Implement Vapor.Client conformance for URLSession and use a client ba…

…sed on that throughout OneRoster (due to incompatibilities between certain OneRoster servers and AHC's stricter standards compliance). (#8)

Sources/OneRoster/Client/Application+OneRosterClient.swift

@@ -27,7 +27,7 @@ extension Application {
     ///   missing, it will be added for all OneRoster requests. **However**, if the suffix _is_ provided, it is stripped
     ///   for requests relating to authorization, such as OAuth 2 token grant requests.
     public func oneRoster(baseUrl: URL) -> OneRosterClient {
-        return OneRosterClient(baseUrl: baseUrl, client: self.client, logger: self.logger)
+        return OneRosterClient(baseUrl: baseUrl, client: self.sharedUrlSessionClient, logger: self.logger)
     }
 
     /// Get a `OneRosterClient` suitable for making OneRoster requests to the given base URL using OAuth1 authentication

Sources/OneRoster/Client/OAuth1.swift

@@ -224,28 +224,27 @@ extension MessageAuthenticationCode {
 extension Application {
     /// Get an `OAuth1Client` suitable for automatically calculating an OAuth 1 signature for each request.
     ///
-    /// Uses the application's default `Client` and `Logger`.
+    /// Uses the application's shared `URLSesssion` client and default `Logger`.
     ///
     /// - Parameters:
     ///   - parameters: A set of OAuth 1 parameters containing the neceessary information (including sensitive
     ///     credentials such as a client secret) for signing requests. Credentials are retained in memory for
     ///     the lifetime of the client, due to the need to reuse them for each request.
     public func oauth1(parameters: OAuth1.Parameters) -> OAuth1.Client {
-        OAuth1.Client(client: self.client, logger: self.logger, parameters: parameters)
+        OAuth1.Client(client: self.sharedUrlSessionClient, logger: self.logger, parameters: parameters)
     }
 }
 
 extension Request {
     /// Get an `OAuth1Client` suitable for automatically calculating an OAuth 1 signature for each request.
     ///
-    /// Uses the request's default `Client` and `Logger`.
+    /// Uses the request's shared `URLSesssion` client and default `Logger`.
     ///
     /// - Parameters:
-    /// - Parameters:
     ///   - parameters: A set of OAuth 1 parameters containing the neceessary information (including sensitive
     ///     credentials such as a client secret) for signing requests. Credentials are retained in memory for
     ///     the lifetime of the client, due to the need to reuse them for each request.
     public func oauth1(parameters: OAuth1.Parameters) -> OAuth1.Client {
-        OAuth1.Client(client: self.client, logger: self.logger, parameters: parameters)
+        OAuth1.Client(client: self.sharedUrlSessionClient, logger: self.logger, parameters: parameters)
     }
 }

Sources/OneRoster/Client/OAuth2.swift

@@ -256,7 +256,7 @@ public enum OAuth2 {
 extension Application {
     /// Get an `OAuth2Client` suitable for automatically obtaining access tokens as needed to fulfill each request.
     ///
-    /// Uses the application's default `Client` and `Logger`.
+    /// Uses the application's shared `URLSesssion` client and default `Logger`.
     ///
     /// - Parameters:
     ///   - parameters: A closure which returns a future whose value is a set of OAuth 2 parameters containing the
@@ -265,14 +265,14 @@ extension Application {
     ///     as long as required to make a request for an access token. The closure may return `nil` to indicate that
     ///     the appropriate parameters are no longer available.
     public func oauth2(parameters: @escaping (OAuth2.Client) -> EventLoopFuture<OAuth2.Parameters?>) -> OAuth2.Client {
-        OAuth2.Client(client: self.client, logger: self.logger, parametersCallback: parameters)
+        OAuth2.Client(client: self.sharedUrlSessionClient, logger: self.logger, parametersCallback: parameters)
     }
 }
 
 extension Request {
     /// Get an `OAuth2Client` suitable for automatically obtaining access tokens as needed to fulfill each request.
     ///
-    /// Uses the request's default `Client` and `Logger`.
+    /// Uses the request's shared `URLSesssion` client and default `Logger`.
     ///
     /// - Parameters:
     ///   - parameters: A closure which returns a future whose value is a set of OAuth 2 parameters containing the
@@ -281,6 +281,6 @@ extension Request {
     ///     as long as required to make a request for an access token. The closure may return `nil` to indicate that
     ///     the appropriate parameters are no longer available.
     public func oauth2(parameters: @escaping (OAuth2.Client) -> EventLoopFuture<OAuth2.Parameters?>) -> OAuth2.Client {
-        OAuth2.Client(client: self.client, logger: self.logger, parametersCallback: parameters)
+        OAuth2.Client(client: self.sharedUrlSessionClient, logger: self.logger, parametersCallback: parameters)
     }
 }

