[processing] make location of GDAL help files configurable.

This prevents errors when algorithm help requested and there is no
access to the Internet (e.g. closed networks)

Author: alexbruy

python/plugins/processing/algs/gdal/GdalAlgorithm.py

@@ -29,11 +29,12 @@
 import re
 
 from qgis.PyQt.QtGui import QIcon
+from qgis.PyQt.QtCore import QUrl
 
 from processing.core.GeoAlgorithm import GeoAlgorithm
 from processing.algs.gdal.GdalAlgorithmDialog import GdalAlgorithmDialog
 from processing.algs.gdal.GdalUtils import GdalUtils
-from processing.tools import dataobjects
+from processing.tools import dataobjects, system
 
 pluginPath = os.path.normpath(os.path.join(
     os.path.split(os.path.dirname(__file__))[0], os.pardir))
@@ -67,10 +68,18 @@ def processAlgorithm(self, progress):
         GdalUtils.runGdal(commands, progress)
 
     def shortHelp(self):
-        return self._formatHelp('''This algorithm is based on the GDAL %s module.
-
-                For more info, see the <a href = 'http://www.gdal.org/%s.html'> module help</a>
-                ''' % (self.commandName(), self.commandName()))
+        helpPath = GdalUtils.gdalHelpPath()
+        if helpPath == '':
+            return
+
+        if os.path.exists(helpPath):
+            url = QUrl.fromLocalFile(os.path.join(helpPath, '{}.html'.format(self.commandName()))).toString()
+        else:
+            url = helpPath + '{}.html'.format(self.commandName())
+
+        return self._formatHelp('''This algorithm is based on the GDAL {} module.
+                For more info, see the <a href={}> module help</a>
+                '''.format(self.commandName(), url))
 
     def commandName(self):
         alg = self.getCopy()

python/plugins/processing/algs/gdal/GdalOgrAlgorithmProvider.py

@@ -29,6 +29,7 @@
 from qgis.PyQt.QtGui import QIcon
 
 from processing.core.AlgorithmProvider import AlgorithmProvider
+from processing.core.ProcessingConfig import ProcessingConfig, Setting
 from .GdalUtils import GdalUtils
 
 from .nearblack import nearblack
@@ -98,6 +99,18 @@ def __init__(self):
         AlgorithmProvider.__init__(self)
         self.createAlgsList()
 
+    def initializeSettings(self):
+        AlgorithmProvider.initializeSettings(self)
+        ProcessingConfig.addSetting(Setting(
+            self.getDescription(),
+            GdalUtils.GDAL_HELP_PATH,
+            self.tr('Location of GDAL docs'),
+            GdalUtils.gdalHelpPath()))
+
+    def unload(self):
+        AlgorithmProvider.unload(self)
+        ProcessingConfig.removeSetting(GdalUtils.GDAL_HELP_PATH)
+
     def getDescription(self):
         return self.tr('GDAL/OGR')
 

python/plugins/processing/algs/gdal/GdalUtils.py

@@ -34,7 +34,9 @@
 from qgis.PyQt.QtCore import QSettings
 from qgis.core import QgsApplication, QgsVectorFileWriter
 from processing.core.ProcessingLog import ProcessingLog
+from processing.core.ProcessingConfig import ProcessingConfig
 from processing.core.SilentProgress import SilentProgress
+from processing.tools.system import isWindows, isMac
 
 try:
     from osgeo import gdal
@@ -45,6 +47,8 @@
 
 class GdalUtils:
 
+    GDAL_HELP_PATH = 'GDAL_HELP_PATH'
+
     supportedRasters = None
 
     @staticmethod
@@ -182,3 +186,21 @@ def escapeAndJoin(strList):
     @staticmethod
     def version():
         return int(gdal.VersionInfo('VERSION_NUM'))
+
+    @staticmethod
+    def gdalHelpPath():
+        helpPath = ProcessingConfig.getSetting(GdalUtils.GDAL_HELP_PATH)
+
+        if helpPath is None:
+            if isWindows():
+                pass
+            elif isMac():
+                pass
+            else:
+                searchPaths = ['/usr/share/doc/libgdal-doc/gdal']
+                for path in searchPaths:
+                    if os.path.exists(path):
+                        helpPath = os.path.abspath(path)
+                        break
+
+        return helpPath if helpPath is not None else 'http://www.gdal.org/'