Pusher HTTP Rust Library

The Rust library for interacting with the Pusher HTTP API.

This package lets you trigger events to your client and query the state of your Pusher channels. When used with a server, you can validate Pusher webhooks and authenticate private- or presence-channels.

The functions that make HTTP requests are async, so you will need to run them with an executer like tokio. The library is a wrapper around the hyper client.

In order to use this library, you need to have a free account on http://pusher.com. After registering, you will need the application credentials for your app.

Table of Contents

• Installation
• Getting Started
• Configuration
  • Additional options
• Usage
  • Triggering events
  • Excluding event recipients
  • Authenticating Channels
  • Application state
  • Webhook validation
• Feature Support
• Developing the Library
  • Running the tests
• License

Installation

Add to your Cargo.toml:

pusher="*"

Supported platforms

• Rust versions 1.39 and above

Getting Started

extern crate pusher; // imports the `pusher` module

use pusher::PusherBuilder; // brings the PusherBuilder into scope

// the functions are async, so we need a reactor running (e.g. tokio)
// this example uses "current_thread" for simplicity
#[tokio::main(flavor = "current_thread")]
async fn main() {
  // initializes a Pusher object with your app credentials
  let pusher = PusherBuilder::new("APP_ID", "KEY", "SECRET").finalize();

  // triggers an event called "my_event" on a channel called "test_channel", with the payload "hello world!"
  let result = pusher.trigger("test_channel", "my_event", "hello world!").await;
  match result {
    Ok(events) => println!("Successfully published: {:?}", events),
    Err(err) => println!("Failed to publish: {}", err),
  }
}

Configuration

There easiest way to configure the library is by creating a new Pusher instance:

let pusher = PusherBuilder::new("id", "key", "secret").finalize();

PusherBuilder::new returns a PusherBuilder, on which to chain configuration methods, before calling finalize().

Additional options

Instantiation From URL

PusherBuilder::from_url("http://key:secret@api.host.com/apps/id").finalize();

Instantiation From Environment Variable

PusherBuilder::from_env("PUSHER_URL").finalize();

This is particularly relevant if you are using Pusher as a Heroku add-on, which stores credentials in a "PUSHER_URL" environment variable.

HTTPS

To ensure requests occur over HTTPS, call secure() before finalize().

let pusher = PusherBuilder::new("id", "key", "secret").secure().finalize();

Changing Host

Calling host() before finalize() will make sure requests are sent to your specified host.

let pusher = PusherBuilder::new("id", "key", "secret").host("foo.bar.com").finalize();

By default, this is "api.pusherapp.com".

Changing the underlying hyper::client::connect::Connect

The above functions have equivalent functions that also allow a custom Connect to be provided. E.g.:

let pusher = PusherBuilder::new_with_client(my_client, "id", "key", "secret").host("foo.bar.com").finalize();

Usage

Triggering events

It is possible to trigger an event on one or more channels. Channel names can contain only characters which are alphanumeric, _ or `-`` and have to be at most 200 characters long. Event name can be at most 200 characters long too.

Single channel

async fn trigger<S: serde::Serialize>(&self, channel: &str, event: &str, payload: S)

Argument	Description
channel &str	The name of the channel you wish to trigger on.
event &str	The name of the event you wish to trigger
data S: serde::Serialize	The payload you wish to send. Must be marshallable into JSON.

Return Value	Description
result Result<TriggeredEvents, String>	If the trigger was successful and you are connected to certain clusters, an object containing the event_ids field will be returned as part of a Result. An Err value will be returned if any errors were encountered.

Example

let mut hash_map = HashMap::new();
hash_map.insert("message", "hello world");

pusher.trigger("test_channel", "my_event", &hash_map).await;

Multiple channels

async fn trigger_multi<S: serde::Serialize>(&self, channels: &[&str], event: &str, payload: S)

Argument	Description
channels &[&str]	A vector of channel names you wish to send an event on. The maximum length is 10.
event &str	As above.
data S: serde::Serialize	As above.

Return Value	Description
result Result<TriggeredEvents, String>	As above.

Example

let channels = vec!["test_channel", "test_channel2"];

pusher.trigger_multi(&channels, "my_event", "hello").await;

Excluding event recipients

trigger_exclusive and trigger_multi_exclusive follow the patterns above, except a socket_id is given as the last parameter.