Sources/OneRoster/Client/Request+OneRosterClient.swift

@@ -18,7 +18,7 @@ import Vapor
 extension Request {
     /// Get a `OneRosterClient` suitable for making OneRoster requests to the given base URL without authentication.
     ///
-    /// Uses the request's default `Client` and `Logger`.
+    /// Uses the request's shared `URLSesssion` client and default `Logger`.
     ///
     /// - Important: The base URL is allowed to be either a true "base" (the root to which the OneRoster RESTful path
     ///   and version should be appended, i.e. <https://example.com/oneroster>) or the RESTful base (e.g.
@@ -27,7 +27,7 @@ extension Request {
     ///   missing, it will be added for all OneRoster requests. **However**, if the suffix _is_ provided, it is stripped
     ///   for requests relating to authorization, such as OAuth 2 token grant requests.
     public func oneRoster(baseUrl: URL) -> OneRosterClient {
-        return OneRosterClient(baseUrl: baseUrl, client: self.client, logger: self.logger)
+        return OneRosterClient(baseUrl: baseUrl, client: self.sharedUrlSessionClient, logger: self.logger)
     }
 
     /// Get a `OneRosterClient` suitable for making OneRoster requests to the given base URL using OAuth1 authentication

Sources/OneRoster/Client/URLSessionClient.swift

@@ -0,0 +1,81 @@
+import Vapor
+import NIOCore
+import Logging
+import Foundation
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+
+internal struct URLSessionClient: Vapor.Client {
+    let session: URLSession
+    let eventLoop: EventLoop
+    let logger: Logger
+
+    static func shared(on eventLoop: EventLoop, logger: Logger) -> Client {
+        URLSessionClient(session: .shared, eventLoop: eventLoop, logger: logger)
+    }
+
+    func delegating(to eventLoop: EventLoop) -> Client {
+        URLSessionClient(session: self.session, eventLoop: eventLoop, logger: self.logger)
+    }
+
+    func logging(to logger: Logger) -> Client {
+        URLSessionClient(session: self.session, eventLoop: self.eventLoop, logger: logger)
+    }
+
+    func send(_ request: ClientRequest) -> EventLoopFuture<ClientResponse> {
+        guard let foundationUrl = URL(string: request.url.string) else {
+            return self.eventLoop.makeFailedFuture(Abort(.internalServerError, reason: "Client request with invalid URL"))
+        }
+
+        var foundationRequest = URLRequest(url: foundationUrl)
+
+        request.headers.forEach { foundationRequest.addValue($1, forHTTPHeaderField: $0) }
+        foundationRequest.httpBody = request.body.map { Data($0.readableBytesView) }
+        foundationRequest.httpMethod = request.method.string
+        foundationRequest.cachePolicy = .reloadIgnoringLocalCacheData
+
+        let promise = self.eventLoop.makePromise(of: ClientResponse.self)
+
+        let dataTask = self.session.dataTask(with: foundationRequest, completionHandler: { data, response, error in
+            if let error = error {
+                return promise.fail(error)
+            }
+            guard let response = response as? HTTPURLResponse else {
+                return promise.fail(Abort(.internalServerError, reason: "Client received no error but wrong kind of response"))
+            }
+
+            let clientResponse = ClientResponse(
+                status: HTTPStatus(statusCode: response.statusCode),
+                headers: .init(response.allHeaderFields.compactMapValues { $0 as? String }.compactMap { k, v in (k.base as? String).map { ($0, v) } }),
+                body: data.map { .init(data: $0) }
+            )
+            return promise.succeed(clientResponse)
+        })
+
+        dataTask.resume()
+        return promise.futureResult
+    }
+}
+
+extension Application.Clients.Provider {
+    public static var sharedUrlSession: Self {
+        .init {
+            $0.clients.use {
+                URLSessionClient.shared(on: $0.eventLoopGroup.any(), logger: $0.logger)
+            }
+        }
+    }
+}
+
+extension Application {
+    public var sharedUrlSessionClient: Client {
+        URLSessionClient.shared(on: self.eventLoopGroup.any(), logger: self.logger)
+    }
+}
+
+extension Request {
+    public var sharedUrlSessionClient: Client {
+        URLSessionClient.shared(on: self.eventLoop, logger: self.logger)
+    }
+}