Pusher Channels

use pusher.qweruse pusher_trigger, pusher_trigger_batch from pusher      // Quillo 0.6: only these

ureq = "2"hmac = "0.12"sha2 = "0.10"md-5 = "0.10"hex = "0.4"

// Live updates through Pusher Channels (or a Soketi server): an order's status sent to its// channels, a batch, who is on the presence channel, the auth answers a browser's pusher-js asks// for, and a webhook from Pusher checked before it is believed.////   PUSHER_APP_ID=... PUSHER_KEY=... PUSHER_SECRET=... PUSHER_HOST=https://api-eu.pusher.com quillo run pusher.qwe//   then open http://localhost:8080/trigger, /batch, /channels, /auth and /webhook-check//// It needs a Pusher app (the dashboard's App Keys), or Soketi: PUSHER_HOST=http://127.0.0.1:6001.// Point the app's webhooks at POST /pusher/webhook, and pusher-js's channelAuthorization at// POST /pusher/auth.use "pusher.qwer"let app = {    app_id: env("PUSHER_APP_ID", ""),    key: env("PUSHER_KEY", ""),    secret: env("PUSHER_SECRET", ""),    host: env("PUSHER_HOST", "https://api-mt1.pusher.com"),    timeout_ms: 5000,}// An order shipped: the shop's private channel and the public news feed hear it.route GET /trigger = {    sent: pusher_trigger(app, ["private-orders", "news"], "order-shipped", { order: 1001, carrier: "DHL" }, { info: "subscription_count" })?,}route GET /batch = {    sent: pusher_trigger_batch(app, [        { channel: "private-orders", name: "order-paid", data: { order: 1002 } },        { channel: "presence-lobby", name: "announcement", data: "Doors open at 9" },    ])?,}route GET /channels = {    presence: pusher_channels(app, { prefix: "presence-", info: "user_count" })?.channels,    lobby: pusher_channel(app, "presence-lobby", ["user_count", "subscription_count"])?,    users: pusher_users(app, "presence-lobby")?,    not_presence: pusher_channel(app, "news", "user_count").error,}// What pusher-js posts here (socket_id and channel_name) is answered with a signature, once the// visitor is known to be allowed on that channel.route POST /pusher/auth {    let f = request.json ?? request.form    if f.socket_id == null || f.channel_name == null { reply 400 "send socket_id and channel_name" }    let user = { user_id: "7", user_info: { name: "Ada" } }    pusher_auth(app, f.socket_id, f.channel_name, user)?}// Pusher's own examples (key 278d425bdf160c739803, secret 7ad3773142a6692b25b8): the plugin's// signatures must come out as the documentation's.let docs = { app_id: "3", key: "278d425bdf160c739803", secret: "7ad3773142a6692b25b8", host: "api.pusherapp.com" }route GET /auth = {    private: pusher_auth(docs, "1234.1234", "private-foobar", null)?.auth,    presence: pusher_auth(docs, "1234.1234", "presence-foobar", { user_id: 10, user_info: { name: "Mr. Channels" } })?,    rest: pusher_sign(docs, "POST", "/apps/3/events", {}, "{\"name\":\"foo\",\"channels\":[\"project-3\"],\"data\":\"{\\\"some\\\":\\\"data\\\"}\"}", 1353088179)?,    public: pusher_auth(docs, "1234.1234", "news", null).error,}// Webhooks: believed only when signed with the app's secret.route POST /pusher/webhook {    let hook = pusher_webhook(app, request.headers, request.body)    if is_err(hook) { reply 401 hook.error }    { got: len(hook.events) }}// The check above, on a body signed here, and on the same body changed after signing.route GET /webhook-check {    let body = json.stringify({ time_ms: 1730000000000, events: [{ name: "channel_occupied", channel: "private-orders" }] })    let headers = { "x-pusher-key": app.key, "x-pusher-signature": pusher_webhook_sign(app, body)? }    {        good: pusher_webhook(app, headers, body)?.events,        tampered: pusher_webhook(app, headers, body + " ").error,    }}

