angular-server-side-configuration

angular-server-side-configuration

Configure an angular application at runtime on the server via environment variables.

Motivation

The Angular CLI provides build time configuration (via environment.ts). In a Continuous Delivery environment this is sometimes not enough.

How it works & Limitations

Environment variables are used for configuration. This package provides a script to search for usages in bundled angular files and a script for inserting populated environment variables into index.html file(s) (Missing environment variables will be represented by null). This should be done on the host serving the bundled angular files.

AOT

This will not work in Module.forRoot or Module.forChild scripts or parameters. These are build time only due to AOT restrictions.

Getting Started

npm install --save angular-server-side-configuration

environment.prod.ts

Use process.env.NAME in your environment.prod.ts, where NAME is the environment variable that should be used.

export const environment = {
  production: process.env.PROD !== 'false',
  apiAddress: process.env.API_ADDRESS || 'https://example-api.com'
};

polyfill.ts

Import angular-server-side-configuration/process in polyfill.ts. This will enable the typings for process.env.* in the code and register a fallback value for process.env.

/**
 * This file includes polyfills needed by Angular and is loaded before the app.
 * You can add your own extra polyfills to this file.
...

/***************************************************************************************************
 * APPLICATION IMPORTS
 */

import 'angular-server-side-configuration/process';

server.ts (or any script executed on the host)

EnvironmentVariablesConfiguration provides a way of looking for usages of process.env.* in the bundled angular javascript files and provides a way of inserting the environment variables into the index.html file(s).

...
import { EnvironmentVariablesConfiguration } from 'angular-server-side-configuration';
import * as express from 'express';
...
const app = express();
const envVariables = EnvironmentVariablesConfiguration.searchEnvironmentVariables(bundledAngularFilesRoot);
...
envVariables.insertAndSaveRecursively(bundledAngularFilesRoot)
  .then(() => {
    app.listen(PORT, () => {
      console.log(`Node server listening on http://localhost:${PORT}`);
    });
  });

Documentation

process

Import angular-server-side-configuration/process in polyfill.ts. This will enable the typings for process.env.* in the code and register a fallback value for process.env.

import 'angular-server-side-configuration/process';

EnvironmentVariablesConfiguration

Constructor

Accepts an array of environment variables.

const envVariables = new EnvironmentVariablesConfiguration(['PROD', 'API_ADDRESS']);

EnvironmentVariablesConfiguration.searchEnvironmentVariables

By default the searchEnvironmentVariables method uses a regex (/process\s*\.\s*env\s*\.\s*[a-zA-Z0-9_]+/gm) to look for process.env.* usages. It is possible to provide a discovery function in the options as a second parameter.

root The root directory from which to search.
options Optional options for searching environment variables.
options.filePattern The file pattern in which environment variables should be searched (Defaults to /.js$/).
options.environmentVariablesDiscovery The function to discover environment variables in the matched files (Defaults to process.env.VARIABLE => VARIABLE).

Returns an instance of EnvironmentVariablesConfiguration.

const envVariables: EnvironmentVariablesConfiguration =
  EnvironmentVariablesConfiguration.searchEnvironmentVariables(bundledAngularFilesRoot);

EnvironmentVariablesConfiguration.prototype.populateVariables

Generates an object, with the environment variable names being the key and the actual values being the values. Missing environment variables will be represented by null.

const envVariables = new EnvironmentVariablesConfiguration(['PROD', 'API_ADDRESS']);
process.env.API_ADDRESS = 'https://example-api.com';
const variables = envVariables.populateVariables();
// { PROD: null, API_ADDRESS: 'https://example-api.com' }

EnvironmentVariablesConfiguration.prototype.generateIIFE

Generates the IIFE in which the environment variables are assigned to window.process.env.

const envVariables = new EnvironmentVariablesConfiguration(['PROD', 'API_ADDRESS']);
process.env.API_ADDRESS = 'https://example-api.com';
const iife = envVariables.generateIIFE();
// (function(self){self.process={env:{"PROD":null,"API_ADDRESS":"https://example-api.com"};})(window)

EnvironmentVariablesConfiguration.prototype.apply

Inserts the discovered environment variables as an IIFE wrapped in a script tag into the specified file content without saving the file.

file The file to be read.
options Optional options for insertion.
options.insertionRegex The replacement pattern, where the configuration should be inserted (Defaults to /<!--\s*CONFIG\s*-->/).

Returns a promise, which resolves to the file content with the environment variables inserted.

const envVariables = EnvironmentVariablesConfiguration.searchEnvironmentVariables(bundledAngularFilesRoot);
const content = await envVariables.apply(pathToIndexHtml);
// <html>...<script>(function(self){self.process={env:{"PROD":null,"API_ADDRESS":"https://example-api.com"};})(window)</script>...</html>

EnvironmentVariablesConfiguration.prototype.insertAndSave

Inserts the discovered environment variables as an IIFE wrapped in a script tag into the specified file.

file The file into which the environment variables should be inserted.
options Optional options for insertion.
options.insertionRegex The replacement pattern, where the configuration should be inserted (Defaults to /<!--\s*CONFIG\s*-->/).

Returns a promise, which resolves after the enivornment variables have been saved to the given file.

const envVariables = EnvironmentVariablesConfiguration.searchEnvironmentVariables(bundledAngularFilesRoot);
await envVariables.insertAndSave(pathToIndexHtml);

EnvironmentVariablesConfiguration.prototype.insertAndSave

Inserts the discovered enviornment variables as an IIFE wrapped in a script tag into the matched files.

root The root directory from which to search insertion files.
options Optional options for insertion.
options.filePattern The file pattern in which the configuration should be inserted (Defaults to /index.html$/).
options.insertionRegex The replacement pattern, where the configuration should be inserted (Defaults to /<!--\s*CONFIG\s*-->/).

Returns a promise, which resolves after the environment variables have been inserted to all matched files.

const envVariables = EnvironmentVariablesConfiguration.searchEnvironmentVariables(bundledAngularFilesRoot);
await envVariables.insertAndSaveRecursively(bundledAngularFilesRoot);

License

Apache License, Version 2.0