python
auth
iface = start_qgis()
Plugins; Developing, Python; Authentication infrastructure
Hint
The code snippets on this page need the following imports if you're outside the pyqgis console:
auth
- from qgis.core import (
QgsApplication, QgsRasterLayer, QgsAuthMethodConfig, QgsDataSourceUri, QgsPkiBundle, QgsMessageLog,
)
- from qgis.gui import (
QgsAuthAuthoritiesEditor, QgsAuthConfigEditor, QgsAuthConfigSelect, QgsAuthSettingsWidget,
)
- from qgis.PyQt.QtWidgets import (
QWidget, QTabWidget,
)
from qgis.PyQt.QtNetwork import QSslCertificate
html
User reference of the Authentication infrastructure can be read in the User Manual in the authentication_overview
paragraph.
This chapter describes the best practices to use the Authentication system from a developer perspective.
The authentication system is widely used in QGIS Desktop by data providers whenever credentials are required to access a particular resource, for example when a layer establishes a connection to a Postgres database.
There are also a few widgets in the QGIS gui library that plugin developers can use to easily integrate the authentication infrastructure into their code:
QgsAuthConfigEditor <qgis.gui.QgsAuthConfigEditor>
QgsAuthConfigSelect <qgis.gui.QgsAuthConfigSelect>
QgsAuthSettingsWidget <qgis.gui.QgsAuthSettingsWidget>
A good code reference can be read from the authentication infrastructure tests code <tests/src/python/test_qgsauthsystem.py>
.
Warning
Due to the security constraints that were taken into account during the authentication infrastructure design, only a selected subset of the internal methods are exposed to Python.
Here are some definition of the most common objects treated in this chapter.
- Master Password
Password to allow access and decrypt credential stored in the QGIS Authentication DB
- Authentication Database
A
Master Password
crypted sqlite dbqgis-auth.db
whereAuthentication Configuration
are stored. e.g user/password, personal certificates and keys, Certificate Authorities- Authentication DB
Authentication Database
- Authentication Configuration
A set of authentication data depending on
Authentication Method
. e.g Basic authentication method stores the couple of user/password.- Authentication Config
Authentication Configuration
- Authentication Method
A specific method used to get authenticated. Each method has its own protocol used to gain the authenticated level. Each method is implemented as shared library loaded dynamically during QGIS authentication infrastructure init.
The QgsAuthManager <qgis.core.QgsAuthManager>
singleton is the entry point to use the credentials stored in the QGIS encrypted Authentication DB
, i.e. the qgis-auth.db
file under the active user profile <user_profiles>
folder.
This class takes care of the user interaction: by asking to set a master password or by transparently using it to access encrypted stored information.
The following snippet gives an example to set master password to open the access to the authentication settings. Code comments are important to understand the snippet.
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authMgr = QgsApplication.authManager()
# check if QgsAuthManager has already been initialized... a side effect # of the QgsAuthManager.init() is that AuthDbPath is set. # QgsAuthManager.init() is executed during QGIS application init and hence # you do not normally need to call it directly. if authMgr.authenticationDatabasePath(): # already initialized => we are inside a QGIS app. if authMgr.masterPasswordIsSet(): msg = 'Authentication master password not recognized' assert authMgr.masterPasswordSame("your master password"), msg else: msg = 'Master password could not be set' # The verify parameter checks if the hash of the password was # already saved in the authentication db assert authMgr.setMasterPassword("your master password", verify=True), msg else: # outside qgis, e.g. in a testing environment => setup env var before # db init os.environ['QGIS_AUTH_DB_DIR_PATH'] = "/path/where/located/qgis-auth.db" msg = 'Master password could not be set' assert authMgr.setMasterPassword("your master password", True), msg authMgr.init("/path/where/located/qgis-auth.db")
Any stored credential is a Authentication Configuration
instance of the QgsAuthMethodConfig <qgis.core.QgsAuthMethodConfig>
class accessed using a unique string like the following one:
authcfg = 'fm1s770'
that string is generated automatically when creating an entry using the QGIS API or GUI, but it might be useful to manually set it to a known value in case the configuration must be shared (with different credentials) between multiple users within an organization.