//! Pusher Channels (and Soketi, which speaks the same HTTP API) from the server: events triggered on channels with the signed request Pusher wants, batches, channel and presence user queries, the private and presence channel signatures a browser asks for, and webhook signatures checked.//! version: 1.0.0//!//! [dependencies]//! ureq = "2"//! hmac = "0.12"//! sha2 = "0.10"//! md-5 = "0.10"//! hex = "0.4"use hmac::{Hmac, Mac};use md5::{Digest, Md5};use serde_json::{json, Value};use std::time::{Duration, SystemTime, UNIX_EPOCH};// `app` is a map: { app_id, key, secret, host, timeout_ms }. `host` is the API's address: a URL// (https://api-eu.pusher.com, http://127.0.0.1:6001 for Soketi) or a bare host name, or give// `cluster` (eu, mt1, us2, ap1, ...) for Pusher's own api-<cluster>.pusher.com.struct App {    id: String,    key: String,    secret: String,    base: String,    timeout: Duration,}fn s(o: &Value, k: &str) -> Option<String> {    match o.get(k) {        Some(Value::String(s)) if !s.is_empty() => Some(s.clone()),        Some(Value::Number(n)) => Some(n.to_string()),        _ => None,    }}fn app_of(app: &Value) -> Result<App, String> {    if !app.is_object() {        return Err("the app must be a map: { app_id, key, secret, host or cluster }".into());    }    for k in app.as_object().into_iter().flat_map(|m| m.keys()) {        if !["app_id", "key", "secret", "host", "cluster", "timeout_ms"].contains(&k.as_str()) {            return Err(format!("the app has no setting `{}`; it takes app_id, key, secret, host, cluster, timeout_ms", k));        }    }    let need = |k: &str| s(app, k).ok_or(format!("the app needs `{}` (from the Pusher dashboard's App Keys)", k));    let host = match (s(app, "host"), s(app, "cluster")) {        (Some(h), _) => h,        (None, Some(c)) => format!("api-{}.pusher.com", c),        (None, None) => return Err("give the app a `host` (a URL, like https://api-eu.pusher.com) or a `cluster` (like eu)".into()),    };    let base = if host.starts_with("http://") || host.starts_with("https://") { host.trim_end_matches('/').to_string() } else { format!("https://{}", host.trim_end_matches('/')) };    let timeout = Duration::from_millis(app.get("timeout_ms").and_then(|v| v.as_i64()).unwrap_or(10_000).clamp(100, 120_000) as u64);    Ok(App { id: need("app_id")?, key: need("key")?, secret: need("secret")?, base, timeout })}fn hmac_hex(secret: &str, text: &str) -> String {    let mut m = Hmac::<sha2::Sha256>::new_from_slice(secret.as_bytes()).expect("HMAC takes any key");    m.update(text.as_bytes());    hex::encode(m.finalize().into_bytes())}fn enc(s: &str) -> String {    let mut o = String::new();    for b in s.bytes() {        if b.is_ascii_alphanumeric() || b"-_.~,".contains(&b) {            o.push(b as char);        } else {            o.push_str(&format!("%{:02X}", b));        }    }    o}/// The query string Pusher's signature covers: parameters sorted by key (lowercase), `key=value` joined by `&`, then auth_signature.fn signed_query(a: &App, method: &str, path: &str, params: &[(String, String)], body: &str, ts: u64) -> String {    let mut p: Vec<(String, String)> = params.iter().map(|(k, v)| (k.to_lowercase(), v.clone())).collect();    p.push(("auth_key".into(), a.key.clone()));    p.push(("auth_timestamp".into(), ts.to_string()));    p.push(("auth_version".into(), "1.0".into()));    if !body.is_empty() {        p.push(("body_md5".into(), hex::encode(Md5::digest(body.as_bytes()))));    }    p.sort();    let plain = p.iter().map(|(k, v)| format!("{}={}", k, v)).collect::<Vec<_>>().join("&");    let sig = hmac_hex(&a.secret, &format!("{}\n{}\n{}", method, path, plain));    let encoded = p.iter().map(|(k, v)| format!("{}={}", k, enc(v))).collect::<Vec<_>>().join("&");    format!("{}&auth_signature={}", encoded, sig)}fn now_s() -> u64 {    SystemTime::now().duration_since(UNIX_EPOCH).map(|d| d.as_secs()).unwrap_or(0)}fn call(a: &App, method: &str, path: &str, params: &[(String, String)], body: Option<&Value>) -> Result<Value, String> {    let text = body.map(|b| b.to_string()).unwrap_or_default();    let q = signed_query(a, method, path, params, &text, now_s());    let url = format!("{}{}?