Improve header access

Sources/App/API/HeaderKey.swift

@@ -0,0 +1,41 @@
+import Foundation
+import Vapor
+
+enum HeaderKey: String {
+    case name
+    case password
+    case email
+    case token
+}
+
+extension Request {
+
+    /**
+     Get a header for a key, or abort with a `badRequest`.
+     */
+    func header(_ key: HeaderKey) throws -> String {
+        guard let value = headers.first(name: key.rawValue) else {
+            throw Abort(.badRequest)
+        }
+        return value
+    }
+
+    func optionalHeader(_ key: HeaderKey) -> String? {
+        headers.first(name: key.rawValue)
+    }
+
+    /**
+     Get the password from the request header and hash it.
+
+     Possible error responses:
+     - `400`: No password header found
+     - `424`: Failed to hash the password
+     */
+    func hashedPassword() throws -> String {
+        let password = try header(.password)
+        guard let hash = try? self.password.hash(password) else {
+            throw Abort(.failedDependency) // 424
+        }
+        return hash
+    }
+}

Sources/App/routes.swift

@@ -57,12 +57,11 @@ func registerPlayer(_ app: Application) {
 
         guard name.count < maximumPlayerNameLength,
               password.count < maximumPasswordLength else {
-                  throw Abort(.notAcceptable) // 406
-              }
-        
-        guard let hash = try? req.password.hash(password) else {
-            throw Abort(.failedDependency) // 424
+            throw Abort(.notAcceptable) // 406
         }
+        
+        let hash = try req.hashedPassword() // errors: 400, 424
+
         // Can throw conflict (409)
         return server.registerPlayer(named: name, hash: hash, in: req.db)
     }