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  • Objective C style nil in java?

    - by Usman Ismail
    Objective C has a concept of a nil object which would accept any method call with any parameters without complaining and silently return another nil. I have used something similar in Java using easymock and mockito for testing. Is there something similar for main line code? Is it even a good idea to have something like this? One use-case where I am considering using it is with optional metrics. We have codahale metrics counters on which we call mark() every time an event is generated. This is surrounded by an If/then to check for metrics enabled flag. I could just use a nil object as counter and silently accept the mark call if metrics are not enabled.

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  • NullReferenceException when accessing variables in a 2D array in Unity

    - by Syed
    I have made a class including variables in Monodevelop which is: public class GridInfo : MonoBehaviour { public float initPosX; public float initPosY; public bool inUse; public int f; public int g; public int h; public GridInfo parent; public int y,x; } Now I am using its class variable in another class, Map.cs which is: public class Map : MonoBehaviour { public static GridInfo[,] Tile = new GridInfo[17, 23]; void Start() { Tile[0,0].initPosX = initPosX; //Line 49 } } I am not getting any error on runtime, but when I play in unity it is giving me error NullReferenceException: Object reference not set to an instance of an object Map.Start () (at Assets/Scripts/Map.cs:49) I am not inserting this script in any gameobject, as Map.cs will make a GridInfo type array, I have also tried using variables using GetComponent, where is the problem ?

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  • OpenIndiana (illumos): vmxnet3 interface lost on reboot

    - by protomouse
    I want my VMware vmxnet3 interface to be brought up with DHCP on boot. I can manually configure the NIC with: # ifconfig vmxnet3s0 plumb # ipadm create-addr -T dhcp vmxnet3s0/v4dhcp But after creating /etc/dhcp.vmxnet3s0 and rebooting, the interface is down and the logs show: Aug 13 09:34:15 neumann vmxnet3s: [ID 654879 kern.notice] vmxnet3s:0: getcapab(0x200000) -> no Aug 13 09:34:15 neumann vmxnet3s: [ID 715698 kern.notice] vmxnet3s:0: stop() Aug 13 09:34:17 neumann vmxnet3s: [ID 654879 kern.notice] vmxnet3s:0: getcapab(0x200000) -> no Aug 13 09:34:17 neumann vmxnet3s: [ID 920500 kern.notice] vmxnet3s:0: start() Aug 13 09:34:17 neumann vmxnet3s: [ID 778983 kern.notice] vmxnet3s:0: getprop(TxRingSize) -> 256 Aug 13 09:34:17 neumann vmxnet3s: [ID 778983 kern.notice] vmxnet3s:0: getprop(RxRingSize) -> 256 Aug 13 09:34:17 neumann vmxnet3s: [ID 778983 kern.notice] vmxnet3s:0: getprop(RxBufPoolLimit) -> 512 Aug 13 09:34:17 neumann nwamd[491]: [ID 605049 daemon.error] 1: nwamd_set_unset_link_properties: dladm_set_linkprop failed: operation not supported Aug 13 09:34:17 neumann vmxnet3s: [ID 654879 kern.notice] vmxnet3s:0: getcapab(0x20000) -> no Aug 13 09:34:17 neumann nwamd[491]: [ID 751932 daemon.error] 1: nwamd_down_interface: ipadm_delete_addr failed on vmxnet3s0: Object not found Aug 13 09:34:17 neumann nwamd[491]: [ID 819019 daemon.error] 1: nwamd_plumb_unplumb_interface: plumb IPv4 failed for vmxnet3s0: Operation not supported on disabled object Aug 13 09:34:17 neumann nwamd[491]: [ID 160156 daemon.error] 1: nwamd_plumb_unplumb_interface: plumb IPv6 failed for vmxnet3s0: Operation not supported on disabled object Aug 13 09:34:17 neumann nwamd[491]: [ID 771489 daemon.error] 1: add_ip_address: ipadm_create_addr failed on vmxnet3s0: Operation not supported on disabled object Aug 13 09:34:17 neumann nwamd[491]: [ID 405346 daemon.error] 9: start_dhcp: ipadm_create_addr failed for vmxnet3s0: Operation not supported on disabled object I then tried disabling network/physical:nwam in favour of network/physical:default. This works, the interface is brought up but physical:default fails and my network services (e.g. NFS) refuse to start. # ifconfig -a lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1 inet 127.0.0.1 netmask ff000000 vmxnet3s0: flags=1004843<UP,BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 vmxnet3s0:1: flags=1004842<BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 vmxnet3s0:2: flags=1004842<BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 vmxnet3s0:3: flags=1004842<BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 vmxnet3s0:4: flags=1004842<BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 vmxnet3s0:5: flags=1004842<BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 vmxnet3s0:6: flags=1004842<BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 vmxnet3s0:7: flags=1004842<BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 vmxnet3s0:8: flags=1004842<BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 9000 index 2 inet 192.168.178.248 netmask ffffff00 broadcast 192.168.178.255 lo0: flags=2002000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv6,VIRTUAL> mtu 8252 index 1 inet6 ::1/128 vmxnet3s0: flags=20002000840<RUNNING,MULTICAST,IPv6> mtu 9000 index 2 inet6 ::/0 # cat /var/svc/log/network-physical\:default.log [ Aug 16 09:46:39 Enabled. ] [ Aug 16 09:46:41 Executing start method ("/lib/svc/method/net-physical"). ] [ Aug 16 09:46:41 Timeout override by svc.startd. Using infinite timeout. ] starting DHCP on primary interface vmxnet3s0 ifconfig: vmxnet3s0: DHCP is already running [ Aug 16 09:46:43 Method "start" exited with status 96. ] NFS server not running: # svcs -xv network/nfs/server svc:/network/nfs/server:default (NFS server) State: offline since August 16, 2012 09:46:40 AM UTC Reason: Service svc:/network/physical:default is not running because a method failed. See: http://illumos.org/msg/SMF-8000-GE Path: svc:/network/nfs/server:default svc:/milestone/network:default svc:/network/physical:default Reason: Service svc:/network/physical:nwam is disabled. See: http://illumos.org/msg/SMF-8000-GE Path: svc:/network/nfs/server:default svc:/milestone/network:default svc:/network/physical:nwam Reason: Service svc:/network/nfs/nlockmgr:default is disabled. See: http://illumos.org/msg/SMF-8000-GE Path: svc:/network/nfs/server:default svc:/network/nfs/nlockmgr:default See: man -M /usr/share/man -s 1M nfsd Impact: This service is not running. I'm new to the world of Solaris, so any help solving would be much appreciated. Thanks!

