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goto_engine.py
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goto_engine.py
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## This file is part of Invenio.
## Copyright (C) 2012 CERN.
##
## Invenio 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.
##
## Invenio is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Invenio; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
"""
Redirecting engine.
"""
import os
import optparse
from invenio.config import CFG_PYLIBDIR
from invenio.dbquery import run_sql, IntegrityError
from invenio.jsonutils import json, json_unicode_to_utf8
from invenio.pluginutils import PluginContainer, get_callable_documentation
from invenio.textutils import wait_for_user
CFG_GOTO_PLUGINS = PluginContainer(os.path.join(CFG_PYLIBDIR, 'invenio',
'goto_plugins', 'goto_plugin_*.py'), plugin_builder=lambda name, code: code.goto)
def register_redirection(label, plugin, parameters=None, update_on_duplicate=False):
"""
Register a redirection from /goto/<LABEL> to the URL returned by running the
given plugin (as available in CFG_GOTO_PLUGINS), with the given parameters.
@param label: the uniquely identifying label for this redirection
@type label: string
@param plugin: the algorithm that should resolve the redirection, usually:
"goto_plugin_FOO"
@type plugin: string
@param parameters: further parameters that should be passed to the plugin.
This should be a dictionary or None. Note that these parameters could
be overridden by the query parameters.
@type parameters: dict or None
@param update_on_duplicate: if False (default), if the label already exist it
L{register_redirection} will raise a ValueError exception. If True, it
will implicitly call L{update_redirection}.
@type update_on_duplicate: bool
@raises: ValueError in case of duplicate label and L{update_on_duplicate} is
set to False.
@note: parameters are going to be serialized to JSON before being stored
in the DB. Hence only JSON-serializable values should be put there.
"""
if run_sql("SELECT label FROM goto WHERE label=%s", (label, )):
raise ValueError("%s label already exists" % label)
if plugin not in CFG_GOTO_PLUGINS:
raise ValueError("%s plugin does not exist" % plugin)
if parameters is None:
parameters = {}
try:
parameters.items() ## dummy test to see if it exposes the dict interface
json_parameters = json.dumps(parameters)
except Exception, err:
raise ValueError("The parameters %s do not specify a valid JSON map: %s" % (parameters, err))
try:
run_sql("INSERT INTO goto(label, plugin, parameters, creation_date, modification_date) VALUES(%s, %s, %s, NOW(), NOW())", (label, plugin, json_parameters))
except IntegrityError:
if run_sql("SELECT label FROM goto WHERE label=%s", (label,)):
if update_on_duplicate:
update_redirection(label=label, plugin=plugin, parameters=parameters)
else:
raise ValueError("%s label already exists" % label)
else:
## This is due to some other issue
raise
def update_redirection(label, plugin, parameters=None):
"""
Update an existing redirection from /goto/<LABEL> to the URL returned by
running the given plugin (as available in CFG_GOTO_PLUGINS), with the given
parameters.
@param label: the uniquely identifying label for this redirection
@type label: string
@param plugin: the algorithm that should resolve the redirection, usually:
"goto_plugin_FOO"
@type plugin: string
@param parameters: further parameters that should be passed to the plugin.
This should be a dictionary or None. Note that these parameters could
be overridden by the query parameters.
@type parameters: dict or None
@raises: ValueError in case the label does not already exist.
@note: parameters are going to be serialized to JSON before being stored
in the DB. Hence only JSON-serializable values should be put there.
"""
if not run_sql("SELECT label FROM goto WHERE label=%s", (label, )):
raise ValueError("%s label does not already exist" % label)
if plugin not in CFG_GOTO_PLUGINS:
raise ValueError("%s plugin does not exist" % plugin)
if parameters is None:
parameters = {}
try:
parameters.items() ## dummy test to see if it exposes the dict interface
json_parameters = json.dumps(parameters)
except Exception, err:
raise ValueError("The parameters %s do not specify a valid JSON map: %s" % (parameters, err))
run_sql("UPDATE goto SET plugin=%s, parameters=%s, modification_date=NOW() WHERE label=%s", (plugin, json_parameters, label))
def drop_redirection(label):
"""
Delete an existing redirection identified by label.
@param label: the uniquely identifying label for this redirection
@type label: string
"""
run_sql("DELETE FROM goto WHERE label=%s", (label, ))
def get_redirection_data(label):
"""
Returns all information about a given redirection identified by label.
@param label: the label identifying the redirection
@type label: string
@returns: a dictionary with the following keys:
* label: the label
* plugin: the name of the plugin
* parameters: the parameters that are passed to the plugin
(deserialized from JSON)
* creation_date: datetime object on when the redirection was first
created.
* modification_date: datetime object on when the redirection was
last modified.
@rtype: dict
@raises ValueError: in case the label does not exist.
