express-hateoas-links

Extends express res.json to simplify building HATEOAS enabled REST API's by appending links to JSON responses.

Installation

npm install --save express-hateoas-links

Usage

// send person object with HATEOAS links added
res.json(personObject, [
    { rel: "self", method: "GET", href: 'http://127.0.0.1' },
    { rel: "create", method: "POST", title: 'Create Person', href: 'http://127.0.0.1/person' }
]);

Optionally exclude/remove links based on rel value:

res.json(personObject, [
    { rel: "self", method: "GET", href: 'http://127.0.0.1' },
    { rel: "create", method: "POST", title: 'Create Person', href: 'http://127.0.0.1/person' }
], [ 'create' ]); // <- removes `create` link

Typical use case

The example below adds a self & create link to a JSON schema used to create a person. This allows the consuming application to understand what properties are required to create a Person and the destination URL to post to, removing the need for the application to hard code API links.

var express = require('express');
var app = express();
var hateoasLinker = require('express-hateoas-links');

// replace standard express res.json with the new version
app.use(hateoasLinker);

// standard express route
app.get('/', function(req, res){

    // create an example JSON Schema
    var personSchema = {
        "name": "Person",
        "description": "This JSON Schema defines the parameters required to create a Person object",
        "properties": {
            "name": {
                "title": "Name",
                "description": "Please enter your full name",
                "type": "string",
                "maxLength": 30,
                "minLength": 1,
                "required": true
            },
            "jobTitle": {
                "title": "Job Title",
                "type": "string"
            },
            "telephone": {
                "title": "Telephone Number",
                "description": "Please enter telephone number including country code",
                "type": "string",
                "required": true
            }
        }
    };

    // call res.json as normal but pass second param as array of links
    res.json(personSchema, [
        { rel: "self", method: "GET", href: 'http://127.0.0.1' },
        { rel: "create", method: "POST", title: 'Create Person', href: 'http://127.0.0.1/person' }
    ]);
});

// express route to process the person creation
app.post('/person', function(req, res){
    // do some stuff with the person data
});

You can set req.disableHATEOAS = false within a controller or pass ?hateoas=false to disable HATEOAS links.

Output

{
    "name": "Person",
    "description": "This JSON Schema defines the parameters required to create a Person object",
    "properties": {
        "name": {
            "title": "Name",
            "description": "Please enter your full name",
            "type": "string",
            "maxLength": 30,
            "minLength": 1,
            "required": true
        },
        "jobTitle": {
            "title": "Job Title",
            "type": "string"
        },
        "telephone": {
            "title": "Telephone Number",
            "description": "Please enter telephone number including country code",
            "type": "string",
            "required": true
        }
    },
    "links":[
        {
            "rel": "self",
            "method": "GET",
            "href": "http://127.0.0.1"
        },
        {
            "rel": "create",
            "method": "POST",
            "title": "Create Person",
            "href": "http://127.0.0.1/person"
        }
    ]
}

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -m 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request

Tests

You can run the unit tests by changing directory into the express-hateoas-links director within your node_modules folder, and run the following commands:

npm install   // install modules dev dependencies
npm test      // run unit tests

Star the repo

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History

For change-log, check releases.

License

Licensed under MIT License © Orca Scan, the Barcode Scanner app.