_qwerty.yaml
lib/conf/config_jenkins.yaml

and use them with pub:

pub build --mode=qwerty
pub serve --mode=jenkins
        

Polymer

With Polymer, place fnx_config transformer after web_components

- web_components:
		entry_points: web/index.html
- reflectable:
		entry_points: web/index.dart
- fnx_config

Libraries

fnx_config.read

Methods to access your configuration.

fnx_config.transform

Transformer which includes build mode dependent configuration into your HTML file.