Merge pull request #365 from zephraph/custom-locators

Added ```Add Location Strategy``` Keyword

Author: zephraph

CHANGES.rst

@@ -28,6 +28,7 @@ Release Notes
 - 'Capture Screenshot' now attempts to create its containing directory if the directory
   specified in the filename does not exist.
 - 'Choose File' now fails if the file doesn't exist
+- Added new keywords 'Add Location Strategy' and 'Remove Location Strategy'
   [zephraph]
 
 - Added 'Get Window Position' and 'Set Window Position' keywords matching the

src/Selenium2Library/__init__.py

@@ -1,6 +1,7 @@
 import os
 from keywords import *
 from version import VERSION
+from utils import LibraryListener
 
 __version__ = VERSION
 
@@ -79,6 +80,25 @@ class Selenium2Library(
     | css        | Table Should Contain `|` css=table.my_class `|` text               | Matches by @id or @name attribute |
     | xpath      | Table Should Contain `|` xpath=//table/[@name="my_table"] `|` text | Matches by @id or @name attribute |
 
+    = Custom Locators =
+
+    If more complex lookups are required than what is provided through the default locators, custom lookup strategies can
+    be created. Using custom locators is a two part process. First, create a keyword that returns the WebElement
+    that should be acted on.
+
+    | Custom Locator Strategy | [Arguments] | ${browser} | ${criteria} | ${tag} | ${constraints} |
+    |   | ${retVal}= | Execute Javascript | return window.document.getElementById('${criteria}'); |
+    |   | [Return] | ${retVal} |
+
+    This keyword is a reimplementation of the basic functionality of the `id` locator where `${browser}` is a reference
+    to the WebDriver instance and `${criteria}` is the text of the locator (i.e. everything that comes after the = sign).
+    To use this locator it must first be registered with `Add Location Strategy`.
+
+    Add Location Strategy  custom  Custom Locator Strategy
+
+    The first argument of `Add Location Strategy` specifies the name of the lookup strategy (which must be unique). After
+    registration of the lookup strategy, the usage is the same as other locators. See `Add Location Strategy` for more details.
+
     = Timeouts =
 
     There are several `Wait ...` keywords that take timeout as an
@@ -129,3 +149,4 @@ def __init__(self, timeout=5.0, implicit_wait=0.0, run_on_failure='Capture Page
         self.set_selenium_timeout(timeout)
         self.set_selenium_implicit_wait(implicit_wait)
         self.register_keyword_to_run_on_failure(run_on_failure)
+        self.ROBOT_LIBRARY_LISTENER = LibraryListener()

src/Selenium2Library/keywords/_element.py

@@ -2,6 +2,7 @@
 from selenium.webdriver.common.action_chains import ActionChains
 from Selenium2Library import utils
 from Selenium2Library.locators import ElementFinder
+from Selenium2Library.locators import CustomLocator
 from keywordgroup import KeywordGroup
 
 class _ElementKeywords(KeywordGroup):
@@ -601,6 +602,38 @@ def xpath_should_match_x_times(self, xpath, expected_xpath_count, message='', lo
         self._info("Current page contains %s elements matching '%s'."
                    % (actual_xpath_count, xpath))
 
+    # Public, custom
+    def add_location_strategy(self, strategy_name, strategy_keyword, persist=False):
+        """Adds a custom location strategy based on a user keyword. Location strategies are
+        automatically removed after leaving the current scope by default. Setting `persist`
+        to any non-empty string will cause the location strategy to stay registered throughout
+        the life of the test.
+
+        Trying to add a custom location strategy with the same name as one that already exists will
+        cause the keyword to fail.
+
+        Custom locator keyword example:
+        | Custom Locator Strategy | [Arguments] | ${browser} | ${criteria} | ${tag} | ${constraints} |
+        |   | ${retVal}= | Execute Javascript | return window.document.getElementById('${criteria}'); |
+        |   | [Return] | ${retVal} |
+
+        Usage example:
+        | Add Location Strategy | custom | Custom Locator Strategy |
+        | Page Should Contain Element | custom=my_id |
+
+        See `Remove Location Strategy` for details about removing a custom location strategy.
+        """
+        strategy = CustomLocator(strategy_name, strategy_keyword)
+        self._element_finder.register(strategy, persist)
+
+    def remove_location_strategy(self, strategy_name):
+        """Removes a previously added custom location strategy.
+        Will fail if a default strategy is specified.
+
+        See `Add Location Strategy` for details about adding a custom location strategy.
+        """
+        self._element_finder.unregister(strategy_name)
+
     # Private
 
