feat: APNS Router (#201)

* Start working on the APNS router

* Use a fork of a2 temporarily to support our use case

Changes made in the fork:
1. Support creating a client with the raw cert and key data (no
   password).
2. Impl Deserialize for the APS struct (and sub-structs)

Also improved error handling during APNS router creation, and started on
the router impl.

* Implement the APNS router happy path

* Handle APNS errors

* Switch to the "autoendpoint" branch of the a2 fork

This branch contains all of the changes made in the fork.

* Implement Router::register for ApnsRouter

* Remove old TooMuchData error

* Abstract the a2 client behind a trait and add a bunch of APNS tests

* Convert float values in APS data from DynamoDb into integers

Also, if the user has invalid APS data in the DB, an error is returned
during routing.

* Remove redundant APNS metric

* Give APNS an expiration timestamp when routing notifications

* Check the final APNS payload against the size limit

* Drop the user if APNS says they are unregistered

* Add some details about the a2 fork

Closes #164

autoendpoint/Cargo.toml

@@ -5,6 +5,13 @@ authors = ["Mark Drobnak <[email protected]>", "jrconlin <[email protected]
 edition = "2018"
 
 [dependencies]
+# Using a fork temporarily until these three PRs are merged:
+# - https://github.com/pimeys/a2/pull/49
+# - https://github.com/pimeys/a2/pull/48
+# - https://github.com/pimeys/a2/pull/47
+# The `autoendpoint` branch merges these three PRs together.
+# The version of a2 at the time of the fork is v0.5.3.
+a2 = { git = "https://github.com/Mcat12/a2.git", branch = "autoendpoint" }
 actix-web = "2.0"
 actix-rt = "1.0"
 actix-cors = "0.2.0"
@@ -38,6 +45,7 @@ slog-mozlog-json = "0.1"
 slog-scope = "4.3"
 slog-stdlog = "4.0"
 slog-term = "2.5"
+tokio = { version = "0.2", features = ["fs"] }
 thiserror = "1.0"
 url = "2.1"
 uuid = { version = "0.8.1", features = ["serde", "v4"] }
@@ -49,4 +57,4 @@ yup-oauth2 = "4.1.2"
 mockall = "0.7.1"
 mockito = "0.26.0"
 tempfile = "3.1.0"
-tokio = { version = "0.2.12", features = ["macros"] }
+tokio = { version = "0.2", features = ["macros"] }

autoendpoint/src/extractors/router_data_input.rs

@@ -7,7 +7,6 @@ use futures::future::LocalBoxFuture;
 use futures::FutureExt;
 use lazy_static::lazy_static;
 use regex::Regex;
-use std::collections::HashMap;
 use uuid::Uuid;
 
 lazy_static! {
@@ -24,7 +23,7 @@ pub struct RouterDataInput {
     #[serde(rename = "channelID")]
     pub channel_id: Option<Uuid>,
     pub key: Option<String>,
-    pub aps: Option<HashMap<String, serde_json::Value>>,
+    pub aps: Option<serde_json::Value>,
 }
 
 impl FromRequest for RouterDataInput {

autoendpoint/src/extractors/routers.rs

@@ -1,3 +1,4 @@
+use crate::routers::apns::router::ApnsRouter;
 use crate::routers::fcm::router::FcmRouter;
 use crate::routers::webpush::WebPushRouter;
 use crate::routers::Router;
@@ -49,6 +50,7 @@ impl Display for RouterType {
 pub struct Routers {
     webpush: WebPushRouter,
     fcm: Arc<FcmRouter>,
+    apns: Arc<ApnsRouter>,
 }
 
 impl FromRequest for Routers {
@@ -69,6 +71,7 @@ impl FromRequest for Routers {
                 endpoint_url: state.settings.endpoint_url.clone(),
             },
             fcm: state.fcm_router.clone(),
+            apns: state.apns_router.clone(),
         })
     }
 }
@@ -79,7 +82,7 @@ impl Routers {
         match router_type {
             RouterType::WebPush => &self.webpush,
             RouterType::FCM => self.fcm.as_ref(),
-            RouterType::APNS => unimplemented!(),
+            RouterType::APNS => self.apns.as_ref(),
             RouterType::ADM => unimplemented!(),
         }
     }

autoendpoint/src/routers/apns/error.rs

@@ -0,0 +1,82 @@
+use crate::error::ApiErrorKind;
+use crate::routers::RouterError;
+use actix_web::http::StatusCode;
+use std::io;
+
+/// Errors that may occur in the Apple Push Notification Service router
+#[derive(thiserror::Error, Debug)]
+pub enum ApnsError {
+    #[error("Failed to decode the channel settings")]
+    ChannelSettingsDecode(#[from] serde_json::Error),
+
+    #[error("IO Error: {0}")]
+    Io(#[from] io::Error),
+
+    #[error("Error while setting up APNS clients: {0}")]
+    ApnsClient(#[source] a2::Error),
+
+    #[error("Error while checking the message size limit: {0}")]
+    SizeLimit(#[source] a2::Error),
+
+    #[error("APNS error, {0}")]
+    ApnsUpstream(#[source] a2::Error),
+
+    #[error("No device token found for user")]
+    NoDeviceToken,
+
+    #[error("No release channel found for user")]
+    NoReleaseChannel,
+
+    #[error("Release channel is invalid")]
+    InvalidReleaseChannel,
+
+    #[error("Invalid APS data")]
+    InvalidApsData,
+
+    #[error("APNS recipient no longer available")]
+    Unregistered,
+}
+
+impl ApnsError {
+    /// Get the associated HTTP status code
+    pub fn status(&self) -> StatusCode {
+        match self {
+            ApnsError::InvalidReleaseChannel
+            | ApnsError::InvalidApsData
+            | ApnsError::SizeLimit(_) => StatusCode::BAD_REQUEST,
+
+            ApnsError::NoDeviceToken | ApnsError::NoReleaseChannel | ApnsError::Unregistered => {
+                StatusCode::GONE
+            }
+
+            ApnsError::ChannelSettingsDecode(_) | ApnsError::Io(_) | ApnsError::ApnsClient(_) => {
+                StatusCode::INTERNAL_SERVER_ERROR
+            }
+
+            ApnsError::ApnsUpstream(_) => StatusCode::BAD_GATEWAY,
+        }
+    }
+
+    /// Get the associated error number
+    pub fn errno(&self) -> Option<usize> {
+        match self {
+            ApnsError::NoDeviceToken | ApnsError::NoReleaseChannel | ApnsError::Unregistered => {
+                Some(106)
+            }
+
+            ApnsError::ChannelSettingsDecode(_)
+            | ApnsError::Io(_)
+            | ApnsError::ApnsClient(_)
+            | ApnsError::ApnsUpstream(_)
+            | ApnsError::InvalidReleaseChannel
+            | ApnsError::InvalidApsData
+            | ApnsError::SizeLimit(_) => None,
+        }
+    }
+}
+
+impl From<ApnsError> for ApiErrorKind {
+    fn from(e: ApnsError) -> Self {
+        ApiErrorKind::Router(RouterError::Apns(e))
+    }
+}

autoendpoint/src/routers/apns/mod.rs

@@ -0,0 +1,5 @@
+//! A notification router for Apple devices, using Apple Push Notification Service
+
+pub mod error;
+pub mod router;
+pub mod settings;