pgadmin4/web/pgadmin/browser/utils.py

##########################################################################
#
# pgAdmin 4 - PostgreSQL Tools
#
# Copyright (C) 2013 - 2015, The pgAdmin Development Team
# This software is released under the PostgreSQL Licence
#
##########################################################################

"""Browser helper utilities"""

from abc import ABCMeta, abstractmethod, abstractproperty
from collections import OrderedDict
import flask
from flask.views import View, MethodViewType, with_metaclass
from flask.ext.babel import gettext
import six

from config import PG_DEFAULT_DRIVER
from pgadmin.browser import PgAdminModule
from pgadmin.utils.ajax import make_json_response

@six.add_metaclass(ABCMeta)
class NodeAttr(object):
    """
    """

    @abstractmethod
    def validate(self, mode, value):
        pass

    @abstractmethod
    def schema(self):
        pass


class PGChildModule:
    """
    class PGChildModule

    This is a base class for children/grand-children of PostgreSQL, and
    all Postgres Plus version (i.e. Postgres Plus Advanced Server, Green Plum,
    etc).

    Method:
    ------
    * BackendSupported(manager)
    - Return True when it supports certain version.
      Uses the psycopg2 server connection manager as input for checking the
      compatibility of the current module.

    * AddAttr(attr)
    - This adds the attribute supported for specific version only. It takes
      NodeAttr as input, and update max_ver, min_ver variables for this module.
    """

    def __init__(self, *args, **kwargs):
        self.min_ver = 1000000000
        self.max_ver = 0
        self.attributes = {}

        super(PGChildModule, self).__init__(*args, **kwargs)

    def BackendSupported(self, mangaer):
        sversion = getattr(mangaer, 'sversion', None)
        if (sversion is None or not isinstance(sversion, int)):
            return False

        if (self.min_ver is None and self.max_ver is None):
            return True

        assert(self.max_ver is None or isinstance(self.max_ver, int))
        assert(self.min_ver is None or isinstance(self.min_ver, int))
        assert(self.server_type is None or isinstance(self.server_type, list))

        if self.server_type is None or manager.server_type in self.server_type:
            if self.min_ver is None or self.min_ver <= sversion:
                if self.max_ver is None or self.max_ver >= sversion:
                    return True

        return False

    @abstractmethod
    def get_nodes(self, sid=None, **kwargs):
        pass

    def AddAttr(self, attr):
        assert(isinstance(attr, PGNodeAttr))

        name = getattr(attr, 'name', None)
        assert(name is not None and isinstance(name, str))
        assert(name not in self.attributes)
        # TODO:: Check for naming convention

        min_ver = getattr(attr, 'min_ver', None)
        assert(min_ver is None or isinstance(min_ver, int))

        max_ver = getattr(attr, 'max_ver', None)
        assert(max_ver is None or isinstance(max_ver, int))

        self.attributes[name] = attr

        if max_ver is None:
            self.max_ver = None
        elif self.max_var is not None and self.max_ver < max_ver:
            self.max_ver < max_ver

        if min_ver is None:
            self.min_ver = None
        elif self.min_ver is not None and self.min_ver > min_ver:
            self.min_ver = min_ver


class NodeView(with_metaclass(MethodViewType, View)):
    """
    A PostgreSQL Object has so many operaions/functions apart from CRUD
    (Create, Read, Update, Delete):
    i.e.
    - Reversed Engineered SQL
    - Modified Query for parameter while editing object attributes
      i.e. ALTER TABLE ...
    - Statistics of the objects
    - List of dependents
    - List of dependencies
    - Listing of the children object types for the certain node
      It will used by the browser tree to get the children nodes

    This class can be inherited to achieve the diffrent routes for each of the
    object types/collections.

    OPERATION      |              URL       | Method
    ---------------+------------------------+--------
    List           | /obj/[Parent URL]/     | GET
    Properties     | /obj/[Parent URL]/id   | GET
    Create         | /obj/[Parent URL]/     | POST
    Delete         | /obj/[Parent URL]/id   | DELETE
    Update         | /obj/[Parent URL]/id   | PUT

    SQL (Reversed  | /sql/[Parent URL]/id   | GET
    Engineering)   |
    SQL (Modified  | /sql/[Parent URL]/id   | POST
    Properties)    |

    Statistics     | /stats/[Parent URL]/id | GET
    Dependencies   | /deps/[Parent URL]/id  | GET
    Dependents     | /deps/[Parent URL]/id  | POST

    Children Nodes | /nodes/[Parent URL]/id | GET

    NOTE:
    Parent URL can be seen as the path to identify the particular node.

    i.e.
    In order to identify the TABLE object, we need server -> database -> schema
    information.
    """
    operations = dict({
        'obj': [
            {'get': 'properties', 'delete': 'delete', 'put': 'update'},
            {'get': 'list', 'post': 'create'}
        ],
        'nodes': [{'get': 'nodes'}],
        'sql': [{'get': 'sql', 'post': 'modified_sql'}],
        'stats': [{'get': 'statistics'}],
        'deps': [{'get': 'dependencies', 'post': 'dependents'}],
        'module.js': [{}, {}, {'get': 'module_js'}]
    })

