Fix automatic font download on Windows

python/PyQt6/core/auto_generated/textrenderer/qgsfontmanager.sip.in

@@ -278,7 +278,7 @@ tasks, e.g. the font family name if known.
 .. versionadded:: 3.38
 %End
 
-    bool installFontsFromData( const QByteArray &data, QString &errorMessage /Out/, QStringList &families /Out/, QString &licenseDetails /Out/, const QString &filename = QString() );
+    bool installFontsFromData( const QByteArray &data, QString &errorMessage /Out/, QStringList &families /Out/, QString &licenseDetails /Out/, const QString &filename = QString(), const QString &extension = QString() );
 %Docstring
 Installs local user fonts from the specified raw ``data``.
 
@@ -287,6 +287,7 @@ or a zipped archive of font files.
 
 :param data: raw font data or zipped font data
 :param filename: filename hint for destination file. Will be ignored for archived content (e.g. zip file data)
+:param extension: known file extension (eg "ttf", "otf") for font. Should be specified to avoid issues with font installation on Windows if filename is not specified (since QGIS 3.38)
 
 :return: - ``True`` if installation was successful.
          - errorMessage: will be set to a descriptive error message if the installation fails

python/core/auto_generated/textrenderer/qgsfontmanager.sip.in

@@ -278,7 +278,7 @@ tasks, e.g. the font family name if known.
 .. versionadded:: 3.38
 %End
 
-    bool installFontsFromData( const QByteArray &data, QString &errorMessage /Out/, QStringList &families /Out/, QString &licenseDetails /Out/, const QString &filename = QString() );
+    bool installFontsFromData( const QByteArray &data, QString &errorMessage /Out/, QStringList &families /Out/, QString &licenseDetails /Out/, const QString &filename = QString(), const QString &extension = QString() );
 %Docstring
 Installs local user fonts from the specified raw ``data``.
 
@@ -287,6 +287,7 @@ or a zipped archive of font files.
 
 :param data: raw font data or zipped font data
 :param filename: filename hint for destination file. Will be ignored for archived content (e.g. zip file data)
+:param extension: known file extension (eg "ttf", "otf") for font. Should be specified to avoid issues with font installation on Windows if filename is not specified (since QGIS 3.38)
 
 :return: - ``True`` if installation was successful.
          - errorMessage: will be set to a descriptive error message if the installation fails

src/core/textrenderer/qgsfontmanager.cpp

@@ -1855,8 +1855,15 @@ void QgsFontManager::downloadAndInstallFont( const QgsFontDownloadDetails &detai
       QStringList thisUrlFamilies;
       const QByteArray fontData  = allFontData[i];
       const QString contentDispositionFilename = task->contentDispositionFilenames().at( i );
+      QString extension;
+      if ( contentDispositionFilename.isEmpty() )
+      {
+        const QUrl originalUrl = details.fontUrls().value( i );
+        const thread_local QRegularExpression rxExtension( QStringLiteral( "^.*\\.(\\w+?)$" ) );
+        extension = rxExtension.match( originalUrl.toString() ).captured( 1 );
+      }
       QString thisLicenseDetails;
-      if ( !installFontsFromData( fontData, errorMessage, thisUrlFamilies, thisLicenseDetails, contentDispositionFilename ) )
+      if ( !installFontsFromData( fontData, errorMessage, thisUrlFamilies, thisLicenseDetails, contentDispositionFilename, extension ) )
       {
         QgsReadWriteLocker locker( mReplacementLock, QgsReadWriteLocker::Write );
         mPendingFontDownloads.remove( identifier );
@@ -1900,13 +1907,20 @@ void QgsFontManager::downloadAndInstallFont( const QUrl &url, const QString &ide
   downloadAndInstallFont( QgsFontDownloadDetails( identifier, { url.toString() } ) );
 }
 
-bool QgsFontManager::installFontsFromData( const QByteArray &data, QString &errorMessage, QStringList &families, QString &licenseDetails, const QString &filename )
+bool QgsFontManager::installFontsFromData( const QByteArray &data, QString &errorMessage, QStringList &families, QString &licenseDetails, const QString &filename, const QString &extension )
 {
   errorMessage.clear();
   families.clear();
   licenseDetails.clear();
 
   QTemporaryFile tempFile;
+  if ( !extension.isEmpty() )
+  {
+    QString cleanedExtension = extension;
+    if ( cleanedExtension.startsWith( '.' ) )
+      cleanedExtension = cleanedExtension.mid( 1 );
+    tempFile.setFileTemplate( QStringLiteral( "%1/XXXXXX.%2" ).arg( QDir::tempPath(), cleanedExtension ) );
+  }
   QTemporaryDir tempDir;
 
   QgsReadWriteLocker locker( mReplacementLock, QgsReadWriteLocker::Read );
@@ -1927,7 +1941,7 @@ bool QgsFontManager::installFontsFromData( const QByteArray &data, QString &erro
   QString sourcePath = tempFile.fileName();
 
   //try to install the data directly as a font
-  int id = QFontDatabase::addApplicationFont( sourcePath );
+  int id = QFontDatabase::addApplicationFontFromData( data );
   if ( id != -1 )
   {
     // successfully loaded data as a font

src/core/textrenderer/qgsfontmanager.h

@@ -328,10 +328,11 @@ class CORE_EXPORT QgsFontManager : public QObject
      * \param families will be populated with a list of font families installed from the data
      * \param licenseDetails will be populated with font license details, if found
      * \param filename filename hint for destination file. Will be ignored for archived content (e.g. zip file data)
+     * \param extension known file extension (eg "ttf", "otf") for font. Should be specified to avoid issues with font installation on Windows if filename is not specified (since QGIS 3.38)
      *
      * \returns TRUE if installation was successful.
      */
-    bool installFontsFromData( const QByteArray &data, QString &errorMessage SIP_OUT, QStringList &families SIP_OUT, QString &licenseDetails SIP_OUT, const QString &filename = QString() );
+    bool installFontsFromData( const QByteArray &data, QString &errorMessage SIP_OUT, QStringList &families SIP_OUT, QString &licenseDetails SIP_OUT, const QString &filename = QString(), const QString &extension = QString() );
 
     /**
      * Adds a \a directory to use for user fonts.