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  • Assign highest priority to my local repository

    - by Anwar Shah
    Original question was : "How to assign highest priority to local repository without using sources.list file" I have setup a local repository with packages I downloaded. I use it to avoid downloading the same packages over the Internet, when I need to reinstall my Ubuntu. It is a basic repository, created with apt-ftparchive packages . > Packages. I made this a trusted repository to avoid "unauthenticated repository" warning. (When you have a untrusted repository, apt or synaptic try to download the same packages over the Internet, 'cause it is trusted). I have been using this local repository for at least 1 years. But I have to always put my local repository line at the top of the sources.list file to use this. But this is annoying, since I must open a terminal and do some typing on it every time I reinstall Ubuntu, though there is a better tool software-properties-gtk. I cannot use this tool since it place the source line at the end of `sources.list. And the real problem is that, the apt or synaptic always download a package from the source which is mentioned earlier, without inspecting whether the packages are already available in the local repository. So, I have no choice but to place the local source at the top of sources.list doing terminal (I actually don't hate terminal, but I need a solution) . I have tried this method. But this does not help me. My preference file is this in /etc/apt/preferences.d/local-pin-900 Package: * Pin: release o=Local,n=ubuntu-local Pin-Priority: 900 My release file is this Origin: Local Label: Local-Ubuntu Description: Local Ubuntu Repository Codename: ubuntu-local MD5Sum: ed43222856d18f389c637ac3d7dd6f85 1043412 Packages d41d8cd98f00b204e9800998ecf8427e 0 Sources When I enable the apt-preference, the apt-cache policy correctly shows the preference, e.g. It shows the local repository has the highest priority. But when I do this sudo apt-get install <package-name>, apt tries to download it from Internet. But when I place my local-repo at the top, it installs from local repository. So, My question is - 'Is it possible to force apt to use local repository when the package is available in local repository, without explicitly placing "the local source" at the top of my repository list (e.g sources.list file) ?' Edit: output of apt-cache policy $package_name is as follows nautilus-wipe: Installed: (none) Candidate: 0.1.1-2 Version table: 0.1.1-2 0 500 http://archive.ubuntu.com/ubuntu/ precise/universe i386 Packages 900 file:/media/Main/Linux-Software/Ubuntu/Precise/ Packages It is showing that my local repository has higher preference, though it is not the one which comes first in sources.list file. Here is the output of apt-get install nautilus-wipe Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: nautilus-wipe 0 upgraded, 1 newly installed, 0 to remove and 131 not upgraded. Need to get 30.7 kB of archives. After this operation, 150 kB of additional disk space will be used. 'http://archive.ubuntu.com/ubuntu/pool/universe/n/nautilus-wipe/nautilus-wipe_0.1.1-2_i386.deb' nautilus-wipe_0.1.1-2_i386.deb 30730 MD5Sum:7d497b8dfcefe1c0b51a45f3b0466994 It is still trying to get the file from Internet, though I think it should be happy with the local one.

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  • ASP.NET Web API and Simple Value Parameters from POSTed data

    - by Rick Strahl
    In testing out various features of Web API I've found a few oddities in the way that the serialization is handled. These are probably not super common but they may throw you for a loop. Here's what I found. Simple Parameters from Xml or JSON Content Web API makes it very easy to create action methods that accept parameters that are automatically parsed from XML or JSON request bodies. For example, you can send a JavaScript JSON object to the server and Web API happily deserializes it for you. This works just fine:public string ReturnAlbumInfo(Album album) { return album.AlbumName + " (" + album.YearReleased.ToString() + ")"; } However, if you have methods that accept simple parameter types like strings, dates, number etc., those methods don't receive their parameters from XML or JSON body by default and you may end up with failures. Take the following two very simple methods:public string ReturnString(string message) { return message; } public HttpResponseMessage ReturnDateTime(DateTime time) { return Request.CreateResponse<DateTime>(HttpStatusCode.OK, time); } The first one accepts a string and if called with a JSON string from the client like this:var client = new HttpClient(); var result = client.PostAsJsonAsync<string>(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, "Hello World").Result; which results in a trace like this: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 13Expect: 100-continueConnection: Keep-Alive "Hello World" produces… wait for it: null. Sending a date in the same fashion:var client = new HttpClient(); var result = client.PostAsJsonAsync<DateTime>(http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime, new DateTime(2012, 1, 1)).Result; results in this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 30Expect: 100-continueConnection: Keep-Alive "\/Date(1325412000000-1000)\/" (yes still the ugly MS AJAX date, yuk! This will supposedly change by RTM with Json.net used for client serialization) produces an error response: The parameters dictionary contains a null entry for parameter 'time' of non-nullable type 'System.DateTime' for method 'System.Net.Http.HttpResponseMessage ReturnDateTime(System.DateTime)' in 'AspNetWebApi.Controllers.AlbumApiController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Basically any simple parameters are not parsed properly resulting in null being sent to the method. For the string the call doesn't fail, but for the non-nullable date it produces an error because the method can't handle a null value. This behavior is a bit unexpected to say the least, but there's a simple solution to make this work using an explicit [FromBody] attribute:public string ReturnString([FromBody] string message) andpublic HttpResponseMessage ReturnDateTime([FromBody] DateTime time) which explicitly instructs Web API to read the value from the body. UrlEncoded Form Variable Parsing Another similar issue I ran into is with POST Form Variable binding. Web API can retrieve parameters from the QueryString and Route Values but it doesn't explicitly map parameters from POST values either. Taking our same ReturnString function from earlier and posting a message POST variable like this:var formVars = new Dictionary<string,string>(); formVars.Add("message", "Some Value"); var content = new FormUrlEncodedContent(formVars); var client = new HttpClient(); var result = client.PostAsync(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, content).Result; which produces this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/x-www-form-urlencodedHost: rasxpsContent-Length: 18Expect: 100-continue message=Some+Value When calling ReturnString:public string ReturnString(string message) { return message; } unfortunately it does not map the message value to the message parameter. This sort of mapping unfortunately is not available in Web API. Web API does support binding to form variables but only as part of model binding, which binds object properties to the POST variables. Sending the same message as in the previous example you can use the following code to pick up POST variable data:public string ReturnMessageModel(MessageModel model) { return model.Message; } public class MessageModel { public string Message { get; set; }} Note that the model is bound and the message form variable is mapped to the Message property as would other variables to properties if there were more. This works but it's not very dynamic. There's no real easy way to retrieve form variables (or query string values for that matter) in Web API's Request object as far as I can discern. Well only if you consider this easy:public string ReturnString() { var formData = Request.Content.ReadAsAsync<FormDataCollection>().Result; return formData.Get("message"); } Oddly FormDataCollection does not allow for indexers to work so you have to use the .Get() method which is rather odd. If you're running under IIS/Cassini you can always resort to the old and trusty HttpContext access for request data:public string ReturnString() { return HttpContext.Current.Request.Form["message"]; } which works fine and is easier. It's kind of a bummer that HttpRequestMessage doesn't expose some sort of raw Request object that has access to dynamic data - given that it's meant to serve as a generic REST/HTTP API that seems like a crucial missing piece. I don't see any way to read query string values either. To me personally HttpContext works, since I don't see myself using self-hosted code much.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Should I be using a JavaScript SPA designed when security is important

