Merge pull request #331 from alfasoftware/fix/validate-Postgres-conne…

…ction-getStandardConformingStrings

Adding validation preventing standard_conforming_strings=off

morf-core/src/main/java/org/alfasoftware/morf/jdbc/AbstractConnectionResources.java

@@ -16,6 +16,7 @@
 package org.alfasoftware.morf.jdbc;
 
 
+import java.lang.reflect.InvocationTargetException;
 import java.sql.Array;
 import java.sql.Blob;
 import java.sql.CallableStatement;
@@ -44,6 +45,7 @@
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 
 /**
@@ -293,10 +295,17 @@ public Connection getConnection(String username, String password) throws SQLExce
       log.info("Opening new database connection to [" + AbstractConnectionResources.this.getJdbcUrl() + "] with username [" + username + "] for schema [" + AbstractConnectionResources.this.getSchemaName() + "]");
       loadJdbcDriver();
       Connection connection = openConnection(username, password);
+      validateConnection(connection);
       return log.isDebugEnabled() ? new LoggingConnection(connection) : connection;
     }
 
 
+    private void validateConnection(Connection connection) {
+      final String databaseType = getDatabaseType();
+      validatePgConnectionStandardConformingStrings(databaseType, connection);
+    }
+
+
     private void loadJdbcDriver() {
       String driverClassName = findDatabaseType().driverClassName();
       try {
@@ -327,6 +336,35 @@ private Connection openConnection(String username, String password) throws SQLEx
   }
 
 
+  @VisibleForTesting
+  static void validatePgConnectionStandardConformingStrings(String databaseType, Connection connection) {
+    final String getStandardConformingStringsMethodName = "getStandardConformingStrings";
+
+    if ("PGSQL".equals(databaseType)) {
+      try {
+        // see org.postgresql.core.BaseConnection.getStandardConformingStrings()
+        // see org.postgresql.jdbc.PgConnection.getStandardConformingStrings()
+        boolean standardConformingStrings = connection.getClass()
+            .getMethod(getStandardConformingStringsMethodName)
+            .invoke(connection)
+            .equals(Boolean.TRUE);
+
+        if (log.isDebugEnabled()) log.debug(getStandardConformingStringsMethodName + "(): " + standardConformingStrings);
+
+        if (!standardConformingStrings) {
+          throw new IllegalStateException("Postgres: standard_conforming_strings=off config value has been detected, which is not supported");
+        }
+      }
+      catch (NoSuchMethodException e) {
+        throw new IllegalStateException(getStandardConformingStringsMethodName + "(): no such method on " + connection, e);
+      }
+      catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException | SecurityException e) {
+        throw new IllegalStateException(getStandardConformingStringsMethodName + "(): invoking such method on " + connection, e);
+      }
+    }
+  }
+
+
   private static final class LoggingConnection implements Connection {
 
     final int id = new Random().nextInt(0xFFFF);

morf-core/src/test/java/org/alfasoftware/morf/jdbc/TestAbstractConnectionResources.java

@@ -0,0 +1,90 @@
+package org.alfasoftware.morf.jdbc;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.assertThrows;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.sql.Connection;
+
+import org.hamcrest.Matchers;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+public class TestAbstractConnectionResources {
+
+  /**
+   * Test happy path for non-Postgres connections.
+   */
+  @Test
+  public void testValidatePgConnectionStandardConformingStringsOther() {
+    AbstractConnectionResources.validatePgConnectionStandardConformingStrings("OTHER", mock(Connection.class));
+  }
+
+
+  /**
+   * Test happy path for Postgres connections, where standard_conforming_strings is on, which is good.
+   */
+  @Test
+  public void testValidatePgConnectionStandardConformingStringsTrue() {
+    MockPgConnection mockPgConnection = mock(MockPgConnection.class);
+    when(mockPgConnection.getStandardConformingStrings()).thenReturn(true);
+
+    AbstractConnectionResources.validatePgConnectionStandardConformingStrings("PGSQL", mockPgConnection);
+  }
+
+
+  /**
+   * Test unhappy path for Postgres connections, where standard_conforming_strings is off, and therefore wrong.
+   */
+  @Test
+  public void testValidatePgConnectionStandardConformingStringsFalse() {
+    MockPgConnection mockPgConnection = mock(MockPgConnection.class);
+    when(mockPgConnection.getStandardConformingStrings()).thenReturn(false);
+
+    IllegalStateException exception = assertThrows(IllegalStateException.class,
+      () -> AbstractConnectionResources.validatePgConnectionStandardConformingStrings("PGSQL", mockPgConnection));
+
+    assertThat(exception.getMessage(), Matchers.containsString("standard_conforming_strings=off"));
+  }
+
+
+  /**
+   * Test unhappy path for Postgres connections, where we cannot find the expected method.
+   */
+  @Test
+  public void testValidatePgConnectionStandardConformingStringsPrivateMethod() {
+    IllegalStateException exception = assertThrows(IllegalStateException.class,
+        () -> AbstractConnectionResources.validatePgConnectionStandardConformingStrings("PGSQL", mock(PrivatePgConnection.class, Mockito.CALLS_REAL_METHODS)));
+
+    assertThat(exception.getMessage(), Matchers.containsString("invoking such method"));
+  }
+
+
+  /**
+   * Test unhappy path for Postgres connections, where we cannot invoke the expected method.
+   */
+  @Test
+  public void testValidatePgConnectionStandardConformingStringsMissingMethod() {
+    IllegalStateException exception = assertThrows(IllegalStateException.class,
+        () -> AbstractConnectionResources.validatePgConnectionStandardConformingStrings("PGSQL", mock(Connection.class)));
+
+    assertThat(exception.getMessage(), Matchers.containsString("no such method"));
+  }
+
+
+  /** Helper interface for testing */
+  private interface MockPgConnection extends Connection {
+    // see org.postgresql.core.BaseConnection.getStandardConformingStrings()
+    boolean getStandardConformingStrings();
+  }
+
+
+  /** Helper class for testing */
+  abstract class PrivatePgConnection implements Connection {
+    // see org.postgresql.core.BaseConnection.getStandardConformingStrings()
+    public boolean getStandardConformingStrings() throws java.lang.reflect.InvocationTargetException {
+      throw new java.lang.reflect.InvocationTargetException(null); // emulating reflection issues
+    }
+  }
+}