Merge pull request #36 from natebird/2.0.0-beta2

Most of changes below are to make things consistent with the Vapor MySQL counterpart and to help support features in the PostgreSQL Driver.

Changes:

Rename connection parameter from host to hostname. This allows for supporting master and read replica in PostgreSQL Driver.
Rename connected boolean to isConnected.
Rename connection pointer to cConnection.
Rename error var to lastError.
Move all connection tests into the ConnectionTests file.
New:

Add Error class for better error messaging.
Add Context class with isPostgreSQL var.

Sources/PostgreSQL/Connection.swift

@@ -1,12 +1,14 @@
 import CPostgreSQL
 
+// This structure represents a handle to one database connection.
+// It is used for almost all PostgreSQL functions.
+// Do not try to make a copy of a PostgreSQL structure.
+// There is no guarantee that such a copy will be usable.
 public final class Connection: ConnInfoInitializable {
-    public typealias ConnectionPointer = OpaquePointer
+    public let cConnection: OpaquePointer
     public var configuration: Configuration?
-    private(set) var connection: ConnectionPointer!
-
-    public var connected: Bool {
-        if let connection = connection, PQstatus(connection) == CONNECTION_OK {
+    public var isConnected: Bool {
+        if PQstatus(cConnection) == CONNECTION_OK {
             return true
         }
         return false
@@ -20,13 +22,13 @@ public final class Connection: ConnInfoInitializable {
             string = info
         case .params(let params):
             string = params.map({ "\($0)='\($1)'" }).joined()
-        case .basic(let host, let port, let database, let user, let password):
-            string = "host='\(host)' port='\(port)' dbname='\(database)' user='\(user)' password='\(password)' client_encoding='UTF8'"
+        case .basic(let hostname, let port, let database, let user, let password):
+            string = "host='\(hostname)' port='\(port)' dbname='\(database)' user='\(user)' password='\(password)' client_encoding='UTF8'"
         }
 
-        self.connection = PQconnectdb(string)
-        if !self.connected {
-            throw DatabaseError.cannotEstablishConnection(error)
+        self.cConnection = PQconnectdb(string)
+        if isConnected == false {
+            throw DatabaseError.cannotEstablishConnection(lastError)
         }
     }
 
@@ -59,7 +61,7 @@ public final class Connection: ConnInfoInitializable {
         }
 
         let res: Result.Pointer = PQexecParams(
-            connection, query,
+            cConnection, query,
             Int32(values.count),
             types, paramValues.map {
                 UnsafePointer<Int8>($0)
@@ -84,35 +86,39 @@ public final class Connection: ConnInfoInitializable {
         }
     }
 
+    public func status() -> ConnStatusType {
+        return PQstatus(cConnection)
+    }
+
     public func reset() throws {
-        guard self.connected else {
-            throw DatabaseError.cannotEstablishConnection(error)
+        guard self.isConnected else {
+            throw PostgreSQLError(.connection_failure, reason: lastError)
         }
 
-        PQreset(connection)
+        PQreset(cConnection)
     }
 
     public func close() throws {
-        guard self.connected else {
-            throw DatabaseError.cannotEstablishConnection(error)
+        guard self.isConnected else {
+            throw PostgreSQLError(.connection_does_not_exist, reason: lastError)
         }
 
-        PQfinish(connection)
+        PQfinish(cConnection)
     }
 
-    public var error: String {
-        guard let s = PQerrorMessage(connection) else {
+    // Contains the last error message generated by the PostgreSQL connection.
+    public var lastError: String {
+        guard let errorMessage = PQerrorMessage(cConnection) else {
             return ""
         }
-        return String(cString: s)
+        return String(cString: errorMessage)
     }
 
     deinit {
         try? close()
     }
 
     // MARK: - Load Configuration
-
     private func getConfiguration() throws -> Configuration {
         if let configuration = self.configuration {
             return configuration
@@ -127,9 +133,20 @@ public final class Connection: ConnInfoInitializable {
     }
 
     private func getBooleanParameterStatus(key: String, `default` defaultValue: Bool = false) -> Bool {
-        guard let value = PQparameterStatus(connection, "integer_datetimes") else {
+        guard let value = PQparameterStatus(cConnection, "integer_datetimes") else {
             return defaultValue
         }
         return String(cString: value) == "on"
     }
 }
+
+extension Connection {
+    @discardableResult
+    public func execute(_ query: String, _ representable: [NodeRepresentable]) throws -> Node {
+        let values = try representable.map {
+            return try $0.makeNode(in: PostgreSQLContext.shared)
+        }
+
+        return try execute(query, values)
+    }
+}

