Mercurial > hg > ltpda
changeset 2:18e956c96a1b database-connection-manager
Add LTPDADatabaseConnectionManager implementation. Matlab code
author | Daniele Nicolodi <nicolodi@science.unitn.it> |
---|---|
date | Sun, 04 Dec 2011 21:23:09 +0100 |
parents | 2014ba5b353a |
children | 960fe1aa1c10 |
files | m-toolbox/classes/+utils/@credentials/credentials.m m-toolbox/classes/+utils/@mysql/connect.m m-toolbox/classes/+utils/@mysql/mysql.m m-toolbox/classes/@LTPDADatabaseConnectionManager/LTPDADatabaseConnectionManager.m |
diffstat | 4 files changed, 733 insertions(+), 0 deletions(-) [+] |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/m-toolbox/classes/+utils/@credentials/credentials.m Sun Dec 04 21:23:09 2011 +0100 @@ -0,0 +1,183 @@ +classdef credentials + + properties + + hostname = []; + database = []; + username = []; + password = []; + expiry = 0; + + end % properties + + methods + + function obj = credentials(hostname, database, username, password) + % CREDENTIALS Constructor for credentials objects. + % + % Those are simple container objects to hold credentials required for + % establishing a connection to a database server, in addition to an + % expiry time. + % + % CREDENTIALS(hostname, database, username, password) The constructor can + % be called with any number of arguments. The default value for the object + % properties is the empty vector. + + switch nargin + case 1 + obj.hostname = hostname; + case 2 + obj.hostname = hostname; + obj.database = database; + case 3 + obj.hostname = hostname; + obj.database = database; + obj.username = username; + case 4 + obj.hostname = hostname; + obj.database = database; + obj.username = username; + obj.password = password; + end + end + + function str = char(obj, mode) + % CHAR Convert a credentials object to string representation. + % + % It takes an optional second argument that defines the representation to + % use. The default is to replace the password, if present, with the YES + % string, other possible modes are SHORT where password is omitted, or FULL + % where the password is shown at it is. + + if nargin < 2 + mode = ''; + end + switch mode + case 'short' + % do not show password + frm = 'mysql://%s/%s username=%s'; + str = sprintf(frm, obj.hostname, obj.database, obj.username); + case 'full' + % show password + frm = 'mysql://%s/%s username=%s password=%s'; + str = sprintf(frm, obj.hostname, obj.database, obj.username, obj.password); + otherwise + % by default only show if a password is known + passwd = []; + if ischar(obj.password) + passwd = 'YES'; + end + frm = 'mysql://%s/%s username=%s password=%s'; + str = sprintf(frm, obj.hostname, obj.database, obj.username, passwd); + end + end + + function disp(objs) + % DISP Overloaded display method for credentials objects. + % + % Uses the default string representation of the char() method where the + % password, if present, is replaced with the string YES. + + for obj = objs + disp([' ' char(obj) char(10)]); + end + end + + function len = length(obj) + % LENGTH Returns the number of not null fields in the object. + + len = 0; + if ~isempty(obj.hostname) + len = len + 1; + end + if ~isempty(obj.database) + len = len + 1; + end + if ~isempty(obj.username) + len = len + 1; + end + if ~isempty(obj.password) + len = len + 1; + end + end + + function rv = complete(obj) + % COMPLETE Checks if the credentials are complete. + % + % Credentials object are complete when they contains all the required + % information to connect to a database. Namely the HOSTNAME, DATABASE + % and USERNAME properties should not be empty, the PASSWORD property is + % allowed to be an empty string '' but not []. + + info = {'hostname', 'database', 'username'}; + for kk = 1:numel(info) + if isempty(obj.