{}", a.base, path, q);    let agent = ureq::AgentBuilder::new().timeout(a.timeout).build();    let req = agent.request(method, &url);    let r = if body.is_some() { req.set("Content-Type", "application/json").send_string(&text) } else { req.call() };    match r {        Ok(resp) => {            let t = resp.into_string().map_err(|e| e.to_string())?;            if t.trim().is_empty() {                return Ok(json!({}));            }            serde_json::from_str(&t).map_err(|_| format!("Pusher's answer is not JSON: {:?}", t.chars().take(200).collect::<String>()))        }        Err(ureq::Error::Status(code, resp)) => {            let t = resp.into_string().unwrap_or_default();            let hint = match code {                401 => " (check the app's key and secret, and the server's clock)",                403 => " (the app is disabled, or over its message quota)",                404 => " (check app_id and the host)",                413 => " (an event's data is at most 10 KB)",                _ => "",            };            Err(format!("Pusher answered {}: {}{}", code, t.trim(), hint))        }        Err(e) => Err(format!("cannot reach Pusher at {}: {}", a.base, e)),    }}fn valid_channel(c: &str) -> Result<(), String> {    if c.is_empty() || c.len() > 200 || !c.chars().all(|ch| ch.is_ascii_alphanumeric() || "-_=@,.;".contains(ch)) {        return Err(format!("{:?} is not a Pusher channel name: up to 200 of a-z, A-Z, 0-9 and - _ = @ , . ;", c));    }    Ok(())}fn valid_socket(id: &str) -> Result<(), String> {    let ok = id.split_once('.').map(|(a, b)| !a.is_empty() && !b.is_empty() && a.bytes().all(|c| c.is_ascii_digit()) && b.bytes().all(|c| c.is_ascii_digit())).unwrap_or(false);    if ok { Ok(()) } else { Err(format!("{:?} is not a socket id (it looks like 1234.5678, from the browser's pusher.connection.socket_id)", id)) }}fn data_text(d: &Value) -> String {    match d {        Value::String(s) => s.clone(),        other => other.to_string(),    }}fn info_param(v: &Value) -> Result<Option<String>, String> {    match v {        Value::Null => Ok(None),        Value::String(s) if s.is_empty() => Ok(None),        Value::String(s) => Ok(Some(s.clone())),        Value::Array(a) => Ok(Some(a.iter().map(|x| x.as_str().map(|s| s.to_string()).ok_or("info must be texts, like [\"user_count\"]")).collect::<Result<Vec<_>, _>>()?.join(","))),        _ => Err("info must be a text or a list, like [\"user_count\", \"subscription_count\"]".into()),    }}/// Triggers `event` on `channels` (one name or a list of up to 100) with `data` (text, or anything else as JSON, at most 10 KB); options: socket_id (leave that browser out), info ("subscription_count", "user_count"). Gives Pusher's answer ({} or { channels }).pub fn pusher_trigger(app: serde_json::Value, channels: serde_json::Value, event: &str, data: serde_json::Value, options: serde_json::Value) -> Result<serde_json::Value, String> {    let a = app_of(&app)?;    let chans: Vec<String> = match &channels {        Value::String(c) => vec![c.clone()],        Value::Array(l) => l.iter().map(|x| x.as_str().map(|s| s.to_string()).ok_or("channels must be texts".to_string())).collect::<Result<_, _>>()?,        _ => return Err("channels must be a channel name or a list of them".into()),    };    if chans.is_empty() || chans.len() > 100 {        return Err(format!("an event goes to 1 to 100 channels, not {}", chans.len()));    }    for c in &chans {        valid_channel(c)?;    }    if event.is_empty() || event.len() > 200 {        return Err("an event name is 1 to 200 characters".into());    }    let text = data_text(&data);    if text.len() > 10_240 {        return Err(format!("the event's data is {} bytes; Pusher takes at most 10240", text.len()));    }    let mut body = json!({ "name": event, "data": text, "channels": chans });    if let Some(sid) = s(&options, "socket_id") {        valid_socket(&sid)?;        body["socket_id"] = json!(sid);    }    if let Some(i) = info_param(options.get("info").unwrap_or(&Value::Null))? {        body["info"] = json!(i);    }    call(&a, "POST", &format!