These methods allow you to exclude a recipient whose connection has that socket_id from receiving the event. You can read more here.

Examples

On one channel:

pusher.trigger_exclusive("test_channel", "my_event", "hello", "123.12").await;

On multiple channels:

let channels = vec!["test_channel", "test_channel2"];
pusher.trigger_multi_exclusive(&channels, "my_event", "hello", "123.12").await;

Authenticating Channels

Application security is very important so Pusher provides a mechanism for authenticating a user’s access to a channel at the point of subscription.

This can be used both to restrict access to private channels, and in the case of presence channels notify subscribers of who else is also subscribed via presence events.

This library provides a mechanism for generating an authentication signature to send back to the client and authorize them.

For more information see our docs.

Private channels

fn authenticate_private_channel(&self, channel_name: &str, socket_id: &str)

Argument	Description
channel_name &str	The channel name in the request sent by the client
socket_id &str	The socket id in the request sent by the client

Return Value	Description
Result <String, &str>	The Ok value will be the response to send back to the client, carrying an authentication signature. An Err value will be a string describing any errors generated

Example using hyper

async fn pusher_auth(req: Request<Body>) -> Result<Response<Body>, Error> {
  let body = to_bytes(req).await.unwrap();
  let params = parse(body.as_ref()).into_owned().collect::<HashMap<String, String>>();
  let channel_name = params.get("channel_name").unwrap();
  let socket_id = params.get("socket_id").unwrap();
  let auth_signature = pusher.authenticate_private_channel(channel_name, socket_id).unwrap();
  Ok(Response::new(auth_signature.into()))
}

Authenticating presence channels

Using presence channels is similar to private channels, but in order to identify a user, clients are sent a user_id and, optionally, custom data.

fn authenticate_presence_channel(&self, channel_name: &str, socket_id: &str, member: &Member)

Argument	Description
channel_name &str	The channel name in the request sent by the client
socket_id &str	The socket id in the request sent by the client
member &pusher::Member	A struct representing what to assign to a channel member, consisting of a user_id and any custom user_info. See below

Custom Types

pusher::Member

pub struct Member<'a> {
  pub user_id: &'a str,
  pub user_info: Option<HashMap<&'a str, &'a str>>,
}

Example using hyper

async fn pusher_auth(req: Request<Body>) -> Result<Response<Body>, Error> {
  let body = to_bytes(req).await.unwrap();
  let params = parse(body.as_ref()).into_owned().collect::<HashMap<String, String>>();
  let channel_name = params.get("channel_name").unwrap();
  let socket_id = params.get("socket_id").unwrap();

  let mut member_data = HashMap::new();
  member_data.insert("twitter", "jamiepatel");
  let member = pusher::Member{user_id: "4", user_info: Some(member_data)};

  let auth_signature = pusher.authenticate_presence_channel(channel_name, socket_id, &member).unwrap();
  Ok(Response::new(auth_signature.into()))
}

Application state

This library allows you to query our API to retrieve information about your application's channels, their individual properties, and, for presence-channels, the users currently subscribed to them.

Get the list of channels in an application

async fn channels(&self)

Requesting a list of application channels without any query options.

Return Value	Description
result Result<ChannelList, String>	The Ok value will be a struct representing the list of channels. See below. An Err value will represent any errors encountered.

async fn channels_with_options(&self, params: QueryParameters)

Adding options to your channels request.

Argument	Description
params QueryParameters	A vector of tuples with query options. Where the first value of a tuple is "filter_by_prefix", the API will filter the returned channels with the second value. To get number of users subscribed to a presence-channel, specify an "info" value in a tuple with a corresponding "user_count" value.

Return Value	Description
result Result<ChannelList, String>	As above.

Custom Types

pusher::ChannelsList

pub struct ChannelList {
  pub channels: HashMap<String, Channel>,
}

pusher::Channel

pub struct Channel {
  pub occupied: Option<bool>,
  pub user_count: Option<i32>,
  pub subscription_count: Option<i32>,
}

Example

Without options:

pusher.channels().await;
//=> Ok(ChannelList { channels: {"presence-chatroom": Channel { occupied: None, user_count: None, subscription_count: None }, "presence-notifications": Channel { occupied: None, user_count: None, subscription_count: None }} })

With options:

let channels_params = vec![("filter_by_prefix", "presence-"), ("info", "user_count")];
pusher.channels_with_options(channels_params).await;
//=> Ok(ChannelList { channels: {"presence-chatroom": Channel { occupied: None, user_count: Some(92), subscription_count: None }, "presence-notifications": Channel { occupied: None, user_count: Some(29), subscription_count: None }} })

Get the state of a single channel

async fn channel(&self, channel_name: &str)

Requesting the state of a single channel without any query options.

