Improve documentation

README.md

@@ -3,8 +3,9 @@
 [![CI status](https://github.com/clue/reactphp-eventsource/actions/workflows/ci.yml/badge.svg)](https://github.com/clue/reactphp-eventsource/actions)
 [![installs on Packagist](https://img.shields.io/packagist/dt/clue/reactphp-eventsource?color=blue&label=installs%20on%20Packagist)](https://packagist.org/packages/clue/reactphp-eventsource)
 
-Event-driven EventSource client, receiving streaming messages from any HTML5 Server-Sent Events (SSE) server,
-built on top of [ReactPHP](https://reactphp.org/).
+Instant real-time updates. Lightweight EventSource client receiving live
+messages via HTML5 Server-Sent Events (SSE). Fast stream processing built on top
+of [ReactPHP](https://reactphp.org/)'s event-driven architecture.
 
 > Note: This project is in early alpha stage! Feel free to report any issues you encounter.
 
@@ -13,25 +14,48 @@ built on top of [ReactPHP](https://reactphp.org/).
 * [Quickstart example](#quickstart-example)
 * [Usage](#usage)
     * [EventSource](#eventsource)
+        * [message event](#message-event)
+        * [open event](#open-event)
+        * [error event](#error-event)
+        * [EventSource::$readyState](#eventsourcereadystate)
+        * [EventSource::$url](#eventsourceurl)
+        * [close()](#close)
+    * [MessageEvent](#messageevent)
+        * [MessageEvent::$data](#messageeventdata)
+        * [MessageEvent::$lastEventId](#messageeventlasteventid)
+        * [MessageEvent::$type](#messageeventtype)
 * [Install](#install)
 * [Tests](#tests)
 * [License](#license)
+* [More](#more)
 
 ## Quickstart example
 
 Once [installed](#install), you can use the following code to stream messages
 from any Server-Sent Events (SSE) server endpoint:
 
+```
+data: {"name":"Alice","message":"Hello everybody!"}
+
+data: {"name":"Bob","message":"Hey Alice!"}
+
+data: {"name":"Carol","message":"Nice to see you Alice!"}
+
+data: {"name":"Alice","message":"What a lovely chat!"}
+
+data: {"name":"Bob","message":"Yeah, all powered by ReactPHP, such an awesome piece of technology :)"}
+```
+
 ```php
 $es = new Clue\React\EventSource\EventSource('https://example.com/stream.php');
 
 $es->on('message', function (Clue\React\EventSource\MessageEvent $message) {
-    //$data = json_decode($message->data);
-    var_dump($message);
+    $json = json_decode($message->data);
+    echo $json->name . ': ' . $json->message . PHP_EOL;
 });
 ```
 
-See the [examples](examples).
+See the [examples](examples/).
 
 ## Usage
 
@@ -77,6 +101,205 @@ here in order to use the [default loop](https://github.com/reactphp/event-loop#l
 This value SHOULD NOT be given unless you're sure you want to explicitly use a
 given event loop instance.
 