QgsAuthMethodConfig <qgis.core.QgsAuthMethodConfig>
is the base class for any Authentication Method
. Any Authentication Method sets a configuration hash map where authentication information will be stored. Hereafter a useful snippet to store PKI-path credentials for a hypothetical alice user:
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authMgr = QgsApplication.authManager() # set alice PKI data config = QgsAuthMethodConfig() config.setName("alice") config.setMethod("PKI-Paths") config.setUri("https://example.com") config.setConfig("certpath", "path/to/alice-cert.pem" ) config.setConfig("keypath", "path/to/alice-key.pem" ) # check if method parameters are correctly set assert config.isValid()
# register alice data in authdb returning the authcfg
of the stored # configuration authMgr.storeAuthenticationConfig(config) newAuthCfgId = config.id() assert newAuthCfgId
Authentication Method
libraries are loaded dynamically during authentication manager init. Available authentication methods are:
Basic
User and password authenticationEsriToken
ESRI token based authenticationIdentity-Cert
Identity certificate authenticationOAuth2
OAuth2 authenticationPKI-Paths
PKI paths authenticationPKI-PKCS#12
PKI PKCS#12 authentication
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authMgr = QgsApplication.authManager() # add authorities cacerts = QSslCertificate.fromPath( "/path/to/ca_chains.pem" ) assert cacerts is not None # store CA authMgr.storeCertAuthorities(cacerts) # and rebuild CA caches authMgr.rebuildCaCertsCache() authMgr.rebuildTrustedCaCertsCache()
A convenience class to pack PKI bundles composed on SslCert, SslKey and CA chain is the QgsPkiBundle <qgis.core.QgsPkiBundle>
class. Hereafter a snippet to get password protected:
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# add alice cert in case of key with pwd caBundlesList = [] # List of CA bundles bundle = QgsPkiBundle.fromPemPaths( "/path/to/alice-cert.pem", "/path/to/alice-key_w-pass.pem", "unlock_pwd", caBundlesList ) assert bundle is not None # You can check bundle validity by calling: # bundle.isValid()
Refer to QgsPkiBundle <qgis.core.QgsPkiBundle>
class documentation to extract cert/key/CAs from the bundle.
We can remove an entry from Authentication Database
using it's authcfg
identifier with the following snippet:
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authMgr = QgsApplication.authManager() authMgr.removeAuthenticationConfig( "authCfg_Id_to_remove" )
The best way to use an Authentication Config
stored in the Authentication DB
is referring it with the unique identifier authcfg
. Expanding, means convert it from an identifier to a complete set of credentials. The best practice to use stored Authentication Config
s, is to leave it managed automatically by the Authentication manager. The common use of a stored configuration is to connect to an authentication enabled service like a WMS or WFS or to a DB connection.
Note
Take into account that not all QGIS data providers are integrated with the Authentication infrastructure. Each authentication method, derived from the base class QgsAuthMethod <qgis.core.QgsAuthMethod>
and support a different set of Providers. For example the certIdentity()
<qgis.core.QgsAuthManager.certIdentity>
method supports the following list of providers:
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authM = QgsApplication.authManager() print(authM.authMethod("Identity-Cert").supportedDataProviders())
Sample output:
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['ows', 'wfs', 'wcs', 'wms', 'postgres']
For example, to access a WMS service using stored credentials identified with authcfg = 'fm1s770'
, we just have to use the authcfg
in the data source URL like in the following snippet:
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authCfg = 'fm1s770' quri = QgsDataSourceUri() quri.setParam("layers", 'usa:states') quri.setParam("styles", '') quri.setParam("format", 'image/png') quri.setParam("crs", 'EPSG:4326') quri.setParam("dpiMode", '7') quri.setParam("featureCount", '10') quri.setParam("authcfg", authCfg) # <---- here my authCfg url parameter quri.setParam("contextualWMSLegend", '0') quri.setParam("url", 'https://my_auth_enabled_server_ip/wms') rlayer = QgsRasterLayer(str(quri.encodedUri(), "utf-8"), 'states', 'wms')
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WMS(1): Download of capabilities failed: network request update failed for authentication config
In the upper case, the wms
provider will take care to expand authcfg
URI parameter with credential just before setting the HTTP connection.