(info{kk})) + rv = false; + return; + end + end + if ~ischar(obj.password) + rv = false; + return; + end + rv = true; + end + + function rv = expired(obj) + % EXPIRED Checks if the credentials are expired. + % + % Credential objects expire when their expiry time is smaller than the + % current time in seconds since the epoch, as obtained by the time() + % function. Credentials with zero or negative expiry time never expire. + + rv = false; + if obj.expiry > 0 && double(time()) > obj.expiry + rv = true; + end + end + + function rv = match(obj, hostname, database, username) + % MATCH Check if the credentials object matches the given information. + % + % MATCH(obj, hostname) Returns true when HOSTANAME parameter match + % the object properties. + % + % MATCH(obj, hostname, database) Returns true when HOSTANAME and + % DATABASE parameters match the object properties. + % + % MATCH(obj, hostname, database, username) Returns true when + % HOSTANAME, DATABASE, and USERNAME parameters match the object + % properties. + + % default arguments + switch nargin + case 4 + case 3 + username = []; + case 2 + username = []; + database = []; + otherwise + error('### wrong number of parameters'); + end + + % default return value + rv = true; + + if ~strcmp(obj.hostname, hostname) + rv = false; + return; + end + if ischar(database) && ~strcmp(obj.database, database) + rv = false; + return; + end + if ischar(username) && ~strcmp(obj.username, username) + rv = false; + return; + end + end + + end % methods + +end \ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/m-toolbox/classes/+utils/@mysql/connect.m Sun Dec 04 21:23:09 2011 +0100 @@ -0,0 +1,38 @@ +function conn = connect(hostname, database, username, password) +% CONNECT Opens a connection to the given database. +% +% CALL: +% +% conn = utils.mysql.connect(hostname, database, username, password) +% +% This function returns a Java object implementing the java.sql.Connection +% interface connected to the given database using the provided credentials. +% If the connection fails because the given username and password pair is not +% accepted by the server an utils:mysql:connect:AccessDenied error is thrown. +% + + % informative message + import utils.const.* + utils.helper.msg(msg.PROC1, 'connection to mysql://%s/%s username=%s', hostname, database, username); + + % connection credential + uri = sprintf('jdbc:mysql://%s/%s', hostname, database); + db = javaObject('com.mysql.jdbc.Driver'); + pl = javaObject('java.util.Properties'); + pl.setProperty(db.USER_PROPERTY_KEY, username); + pl.setProperty(db.PASSWORD_PROPERTY_KEY, password); + + try + % connect + conn = db.connect(uri, pl); + catch ex + % haven't decided yet if this code should be here or higher in the stack + if strcmp(ex.identifier, 'MATLAB:Java:GenericException') + % exceptions handling in matlab sucks + if ~isempty(strfind(ex.message, 'java.sql.SQLException: Access denied')) + throw(MException('utils:mysql:connect:AccessDenied', '### access denied').addCause(ex)); + end + end + rethrow(ex); + end +end
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/m-toolbox/classes/+utils/@mysql/mysql.m Sun Dec 04 21:23:09 2011 +0100 @@ -0,0 +1,10 @@ +classdef mysql +% UTILS.MYSQL MySQL database utilities. + + methods (Static) + + conn = connect(hostname, database, username, password) + + end % static methods + +end
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/m-toolbox/classes/@LTPDADatabaseConnectionManager/LTPDADatabaseConnectionManager.m Sun Dec 04 21:23:09 2011 +0100 @@ -0,0 +1,502 @@ +classdef LTPDADatabaseConnectionManager < handle + + properties(SetAccess=private) + + connections = {}; + credentials = {}; + + p_credentialsExpiry = 3600; + p_cachePassword = 2; + p_maxConnectionsNumber = 10; + + end % private properties + + properties(Dependent=true) + + credentialsExpiry; % seconds + cachePassword; % 0=no 1=yes 2=ask + maxConnectionsNumber; + + end % dependent properties + + methods(Static) + + function reset() + % RESET Resets the state of the connection manager. + % + % This static method removes the LTPDADatabaseConnectionManager + % instance data from the appdata storage. Causes the reset of the + % credentials cache and the removal of all the connections from + % the connection pool. + + rmappdata(0, LTPDADatabaseConnectionManager.appdataKey); + end + + + function key = appdataKey() + % APPDATAKEY Returns the key used to store instance data in appdata. + % + % This is defined as static method, and not has an instance constant + % property, to to be accessible by the reset static method. + + key = 