[Qgis-developer] PyQGIS: do WMS and WFS providers use QgsNetworkAccessManager.instance()?

[Luigi Pirelli]

Hi Enzo

AFAIK Shibboleth it's still not (still) supported by
AuthenticationManager, and Auth Manager have to be better integrated
in QgsConnectionManager class.

thanks for the workaroud, but a good procedure would be:

1) Create a Shibboleth authentication plugin for Auth Manager (in a
while will be available the single sign-on OAuth authentication).
Larry Shaffer by Boundless just did a proof of concept during these
days in Girona Hackfest that can be used as development base.

2) Support the complete integration of the AuthManager in
QgsNetworkAccessManager that would become THE way to use any
connection. Future QGIS will have PyQGIS access to AuthManager almost
removed to leave the auth access only managed by NetworkManager.
This integration will request a refactory of OWS providers that
actually use directly AuthManager (and also PostGis provider)

btw code snippets and use cases are always really useful :)

I'm just investigating how to integrate AuthManager and NetworkManager
(Qt) with Windows key store (Credential Management). If you have
suggestions are really welcome :)

regards
Luigi Pirelli

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On 27 May 2016 at 13:24, enzogis <enzo.ciarmoli at csi.it> wrote:
> Hi all,
> The main goal is to access to WMS/WFS exposed  behind Shibboleth
> authentication page.
> I made many tests and partially I have success with a workaround: not sure
> but if I'm not wrong then I could signal a strange behaviour of wms provider
> with QgsNetworkAccessManager.instance()
>
> The problem is complex, I try to shortly explain:
>
> I need to load WMS/WFS layers that are exposed behind Shibboleth (SAML2)
> authentication page.
> From a web browser, the authentication system consists of these steps:
> - call the url
> http://example/wms?service=WMS&version=1.1.0&request=GetCapabilities
> - the system redirect to main authentication page https://secure/login.jsp
> with many options
> - the user indicates a valid PKCS#12 certificate
> - only after success it redirect to the first url and the user could see the
> wms response.
>
> In QGIS 2.14.3 I imported certificate but when I try to load that WMS layer,
> it shows an error: it expected wms capabilties response but it receive an
> html from main authentication page.
>
> Workaround:
> Thus, to achieve the goal, I replicated in Python the authentication process
> with a custom QWebView and extended QNetworkAccessManager with SSL support
> to use certificate.
> After succesfully access, the script dump cookies from the CookieJar and
> transfers them to  QgsNetworkAccessManager.instance().
> In that situation, the instance is authenticated and i can manually load
> layers and Shibboleth trusts cookies.
>
> That workaround works fine for WFS , but it fails for WMS.
>
> When i try to connect to WMS manually it have success and it shows a list of
> capabilities , but when i select a layer and  i try to load it shows an
> error: in error logs there are html tags from the main authentication page.
> It seems that WMS provider uses QgsNetworkAccessManager.instance() only for
> get capabilities but not for loading each layer.
>
> Instead, the same solution works fine for WFS:  from the dialog that show
> capabilities I can load a layer in QGIS and I assume that it uses
> authenticated QgsNetworkAccessManager.instance().
>
> That different behaviour of wms and wfs providers is correct?
> It is a bug or I misunderstand something?
>
> Any suggestion would be greatly appreciated.
> If necessary for details I will attach code snippet.
>
> TIA
> --
> Enzo Ciarmoli
>
>
>
> --
> View this message in context: http://osgeo-org.1560.x6.nabble.com/PyQGIS-do-WMS-and-WFS-providers-use-QgsNetworkAccessManager-instance-tp5268513.html
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