"""
res = run_sql("SELECT label, plugin, parameters, creation_date, modification_date FROM goto WHERE label=%s", (label, ))
if res:
return {'label': res[0][0],
'plugin': CFG_GOTO_PLUGINS[res[0][1]],
'parameters': json_unicode_to_utf8(json.loads(res[0][2])),
'creation_date': res[0][3],
'modification_date': res[0][4]}
else:
raise ValueError("%s label does not exist" % label)
def is_redirection_label_already_taken(label):
"""
Returns True in case the given label is already taken.
"""
return bool(run_sql("SELECT label FROM goto WHERE label=%s", (label,)))
def main():
"""
Entry point for the CLI
"""
def get_json_parameters_from_cli(option, dummy_opt_str, value, dummy_parser):
try:
option.parameters = json_unicode_to_utf8(json.loads(value))
except Exception, err:
raise optparse.OptionValueError("Cannot parse as a valid JSON serialization the provided parameters: %s. %s" % (value, err))
def get_parameter_from_cli(option, dummy_opt_str, value, dummy_parser):
if not hasattr(option, 'parameters'):
option.parameters = {}
param, value = value.split('=', 1)
try:
value = int(value)
except:
pass
option.parameters[param] = value
parser = optparse.OptionParser()
plugin_group = optparse.OptionGroup(parser, "Plugin Administration Options")
plugin_group.add_option("--list-plugins", action="store_const", dest="action", const="list-goto-plugins", help="List available GOTO plugins and their documentation")
plugin_group.add_option("--list-broken-plugins", action="store_const", dest="action", const="list-broken-goto-plugins", help="List broken GOTO plugins")
parser.add_option_group(plugin_group)
redirection_group = optparse.OptionGroup(parser, "Redirection Manipultation Options")
redirection_group.add_option("-r", "--register-redirection", metavar="LABEL", action="store", dest="register", help="Register a redirection with the provided LABEL")
redirection_group.add_option("-u", "--update-redirection", metavar="LABEL", action="store", dest="update", help="Update the redirection specified by the provided LABEL")
redirection_group.add_option("-g", "--get-redirection", metavar="LABEL", action="store", dest="get_redirection", help="Get all information about a redirection specified by LABEL")
redirection_group.add_option("-d", "--drop-redirection", metavar="LABEL", action="store", dest="drop_redirection", help="Drop an existing redirection specified by LABEL")
parser.add_option_group(redirection_group)
specific_group = optparse.OptionGroup(parser, "Specific Options")
specific_group.add_option("-P", "--plugin", metavar="PLUGIN", action="store", dest="plugin", help="Specify the plugin to use when registering or updating a redirection")
specific_group.add_option("-j", "--json-parameters", metavar="PARAMETERS", action="callback", type="string", callback=get_json_parameters_from_cli, help="Specify the parameters to provide to the plugin (serialized in JSON)")
specific_group.add_option("-p", "--parameter", metavar="PARAM=VALUE", action="callback", callback=get_parameter_from_cli, help="Specify a single PARAM=VALUE parameter to be provided to the plugin (alternative to the JSON serialization)", type="string")
parser.add_option_group(specific_group)
(options, dummy_args) = parser.parse_args()
if options.action == "list-goto-plugins":
print "GOTO plugins found:"
for component, goto in CFG_GOTO_PLUGINS.items():
print component + ' -> ' + get_callable_documentation(goto)
elif options.action == 'list-broken-goto-plugins':
print "Broeken GOTO plugins found:"
for component, error in CFG_GOTO_PLUGINS.get_broken_plugins().items():
print component + '->' + str(error)
elif options.register:
label = options.register
plugin = options.plugin
parameters = getattr(options, 'parameters', {})
if not plugin in CFG_GOTO_PLUGINS:
parser.error("%s is not a valid plugin" % plugin)
if is_redirection_label_already_taken(label):
parser.error("The specified label %s is already taken" % label)
register_redirection(label, plugin, parameters)
print "The redirection %s was successfully registered for the plugin %s with parameters %s" % (label, plugin, parameters)
elif options.update:
label = options.update
if not is_redirection_label_already_taken(label):
parser.error("The specified label %s does not exist" % label)
redirection_data = get_redirection_data(label)
plugin = options.plugin or redirection_data['plugin']
parameters = options.parameters or redirection_data['parameters']
if not plugin in CFG_GOTO_PLUGINS:
parser.error("%s is not a valid plugin" % plugin)
update_redirection(label, plugin, parameters=None)
print "The redirection %s was successfully updated for the plugin %s with parameters %s" % (label, plugin, parameters)
elif options.get_redirection:
label = options.get_redirection
if not is_redirection_label_already_taken(label):
parser.error("The specified label %s does not exist" % label)
print get_redirection_data(label)
elif options.drop_redirection:
label = options.drop_redirection
if is_redirection_label_already_taken(label):
wait_for_user("Are you sure you want to drop the redirection: %s\n%s" % (label, get_redirection_data(label)))
drop_redirection(label)
print "The redirection %s was successfully dropped" % label
else:
print "The specified label %s is not registered with any redirection" % label
else:
parser.print_help()
if __name__ == "__main__":
main()

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