     def _element_find(self, locator, first_only, required, tag=None):
@@ -727,4 +760,3 @@ def _page_should_not_contain_element(self, locator, tag, message, loglevel):
             raise AssertionError(message)
         self._info("Current page does not contain %s '%s'."
                    % (element_name, locator))
-

src/Selenium2Library/locators/__init__.py

@@ -1,9 +1,11 @@
 from elementfinder import ElementFinder
 from tableelementfinder import TableElementFinder
 from windowmanager import WindowManager
+from customlocator import CustomLocator
 
 __all__ = [
-    "ElementFinder", 
-    "TableElementFinder", 
-    "WindowManager"
-]
+    "ElementFinder",
+    "TableElementFinder",
+    "WindowManager",
+    "CustomLocator"
+]

src/Selenium2Library/locators/customlocator.py

@@ -0,0 +1,19 @@
+from robot.libraries.BuiltIn import BuiltIn
+
+try:
+    string_type = basestring
+except NameError:
+    string_type = str
+
+class CustomLocator(object):
+
+    def __init__(self, name, keyword):
+        self.name = name
+        self.keyword = keyword
+
+    def find(self, *args):
+        element = BuiltIn().run_keyword(self.keyword, *args)
+        if hasattr(element, '__len__') and (not isinstance(element, string_type)):
+            return element
+        else:
+            return [element]

src/Selenium2Library/locators/elementfinder.py

@@ -1,6 +1,7 @@
 from Selenium2Library import utils
 from robot.api import logger
 from robot.utils import NormalizedDict
+from robot.libraries.BuiltIn import BuiltIn
 
 
 class ElementFinder(object):
@@ -22,6 +23,7 @@ def __init__(self):
             'default': self._find_by_default
         }
         self._strategies = NormalizedDict(initial=strategies, caseless=True, spaceless=True)
+        self._default_strategies = strategies.keys()
 
     def find(self, browser, locator, tag=None):
         assert browser is not None
@@ -35,6 +37,30 @@ def find(self, browser, locator, tag=None):
         (tag, constraints) = self._get_tag_and_constraints(tag)
         return strategy(browser, criteria, tag, constraints)
 
+    def register(self, strategy, persist):
+        if strategy.name in self._strategies:
+            raise AttributeError("The custom locator '" + strategy.name +
+            "' cannot be registered. A locator of that name already exists.")
+        self._strategies[strategy.name] = strategy.find
+
+        if not persist:
+            # Unregister after current scope ends
+            suite = BuiltIn().get_variable_value('${SUITE NAME}')
+            test  = BuiltIn().get_variable_value('${TEST NAME}', '')
+            scope =  suite + '.' + test if test != '' else suite
+            utils.events.on('scope_end', scope, self.unregister, strategy.name)
+
+    def unregister(self, strategy_name):
+        if strategy_name in self._default_strategies:
+            raise AttributeError("Cannot unregister the default strategy '" + strategy_name + "'")
+        elif strategy_name not in self._strategies:
+            logger.info("Cannot unregister the non-registered strategy '" + strategy_name + "'")
+        else:
+            del self._strategies[strategy_name]
+
+    def has_strategy(self, strategy_name):
+        return strategy_name in self.strategies
+
     # Strategy routines, private
 
     def _find_by_identifier(self, browser, criteria, tag, constraints):
@@ -90,7 +116,7 @@ def _find_by_tag_name(self, browser, criteria, tag, constraints):
         return self._filter_elements(
             browser.find_elements_by_tag_name(criteria),
             tag, constraints)
-            
+
     def _find_by_sc_locator(self, browser, criteria, tag, constraints):
         js = "return isc.AutoTest.getElement('%s')" % criteria.replace("'", "\\'")
         return self._filter_elements([browser.execute_script(js)], tag, constraints)

src/Selenium2Library/utils/__init__.py

@@ -1,13 +1,17 @@
 import os
 from fnmatch import fnmatch
 from browsercache import BrowserCache
+from librarylistener import LibraryListener
+import events
 