    - by ryanzec
    I asked something kind of similar on stackoverflow with a particular piece of code however I want to try to ask this in a broader sense. So I have this web application that I have started to write in backbone using a Single Page Architecture (SPA) however I am starting to second guess myself because of security. Now we are not storing and sending credit card information or anything like that through this web application but we are storing sensitive information that people are uploading to us and will have the ability to re-download too. The obviously security concern that I have with JavaScript is that you can't trust anything that comes from JavaScript however in a Backbone SPA application, everything is being sent through JavaScript. There are two security features that I will have to build in JavaScript; permissions and authentication. The authentication piece is just me override the Backbone.Router.prototype.navigate method to check the fragment it is trying to load and if the JavaScript application.session.loggedIn is not set to true (and they are not viewing a none authenticated page), they are redirected to the login page automatically. The user could easily modify application.session.loggedIn to equal true (or modify Backbone.Router.prototype.navigate method) but then they would also have to not so easily dynamically embedded a link into the page (or modify a current one) that has the proper classes, data-* attributes, and href values to then load a page that should only be loaded when they user has logged in (and has the permissions). So I have an acl object that deals with the permissions stuff. All someone would have to do to view pages or parts of pages they should not be able to is to call acl.addPermission(resource, permission) with the proper permissions or modify the acl.hasPermission() to always return true and then navigate away and then back to the page. Now certain things is EMCAScript 5 like Object.seal() or Object.freeze() would help with some of this however we have to support IE 8 which does not support those pieces of functionality. Now the REST API also performs security checks on every request so technically even if they are able to see parts of the interface that they should not be able to, they still should not be able to actually affect any data. The main benefits for me in developing a JavaScript SPA application is that the application is a lot more responsive since it is only transferring the minimum amount of JSON data for the requested action and performing the minimum amount of work too. There are also other things that I think are beneficial like you are going to have to develop an API for the data (which is good if you want expand your application to different platforms/technologies) or their is more of a separation between front-end and back-end however if security is a concern, it is really wise to go down the road of a JavaScript SPA application for the front-end?

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  • MySQL is running VERY slow

