Fix issue when user has ginga < v5.x installed

Author: ejeschke

stginga/plugins/local_plugin_mixin.py

@@ -3,7 +3,6 @@
 # STDLIB
 import json
 import os
-import re
 
 # THIRD-PARTY
 from astropy.utils.misc import JsonCustomEncoder
@@ -19,21 +18,35 @@
     pass
 
 # STGINGA
-import stginga
 from stginga import utils
 
 __all__ = ['HelpMixin', 'MEFMixin', 'ParamMixin']
 
 
-# base of our online documentation
-rtd_base_url = "https://stginga.readthedocs.io/en/"
-
-
 class HelpMixin(object):
     def help(self):
         """Display online help for the plugin."""
-        url = get_online_docs_url(self)
-        self.fv.help_plugin(self, url=url)
+        if self.fv.gpmon.has_plugin('WBrowser') and Widgets.has_webkit:
+            # ginga < v5.x
+            self.fv.start_global_plugin('WBrowser')
+
+            # need to let GUI finish processing, it seems
+            self.fv.update_pending()
+
+            obj = self.fv.gpmon.get_plugin('WBrowser')
+
+            # Unlike Ginga, we do not attempt to download offline doc
+            # but just point to online doc directly.
+            obj.browse(self.help_url)
+            return
+
+        if not hasattr(self.fv, 'help_plugin'):
+            # ginga < v5.x but somehow user doesn't have WBrowser plugin
+            self._help_docstring()   # works same as in v4.x
+            return
+
+        # ginga v5.x
+        self.fv.help_plugin(self, url=self.help_url)
 
 
 class MEFMixin(object):
@@ -285,34 +298,3 @@ def ingest_params(self, pardict):
         """Ingest dictionary containing plugin parameters into plugin
         GUI and internal variables."""
         raise NotImplementedError('To be implemented by Ginga local plugin')
-
-
-def get_online_docs_url(plugin=None):
-    """
-    Return URL to online documentation closest to this stginga version.
-
-    Parameters
-    ----------
-    plugin : obj or `None`
-        Plugin object. If given, URL points to plugin doc directly.
-        If this function is called from within plugin class,
-        pass ``self`` here.
-
-    Returns
-    -------
-    url : str
-        URL to online documentation (top-level, if plugin == None).
-
-    """
-    stginga_ver = stginga.__version__
-    if re.match(r'^\d+\.\d+\.\d+$', stginga_ver):
-        rtd_version = stginga_ver
-    else:
-        # default to latest
-        rtd_version = 'latest'
-    url = f"{rtd_base_url}{rtd_version}"
-    if plugin is not None:
-        plugin_name = str(plugin)
-        url += f'/stginga/plugins_manual/{plugin_name}.html'
-
-    return url