+#### message event
+
+The `message` event will be emitted whenever an EventSource message is received.
+
+```php
+$es->on('message', function (Clue\React\EventSource\MessageEvent $message) {
+    // $json = json_decode($message->data);
+    var_dump($message);
+});
+```
+
+The EventSource stream may emit any number of messages over its lifetime. Each
+`message` event will receive a [`MessageEvent` object](#messageevent).
+
+The [`MessageEvent::$data` property](#messageeventdata) can be used to access
+the message payload data. It is commonly used for transporting structured data
+such as JSON:
+
+```
+data: {"name":"Alice","age":30}
+
+data: {"name":"Bob","age":50}
+```
+```php
+$es->on('message', function (Clue\React\EventSource\MessageEvent $message) {
+    $json = json_decode($message->data);
+    echo "{$json->name} is {$json->age} years old" . PHP_EOL;
+});
+```
+
+The EventSource stream may specify an event type for each incoming message. This
+`event` field can be used to emit appropriate event types like this:
+
+```
+data: Alice
+event: join
+
+data: Hello!
+event: chat
+
+data: Bob
+event: leave
+```
+```php
+$es->on('join', function (Clue\React\EventSource\MessageEvent $message) {
+    echo $message->data . ' joined' . PHP_EOL;
+});
+
+$es->on('chat', function (Clue\React\EventSource\MessageEvent $message) {
+    echo 'Message: ' . $message->data . PHP_EOL;
+});
+
+$es->on('leave', function (Clue\React\EventSource\MessageEvent $message) {
+    echo $message->data . ' left' . PHP_EOL;
+});
+```
+
+See also [`MessageEvent::$type` property](#messageeventtype) for more details.
+
+#### open event
+
+The `open` event will be emitted when the EventSource connection is successfully established.
+
+```php
+$es->on('open', function () {
+    echo 'Connection opened' . PHP_EOL;
+});
+```
+
+Once the EventSource connection is open, it may emit any number of
+[`message` events](#message-event).
+
+If the connection can not be opened successfully, it will emit an
+[`error` event](#error-event) instead.
+
+#### error event
+
+The `error` event will be emitted when the EventSource connection fails.
+The event receives a single `Exception` argument for the error instance.
+
+```php
+$redis->on('error', function (Exception $e) {
+    echo 'Error: ' . $e->getMessage() . PHP_EOL;
+});
+```
+
+The EventSource connection will be retried automatically when it is temporarily
+disconnected. If the server sends a non-successful HTTP status code or an
+invalid `Content-Type` response header, the connection will fail permanently.
+
+```php
+$es->on('error', function (Exception $e) use ($es) {
+    if ($es->readyState === Clue\React\EventSource\EventSource::CLOSED) {
+        echo 'Permanent error: ' . $e->getMessage() . PHP_EOL;
+    } else {
+        echo 'Temporary error: ' . $e->getMessage() . PHP_EOL;
+    }
+});
+```
+
+See also the [`EventSource::$readyState` property](#eventsourcereadystate).
+
+#### EventSource::$readyState
+
+The `int $readyState` property can be used to
+check the current EventSource connection state.
+
+The state is read-only and can be in one of three states over its lifetime:
+
+* `EventSource::CONNECTING`
+* `EventSource::OPEN`
+* `EventSource::CLOSED`
+
+#### EventSource::$url
+
+The `readonly string $url` property can be used to
+get the EventSource URL as given to the constructor.
+
+#### close()
+
+The `close(): void` method can be used to
+forcefully close the EventSource connection.
+
+This will close any active connections or connection attempts and go into the
+`EventSource::CLOSED` state.
+
+### MessageEvent
+
+The `MessageEvent` class represents an incoming EventSource message.
+
+#### MessageEvent::$data
+
+The `readonly string $data` property can be used to
+access the message payload data.
+
+```
+data: hello
+```
+```php
+assert($message->data === 'hello');
+```
+
+The `data` field may also span multiple lines. This is commonly used for
+transporting structured data such as JSON:
+
+```
+data: {
+data:     "message": "hello"
+data: }
+```
+```php
+$json = json_decode($message->data);
+assert($json->message === 'hello');
+```
+
+If the message does not contain a `data` field or the `data` field is empty, the
+message will be discarded without emitting an event.
+
+#### MessageEvent::$lastEventId
+
+The `readonly string $lastEventId` property can be used to
+access the last event ID.
+
+```
+data: hello
+id: 1
+```
+```php
+assert($message->data === 'hello');
+assert($message->lastEventId === '1');
+```
+
+Internally, the `id` field will automatically be used as the `Last-Event-ID` HTTP
+request header in case the connection is interrupted.
+
+If the message does not contain an `id` field, the `$lastEventId` property will
+be the value of the last ID received. If no previous message contained an ID, it
+will default to an empty string.
+
+#### MessageEvent::$type
+
+The `readonly string $type` property can be used to
+access the message event type.
+
+```
+data: Alice
+event: join
+```
+```php
+assert($message->data === 'Alice');
+assert($message->type === 'join');
+```
+
+Internally, the `event` field will be used to emit the appropriate event type.
+See also [`message` event](#message-event).
+
+If the message does not contain a `event` field or the `event` field is empty,
+the `$type` property will default to `message`.
+
 ## Install
 
 The recommended way to install this library is [through Composer](https://getcomposer.org/).
@@ -105,7 +328,7 @@ $ composer install
 To run the test suite, go to the project root and run:
 
 ```bash
-$ php vendor/bin/phpunit
+$ vendor/bin/phpunit
 ```
 
 ## License
@@ -114,3 +337,12 @@ This project is released under the permissive [MIT license](LICENSE).
 
 > Did you know that I offer custom development services and issuing invoices for
   sponsorships of releases and for contributions? Contact me (@clue) for details.
+
+## More
+
+* If you want to learn more about processing streams of data, refer to the documentation of
+  the underlying [react/stream](https://github.com/reactphp/stream) component.
+
+* If you're looking to run the server side of your Server-Sent Events (SSE)
+  application, you may want to use the powerful server implementation provided
+  by [Framework X](https://framework-x.org/).

composer.json

@@ -1,6 +1,6 @@
 {
     "name": "clue/reactphp-eventsource",
-    "description": "Event-driven EventSource client, receiving streaming messages from any HTML5 Server-Sent Events (SSE) server, built on top of ReactPHP",
+    "description": "Instant real-time updates. Lightweight EventSource client receiving live messages via HTML5 Server-Sent Events (SSE). Fast stream processing built on top of ReactPHP's event-driven architecture.",
     "keywords": ["EventSource", "Server-Side Events", "SSE", "event-driven", "ReactPHP", "async"],
     "homepage": "https://github.com/clue/reactphp-eventsource",
     "license": "MIT",

examples/stream.php

@@ -9,7 +9,7 @@
 $es = new Clue\React\EventSource\EventSource($argv[1]);
 
 $es->on('message', function (Clue\React\EventSource\MessageEvent $message) {
-    //$data = json_decode($message->data);
+    // $json = json_decode($message->data);
     var_dump($message);
 });