 __all__ = [
     "get_child_packages_in",
     "get_module_names_under",
     "import_modules_under",
     "escape_xpath_value",
-    "BrowserCache"
+    "BrowserCache",
+    "LibraryListener",
+    "events"
 ]
 
 # Public
@@ -18,7 +22,7 @@ def get_child_packages_in(root_dir, include_root_package_name=True, exclusions=N
     _discover_child_package_dirs(
         root_dir,
         _clean_exclusions(exclusions),
-        lambda abs_path, relative_path, name: 
+        lambda abs_path, relative_path, name:
             packages.append(root_package_str + relative_path.replace(os.sep, '.')))
     return packages
 
@@ -29,7 +33,7 @@ def get_module_names_under(root_dir, include_root_package_name=True, exclusions=
         root_dir,
         _clean_exclusions(exclusions),
         pattern if pattern is not None else "*.*",
-        lambda abs_path, relative_path, name: 
+        lambda abs_path, relative_path, name:
             module_names.append(root_package_str + os.path.splitext(relative_path)[0].replace(os.sep, '.')))
     return module_names
 
@@ -65,7 +69,7 @@ def _discover_child_package_dirs(root_dir, exclusions, callback, relative_dir=No
         item_abs_path = os.path.join(root_dir, item_relative_path)
         if os.path.isdir(item_abs_path):
             if os.path.exists(os.path.join(item_abs_path, "__init__.py")):
-                exclusion_matches = [ exclusion for exclusion in exclusions 
+                exclusion_matches = [ exclusion for exclusion in exclusions
                     if os.sep + item_relative_path.lower() + os.sep == exclusion ]
                 if not exclusion_matches:
                     callback(item_abs_path, item_relative_path, item)

src/Selenium2Library/utils/events/__init__.py

@@ -0,0 +1,27 @@
+from scope_event import ScopeStart, ScopeEnd
+
+_registered_events = [ ScopeStart, ScopeEnd ]
+_events = []
+
+__all__ = [
+    "on",
+    "dispatch",
+    "register_event"
+]
+
+def on(event_name, *args, **kwargs):
+    for event in _registered_events:
+        if event.name == event_name:
+            _events.append(event(*args, **kwargs))
+            return
+
+def dispatch(event_name, *args, **kwargs):
+    for event in _events:
+        if event.name == event_name:
+            event.trigger(*args, **kwargs)
+
+def register_event(event):
+    for registered_event in _registered_events:
+        if event.name == registered_event.name:
+            raise AttributeError("An event with the name " + event.name + " already exists.")
+    _registered_events.append(event)

src/Selenium2Library/utils/events/event.py

@@ -0,0 +1,7 @@
+import abc
+
+class Event(object):
+
+    @abc.abstractmethod
+    def trigger(self, *args, **kwargs):
+        pass

src/Selenium2Library/utils/events/scope_event.py

@@ -0,0 +1,18 @@
+from event import Event
+
+class ScopeEvent(Event):
+    def __init__(self, scope, action, *args, **kwargs):
+        self.scope = scope
+        self.action = action
+        self.action_args = args
+        self.action_kwargs = kwargs
+
+    def trigger(self, *args, **kwargs):
+        if args[0] == self.scope:
+            self.action(*self.action_args, **self.action_kwargs)
+
+class ScopeStart(ScopeEvent):
+    name = 'scope_start'
+
+class ScopeEnd(ScopeEvent):
+    name = 'scope_end'