    - by user1032531
    I have two servers: a VPS and a laptop. I recently re-built both of them, and MySQL is running about 20 times slower on the laptop. Both servers used to run CentOS 5.8 and I think MySQL 5.1, and the laptop used to do great so I do not think it is the hardware. For the VPS, my provider installed CentOS 6.4, and then I installed MySQL 5.1.69 using yum with the CentOS repo. For the laptop, I installed CentOS 6.4 basic server and then installed MySQL 5.1.69 using yum with the CentOS repo. my.cnf for both servers are identical, and I have shown below. For both servers, I've also included below the output from SHOW VARIABLES; as well as output from sysbench, file system information, and cpu information. I have tried adding skip-name-resolve, but it didn't help. The matrix below shows the SHOW VARIABLES output from both servers which is different. Again, MySQL was installed the same way, so I do not know why it is different, but it is and I think this might be why the laptop is executing MySQL so slowly. Why is the laptop running MySQL slowly, and how do I fix it? Differences between SHOW VARIABLES on both servers +---------------------------+-----------------------+-------------------------+ | Variable | Value-VPS | Value-Laptop | +---------------------------+-----------------------+-------------------------+ | hostname | vps.site1.com | laptop.site2.com | | max_binlog_cache_size | 4294963200 | 18446744073709500000 | | max_seeks_for_key | 4294967295 | 18446744073709500000 | | max_write_lock_count | 4294967295 | 18446744073709500000 | | myisam_max_sort_file_size | 2146435072 | 9223372036853720000 | | myisam_mmap_size | 4294967295 | 18446744073709500000 | | plugin_dir | /usr/lib/mysql/plugin | /usr/lib64/mysql/plugin | | pseudo_thread_id | 7568 | 2 | | system_time_zone | EST | PDT | | thread_stack | 196608 | 262144 | | timestamp | 1372252112 | 1372252046 | | version_compile_machine | i386 | x86_64 | +---------------------------+-----------------------+-------------------------+ my.cnf for both servers [root@server1 ~]# cat /etc/my.cnf [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid innodb_strict_mode=on sql_mode=TRADITIONAL # sql_mode=STRICT_TRANS_TABLES,NO_ZERO_DATE,NO_ZERO_IN_DATE character-set-server=utf8 collation-server=utf8_general_ci log=/var/log/mysqld_all.log [root@server1 ~]# VPS SHOW VARIABLES Info Same as Laptop shown below but changes per above matrix (removed to allow me to be under the 30000 characters as required by ServerFault) Laptop SHOW VARIABLES Info auto_increment_increment 1 auto_increment_offset 1 autocommit ON automatic_sp_privileges ON back_log 50 basedir /usr/ big_tables OFF binlog_cache_size 32768 binlog_direct_non_transactional_updates OFF binlog_format STATEMENT bulk_insert_buffer_size 8388608 character_set_client utf8 character_set_connection utf8 character_set_database latin1 character_set_filesystem binary character_set_results utf8 character_set_server latin1 character_set_system utf8 character_sets_dir /usr/share/mysql/charsets/ collation_connection utf8_general_ci collation_database latin1_swedish_ci collation_server latin1_swedish_ci completion_type 0 concurrent_insert 1 connect_timeout 10 datadir /var/lib/mysql/ date_format %Y-%m-%d datetime_format %Y-%m-%d %H:%i:%s default_week_format 0 delay_key_write ON delayed_insert_limit 100 delayed_insert_timeout 300 delayed_queue_size 1000 div_precision_increment 4 engine_condition_pushdown ON error_count 0 event_scheduler OFF expire_logs_days 0 flush OFF flush_time 0 foreign_key_checks ON ft_boolean_syntax + -><()~*:""&| ft_max_word_len 84 ft_min_word_len 4 ft_query_expansion_limit 20 ft_stopword_file (built-in) general_log OFF general_log_file /var/run/mysqld/mysqld.log group_concat_max_len 1024 have_community_features YES have_compress YES have_crypt YES have_csv YES have_dynamic_loading YES have_geometry YES have_innodb YES have_ndbcluster NO have_openssl DISABLED have_partitioning YES have_query_cache YES have_rtree_keys YES have_ssl DISABLED have_symlink DISABLED hostname server1.site2.com identity 0 ignore_builtin_innodb OFF init_connect init_file init_slave innodb_adaptive_hash_index ON innodb_additional_mem_pool_size 1048576 innodb_autoextend_increment 8 innodb_autoinc_lock_mode 1 innodb_buffer_pool_size 8388608 innodb_checksums ON innodb_commit_concurrency 0 innodb_concurrency_tickets 500 innodb_data_file_path ibdata1:10M:autoextend innodb_data_home_dir innodb_doublewrite ON innodb_fast_shutdown 1 innodb_file_io_threads 4 innodb_file_per_table OFF innodb_flush_log_at_trx_commit 1 innodb_flush_method innodb_force_recovery 0 innodb_lock_wait_timeout 50 innodb_locks_unsafe_for_binlog OFF innodb_log_buffer_size 1048576 innodb_log_file_size 5242880 innodb_log_files_in_group 2 innodb_log_group_home_dir ./ innodb_max_dirty_pages_pct 90 innodb_max_purge_lag 0 innodb_mirrored_log_groups 1 innodb_open_files 300 innodb_rollback_on_timeout OFF innodb_stats_method nulls_equal innodb_stats_on_metadata ON innodb_support_xa ON innodb_sync_spin_loops 20 innodb_table_locks ON innodb_thread_concurrency 8 innodb_thread_sleep_delay 10000 innodb_use_legacy_cardinality_algorithm ON insert_id 0 interactive_timeout 28800 join_buffer_size 131072 keep_files_on_create OFF key_buffer_size 8384512 key_cache_age_threshold 300 key_cache_block_size 1024 key_cache_division_limit 100 language /usr/share/mysql/english/ large_files_support ON large_page_size 0 large_pages OFF last_insert_id 0 lc_time_names en_US license GPL local_infile ON locked_in_memory OFF log OFF log_bin OFF log_bin_trust_function_creators OFF log_bin_trust_routine_creators OFF log_error /var/log/mysqld.log log_output FILE log_queries_not_using_indexes OFF log_slave_updates OFF log_slow_queries OFF log_warnings 1 long_query_time 10.000000 low_priority_updates OFF lower_case_file_system OFF lower_case_table_names 0 max_allowed_packet 1048576 max_binlog_cache_size 18446744073709547520 max_binlog_size 1073741824 max_connect_errors 10 max_connections 151 max_delayed_threads 20 max_error_count 64 max_heap_table_size 16777216 max_insert_delayed_threads 20 max_join_size 18446744073709551615 max_length_for_sort_data 1024 max_long_data_size 1048576 max_prepared_stmt_count 16382 max_relay_log_size 0 max_seeks_for_key 18446744073709551615 max_sort_length 1024 max_sp_recursion_depth 0 max_tmp_tables 32 max_user_connections 0 max_write_lock_count 18446744073709551615 min_examined_row_limit 0 multi_range_count 256 myisam_data_pointer_size 6 myisam_max_sort_file_size 9223372036853727232 myisam_mmap_size 18446744073709551615 myisam_recover_options OFF myisam_repair_threads 1 myisam_sort_buffer_size 8388608 myisam_stats_method nulls_unequal myisam_use_mmap OFF net_buffer_length 16384 net_read_timeout 30 net_retry_count 10 net_write_timeout 60 new OFF old OFF old_alter_table OFF old_passwords OFF open_files_limit 1024 optimizer_prune_level 1 optimizer_search_depth 62 optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on pid_file /var/run/mysqld/mysqld.pid plugin_dir /usr/lib64/mysql/plugin port 3306 preload_buffer_size 32768 profiling OFF profiling_history_size 15 protocol_version 10 pseudo_thread_id 3 query_alloc_block_size 8192 query_cache_limit 1048576 query_cache_min_res_unit 4096 query_cache_size 0 query_cache_type ON query_cache_wlock_invalidate OFF query_prealloc_size 8192 rand_seed1 rand_seed2 range_alloc_block_size 4096 read_buffer_size 131072 read_only OFF read_rnd_buffer_size 262144 relay_log relay_log_index relay_log_info_file relay-log.info relay_log_purge ON relay_log_space_limit 0 report_host report_password report_port 3306 report_user rpl_recovery_rank 0 secure_auth OFF secure_file_priv server_id 0 skip_external_locking ON skip_name_resolve OFF skip_networking OFF skip_show_database OFF slave_compressed_protocol OFF slave_exec_mode STRICT slave_load_tmpdir /tmp slave_max_allowed_packet 1073741824 slave_net_timeout 3600 slave_skip_errors OFF slave_transaction_retries 10 slow_launch_time 2 slow_query_log OFF slow_query_log_file /var/run/mysqld/mysqld-slow.log socket /var/lib/mysql/mysql.sock sort_buffer_size 2097144 sql_auto_is_null ON sql_big_selects ON sql_big_tables OFF sql_buffer_result OFF sql_log_bin ON sql_log_off OFF sql_log_update ON sql_low_priority_updates OFF sql_max_join_size 18446744073709551615 sql_mode sql_notes ON sql_quote_show_create ON sql_safe_updates OFF sql_select_limit 18446744073709551615 sql_slave_skip_counter sql_warnings OFF ssl_ca ssl_capath ssl_cert ssl_cipher ssl_key storage_engine MyISAM sync_binlog 0 sync_frm ON system_time_zone PDT table_definition_cache 256 table_lock_wait_timeout 50 table_open_cache 64 table_type MyISAM thread_cache_size 0 thread_handling one-thread-per-connection thread_stack 262144 time_format %H:%i:%s time_zone SYSTEM timed_mutexes OFF timestamp 1372254399 tmp_table_size 16777216 tmpdir /tmp transaction_alloc_block_size 8192 transaction_prealloc_size 4096 tx_isolation REPEATABLE-READ unique_checks ON updatable_views_with_limit YES version 5.1.69 version_comment Source distribution version_compile_machine x86_64 version_compile_os redhat-linux-gnu wait_timeout 28800 warning_count 0 VPS Sysbench Info [root@vps ~]# cat sysbench.txt sysbench 0.4.12: multi-threaded system evaluation benchmark Running the test with following options: Number of threads: 8 Doing OLTP test. Running mixed OLTP test Doing read-only test Using Special distribution (12 iterations, 1 pct of values are returned in 75 pct cases) Using "BEGIN" for starting transactions Using auto_inc on the id column Threads started! Time limit exceeded, exiting... (last message repeated 7 times) Done. OLTP test statistics: queries performed: read: 1449966 write: 0 other: 207138 total: 1657104 transactions: 103569 (1726.01 per sec.) deadlocks: 0 (0.00 per sec.) read/write requests: 1449966 (24164.08 per sec.) other operations: 207138 (3452.01 per sec.) Test execution summary: total time: 60.0050s total number of events: 103569 total time taken by event execution: 479.1544 per-request statistics: min: 1.98ms avg: 4.63ms max: 330.73ms approx. 