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# SSE - Server Sent Events Client/Server Library for Go
## Synopsis
SSE is a client/server implementation for Server Sent Events for Golang.
## Build status
* Master: [](https://circleci.com/gh/r3labs/sse)
## Quick start
To install:
```
go get github.com/r3labs/sse/v2
```
To Test:
```sh
$ make deps
$ make test
```
#### Example Server
There are two parts of the server. It is comprised of the message scheduler and a http handler function.
The messaging system is started when running:
```go
func main() {
server := sse.New()
}
```
To add a stream to this handler:
```go
func main() {
server := sse.New()
server.CreateStream("messages")
}
```
This creates a new stream inside of the scheduler. Seeing as there are no consumers, publishing a message to this channel will do nothing.
Clients can connect to this stream once the http handler is started by specifying _stream_ as a url parameter, like so:
```
http://server/events?stream=messages
```
In order to start the http server:
```go
func main() {
server := sse.New()
// Create a new Mux and set the handler
mux := http.NewServeMux()
mux.HandleFunc("/events", server.ServeHTTP)
http.ListenAndServe(":8080", mux)
}
```
To publish messages to a stream:
```go
func main() {
server := sse.New()
// Publish a payload to the stream
server.Publish("messages", &sse.Event{
Data: []byte("ping"),
})
}
```
Please note there must be a stream with the name you specify and there must be subscribers to that stream
A way to detect disconnected clients:
```go
func main() {
server := sse.New()
mux := http.NewServeMux()
mux.HandleFunc("/events", func(w http.ResponseWriter, r *http.Request) {
go func() {
// Received Browser Disconnection
<-r.Context().Done()
println("The client is disconnected here")
return
}()
server.ServeHTTP(w, r)
})
http.ListenAndServe(":8080", mux)
}
```
#### Example Client
The client exposes a way to connect to an SSE server. The client can also handle multiple events under the same url.
To create a new client:
```go
func main() {
client := sse.NewClient("http://server/events")
}
```
To subscribe to an event stream, please use the Subscribe function. This accepts the name of the stream and a handler function:
```go
func main() {
client := sse.NewClient("http://server/events")
client.Subscribe("messages", func(msg *sse.Event) {
// Got some data!
fmt.Println(msg.Data)
})
}
```
Please note that this function will block the current thread. You can run this function in a go routine.
If you wish to have events sent to a channel, you can use SubscribeChan:
```go
func main() {
events := make(chan *sse.Event)
client := sse.NewClient("http://server/events")
client.SubscribeChan("messages", events)
}
```
#### HTTP client parameters
To add additional parameters to the http client, such as disabling ssl verification for self signed certs, you can override the http client or update its options:
```go
func main() {
client := sse.NewClient("http://server/events")
client.Connection.Transport = &http.Transport{
TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
}
}
```
#### URL query parameters
To set custom query parameters on the client or disable the stream parameter altogether:
```go
func main() {
client := sse.NewClient("http://server/events?search=example")
client.SubscribeRaw(func(msg *sse.Event) {
// Got some data!
fmt.Println(msg.Data)
})
}
```
## Contributing
Please read through our
[contributing guidelines](CONTRIBUTING.md).
Included are directions for opening issues, coding standards, and notes on
development.
Moreover, if your pull request contains patches or features, you must include
relevant unit tests.
## Versioning
For transparency into our release cycle and in striving to maintain backward
compatibility, this project is maintained under [the Semantic Versioning guidelines](http://semver.org/).
## Copyright and License
Code and documentation copyright since 2015 r3labs.io authors.
Code released under
[the Mozilla Public License Version 2.0](LICENSE).
|
