Adds server implementation

Package.swift

@@ -30,10 +30,23 @@ let package = Package(
                 "HaystackClientNIO"
             ]
         ),
+        .library(
+            name: "HaystackServer",
+            targets: [
+                "HaystackServer"
+            ]
+        ),
+        .library(
+            name: "HaystackServerVapor",
+            targets: [
+                "HaystackServerVapor"
+            ]
+        ),
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-crypto.git", "1.0.0" ..< "3.0.0"),
-        .package(url: "https://github.com/swift-server/async-http-client.git", from: "1.9.0")
+        .package(url: "https://github.com/swift-server/async-http-client.git", from: "1.9.0"),
+        .package(url: "https://github.com/vapor/vapor.git", from: "4.0.0"),
     ],
     targets: [
         .target(
@@ -62,7 +75,21 @@ let package = Package(
                 .product(name: "AsyncHTTPClient", package: "async-http-client"),
             ]
         ),
-
+        .target(
+            name: "HaystackServer",
+            dependencies: [
+                "Haystack",
+            ]
+        ),
+        .target(
+            name: "HaystackServerVapor",
+            dependencies: [
+                "Haystack",
+                "HaystackServer",
+                .product(name: "Vapor", package: "vapor")
+            ]
+        ),
+
         // Tests
         .testTarget(
             name: "HaystackTests",
@@ -80,6 +107,14 @@ let package = Package(
             name: "HaystackClientDarwinIntegrationTests",
             dependencies: ["HaystackClientDarwin"]
         ),
+        .testTarget(
+            name: "HaystackServerTests",
+            dependencies: ["HaystackServer"]
+        ),
+        .testTarget(
+            name: "HaystackServerVaporTests",
+            dependencies: ["HaystackServerVapor", .product(name: "XCTVapor", package: "vapor")]
+        ),
     ]
 )
 #else
@@ -97,10 +132,23 @@ let package = Package(
                 "HaystackClientNIO"
             ]
         ),
+        .library(
+            name: "HaystackServer",
+            targets: [
+                "HaystackServer"
+            ]
+        ),
+        .library(
+            name: "HaystackServerVapor",
+            targets: [
+                "HaystackServerVapor"
+            ]
+        ),
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-crypto.git", "1.0.0" ..< "3.0.0"),
-        .package(url: "https://github.com/swift-server/async-http-client.git", from: "1.9.0")
+        .package(url: "https://github.com/swift-server/async-http-client.git", from: "1.9.0"),
+        .package(url: "https://github.com/vapor/vapor.git", from: "4.0.0"),
     ],
     targets: [
         .target(
@@ -122,7 +170,21 @@ let package = Package(
                 .product(name: "AsyncHTTPClient", package: "async-http-client"),
             ]
         ),
-
+        .target(
+            name: "HaystackServer",
+            dependencies: [
+                "Haystack"
+            ]
+        ),
+        .target(
+            name: "HaystackServerVapor",
+            dependencies: [
+                "Haystack",
+                "HaystackServer",
+                .product(name: "Vapor", package: "vapor")
+            ]
+        ),
+
         // Tests
         .testTarget(
             name: "HaystackTests",
@@ -136,6 +198,14 @@ let package = Package(
             name: "HaystackClientNIOIntegrationTests",
             dependencies: ["HaystackClientNIO"]
         ),
+        .testTarget(
+            name: "HaystackServerTests",
+            dependencies: ["HaystackServer"]
+        ),
+        .testTarget(
+            name: "HaystackServerVaporTests",
+            dependencies: ["HaystackServerVapor", .product(name: "XCTVapor", package: "vapor")]
+        ),
     ]
 )
-#endif
+#endif

README.md

@@ -43,7 +43,7 @@ See below for available libraries and descriptions.
 
 ### Haystack
 
-This contains the 
+This contains the
 [Haystack type-system primitives](https://project-haystack.org/doc/docHaystack/Kinds)
 and utilities to interact with them.
 
@@ -101,20 +101,55 @@ Once you create a client, you can use it to make requests:
 ```swift
 func yesterdaysValues() async throws -> Grid {
     let client = ...
-    
+
     // Open and authenticate. This must be called before requests can be made
     try await client.open()
-    
+
     // Request the historical values for @28e7fb7d-e20316e0
     let grid = try await client.hisRead(id: Ref("28e7fb7d-e20316e0"), range: .yesterday)
-    
+
     // Close the client session and log out
     try await client.close()
-    
+
     return grid
 }
 ```
 
+### HaystackServerVapor
+
+A server for the [Haystack HTTP API](https://project-haystack.org/doc/docHaystack/HttpApi) that uses
+[Vapor](https://github.com/vapor/vapor). It's separated from the `HaystackServer` package so that clients may use
+alternative server technologies if they choose, including Hummingbird or NIO directly.
+
+It exposes a `HaystackRouteCollection` that can be registered on a Vapor
+application:
+
+```swift
+let app = Application()
+try app.register(collection: HaystackRouteCollection(delegate: ...))
+```
+
+The delegate is a protocol that can be implemented however the user sees fit, although the standard Haystack
+implementation is defined in `HaystackServer`.
+
+### HaystackServer
+
+This defines the standard functionality and data processing of Haystack API servers, based on generic backing data
+stores. In most cases, Haystack servers should use the `HaystackServer` class and customize storage behavior by
+implementing the `RecordStore`, `HistoryStore`, and `WatchStore` protocols.
+
+```swift
+struct InfluxHistoryStore: HistoryStore {
+    // Define storage behavior here
+    ...
+}
+
+let server = HaystackServer(
+    historyStore: InfluxHistoryStore(),
+    ...
+)
+```
+
 ## License
 
 This package is licensed under the Academic Free License 3.0 for maximum compatibility with