95 percentile: 8.26ms Threads fairness: events (avg/stddev): 12946.1250/381.09 execution time (avg/stddev): 59.8943/0.00 [root@vps ~]# Laptop Sysbench Info [root@server1 ~]# cat sysbench.txt sysbench 0.4.12: multi-threaded system evaluation benchmark Running the test with following options: Number of threads: 8 Doing OLTP test. Running mixed OLTP test Doing read-only test Using Special distribution (12 iterations, 1 pct of values are returned in 75 pct cases) Using "BEGIN" for starting transactions Using auto_inc on the id column Threads started! Time limit exceeded, exiting... (last message repeated 7 times) Done. OLTP test statistics: queries performed: read: 634718 write: 0 other: 90674 total: 725392 transactions: 45337 (755.56 per sec.) deadlocks: 0 (0.00 per sec.) read/write requests: 634718 (10577.78 per sec.) other operations: 90674 (1511.11 per sec.) Test execution summary: total time: 60.0048s total number of events: 45337 total time taken by event execution: 479.4912 per-request statistics: min: 2.04ms avg: 10.58ms max: 85.56ms approx. 95 percentile: 19.70ms Threads fairness: events (avg/stddev): 5667.1250/42.18 execution time (avg/stddev): 59.9364/0.00 [root@server1 ~]# VPS File Info [root@vps ~]# df -T Filesystem Type 1K-blocks Used Available Use% Mounted on /dev/simfs simfs 20971520 16187440 4784080 78% / none tmpfs 6224432 4 6224428 1% /dev none tmpfs 6224432 0 6224432 0% /dev/shm [root@vps ~]# Laptop File Info [root@server1 ~]# df -T Filesystem Type 1K-blocks Used Available Use% Mounted on /dev/mapper/vg_server1-lv_root ext4 72383800 4243964 64462860 7% / tmpfs tmpfs 956352 0 956352 0% /dev/shm /dev/sdb1 ext4 495844 60948 409296 13% /boot [root@server1 ~]# VPS CPU Info Removed to stay under the 30000 character limit required by ServerFault Laptop CPU Info [root@server1 ~]# cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Duo CPU T7100 @ 1.80GHz stepping : 13 cpu MHz : 800.000 cache size : 2048 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm ida dts tpr_shadow vnmi flexpriority bogomips : 3591.39 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Duo CPU T7100 @ 1.80GHz stepping : 13 cpu MHz : 800.000 cache size : 2048 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 apicid : 1 initial apicid : 1 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm ida dts tpr_shadow vnmi flexpriority bogomips : 3591.39 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: [root@server1 ~]# EDIT New Info requested by shakalandy [root@localhost ~]# cat /proc/meminfo MemTotal: 2044804 kB MemFree: 761464 kB Buffers: 68868 kB Cached: 369708 kB SwapCached: 0 kB Active: 881080 kB Inactive: 246016 kB Active(anon): 688312 kB Inactive(anon): 4416 kB Active(file): 192768 kB Inactive(file): 241600 kB Unevictable: 0 kB Mlocked: 0 kB SwapTotal: 4095992 kB SwapFree: 4095992 kB Dirty: 0 kB Writeback: 0 kB AnonPages: 688428 kB Mapped: 65156 kB Shmem: 4216 kB Slab: 92428 kB SReclaimable: 31260 kB SUnreclaim: 61168 kB KernelStack: 2392 kB PageTables: 28356 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 5118392 kB Committed_AS: 1530212 kB VmallocTotal: 34359738367 kB VmallocUsed: 343604 kB VmallocChunk: 34359372920 kB HardwareCorrupted: 0 kB AnonHugePages: 520192 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 8556 kB DirectMap2M: 2078720 kB [root@localhost ~]# ps aux | grep mysql root 2227 0.0 0.0 108332 1504 ? S 07:36 0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/localhost.badobe.com.pid mysql 2319 0.1 24.5 1470068 501360 ? Sl 07:36 0:57 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --log-error=/var/lib/mysql/localhost.badobe.com.err --pid-file=/var/lib/mysql/localhost.badobe.com.pid root 3579 0.0 0.1 201840 3028 pts/0 S+ 07:40 0:00 mysql -u root -p root 13887 0.0 0.1 201840 3036 pts/3 S+ 18:08 0:00 mysql -uroot -px xxxxxxxxxx root 14449 0.0 0.0 103248 840 pts/2 S+ 18:16 0:00 grep mysql [root@localhost ~]# ps aux | grep mysql root 2227 0.0 0.0 108332 1504 ? S 07:36 0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/localhost.badobe.com.pid mysql 2319 0.1 24.5 1470068 501356 ? Sl 07:36 0:57 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --log-error=/var/lib/mysql/localhost.badobe.com.err --pid-file=/var/lib/mysql/localhost.badobe.com.pid root 3579 0.0 0.1 201840 3028 pts/0 S+ 07:40 0:00 mysql -u root -p root 13887 0.0 0.1 201840 3048 pts/3 S+ 18:08 0:00 mysql -uroot -px xxxxxxxxxx root 14470 0.0 0.0 103248 840 pts/2 S+ 18:16 0:00 grep mysql [root@localhost ~]# vmstat 1 procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 0 0 0 742172 76376 371064 0 0 6 6 78 202 2 1 97 1 0 0 0 0 742164 76380 371060 0 0 0 16 191 467 2 1 93 5 0 0 0 0 742164 76380 371064 0 0 0 0 148 388 2 1 98 0 0 0 0 0 742164 76380 371064 0 0 0 0 159 418 2 1 98 0 0 0 0 0 742164 76380 371064 0 0 0 0 145 380 2 1 98 0 0 0 0 0 742164 76380 371064 0 0 0 0 166 429 2 1 97 0 0 1 0 0 742164 76380 371064 0 0 0 0 148 373 2 1 98 0 0 0 0 0 742164 76380 371064 0 0 0 0 149 382 2 1 98 0 0 0 0 0 742164 76380 371064 0 0 0 0 168 408 2 0 97 0 0 0 0 0 742164 76380 371064 0 0 0 0 165 394 2 1 98 0 0 0 0 0 742164 76380 371064 0 0 0 0 159 354 2 1 98 0 0 0 0 0 742164 76388 371060 0 0 0 16 180 447 2 0 91 6 0 0 0 0 742164 76388 371064 0 0 0 0 143 344 2 1 98 0 0 0 1 0 742784 76416 370044 0 0 28 580 360 678 3 1 74 23 0 1 0 0 744768 76496 367772 0 0 40 1036 437 865 3 1 53 43 0 0 1 0 747248 76596 365412 0 0 48 1224 561 923 3 2 53 43 0 0 1 0 749232 76696 363092 0 0 32 1132 512 883 3 2 52 44 0 0 1 0 751340 76772 361020 0 0 32 1008 472 872 2 1 52 45 0 0 1 0 753448 76840 358540 0 0 36 1088 512 860 2 1 51 46 0 0 1 0 755060 76936 357636 0 0 28 1012 481 922 2 2 52 45 0 0 1 0 755060 77064 357988 0 0 12 896 444 902 2 1 53 45 0 0 1 0 754688 77148 358448 0 0 16 1096 506 1007 1 1 56 42 0 0 2 0 754192 77268 358932 0 0 12 1060 481 957 1 2 53 44 0 0 1 0 753696 77380 359392 0 0 12 1052 512 1025 2 1 55 42 0 0 1 0 751028 77480 359828 0 0 8 984 423 909 2 2 52 45 0 0 1 0 750524 77620 360200 0 0 8 788 367 869 1 2 54 44 0 0 1 0 749904 77700 360664 0 0 8 928 439 924 2 2 55 43 0 0 1 0 749408 77796 361084 0 0 12 976 468 967 1 1 56 43 0 0 1 0 748788 77896 361464 0 0 12 992 453 944 1 2 54 43 0 1 1 0 748416 77992 361996 0 0 12 784 392 868 2 1 52 46 0 0 1 0 747920 78092 362336 0 0 4 896 382 874 1 1 52 46 0 0 1 0 745252 78172 362780 0 0 12 1040 444 923 1 1 56 42 0 0 1 0 744764 78288 363220 0 0 8 1024 448 934 2 1 55 43 0 0 1 0 744144 78408 363668 0 0 8 1000 461 982 2 1 53 44 0 0 1 0 743648 78488 364148 0 0 8 872 443 888 2 1 54 43 0 0 1 0 743152 78548 364468 0 0 16 1020 511 995 2 1 55 43 0 0 1 0 742656 78632 365024 0 0 12 928 431 913 1 2 53 44 0 0 1 0 742160 78728 365468 0 0 12 996 470 955 2 2 54 44 0 1 1 0 739492 78840 365896 0 0 8 988 447 939 1 2 52 46 0 0 1 0 738872 78996 366352 0 0 12 972 442 928 1 1 55 44 0 1 1 0 738244 79148 366812 0 0 8 948 549 1126 2 2 54 43 0 0 1 0 737624 79312 367188 0 0 12 996 456 953 2 2 54 43 0 0 1 0 736880 79456 367660 0 0 12 960 444 918 1 1 53 46 0 0 1 0 736260 79584 368124 0 0 8 884 414 921 1 1 54 44 0 0 1 0 735648 79716 368488 0 0 12 976 450 955 2 1 56 41 0 0 1 0 733104 79840 368988 0 0 12 932 453 918 1 2 55 43 0 0 1 0 732608 79996 369356 0 0 16 916 444 889 1 2 54 43 0 1 1 0 731476 80128 369800 0 0 16 852 514 978 2 2 54 43 0 0 1 0 731244 80252 370200 0 0 8 904 398 870 2 1 55 43 0 1 1 0 730624 80384 370612 0 0 12 1032 447 977 1 2 57 41 0 0 1 0 730004 80524 371096 0 0 12 984 469 941 2 2 52 45 0 0 1 0 729508 80636 371544 0 0 12 928 438 922 2 1 52 46 0 0 1 0 728888 80756 371948 0 0 16 972 439 943 2 1 55 43 0 0 1 0 726468 80900 372272 0 0 8 960 545 1024 2 1 54 43 0 1 1 0 726344 81024 372272 0 0 8 464 490 1057 1 2 53 44 0 0 1 0 726096 81148 372276 0 0 4 328 441 1063 2 1 53 45 0 1 1 0 726096 81256 372292 0 0 0 296 387 975 1 1 53 45 0 0 1 0 725848 81380 372284 0 0 4 332 425 1034 2 1 54 44 0 1 1 0 725848 81496 372300 0 0 4 308 386 992 2 1 54 43 0 0 1 0 725600 81616 372296 0 0 4 328 404 1060 1 1 54 44 0 procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 0 1 0 725600 81732 372296 0 0 4 328 439 1011 1 1 53 44 0 0 1 0 725476 81848 372308 0 0 0 316 441 1023 2 2 52 46 0 1 1 0 725352 81972 372300 0 0 4 344 451 1021 1 1 55 43 0 2 1 0 725228 82088 372320 0 0 0 328 427 1058 1 1 54 44 0 1 1 0 724980 82220 372300 0 0 4 336 419 999 2 1 54 44 0 1 1 0 724980 82328 372320 0 0 4 320 430 1019 1 1 54 44 0 1 1 0 724732 82436 372328 0 0 0 388 363 942 2 1 54 44 0 1 1 0 724608 82560 372312 0 0 4 308 419 993 1 2 54 44 0 1 0 0 724360 82684 372320 0 0 0 304 421 1028 2 1 55 42 0 1 0 0 724360 82684 372388 0 0 0 0 158 416 2 1 98 0 0 1 1 0 724236 82720 372360 0 0 0 6464 243 855 3 2 84 12 0 1 0 0 724112 82748 372360 0 0 0 5356 266 895 3 1 84 12 0 2 1 0 724112 82764 372380 0 0 0 3052 221 511 2 2 93 4 0 1 0 0 724112 82796 372372 0 0 0 4548 325 1067 2 2 81 16 0 1 0 0 724112 82816 372368 0 0 0 3240 259 829 3 1 90 6 0 1 0 0 724112 82836 372380 0 0 0 3260 309 822 3 2 88 8 0 1 1 0 724112 82876 372364 0 0 0 4680 326 978 3 1 77 19 0 1 0 0 724112 82884 372380 0 0 0 512 207 508 2 1 95 2 0 1 0 0 724112 82884 372388 0 0 0 0 138 361 2 1 98 0 0 1 0 0 724112 82884 372388 0 0 0 0 158 397 2 1 98 0 0 1 0 0 724112 82884 372388 0 0 0 0 146 395 2 1 98 0 0 2 0 0 724112 82884 372388 0 0 0 0 160 395 2 1 98 0 0 1 0 0 724112 82884 372388 0 0 0 0 163 382 1 1 98 0 0 1 0 0 724112 82884 372388 0 0 0 0 176 422 2 1 98 0 0 1 0 0 724112 82884 372388 0 0 0 0 134 351 2 1 98 0 0 0 0 0 724112 82884 372388 0 0 0 0 190 429 2 1 97 0 0 0 0 0 724104 82884 372392 0 0 0 0 139 358 2 1 98 0 0 0 0 0 724848 82884 372392 0 0 0 4 211 432 2 1 97 0 0 1 0 0 724980 82884 372392 0 0 0 0 166 370 2 1 98 0 0 0 0 0 724980 82884 372392 0 0 0 0 164 397 2 1 98 0 0 ^C [root@localhost ~]#

