MultiPart post network request stopped working

[raymondnijssen]

What is the bug or the crash?

One of my plugins stopped working in QGIS master, because some of the requests seem invalid. Specifically requests that post data data with a file as multipart content do not work

Steps to reproduce the issue

Not easy to reproduce by clicking, but I wrote a script to test this. I posted it on the developer mailing list: https://lists.osgeo.org/pipermail/qgis-developer/2022-January/064437.html

Versions

Well it depends on the versions. I've been building many to get close to the date it broke:
14 sep: works
1 oct: works
1 dec: works
7 dec: broken
16 dec: broken
1 jan: broken
23 jan: broken

Here's the output for my December 7 build:

<style type="text/css"> p, li { white-space: pre-wrap; } </style>

QGIS version	3.23.0-Master	QGIS code revision	be56138
Qt version	5.12.8
Python version	3.8.10
GDAL/OGR version	3.0.4
PROJ version	6.3.1
EPSG Registry database version	v9.8.6 (2020-01-22)
Compiled against GEOS	3.8.0-CAPI-1.13.1	Running against GEOS	3.8.0-CAPI-1.13.1
SQLite version	3.31.1
PDAL version	2.0.1
PostgreSQL client version	12.9 (Ubuntu 12.9-0ubuntu0.20.04.1)
SpatiaLite version	4.3.0a
QWT version	6.1.4
QScintilla2 version	2.11.2
OS version	Ubuntu 20.04.3 LTS
Active Python plugins
ImaerPlugin	version 3.1.0
plugin_reloader	0.9.1
pdokservicesplugin	3.7.3
qgis_3d_ams	0.1
QuickOSM	2.0.0
firstaid	2.1.5
QCopycanvas	0.5
sagaprovider	2.12.99
processing	2.12.99

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[nyalldawson]

Is this a qgis bug? Looking at the sample code I suspect it's a pyqt/qt bug. Can you reproduce with a standalone pyqt script run outside of qgis?

[m-kuhn]

It's a qgis bug, we are experiencing the same.

Sending data through QgsNetworkAccessManager with post and multipart fails with error 99.
The same works with QNetworkAccessManager.

QgsNetworkAccessManager (no headers printed)

from PyQt5.QtCore import *
from PyQt5.QtNetwork import *

url = QUrl('https://www.opengis.ch')
request = QNetworkRequest(url)
# request.setAttribute(QNetworkRequest.FollowRedirectsAttribute, True)
multi_part = QHttpMultiPart(QHttpMultiPart.MixedType)

reply = QgsNetworkAccessManager.instance().post(request, multi_part)
print(reply.error())
def prn():
    for header in reply.rawHeaderList():
        print(str(header))

reply.finished.connect(prn)

QNetworkAccessManager (headers print fine)

from PyQt5.QtCore import *
from PyQt5.QtNetwork import *

url = QUrl('https://www.opengis.ch')
request = QNetworkRequest(url)
# request.setAttribute(QNetworkRequest.FollowRedirectsAttribute, True)
multi_part = QHttpMultiPart(QHttpMultiPart.MixedType)

nam = QNetworkAccessManager()

reply = nam.post(request, multi_part)
print(reply.error())
def prn():
    for header in reply.rawHeaderList():
        print(str(header))

reply.finished.connect(prn)

It is connected to

QGIS/src/core/network/qgsnetworkaccessmanager.cpp

Line 358 in aa730d6

content = outgoingData->readAll();

, commenting this line fixes the issue

[raymondnijssen]

Thank you Matthias, just tried and it works again!

…

On 26-01-2022 20:14, Matthias Kuhn wrote: Closed #46989 <#46989> via #47006 <#47006>. — Reply to this email directly, view it on GitHub <#46989 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAFGO66ARIL4ZOYW2YCB6EDUYBB27ANCNFSM5MXRHEIQ>. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you authored the thread.Message ID: ***@***.***>