Warning
The developer would have to leave authcfg
expansion to the QgsAuthManager
<qgis.core.QgsAuthManager>
, in this way he will be sure that expansion is not done too early.
Usually an URI string, built using the QgsDataSourceURI <qgis.core.QgsDataSourceUri>
class, is used to set a data source in the following way:
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authCfg = 'fm1s770' quri = QgsDataSourceUri("my WMS uri here") quri.setParam("authcfg", authCfg) rlayer = QgsRasterLayer( quri.uri(False), 'states', 'wms')
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WMS(1): Download of capabilities failed: network request update failed for authentication config
Note
The False
parameter is important to avoid URI complete expansion of the authcfg
id present in the URI.
Other example can be read directly in the QGIS tests upstream as in test_authmanager_pki_ows <tests/src/python/test_authmanager_pki_ows.py>
or test_authmanager_pki_postgres <tests/src/python/test_authmanager_pki_postgres.py>
.
Many third party plugins are using httplib2 or other Python networking libraries to manage HTTP connections instead of integrating with QgsNetworkAccessManager <qgis.core.QgsNetworkAccessManager>
and its related Authentication Infrastructure integration.
To facilitate this integration a helper Python function has been created called NetworkAccessManager
. Its code can be found here.
This helper class can be used as in the following snippet:
http = NetworkAccessManager(authid="my_authCfg", exception_class=My_FailedRequestError)
try:
response, content = http.request( "my_rest_url" )
except My_FailedRequestError, e:
# Handle exception
pass
In this paragraph are listed the available GUIs useful to integrate authentication infrastructure in custom interfaces.
If it's necessary to select a Authentication Configuration
from the set stored in the Authentication DB
it is available in the GUI class QgsAuthConfigSelect <qgis.gui.QgsAuthConfigSelect>
.
and can be used as in the following snippet:
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# create the instance of the QgsAuthConfigSelect GUI hierarchically linked to # the widget referred with parent parent = QWidget() # Your GUI parent widget gui = QgsAuthConfigSelect( parent, "postgres" ) # add the above created gui in a new tab of the interface where the # GUI has to be integrated tabGui = QTabWidget() tabGui.insertTab( 1, gui, "Configurations" )
The above example is taken from the QGIS source code
<src/providers/postgres/qgspgnewconnection.cpp#L42>
. The second parameter of the GUI constructor refers to data provider type. The parameter is used to restrict the compatible Authentication Method
s with the specified provider.
The complete GUI used to manage credentials, authorities and to access to Authentication utilities is managed by the QgsAuthEditorWidgets <qgis.gui.QgsAuthEditorWidgets>
class.
and can be used as in the following snippet:
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# create the instance of the QgsAuthEditorWidgets GUI hierarchically linked to # the widget referred with parent parent = QWidget() # Your GUI parent widget gui = QgsAuthConfigSelect( parent ) gui.show()
An integrated example can be found in the related test
<tests/src/python/test_qgsauthsystem.py#L80>
.
A GUI used to manage only authorities is managed by the QgsAuthAuthoritiesEditor <qgis.gui.QgsAuthAuthoritiesEditor>
class.
and can be used as in the following snippet:
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# create the instance of the QgsAuthAuthoritiesEditor GUI hierarchically # linked to the widget referred with parent parent = QWidget() # Your GUI parent widget gui = QgsAuthAuthoritiesEditor( parent ) gui.show()