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  • How I understood monads, part 1/2: sleepless and self-loathing in Seattle

    - by Bertrand Le Roy
    For some time now, I had been noticing some interest for monads, mostly in the form of unintelligible (to me) blog posts and comments saying “oh, yeah, that’s a monad” about random stuff as if it were absolutely obvious and if I didn’t know what they were talking about, I was probably an uneducated idiot, ignorant about the simplest and most fundamental concepts of functional programming. Fair enough, I am pretty much exactly that. Being the kind of guy who can spend eight years in college just to understand a few interesting concepts about the universe, I had to check it out and try to understand monads so that I too can say “oh, yeah, that’s a monad”. Man, was I hit hard in the face with the limitations of my own abstract thinking abilities. All the articles I could find about the subject seemed to be vaguely understandable at first but very quickly overloaded the very few concept slots I have available in my brain. They also seemed to be consistently using arcane notation that I was entirely unfamiliar with. It finally all clicked together one Friday afternoon during the team’s beer symposium when Louis was patient enough to break it down for me in a language I could understand (C#). I don’t know if being intoxicated helped. Feel free to read this with or without a drink in hand. So here it is in a nutshell: a monad allows you to manipulate stuff in interesting ways. Oh, OK, you might say. Yeah. Exactly. Let’s start with a trivial case: public static class Trivial { public static TResult Execute<T, TResult>( this T argument, Func<T, TResult> operation) { return operation(argument); } } This is not a monad. I removed most concepts here to start with something very simple. There is only one concept here: the idea of executing an operation on an object. This is of course trivial and it would actually be simpler to just apply that operation directly on the object. But please bear with me, this is our first baby step. Here’s how you use that thing: "some string" .Execute(s => s + " processed by trivial proto-monad.") .Execute(s => s + " And it's chainable!"); What we’re doing here is analogous to having an assembly chain in a factory: you can feed it raw material (the string here) and a number of machines that each implement a step in the manufacturing process and you can start building stuff. The Trivial class here represents the empty assembly chain, the conveyor belt if you will, but it doesn’t care what kind of raw material gets in, what gets out or what each machine is doing. It is pure process. A real monad will need a couple of additional concepts. Let’s say the conveyor belt needs the material to be processed to be contained in standardized boxes, just so that it can safely and efficiently be transported from machine to machine or so that tracking information can be attached to it. Each machine knows how to treat raw material or partly processed material, but it doesn’t know how to treat the boxes so the conveyor belt will have to extract the material from the box before feeding it into each machine, and it will have to box it back afterwards. This conveyor belt with boxes is essentially what a monad is. It has one method to box stuff, one to extract stuff from its box and one to feed stuff into a machine. So let’s reformulate the previous example but this time with the boxes, which will do nothing for the moment except containing stuff. public class Identity<T> { public Identity(T value) { Value = value; } public T Value { get; private set;} public static Identity<T> Unit(T value) { return new Identity<T>(value); } public static Identity<U> Bind<U>( Identity<T> argument, Func<T, Identity<U>> operation) { return operation(argument.Value); } } Now this is a true to the definition Monad, including the weird naming of the methods. It is the simplest monad, called the identity monad and of course it does nothing useful. Here’s how you use it: Identity<string>.Bind( Identity<string>.Unit("some string"), s => Identity<string>.Unit( s + " was processed by identity monad.")).Value That of course is seriously ugly. Note that the operation is responsible for re-boxing its result. That is a part of strict monads that I don’t quite get and I’ll take the liberty to lift that strange constraint in the next examples. To make this more readable and easier to use, let’s build a few extension methods: public static class IdentityExtensions { public static Identity<T> ToIdentity<T>(this T value) { return new Identity<T>(value); } public static Identity<U> Bind<T, U>( this Identity<T> argument, Func<T, U> operation) { return operation(argument.Value).ToIdentity(); } } With those, we can rewrite our code as follows: "some string".ToIdentity() .Bind(s => s + " was processed by monad extensions.") .Bind(s => s + " And it's chainable...") .Value; This is considerably simpler but still retains the qualities of a monad. But it is still pointless. Let’s look at a more useful example, the state monad, which is basically a monad where the boxes have a label. It’s useful to perform operations on arbitrary objects that have been enriched with an attached state object. public class Stateful<TValue, TState> { public Stateful(TValue value, TState state) { Value = value; State = state; } public TValue Value { get; private set; } public TState State { get; set; } } public static class StateExtensions { public static Stateful<TValue, TState> ToStateful<TValue, TState>( this TValue value, TState state) { return new Stateful<TValue, TState>(value, state); } public static Stateful<TResult, TState> Execute<TValue, TState, TResult>( this Stateful<TValue, TState> argument, Func<TValue, TResult> operation) { return operation(argument.Value) .ToStateful(argument.State); } } You can get a stateful version of any object by calling the ToStateful extension method, passing the state object in. You can then execute ordinary operations on the values while retaining the state: var statefulInt = 3.ToStateful("This is the state"); var processedStatefulInt = statefulInt .Execute(i => ++i) .Execute(i => i * 10) .Execute(i => i + 2); Console.WriteLine("Value: {0}; state: {1}", processedStatefulInt.Value, processedStatefulInt.State); This monad differs from the identity by enriching the boxes. There is another way to give value to the monad, which is to enrich the processing. An example of that is the writer monad, which can be typically used to log the operations that are being performed by the monad. Of course, the richest monads enrich both the boxes and the processing. That’s all for today. I hope with this you won’t have to go through the same process that I did to understand monads and that you haven’t gone into concept overload like I did. Next time, we’ll examine some examples that you already know but we will shine the monadic light, hopefully illuminating them in a whole new way. Realizing that this pattern is actually in many places but mostly unnoticed is what will enable the truly casual “oh, yes, that’s a monad” comments. Here’s the code for this article: http://weblogs.asp.net/blogs/bleroy/Samples/Monads.zip The Wikipedia article on monads: http://en.wikipedia.org/wiki/Monads_in_functional_programming This article was invaluable for me in understanding how to express the canonical monads in C# (interesting Linq stuff in there): http://blogs.msdn.com/b/wesdyer/archive/2008/01/11/the-marvels-of-monads.aspx

