Add helper methods to get filename from content disposition headers

python/core/auto_generated/network/qgsnetworkcontentfetcher.sip.in

@@ -60,6 +60,13 @@ Optionally, authentication configuration can be set via the ``authcfg`` argument
 Returns a reference to the network reply
 
 :return: QNetworkReply for fetched URL content
+%End
+
+    QString contentDispositionFilename() const;
+%Docstring
+Returns the associated filename from the reply's content disposition header, if present.
+
+.. versionadded:: 3.28
 %End
 
     QString contentAsString() const;

python/core/auto_generated/network/qgsnetworkcontentfetchertask.sip.in

@@ -75,6 +75,13 @@ May return ``None`` if the request has not yet completed.
    the :py:func:`QgsNetworkContentFetcherTask.fetched()` signal.
 %End
 
+    QString contentDispositionFilename() const;
+%Docstring
+Returns the associated filename from the reply's content disposition header, if present.
+
+.. versionadded:: 3.28
+%End
+
     QString contentAsString() const;
 %Docstring
 Returns the fetched content as a string

python/core/auto_generated/network/qgsnetworkreply.sip.in

@@ -125,6 +125,20 @@ can only be done once.
 Blocking network requests (see :py:class:`QgsBlockingNetworkRequest`) will automatically populate this content.
 
 .. seealso:: :py:func:`setContent`
+%End
+
+    static QString extractFilenameFromContentDispositionHeader( QNetworkReply *reply );
+%Docstring
+Extracts the filename component of the content disposition header from a network ``reply``.
+
+.. versionadded:: 3.28
+%End
+
+    static QString extractFileNameFromContentDispositionHeader( const QString &header );
+%Docstring
+Extracts the filename component of the content disposition header from the ``header``.
+
+.. versionadded:: 3.28
 %End
 
 };

src/core/network/qgsnetworkcontentfetcher.cpp

@@ -96,6 +96,11 @@ QNetworkReply *QgsNetworkContentFetcher::reply()
   return mReply;
 }
 
+QString QgsNetworkContentFetcher::contentDispositionFilename() const
+{
+  return mReply ? QgsNetworkReplyContent::extractFilenameFromContentDispositionHeader( mReply ) : QString();
+}
+
 QString QgsNetworkContentFetcher::contentAsString() const
 {
   if ( !mContentLoaded || !mReply )

src/core/network/qgsnetworkcontentfetcher.h

@@ -73,6 +73,13 @@ class CORE_EXPORT QgsNetworkContentFetcher : public QObject
      */
     QNetworkReply *reply();
 
+    /**
+     * Returns the associated filename from the reply's content disposition header, if present.
+     *
+     * \since QGIS 3.28
+     */
+    QString contentDispositionFilename() const;
+
     /**
      * Returns the fetched content as a string
      * \returns string containing network content

src/core/network/qgsnetworkcontentfetchertask.cpp

@@ -18,6 +18,7 @@
 
 #include "qgsnetworkcontentfetchertask.h"
 #include "qgsnetworkcontentfetcher.h"
+#include "qgsnetworkreply.h"
 #include <QEventLoop>
 
 QgsNetworkContentFetcherTask::QgsNetworkContentFetcherTask( const QUrl &url, const QString &authcfg, QgsTask::Flags flags, const QString &description )
@@ -90,6 +91,11 @@ QNetworkReply *QgsNetworkContentFetcherTask::reply()
   return mFetcher ? mFetcher->reply() : nullptr;
 }
 
+QString QgsNetworkContentFetcherTask::contentDispositionFilename() const
+{
+  return mFetcher ? mFetcher->contentDispositionFilename() : QString();
+}
+
 QString QgsNetworkContentFetcherTask::contentAsString() const
 {
   return mFetcher ? mFetcher->contentAsString() : QString();

src/core/network/qgsnetworkcontentfetchertask.h

@@ -87,6 +87,13 @@ class CORE_EXPORT QgsNetworkContentFetcherTask : public QgsTask
      */
     QNetworkReply *reply();
 
+    /**
+     * Returns the associated filename from the reply's content disposition header, if present.
+     *
+     * \since QGIS 3.28
+     */
+    QString contentDispositionFilename() const;
+
     /**
      * Returns the fetched content as a string
      *

src/core/network/qgsnetworkreply.cpp

@@ -15,6 +15,8 @@
 
 #include "qgsnetworkreply.h"
 #include <QNetworkReply>
+#include <QRegularExpression>
+#include <QRegularExpressionMatch>
 