Return Value	Description
result Result<Channel, String>	The Ok value will be a struct representing a channel. See above. An Err value will represent any errors encountered.

async fn channel_with_options(&self, channel_name: &str, params: QueryParameters)

Adding options to your channel request.

Argument	Description
channel_name &str	The name of the channel
params QueryParameters	A vector of tuples with query options. To request information regarding user_count and subscription_count, a tuple must have an "info" value and a value containing a comma-separated list of attributes. An Err will be returned for any invalid API requests.

Return Value	Description
result Result<Channel, String>	As above.

Example

Without options:

pusher.channel("presence-chatroom").await;
//=> Ok(Channel { occupied: Some(true), user_count: None, subscription_count: None })

With options:

let channel_params = vec![("info", "user_count,subscription_count")];
pusher.channel_with_options("presence-chatroom", channel_params).await;
//=> Ok(Channel { occupied: Some(true), user_count: Some(96), subscription_count: Some(96) })

Get a list of users in a presence channel

async fn channel_users(&self, channel_name : &str)

Argument	Description
channel_name &str	The channel name

Return Value	Description
result Result<ChannelUserList, String>	The Ok value will be a struct representing a list of the users subscribed to the presence-channel. See below. The Err value will represent any errors encountered.

Custom Types

pusher::ChannelUserList

pub struct ChannelUserList {
  pub users: Vec<ChannelUser>,
}

pusher::ChannelUser

pub struct ChannelUser {
  pub id: String,
}

Example

pusher.channel_users("presence-chatroom").await;
//=> Ok(ChannelUserList { users: [ChannelUser { id: "red" }, ChannelUser { id: "blue" }] })

Webhook validation

On your dashboard, you can set up webhooks to POST a payload to your server after certain events. Such events include channels being occupied or vacated, members being added or removed in presence-channels, or after client-originated events. For more information see https://pusher.com/docs/webhooks.

This library provides a mechanism for checking that these POST requests are indeed from Pusher, by checking the token and authentication signature in the header of the request.

fn webhook(&self, key: &str, signature: &str, body: &str)

Argument	Description
key &str	The key supplied in the "X-Pusher-Key" header
signature &str	The signature supplied in the "X-Pusher-Signature" header
body &str	The body of the request

Return Value	Description
result Result<Webhook, &str>	If the webhook is valid, the Ok value will be a representation of that webhook that includes its timestamp and associated events. If the webhook is invalid, an Err value will be passed.

Custom Types

pusher::Webhook

pub struct Webhook {
  pub time_ms: i64,
  pub events: Vec<HashMap<String, String>>,
}

Example

pusher.webhook("supplied_key", "supplied_signature", "body")

Feature Support

Feature	Supported
Trigger event on single channel	✔
Trigger event on multiple channels	✔
Excluding recipients from events	✔
Authenticating private channels	✔
Authenticating presence channels	✔
Get the list of channels in an application	✔
Get the state of a single channel	✔
Get a list of users in a presence channel	✔
WebHook validation	✔
Heroku add-on support	✔
Debugging & Logging	✔
Cluster configuration	✔
HTTPS	✔
Timeouts	✘
HTTP Proxy configuration	✘
HTTP KeepAlive	✘

Helper Functionality

These are helpers that have been implemented to to ensure interactions with the HTTP API only occur if they will not be rejected e.g. channel naming conventions.

Helper Functionality	Supported
Channel name validation	✔
Limit to 10 channels per trigger	✔
Limit event name length to 200 chars	✔

Developing the Library

Feel more than free to fork this repo, improve it in any way you'd prefer, and send us a pull request :)

Running the tests

Simply type:

$ cargo test

License

This code is free to use under the terms of the MIT license.

To Do

• Review the use of different string types.
• More test coverage