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  • UserAppDataPath in WPF

    - by psheriff
    In Windows Forms applications you were able to get to your user's roaming profile directory very easily using the Application.UserAppDataPath property. This folder allows you to store information for your program in a custom folder specifically for your program. The format of this directory looks like this: C:\Users\YOUR NAME\AppData\Roaming\COMPANY NAME\APPLICATION NAME\APPLICATION VERSION For example, on my Windows 7 64-bit system, this folder would look like this for a Windows Forms Application: C:\Users\PSheriff\AppData\Roaming\PDSA, Inc.\WindowsFormsApplication1\1.0.0.0 For some reason Microsoft did not expose this property from the Application object of WPF applications. I guess they think that we don't need this property in WPF? Well, sometimes we still do need to get at this folder. You have two choices on how to retrieve this property. Add a reference to the System.Windows.Forms.dll to your WPF application and use this property directly. Or, you can write your own method to build the same path. If you add a reference to the System.Windows.Forms.dll you will need to use System.Windows.Forms.Application.UserAppDataPath to access this property. Create a GetUserAppDataPath Method in WPF If you want to build this path you can do so with just a few method calls in WPF using Reflection. The code below shows this fairly simple method to retrieve the same folder as shown above. C#using System.Reflection; public string GetUserAppDataPath(){  string path = string.Empty;  Assembly assm;  Type at;  object[] r;   // Get the .EXE assembly  assm = Assembly.GetEntryAssembly();  // Get a 'Type' of the AssemblyCompanyAttribute  at = typeof(AssemblyCompanyAttribute);  // Get a collection of custom attributes from the .EXE assembly  r = assm.GetCustomAttributes(at, false);  // Get the Company Attribute  AssemblyCompanyAttribute ct =                 ((AssemblyCompanyAttribute)(r[0]));  // Build the User App Data Path  path = Environment.GetFolderPath(              Environment.SpecialFolder.ApplicationData);  path += @"\" + ct.Company;  path += @"\" + assm.GetName().Version.ToString();   return path;} Visual BasicPublic Function GetUserAppDataPath() As String  Dim path As String = String.Empty  Dim assm As Assembly  Dim at As Type  Dim r As Object()   ' Get the .EXE assembly  assm = Assembly.GetEntryAssembly()  ' Get a 'Type' of the AssemblyCompanyAttribute  at = GetType(AssemblyCompanyAttribute)  ' Get a collection of custom attributes from the .EXE assembly  r = assm.GetCustomAttributes(at, False)  ' Get the Company Attribute  Dim ct As AssemblyCompanyAttribute = _                 DirectCast(r(0), AssemblyCompanyAttribute)  ' Build the User App Data Path  path = Environment.GetFolderPath( _                 Environment.SpecialFolder.ApplicationData)  path &= "\" & ct.Company  path &= "\" & assm.GetName().Version.ToString()   Return pathEnd Function Summary Getting the User Application Data Path folder in WPF is fairly simple with just a few method calls using Reflection. Of course, there is absolutely no reason you cannot just add a reference to the System.Windows.Forms.dll to your WPF application and use that Application object. After all, System.Windows.Forms.dll is a part of the .NET Framework and can be used from WPF with no issues at all. NOTE: Visit http://www.pdsa.com/downloads to get more tips and tricks like this one. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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  • How to implement Undo and Redo feature in as3

    - by Swati Singh
    I am going to create an application in that i have to implement an Undo and Redo feature. In the application there will be multiple objects located on stage and user can customize the position of the objects. But when user clicks on Undo the object go back to their default position and after clicking on redo object will move on the new position. So my question is how can i apply these feature in my application? Is there any library or any third party classes? Can some one help me? Thanks in advance.