("/apps/{}/events", a.id), &[], Some(&body))}/// Triggers up to 10 events in one request: each { channel, name, data, socket_id, info }.pub fn pusher_trigger_batch(app: serde_json::Value, events: Vec<serde_json::Value>) -> Result<serde_json::Value, String> {    let a = app_of(&app)?;    if events.is_empty() || events.len() > 10 {        return Err(format!("a batch holds 1 to 10 events, not {}", events.len()));    }    let mut batch = vec![];    for e in &events {        let ch = s(e, "channel").ok_or("each event needs a `channel`")?;        valid_channel(&ch)?;        let name = s(e, "name").ok_or("each event needs a `name`")?;        let text = data_text(e.get("data").unwrap_or(&Value::Null));        if text.len() > 10_240 {            return Err(format!("an event's data is {} bytes; Pusher takes at most 10240", text.len()));        }        let mut b = json!({ "channel": ch, "name": name, "data": text });        if let Some(sid) = s(e, "socket_id") {            valid_socket(&sid)?;            b["socket_id"] = json!(sid);        }        if let Some(i) = info_param(e.get("info").unwrap_or(&Value::Null))? {            b["info"] = json!(i);        }        batch.push(b);    }    call(&a, "POST", &format!("/apps/{}/batch_events", a.id), &[], Some(&json!({ "batch": batch })))}/// The channels with someone on them; options: prefix (like "presence-"), info ("user_count", for presence channels). Gives { channels: { name: {...} } }.pub fn pusher_channels(app: serde_json::Value, options: serde_json::Value) -> Result<serde_json::Value, String> {    let a = app_of(&app)?;    let mut p = vec![];    if let Some(pre) = s(&options, "prefix") {        p.push(("filter_by_prefix".to_string(), pre));    }    if let Some(i) = info_param(options.get("info").unwrap_or(&Value::Null))? {        p.push(("info".to_string(), i));    }    call(&a, "GET", &format!("/apps/{}/channels", a.id), &p, None)}/// One channel: { occupied, user_count (presence), subscription_count } as asked in `info` ("user_count", "subscription_count", or a list).pub fn pusher_channel(app: serde_json::Value, channel: &str, info: serde_json::Value) -> Result<serde_json::Value, String> {    valid_channel(channel)?;    let a = app_of(&app)?;    let mut p = vec![];    if let Some(i) = info_param(&info)? {        p.push(("info".to_string(), i));    }    call(&a, "GET", &format!("/apps/{}/channels/{}", a.id, channel), &p, None)}/// The ids of the users on a presence channel.pub fn pusher_users(app: serde_json::Value, channel: &str) -> Result<Vec<String>, String> {    valid_channel(channel)?;    if !channel.starts_with("presence-") {        return Err(format!("{} is not a presence channel: only presence- channels have users", channel));    }    let a = app_of(&app)?;    let r = call(&a, "GET", &format!("/apps/{}/channels/{}/users", a.id, channel), &[], None)?;    Ok(r.get("users").and_then(|u| u.as_array()).map(|l| l.iter().filter_map(|u| u.get("id").map(|i| data_text(i))).collect()).unwrap_or_default())}/// Disconnects every connection of a signed-in user (`user_id`, from pusher_user_auth).pub fn pusher_terminate(app: serde_json::Value, user_id: &str) -> Result<serde_json::Value, String> {    if user_id.is_empty() || user_id.len() > 200 {        return Err("a user id is 1 to 200 characters".into());    }    let a = app_of(&app)?;    call(&a, "POST", &format!("/apps/{}/users/{}/terminate_connections", a.id, enc(user_id)), &[], Some(&json!({})))}/// The answer to the browser's auth request for a private or presence channel: { auth } for private-, { auth, channel_data } for presence- with `user` ({ user_id, user_info }; null for a private channel). Check first that this visitor may join it.pub fn pusher_auth(app: serde_json::Value, socket_id: &str, channel: &str, user: serde_json::Value) -> Result<serde_json::Value, String> {    let a = app_of(&app)?;    valid_socket(socket_id)?;    valid_channel(channel)?;    if channel.starts_with("presence-") {        // The user id stays as given, text or number, as the browser's members list shows it.        let uid = match user.get("user_id") {            Some(Value::String(u)) if !u.is_empty() => json!