 QgsNetworkReplyContent::QgsNetworkReplyContent( QNetworkReply *reply )
   : mError( reply->error() )
@@ -75,3 +77,38 @@ QByteArray QgsNetworkReplyContent::rawHeader( const QByteArray &headerName ) con
   }
   return QByteArray();
 }
+
+QString QgsNetworkReplyContent::extractFilenameFromContentDispositionHeader( QNetworkReply *reply )
+{
+  if ( !reply )
+    return QString();
+
+  return extractFileNameFromContentDispositionHeader( reply->header( QNetworkRequest::ContentDispositionHeader ).toString() );
+}
+
+QString QgsNetworkReplyContent::extractFileNameFromContentDispositionHeader( const QString &header )
+{
+  const thread_local QRegularExpression rx( QStringLiteral( R"""(filename[^;\n]*=\s*(UTF-\d['"]*)?((['"]).*?[.]$\2|[^;\n]*)?)""" ), QRegularExpression::PatternOption::CaseInsensitiveOption );
+
+  QRegularExpressionMatchIterator i = rx.globalMatch( header, 0 );
+  QString res;
+  // we want the last match here, as that will have the UTF filename when present
+  while ( i.hasNext() )
+  {
+    const QRegularExpressionMatch match = i.next();
+    res = match.captured( 2 );
+  }
+
+  if ( res.startsWith( '"' ) )
+  {
+    res = res.mid( 1 );
+    if ( res.endsWith( '"' ) )
+      res.chop( 1 );
+  }
+  if ( !res.isEmpty() )
+  {
+    res = QUrl::fromPercentEncoding( res.toUtf8() );
+  }
+
+  return res;
+}

src/core/network/qgsnetworkreply.h

@@ -157,6 +157,20 @@ class CORE_EXPORT QgsNetworkReplyContent
      */
     QByteArray content() const { return mContent; }
 
+    /**
+     * Extracts the filename component of the content disposition header from a network \a reply.
+     *
+     * \since QGIS 3.28
+     */
+    static QString extractFilenameFromContentDispositionHeader( QNetworkReply *reply );
+
+    /**
+     * Extracts the filename component of the content disposition header from the \a header.
+     *
+     * \since QGIS 3.28
+     */
+    static QString extractFileNameFromContentDispositionHeader( const QString &header );
+
   private:
 
     QNetworkReply::NetworkError mError = QNetworkReply::NoError;

tests/src/python/CMakeLists.txt

@@ -220,6 +220,7 @@ ADD_PYTHON_TEST(PyQgsNetworkAccessManager test_qgsnetworkaccessmanager.py)
 ADD_PYTHON_TEST(PyQgsNetworkContentFetcher test_qgsnetworkcontentfetcher.py)
 ADD_PYTHON_TEST(PyQgsNetworkContentFetcherRegistry test_qgsnetworkcontentfetcherregistry.py)
 ADD_PYTHON_TEST(PyQgsNetworkContentFetcherTask test_qgsnetworkcontentfetchertask.py)
+ADD_PYTHON_TEST(PyQgsNetworkReply test_qgsnetworkreply.py)
 ADD_PYTHON_TEST(PyQgsNullSymbolRenderer test_qgsnullsymbolrenderer.py)
 ADD_PYTHON_TEST(PyQgsNumericFormat test_qgsnumericformat.py)
 ADD_PYTHON_TEST(PyQgsNumericFormatGui test_qgsnumericformatgui.py)

tests/src/python/test_qgsnetworkreply.py

@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsNetworkReplyContent
+
+.. note:: This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+"""
+
+from builtins import chr
+from builtins import str
+__author__ = 'Nyall Dawson'
+__date__ = '20/06/2022'
+__copyright__ = 'Copyright 2022, The QGIS Project'
+
+import qgis  # NOQA
+
+import os
+from qgis.testing import unittest, start_app
+from qgis.core import QgsNetworkReplyContent
+from utilities import unitTestDataPath
+from qgis.PyQt.QtCore import QUrl
+from qgis.PyQt.QtNetwork import QNetworkReply, QNetworkRequest
+import socketserver
+import threading
+import http.server
+
+app = start_app()
+
+
+class TestQgsNetworkReply(unittest.TestCase):
+
+    def test_content_disposition_filename(self):
+        self.assertEqual(QgsNetworkReplyContent.extractFileNameFromContentDispositionHeader('x'), '')
+        self.assertEqual(QgsNetworkReplyContent.extractFileNameFromContentDispositionHeader('attachment; filename=content.txt'), 'content.txt')
+        self.assertEqual(
+            QgsNetworkReplyContent.extractFileNameFromContentDispositionHeader("attachment; filename*=UTF-8''filename.txt"), 'filename.txt')
+        self.assertEqual(
+            QgsNetworkReplyContent.extractFileNameFromContentDispositionHeader('attachment; filename="EURO rates"; filename*=utf-8\'\'%e2%82%ac%20rates'), '€ rates')
+        self.assertEqual(
+            QgsNetworkReplyContent.extractFileNameFromContentDispositionHeader('attachment; filename="omáèka.jpg"'), 'omáèka.jpg')
+
+
+if __name__ == "__main__":
+    unittest.main()