Fix connecting to the db when no user is specified for the connection…

ConstraintChecker/checker.py

@@ -25,9 +25,10 @@
 # Import the PyQt and QGIS libraries
 from qgis.PyQt.QtCore import Qt, QAbstractTableModel, QModelIndex, QAbstractItemModel, QSettings
 from qgis.PyQt.QtWidgets import QMessageBox
-from qgis.core import QgsAuthMethodConfig, QgsApplication
+from qgis.core import Qgis, QgsMessageLog
 
 from .constraint_results_dialog import ConstraintResultsDialog
+from .utils import DEBUG, get_db_conn_details
 
 
 class ResultModel(QAbstractTableModel):
@@ -147,28 +148,23 @@ def getDbCursor(self):
             # Looks like the preferred connection could not be found
             raise Exception('The preferred PostGIS connection, '
                             '%s could not be found, please check your Constrain Checker settings')
-        database = str(s.value("PostgreSQL/connections/%s/database" % selectedConnection, ''))
-        user = str(s.value("PostgreSQL/connections/%s/username" % selectedConnection, ''))
-        password = str(s.value("PostgreSQL/connections/%s/password" % selectedConnection, ''))
-        port = int(s.value("PostgreSQL/connections/%s/port" % selectedConnection, 5432))
 
-        auth_manager = QgsApplication.authManager()
-        conf = QgsAuthMethodConfig()
-        configs = {v.name(): k for k, v in auth_manager.availableAuthMethodConfigs().items()}
-        # name of config in auth must match the name of selected connection
-        try:
-            auth_manager.loadAuthenticationConfig(configs[selectedConnection], conf, True)
-            if conf.id():
-                user = conf.config('username', '')
-                password = conf.config('password', '')
-        except KeyError:
-            pass
+        host, database, username, password, port = get_db_conn_details(selectedConnection)
+        if DEBUG:
+            conn_info = f"host: {host}, db:{database}, user: {username}, pass={len(password)}, port={port}"
+            QgsMessageLog.logMessage(f"Constraint checker conn info: {conn_info}", 'Constraint Checker', level=Qgis.Info)
 
-        dbConn = psycopg2.connect(database=database,
-                                  user=user,
-                                  password=password,
-                                  host=host,
-                                  port=port)
+        if not username or not password:
+            # Active Directory authentication possible
+            dbConn = psycopg2.connect(database=database,
+                                      host=host,
+                                      port=port)
+        else:
+            dbConn = psycopg2.connect(database=database,
+                                      user=username,
+                                      password=password,
+                                      host=host,
+                                      port=port)
         dbConn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
         return dbConn.cursor()
 

ConstraintChecker/metadata.txt

@@ -4,7 +4,7 @@ name=Constraint Checker
 qgisMinimumVersion=3.4
 qgisMaximumVersion=3.99
 description=Generate reports of constraints (e.g. planning constraints) applicable to an area of interest.
-version=1.2
+version=1.3
 author=Lutra Consulting for Dartmoor National Park Authority
 [email protected]
 
@@ -15,7 +15,8 @@ about=Generate reports of constraints (e.g. planning constraints) applicable to
 # Optional items:
 
 # Uncomment the following line and add your changelog entries:
-changelog=1.2 - Migration to QGIS 3.x
+changelog=1.3 Fix for psycopg2 connection when Active Directory is used for authentication
+ <p>1.2 - Migration to QGIS 3.x
  <p>1.1.2 - Bug fixes:
   - rubber band color, geometry column configuration (from Matt Travis)
  <p>1.1.1 - Bug fixes:

ConstraintChecker/utils.py

@@ -21,6 +21,10 @@
 """
 
 import string
+from qgis.core import QgsApplication, QgsAuthMethodConfig, QgsSettings
+
+DEBUG = False
+
 
 def dbSafe(s):
     """ Returns true if this string is considered safe to use as a DB 
@@ -29,7 +33,34 @@ def dbSafe(s):
     safeChars = string.digits + string.ascii_letters + '_ '
 
     for char in s:
-        if not char in safeChars:
+        if char not in safeChars:
             return False
     return True
 
+
+def get_db_conn_details(conn_name):
+    s = QgsSettings()
+    s.beginGroup("/PostgreSQL/connections")
+    if conn_name not in s.childGroups():
+        raise Exception(f"No connection named {conn_name} in QGIS settings!")
+    s.endGroup()
+    s.beginGroup(f"/PostgreSQL/connections/{conn_name}")
+    host = s.value("host", "")
+    database = s.value("database", "")
+    username = s.value("username", "")
+    password = s.value("password", "")
+    port = int(s.value("port", 5432))
+    authcfg = s.value("authcfg", None)
+
+    if DEBUG:
+        print(f"Conn details: {host}, {database}, {username}, {len(password)}, {port}")
+
+    if authcfg:
+        conf = QgsAuthMethodConfig()
+        auth_manager = QgsApplication.authManager()
+        auth_manager.loadAuthenticationConfig(authcfg, conf, True)
+        if conf.id():
+            username = conf.config("username", "")
+            password = conf.config("password", "")
+
+    return host, database, username, password, port