'LTPDADatabaseConnectionManager'; + end + + end % static methods + + methods + + function cm = LTPDADatabaseConnectionManager() + % LTPDACONNECTIONMANAGER Manages credentials and database connections. + % + % This constructor returns an handler to a LTPDADatabaseConnectionManager + % class instance. Database connections can be obtained trough the + % obtained object with the connect() method. + % + % The purpose of this class it to keep track of open database connections + % and to cache database credentials. It must be used in all LTPDA toolbox + % functions that required to obtain database connections. Its behaviour can + % be configured via LTPDA toolbox user preferences. The object status is + % persisted trough the appdata matlab facility. + + % import credentials class + import utils.credentials + + % load state from appdata + acm = getappdata(0, cm.appdataKey()); + + if isempty(acm) + % store state in appdata + setappdata(0, cm.appdataKey(), cm); + + import utils.const.* + utils.helper.msg(msg.PROC1, 'new connection manager'); + else + cm = acm; + end + end + + function str = disp(cm) + disp(sprintf('%s()\n', class(cm))); + end + + + function val = get.credentialsExpiry(cm) + % obtain from user preferences + %p = getappdata(0, 'LTPDApreferences'); + val = cm.p_credentialsExpiry; + end + + + function val = get.cachePassword(cm) + % obtain from user preferences + %p = getappdata(0, 'LTPDApreferences'); + val = cm.p_cachePassword; + end + + + function val = get.maxConnectionsNumber(cm) + % obtain from user preferences + %p = getappdata(0, 'LTPDApreferences'); + val = cm.p_maxConnectionsNumber; + end + + + function n = count(cm) + % COUNT Returns the number of open connections in the connections pool. + % + % This method has the side effect of removing all closed connections from + % the connections pool, so that the underlying objects can be garbage + % collected. + + import utils.const.* + + % find closed connections in the pool + mask = false(numel(cm.connections), 1); + for kk = 1:numel(cm.connections) + if cm.connections{kk}.isClosed() + utils.helper.msg(msg.PROC1, 'connection id=%d closed', kk); + mask(kk) = true; + end + end + + % remove them + cm.connections(mask) = []; + + % count remainig ones + n = numel(cm.connections); + end + + function clear(cm) + % CLEAR Removes all cached credentials from the connection manager. + cm.credentials = {}; + end + + + function conn = connect(cm, varargin) + % CONNECT Uses provided credential to establish a database connection. + % + % CONNECT(hostname, database, username, password) Returns an object + % implementing the java.sql.Connection interface handing a connection to + % the specified database. Any of the parameter is optional. The user will + % be queried for the missing information. + % + % The returned connection are added to a connections pool. When the number + % of connections in the pool exceeds a configurable maximum, no more + % connection are instantiated. Closed connections are automatically + % removed from the pool. + % + % CONNECT(pl) Works as the above but the parameters are obtained from the + % plist object PL. If the 'connection' parameter in the plist contains an + % object implementing the java.sql.Connection interface, this object is + % returned instead that opening a new connection. In this case the + % connection in not added to the connection pool. + + import utils.const.* + + % save current credentials cache + cache = cm.credentials; + + % count open connections in the pool + count = cm.count(); + + % check parameters + if numel(varargin) == 1 && isa(varargin{1}, 'plist') + + % extract parameters from plist + pl = varargin{1}; + + % check if we have a connection parameter + conn = find(pl, 'conn'); + if ~isempty(conn) + % check that it implements java.sql.Connection interface + if ~isa(conn, 'java.sql.Connection') + error('### connection is not valid database connection'); + end + % return this connection + return; + end + + % otherwise + hostname = find(pl, 'hostname'); + database = find(pl, 'database'); + username = find(pl, 'username'); + password = find(pl, 'password'); + + % if there is no hostname ignore other parameters + if ~ischar(hostname) || isempty(hostname) + varargin = {}; + % if there is no database ignore other parameters + elseif ~ischar(database) || isempty(database) + varargin = {hostname}; + % if there is no username ignore other parameters + elseif ~ischar(username) || isempty(username) + varargin = {hostname, database}; + % password can not be null but can be an empty string + elseif ~ischar(password) + varargin = {hostname, database, username}; + else + varargin = {hostname, database, username, password}; + end + end + + % check number of connections + if count > cm.maxConnectionsNumber + error('### too many open connections'); + end + + % connect + try + conn = cm.getConnection(varargin{:}); + + % add connection to pool + utils.helper.msg(msg.PROC1, 'add connection to pool'); + cm.connections{end+1} = conn; + + catch ex + % restore our copy of the credentials cache + utils.helper.msg(msg.PROC1, 'undo cache changes'); + cm.credentials = cache; + + % hide implementation details + ex.throw(); + end + end + + + function close(cm, ids) + % CLOSE Forces connections to be closed. + % + % In the case bugs in other routines working with database connections + % produce orphan connections, this method can be used to force the close + % of those connections. + % + % CLOSE(ids) Closes the connections with the corresponding IDs in the + % connections pool. If no ID is given all connections in the pool are + % closed. + + if nargin < 2 + ids = 1:numel(cm.connections); + end + cellfun(@close, cm.connections(ids)); + + % remove closed connections from pool + cm.count(); + end + + + function add(cm, c) + % ADD Adds credentials to the credentials cache. + % + % This method can be used to initialize or add to the cache, credentials + % that will be used in subsequent connections attempts. This method accepts + % only credentials in the form of utils.credentials objects. + + % check input arguments + if nargin < 2 || ~isa(c, 'utils.credentials') + error('### invalid call'); + end + + % add to the cache + cm.cacheCredentials(c); + end + + end % methods + + methods(Access=private) + + function conn = getConnection(cm, varargin) + % GETCONNECTION Where the implementation of the connect method really is. + + import utils.const.* + + % handle variable number of arguments + switch numel(varargin) + case 0 + % find credentials + [hostname, database, username] = cm.selectDatabase([cm.credentials{:}]); + conn = cm.getConnection(hostname, database, username); + + case 1 + % find credentials + cred = cm.findCredentials(varargin{:}); + if numel(cred) == 0 + cred = utils.credentials(varargin{:}); + end + [hostname, database, username] = cm.selectDatabase(cred); + conn = cm.getConnection(hostname, database, username); + + case 2 + % find credentials + cred = cm.findCredentials(varargin{:}); + switch numel(cred) + case 0 + conn = cm.getConnection(varargin{1}, varargin{2}, []); + case 1 + conn = cm.getConnection(cred.hostname, cred.database, cred.username); + otherwise + [hostname, database, username] = cm.selectDatabase(cred); + conn = cm.getConnection(hostname, database, username); + end + + case 3 + % find credentials + cred = cm.findCredentials(varargin{1}, varargin{2}, varargin{3}); + switch numel(cred) + case 0 + % no credentials found + usernames = { varargin{3} }; + if isempty(varargin{3}) + % use usernames for same hostname + tmp = cm.findCredentials(varargin{1}); + if ~isempty(tmp) + usernames = { tmp(:).username }; + end + end + % build credentials objects + tmp = {}; + for kk = 1:numel(usernames) + tmp{kk} = utils.credentials(varargin{1}, varargin{2}, usernames{kk}); + end + % convert from cell array to array + cred = [tmp{:}]; + case 1 + % credentials in cache + utils.helper.msg(msg.PROC1, 'use cached credentials'); + otherwise + % we should not have more than one credentials set + error('### more than one credentials set matching'); + end + + cache = false; + if (numel(cred) > 1) || ~cred.complete + % ask for password + [username, password, cache] = cm.inputCredentials(cred); + + % cache credentials + cred = utils.credentials(varargin{1}, varargin{2}, username); + cm.cacheCredentials(cred); + + % add password to