ResourceManager.js

A manager for localized resources.

General

ResourceManager.js allows you to load and resolve resource-objects from different files.

It also has the capability to load and manage localized resources which allows you to resolve resource-items for the locale of your choice and to take care of locales and their parental relationships which simplifies the creation of resources for different dialects of the same language.

Table of Contents

• ResourceManager.js
  • General
  • Table of Contents
  • Installing ResourceManager.js
  • Resources
    • Example
    • Caching
      • Example
    • Mustache-Resources
      • Example
  • Localized Resources
    • Example
    • Mustache-ResourceManager
      • Example
  • Use with Mustache
    • Example
  • Exception-Handling

Installing ResourceManager.js

ResourceManager.js can be installed using following command:

npm install --save @manuth/resource-manager

Resources

You might want to work with a resource rather than a resource-manager, if you don't care about localization.

ResourceManager.js provides classes for loading resources from different file-types:

• JSONResource for JSON and JSON with Comment-files
• YAMLResource for YAML-files
• JavaScriptResource for .js-files
• ObjectResource for objects

Example

Messages.json:

{
    "StartMessage": "My App just started",
    "WelcomeMessage": {
        "Title": "My App",
        "Message": "Hello and a warmth welcome to My App!"
    },
    "Duplicate.Test": "",
    "Duplicate": {
        "Test": ""
    }
}

Messages.yml:

Test: YAML-Resource

Messages.js:

module.exports = {
    StartMessage: "JavaScript-Resource"
}

const Dialog = require("dialog");
const { JSONResource, ObjectResource, YAMLResource } = require("@manuth/resource-manager");

let jsonResource = new JSONResource("./Messages.json");
let yamlResource = new YAMLResource("./Messages.yml");
let jsResource = new JavaScriptResource("./Messages.js");
let objectResource = new ObjectResource(require("./Messages"));

console.log(jsonResource.Get("StartMessage"));
Dialog.info(jsonResource.Get("WelcomeMessage.Message"), jsonResource.Get("WelcomeMessage.Title"), () =>{});
console.log(jsonResource.Get("Inexistent.Key")); //Throws a "KeyNotFoundException"
console.log(jsonResource.Get("Duplicate.Test")); // Throws a "DuplicateKeyException"
console.log(yamlResource.Get("Test")); // Logs "YAML-Resource"
console.log(jsResource.Get("Test")); // Logs "JavaScript-Resource"
console.log(objectResource.Get("Test")); // Logs "JavaScript-Resource"

Caching

When working with file-resources you can also enable the cache-mode by setting FileResource.Cached.
This forces the system to cache the resource-items of the file and to read resource-items from the cache rather than from the file.

Example

const FileSystem = require("fs");
const { JSONResource } = require("@manuth/resource-manager");

let resource = new JSONResource("./Messages.json");
resource.Cached = true;
console.log(resource.Get("StartMessage"));
FileSystem.unlinkSync("./Messages.json");
console.log(resource.Get("StartMessage")); // Does not throw
FileSystem.writeFileSync("./Messages.json", '{ "Test": "Test" }');
resource.Refresh();
console.log(resource.Get("Test")); // Logs "Test"
console.log(resource.Get("StartMessage")); // Throws a "KeyNotFoundException"

Mustache-Resources

You might want to composite resource-items using mustache.
This can be done by wrapping your resource with a mustache-resource which pre-processes resource-items using mustache.render().

Example

MustacheResource.yml:

ProjectName: My App
Author: m@nuth
Console:
    CopyRightMessage: "{{ProjectName}} © by {{Author}}"

const { MustacheResource, YAMLResource } = require("@manuth/resource-manager");

let resource = new MustacheResource(new YAMLResource("./MustacheResource.yml"));
console.log(resource.Get("Console.CopyRightMessage"));

This produces following output:

My App © by m@nuth

Localized Resources

One thing you might have missed is that a resource also contains information about its locale (the default is the global, invariant culture). This information is used by the ResourceManager to resolve resource-items of the best-matching culture.

The ResourceManager is capable to load resource-files automatically based on their file-name if they follow the path-convention:

{ BaseFileName }[.{ locale-abbreviation }].{ File-Extension }

If you skip the locale-part the global, invariant culture will be set.

Examples:

Resource.json
Resource.de.jsonc
Resource.en.yml
Resource.en-US.js

This might be very useful if you work with similar languages and dialects.

Example

Resource.en.json:

{
    "WelcomeMessage": "Welcome to my awesome web-developer tool",
    "CopyItem": "Copy to Clipboard",
    "UnknownError": "An unexpected error occurred",
    "ColorError": "Please specify a valid color",
    "Duplicate.File": "",
    "Duplicate.Test": "",
    "Duplicate": {
        "Test": ""
    }
}

Resource.en.yml:

Duplicate.File: ""

Resource.en-GB.json:

{
    "ColorError": "Please specify a valid colour"
}

const { CultureInfo, ResourceManager } = require("@manuth/resource-manager");

let manager = new ResourceManager("./Resource", new CultureInfo("en-gb"));
console.log(manager.Get("CopyItem")); // "Copy to Clipboard"
console.log(manager.Get("ColorError")); // "Please specify a valid colour"
console.log(manager.Get("ColorError"), new CultureInfo("en-US")); // "Please specify a valid color"
manager.Locale = new CultureInfo("en");
console.log(manager.Get("ColorError")); // "Please specify a valid color"
console.log(manager.Get("Inexistent.Key")); // Throws a KeyNotFoundException
console.log(manager.Get("Duplicate.Test")); // Throws a DuplicateKeyException
console.log(manager.Get("Duplicate.File")); // Throws a DuplicateKeyException

Mustache-ResourceManager

The resource-manager is is able to work with mustache, too!
The above example can be simplified by wrapping the resource-manager with a MustacheResourceManager which allows you to pre-process localized resource-items.

Example

Resource.en.json:

{
    "Color": "color",
    "WelcomeMessage": "Welcome to my awesome web-developer tool",
    "CopyItem": "Copy to Clipboard",
    "UnknownError": "An unexpected error occurred",
    "ColorError": "Please specify a valid {{Color}}"
}

Resource.en-gb.yml:

Color: colour

const { CultureInfo, MustacheResourceManager, ResourceManager } = require("@manuth/resource-manager");

let manager = new MustacheResourceManager(new ResourceManager("./Resource"));
manager.Locale = new CultureInfo("en-gb");
console.log(manager.Get("WelcomeMessage")); // "Welcome to my awesome web-developer tool"
console.log(manager.Get("ColorError")); // "Please specify a valid colour"
console.log(manager.Get("ColorError", new CultureInfo("en"))); // "Please specify a valid color"

Use with Mustache

The ResourceContext and ResourceManagerContext-classes allow you to use a resource or a resource-manager as a mustache-context, which might be useful for you:

Example

const { CultureInfo, ResourceManager, ResourceManagerContext } = require("@manuth/resource-manager");
const Mustache = require("mustache");

let manager = new ResourceManager("./Resource", new CultureInfo("en"));
Mustache.render(
    `
    <html>
        <head>
        </head>
        <body>
            <div class="container">
                {{WelcomeMessage}}
            </div>
        </body>
    </html>`,
    new ResourceManagerContext(manager));

Exception-Handling

Generally all classes may throw one of these exceptions:

• KeyNotFoundException:
  This error occurs when a key could not be found.
• DuplicateKeyException:
  This error occurs when a key is not distinguishable