    @classmethod
    def generate_ops(cls):
        cmds = []
        for op in cls.operations:
            idx = 0
            for ops in cls.operations[op]:
                meths = []
                for meth in ops:
                    meths.append(meth.upper())
                if len(meths) > 0:
                    cmds.append({
                        'cmd': op, 'req': (idx == 0),
                        'with_id': (idx != 2), 'methods': meths
                        })
                idx += 1
        return cmds

    # Inherited class needs to modify these parameters
    node_type = None
    # This must be an array object with attributes (type and id)
    parent_ids = []
    # This must be an array object with attributes (type and id)
    ids = []

    @classmethod
    def get_node_urls(cls):
        assert cls.node_type is not None, \
            "Please set the node_type for this class ({0})".format(
                str(cls.__class__.__name__))
        common_url = '/'
        for p in cls.parent_ids:
            common_url += '<{0}:{1}>/'.format(str(p['type']), str(p['id']))

        id_url = None
        for p in cls.ids:
            id_url = '{0}<{1}:{2}>'.format(common_url if not id_url else id_url,
                                           p['type'], p['id'])

        return id_url, common_url

    def __init__(self, **kwargs):
        self.cmd = kwargs['cmd']

    # Check the existance of all the required arguments from parent_ids
    # and return combination of has parent arguments, and has id arguments
    def check_args(self, **kwargs):
        has_id = has_args = True
        for p in self.parent_ids:
            if p['id'] not in kwargs:
                has_args = False
                break

        for p in self.ids:
            if p['id'] not in kwargs:
                has_id = False
                break

        return has_args, has_id and has_args

    def dispatch_request(self, *args, **kwargs):
        meth = flask.request.method.lower()
        if meth == 'head':
            meth = 'get'

        assert self.cmd in self.operations, \
                "Unimplemented Command ({0}) for {1}".format(
                    self.cmd,
                    str(self.__class__.__name__)
                    )

        has_args, has_id = self.check_args(**kwargs)

        assert (self.cmd in self.operations and
                (has_id and len(self.operations[self.cmd]) > 0 and
                    meth in self.operations[self.cmd][0]) or
                (not has_id and len(self.operations[self.cmd]) > 1 and
                    meth in self.operations[self.cmd][1]) or
                (len(self.operations[self.cmd]) > 2 and
                    meth in self.operations[self.cmd][2])), \
                "Unimplemented method ({0}) for command ({1}), which {2} an id".format(
                    meth, self.cmd,
                    'requires' if has_id else 'does not require'
                    )

        meth = self.operations[self.cmd][0][meth] if has_id else \
            self.operations[self.cmd][1][meth] if has_args and \
            meth in self.operations[self.cmd][1] else \
            self.operations[self.cmd][2][meth]

        method = getattr(self, meth, None)

        if method is None:
            return make_json_response(
                status=406,
                success=0,
                errormsg=gettext(
                    "Unimplemented method ({0}) for this url ({1})".format(
                        meth, flask.request.path)
                )
            )

        return method(*args, **kwargs)

    @classmethod
    def register_node_view(cls, blueprint):
        cls.blueprint = blueprint
        id_url, url = cls.get_node_urls()

        commands = cls.generate_ops()

        for c in commands:
            if c['with_id']:
                blueprint.add_url_rule(
                        '/{0}{1}'.format(
                            c['cmd'], id_url if c['req'] else url
                            ),
                        view_func=cls.as_view(
                            '{0}{1}'.format(
                                c['cmd'], '_id' if c['req'] else ''
                                ),
                            cmd=c['cmd']
                            ),
                        methods=c['methods']
                        )
            else:
                blueprint.add_url_rule(
                        '/{0}'.format(c['cmd']),
                        view_func=cls.as_view(
                            '{0}'.format(c['cmd']), cmd=c['cmd']
                            ),
                        methods=c['methods']
                        )

    def module_js(self, **kwargs):
        """
        This property defines (if javascript) exists for this node.
        Override this property for your own logic.
        """
        return flask.make_response(
                flask.render_template(
                    "{0}/{0}.js".format(self.node_type)
                    ),
                200, {'Content-Type': 'application/x-javascript'}
                )

    def nodes(self, *args, **kwargs):
        """Build a list of treeview nodes from the child nodes."""
        nodes = []

        for module in self.blueprint.submodules:
            nodes.extend(module.get_nodes(*args, **kwargs))

        return make_json_response(data=nodes)


class PGChildNode(object):

    def nodes(self, sid, **kwargs):
        """Build a list of treeview nodes from the child nodes."""

        from pgadmin.utils.driver import get_driver
        manager = get_driver(PG_DEFAULT_DRIVER).connection_manager(
                sid=sid
                )

        did = None
        if 'did' in kwargs:
            did = kwargs['did']

        conn = manager.connection(did=did)

        if not conn.connected():
            return precondition_required(
                    gettext(
                        "Please make a connection to the server first!"
                        )
                    )

        nodes = []
        for module in self.blueprint.submodules:
            if isinstance(module, PGChildModule):
                if sid is not None and manager is not None and \
                        module.BackendSupported(manager):
                    nodes.extend(module.get_nodes(sid=sid, **kwargs))
            else:
                nodes.extend(module.get_nodes(sid=sid, **kwargs))

        return make_json_response(data=nodes)


class PGChildNodeView(NodeView, PGChildNode):

    pass