credentials + cred.password = password; + end + + % try to connect + try + conn = utils.mysql.connect(cred.hostname, cred.database, cred.username, cred.password); + catch ex + % look for access denied errors + if strcmp(ex.identifier, 'utils:mysql:connect:AccessDenied') + % ask for new new credentials + utils.helper.msg(msg.IMPORTANT, ex.message); + conn = cm.getConnection(varargin{1}, varargin{2}, varargin{3}); + else + % error out + throw(ex); + end + end + + % cache password + if cache + utils.helper.msg(msg.PROC1, 'cache password'); + cm.cacheCredentials(cred); + end + + case 4 + % connect + conn = utils.mysql.connect(varargin{1}, varargin{2}, varargin{3}, varargin{4}); + + if cm.cachePassword == 1 + % cache credentials with password + cred = utils.credentials(varargin{1}, varargin{2}, varargin{3}, varargin{4}); + else + % cache credentials without password + cred = utils.credentials(varargin{1}, varargin{2}, varargin{3}); + end + cm.cacheCredentials(cred); + + otherwise + error('### invalid call') + end + + end + + + function ids = findCredentialsId(cm, varargin) + % FINDCREDENTIALSID Find credentials in the cache and returns their IDs. + + import utils.const.* + ids = []; + + for kk = 1:numel(cm.credentials) + % invalidate expired passwords + if expired(cm.credentials{kk}) + utils.helper.msg(msg.PROC1, 'cache entry id=%d expired', kk); + cm.credentials{kk}.password = []; + cm.credentials{kk}.expiry = 0; + end + + % match input with cache + if match(cm.credentials{kk}, varargin{:}) + ids = [ ids kk ]; + end + end + end + + + function cred = findCredentials(cm, varargin) + % FINDCREDENTIALS Find credentials in the cache and returns them in a list. + + % default + cred = []; + + % search + ids = findCredentialsId(cm, varargin{:}); + + % return a credentials objects array + if ~isempty(ids) + cred = [cm.credentials{ids}]; + end + end + + + function cacheCredentials(cm, c) + % CACHECREDENTIALS Adds to or updates the credentials cache. + + import utils.const.* + + % find entry to update + ids = findCredentialsId(cm, c.hostname, c.database, c.username); + + % set password expiry time + if ischar(c.password) + c.expiry = double(time()) + cm.credentialsExpiry; + end + + if isempty(ids) + % add at the end + utils.helper.msg(msg.PROC1, 'add cache entry %s', char(c)); + cm.credentials{end+1} = c; + else + for id = ids + % update only if the cached informations are less than the one we have + if length(c) > length(cm.credentials{id}) + utils.helper.msg(msg.PROC1, 'update cache entry id=%d %s', id, char(c)); + cm.credentials{id} = c; + else + % always update expiry time + cm.credentials{id}.expiry = c.expiry; + end + end + end + end + + + function [username, password, cache] = inputCredentials(cm, cred) + % INPUTCREDENTIALS Queries the user for database username and password. + + % build a cell array of usernames + users = {}; + for id = 1:numel(cred) + if ~isempty(cred(id).username) + users = [ users { cred(id).username } ]; + end + end + users = sort(unique(users)); + + parent = com.mathworks.mde.desk.MLDesktop.getInstance().getMainFrame(); + dialog = javaObjectEDT('connectionmanager.CredentialsDialog', ... + parent, cred(1).hostname, cred(1).database, users, cm.cachePassword); + dialog.show(); + if dialog.cancelled + throw(MException('utils:mysql:connect:UserCancelled', '### user cancelled')); + end + username = char(dialog.username); + password = char(dialog.password); + cache = logical(dialog.cache); + end + + + function [hostname, database, username] = selectDatabase(cm, credentials) + % SELECTDATABASE Makes the user choose to which database connect to. + + parent = com.mathworks.mde.desk.MLDesktop.getInstance().getMainFrame(); + dialog = javaObjectEDT('connectionmanager.DatabaseSelectorDialog', parent); + for c = credentials + dialog.add(c.hostname, c.database, c.username); + end + dialog.show(); + if dialog.cancelled + throw(MException('utils:mysql:connect:UserCancelled', '### user cancelled')); + end + hostname = char(dialog.hostname); + database = char(dialog.database); + username = char(dialog.username); + if isempty(username) + username = []; + end + end + + end % private methods + +end % classdef