(u),            Some(Value::Number(n)) => json!(n),            _ => return Err("a presence channel needs the user: { user_id, user_info }, user_id a text or a number".into()),        };        let mut cd = json!({ "user_id": uid });        if let Some(info) = user.get("user_info") {            cd["user_info"] = info.clone();        }        let channel_data = cd.to_string();        let sig = hmac_hex(&a.secret, &format!("{}:{}:{}", socket_id, channel, channel_data));        Ok(json!({ "auth": format!("{}:{}", a.key, sig), "channel_data": channel_data }))    } else if channel.starts_with("private-") {        if channel.starts_with("private-encrypted-") {            return Err("encrypted channels need a shared secret per channel, which this plugin does not make".into());        }        let sig = hmac_hex(&a.secret, &format!("{}:{}", socket_id, channel));        Ok(json!({ "auth": format!("{}:{}", a.key, sig) }))    } else {        Err(format!("{} is a public channel: it needs no auth (private- and presence- channels do)", channel))    }}/// The answer to the browser's user sign-in (pusher.signin()): { auth, user_data } for `user` ({ id, user_info, watchlist }).pub fn pusher_user_auth(app: serde_json::Value, socket_id: &str, user: serde_json::Value) -> Result<serde_json::Value, String> {    let a = app_of(&app)?;    valid_socket(socket_id)?;    let id = user.get("id").map(data_text).filter(|u| !u.is_empty()).ok_or("the user needs an `id`")?;    let mut u = user.as_object().cloned().unwrap_or_default();    u.insert("id".into(), json!(id));    let user_data = Value::Object(u).to_string();    let sig = hmac_hex(&a.secret, &format!("{}::user::{}", socket_id, user_data));    Ok(json!({ "auth": format!("{}:{}", a.key, sig), "user_data": user_data }))}/// Checks a webhook from Pusher: `headers` are the request's (x-pusher-key and x-pusher-signature, the HMAC-SHA256 of `body` with the app's secret). Gives { time_ms, events }, or an error when it was not signed by this app.pub fn pusher_webhook(app: serde_json::Value, headers: std::collections::HashMap<String, serde_json::Value>, body: &str) -> Result<serde_json::Value, String> {    let a = app_of(&app)?;    let h = |k: &str| headers.iter().find(|(n, _)| n.eq_ignore_ascii_case(k)).map(|(_, v)| data_text(v));    let key = h("x-pusher-key").ok_or("no X-Pusher-Key header: this did not come from Pusher")?;    if key != a.key {        return Err(format!("the webhook is for app key {}, not this app's", key));    }    let sig = h("x-pusher-signature").ok_or("no X-Pusher-Signature header")?;    let want = hmac_hex(&a.secret, body);    // Compared in constant time.    let same = want.len() == sig.len() && want.bytes().zip(sig.to_ascii_lowercase().bytes()).fold(0u8, |acc, (x, y)| acc | (x ^ y)) == 0;    if !same {        return Err("the webhook's signature does not match: it was not signed with this app's secret".into());    }    let v: Value = serde_json::from_str(body).map_err(|e| format!("the webhook's body is not JSON: {}", e))?;    Ok(json!({ "time_ms": v.get("time_ms").cloned().unwrap_or(Value::Null), "events": v.get("events").cloned().unwrap_or(json!([])) }))}/// Signs a webhook body as Pusher does, for tests: the X-Pusher-Signature value.pub fn pusher_webhook_sign(app: serde_json::Value, body: &str) -> Result<String, String> {    let a = app_of(&app)?;    Ok(hmac_hex(&a.secret, body))}/// The signed query string for any other Pusher API call (`method`, `path` like /apps/123/channels, `params`, `body` text or ""), for a timestamp `ts` (0: now).pub fn pusher_sign(app: serde_json::Value, method: &str, path: &str, params: std::collections::HashMap<String, String>, body: &str, ts: i64) -> Result<String, String> {    let a = app_of(&app)?;    let mut p: Vec<(String, String)> = params.into_iter().collect();    p.sort();    Ok(signed_query(&a, &method.to_uppercase(), path, &p, body, if ts > 0 { ts as u64 } else { now_s() }))}