Sources/PostgreSQL/ConnectionInfo.swift

@@ -3,7 +3,7 @@ import CPostgreSQL
 public enum ConnInfo {
     case raw(String)
     case params([String: String])
-    case basic(host: String, port: Int, database: String, user: String, password: String)
+    case basic(hostname: String, port: Int, database: String, user: String, password: String)
 }
 
 public protocol ConnInfoInitializable {
@@ -14,11 +14,11 @@ extension ConnInfoInitializable {
     public init(params: [String: String]) throws {
         try self.init(conninfo: .params(params))
     }
-    
-    public init(host: String, port: Int, database: String, user: String, password: String) throws {
-        try self.init(conninfo: .basic(host: host, port: port, database: database, user: user, password: password))
+
+    public init(hostname: String, port: Int, database: String, user: String, password: String) throws {
+        try self.init(conninfo: .basic(hostname: hostname, port: port, database: database, user: user, password: password))
     }
-    
+
     public init(conninfo: String) throws {
         try self.init(conninfo: .raw(conninfo))
     }

Sources/PostgreSQL/Context.swift

@@ -0,0 +1,13 @@
+import Node
+
+public final class PostgreSQLContext: Context {
+    internal static let shared = PostgreSQLContext()
+    fileprivate init() {}
+}
+
+extension Context {
+    public var isPostgreSQL: Bool {
+        guard let _ = self as? PostgreSQLContext else { return false }
+        return true
+    }
+}

Sources/PostgreSQL/Database.swift

@@ -18,65 +18,68 @@ enum DataFormat : Int32 {
 public final class Database: ConnInfoInitializable {
     // MARK: - Properties
     public let conninfo: ConnInfo
-    
+
     // MARK: - Init
     public init(conninfo: ConnInfo) throws {
         self.conninfo = conninfo
     }
-    
+
     // MARK: - Connection
+    public func makeConnection() throws -> Connection {
+        return try Connection(conninfo: conninfo)
+    }
+
+    // MARK: - Query Execution
     @discardableResult
     public func execute(_ query: String, _ values: [Node]? = [], on connection: Connection? = nil) throws -> [[String: Node]] {
         guard !query.isEmpty else {
             throw DatabaseError.noQuery
         }
-        
+
         let connection = try connection ?? makeConnection()
 
         return try connection.execute(query, values)
     }
-
-	public func listen(to channel: String, callback: @escaping (Notification) -> Void) {
-		background {
-			do {
-				let connection = try self.makeConnection()
-
-				try self.execute("LISTEN \(channel)", on: connection)
-
-				while true {
-					if connection.connected != true {
-						throw DatabaseError.cannotEstablishConnection(connection.error)
-					}
-
-					PQconsumeInput(connection.connection)
-
-					while let pgNotify = PQnotifies(connection.connection) {
-						let notification = Notification(relname: pgNotify.pointee.relname, extra: pgNotify.pointee.extra, be_pid: pgNotify.pointee.be_pid)
-
-						callback(notification)
-
-						PQfreemem(pgNotify)
-					}
-				}
-			}
-			catch {
-				fatalError("\(error)")
-			}
-		}
-	}
-
-	public func notify(channel: String, payload: String?, on connection: Connection? = nil) throws {
-		let connection = try connection ?? makeConnection()
-
-		if let payload = payload {
-			try execute("NOTIFY \(channel), '\(payload)'", on: connection)
-		}
-		else {
-			try execute("NOTIFY \(channel)", on: connection)
-		}
-	}
-
-    public func makeConnection() throws -> Connection {
-        return try Connection(conninfo: conninfo)
+
+    // MARK: - LISTEN
+    public func listen(to channel: String, callback: @escaping (Notification) -> Void) {
+        background {
+            do {
+                let connection = try self.makeConnection()
+
+                try self.execute("LISTEN \(channel)", on: connection)
+
+                while true {
+                    if connection.isConnected == false {
+                        throw DatabaseError.cannotEstablishConnection(connection.lastError)
+                    }
+
+                    PQconsumeInput(connection.cConnection)
+
+                    while let pgNotify = PQnotifies(connection.cConnection) {
+                        let notification = Notification(relname: pgNotify.pointee.relname, extra: pgNotify.pointee.extra, be_pid: pgNotify.pointee.be_pid)
+
+                        callback(notification)
+
+                        PQfreemem(pgNotify)
+                    }
+                }
+            }
+            catch {
+                fatalError("\(error)")
+            }
+        }
+    }
+
+    // MARK: - NOTIFY
+    public func notify(channel: String, payload: String?, on connection: Connection? = nil) throws {
+        let connection = try connection ?? makeConnection()
+
+        if let payload = payload {
+            try execute("NOTIFY \(channel), '\(payload)'", on: connection)
+        }
+        else {
+            try execute("NOTIFY \(channel)", on: connection)
+        }
     }
 }