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  • ls -l freezes terminal locally and remotely

    - by Jakobud
    I've been reading other SF threads regarding ls not returning results or freezing and stalling terminal sessions and it appears they usually the fault of network problems. My problem however, occurs both over remote SSH sessions but also if I am physically at the server itself... I just installed CentOS 5.4 on one of our servers. I'm setting up some rdiff-backup scripts and when I downloaded librsync and untared it, thats when I started seeing some weird behavior with ls -l. wget http://sourceforge.net/projects/librsync/files/librsync/0.9.7/librsync-0.9.7.tar.gz/download /tmp cd /tmp tar -xzf librsync-0.9.7.tar.gz Simple enough. To view the files in this directory I did this: ls results: librsync-0.9.7 librsync-0.9.7.tar.gz Now, if I ls -l, my terminal freezes. I have to re-ssh in to keep going. After reading SF threads, I thought it was network related. So I was extremely surprised to go sit down at the server itself and see the exact same thing happen... So its obviously not a network issues. Even if I ls /tmp/librsync-0.9.7, my terminal freezes just the same... Next I did an strace and got this (warning: wall of text coming....): strace ls -l /tmp execve("/bin/ls", ["ls", "-l", "/tmp"], [/* 21 vars */]) = 0 brk(0) = 0x1c521000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cc0000 uname({sys="Linux", node="massive.answeron.com", ...}) = 0 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=71746, ...}) = 0 mmap(NULL, 71746, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2b8582cc1000 close(3) = 0 open("/lib64/librt.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0 \"\200\2730\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=53448, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd3000 mmap(0x30bb800000, 2132936, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bb800000 mprotect(0x30bb807000, 2097152, PROT_NONE) = 0 mmap(0x30bba07000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x7000) = 0x30bba07000 close(3) = 0 open("/lib64/libacl.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\31@\2740\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=28008, ...}) = 0 mmap(0x30bc400000, 2120992, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bc400000 mprotect(0x30bc406000, 2093056, PROT_NONE) = 0 mmap(0x30bc605000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x5000) = 0x30bc605000 close(3) = 0 open("/lib64/libselinux.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`E\300\2730\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=95464, ...}) = 0 mmap(0x30bbc00000, 2192784, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bbc00000 mprotect(0x30bbc15000, 2097152, PROT_NONE) = 0 mmap(0x30bbe15000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15000) = 0x30bbe15000 mmap(0x30bbe17000, 1424, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30bbe17000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\220\332\201\2720\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1717800, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd4000 mmap(0x30ba800000, 3498328, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30ba800000 mprotect(0x30ba94d000, 2097152, PROT_NONE) = 0 mmap(0x30bab4d000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x14d000) = 0x30bab4d000 mmap(0x30bab52000, 16728, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30bab52000 close(3) = 0 open("/lib64/libpthread.so.0", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\220W\0\2730\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=145824, ...}) = 0 mmap(0x30bb000000, 2204528, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bb000000 mprotect(0x30bb016000, 2093056, PROT_NONE) = 0 mmap(0x30bb215000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15000) = 0x30bb215000 mmap(0x30bb217000, 13168, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30bb217000 close(3) = 0 open("/lib64/libattr.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\17\300\2750\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=17888, ...}) = 0 mmap(0x30bdc00000, 2110728, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bdc00000 mprotect(0x30bdc04000, 2093056, PROT_NONE) = 0 mmap(0x30bde03000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x3000) = 0x30bde03000 close(3) = 0 open("/lib64/libdl.so.2", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\20\16\300\2720\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=23360, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd5000 mmap(0x30bac00000, 2109696, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bac00000 mprotect(0x30bac02000, 2097152, PROT_NONE) = 0 mmap(0x30bae02000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x30bae02000 close(3) = 0 open("/lib64/libsepol.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0=\0\2740\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=247496, ...}) = 0 mmap(0x30bc000000, 2383136, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bc000000 mprotect(0x30bc03b000, 2097152, PROT_NONE) = 0 mmap(0x30bc23b000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x3b000) = 0x30bc23b000 mmap(0x30bc23c000, 40224, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30bc23c000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd7000 arch_prctl(ARCH_SET_FS, 0x2b8582cd6c50) = 0 mprotect(0x30bba07000, 4096, PROT_READ) = 0 mprotect(0x30bab4d000, 16384, PROT_READ) = 0 mprotect(0x30bb215000, 4096, PROT_READ) = 0 mprotect(0x30ba61b000, 4096, PROT_READ) = 0 mprotect(0x30bae02000, 4096, PROT_READ) = 0 munmap(0x2b8582cc1000, 71746) = 0 set_tid_address(0x2b8582cd6ce0) = 24102 set_robust_list(0x2b8582cd6cf0, 0x18) = 0 futex(0x7fff72d02d6c, FUTEX_WAKE_PRIVATE, 1) = 0 rt_sigaction(SIGRTMIN, {0x30bb005370, [], SA_RESTORER|SA_SIGINFO, 0x30bb00e7c0}, NULL, 8) = 0 rt_sigaction(SIGRT_1, {0x30bb0052b0, [], SA_RESTORER|SA_RESTART|SA_SIGINFO, 0x30bb00e7c0}, NULL, 8) = 0 rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0 getrlimit(RLIMIT_STACK, {rlim_cur=10240*1024, rlim_max=RLIM_INFINITY}) = 0 access("/etc/selinux/", F_OK) = 0 brk(0) = 0x1c521000 brk(0x1c542000) = 0x1c542000 open("/etc/selinux/config", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=448, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cc1000 read(3, "# This file controls the state o"..., 4096) = 448 read(3, "", 4096) = 0 close(3) = 0 munmap(0x2b8582cc1000, 4096) = 0 open("/proc/mounts", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cc1000 read(3, "rootfs / rootfs rw 0 0\n/dev/root"..., 4096) = 577 close(3) = 0 munmap(0x2b8582cc1000, 4096) = 0 open("/selinux/mls", O_RDONLY) = 3 read(3, "1", 19) = 1 close(3) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 3 connect(3, {sa_family=AF_FILE, path="/var/run/setrans/.setrans-unix"...}, 110) = 0 sendmsg(3, {msg_name(0)=NULL, msg_iov(5)=[{"\1\0\0\0", 4}, {"\1\0\0\0", 4}, {"\1\0\0\0", 4}, {"\0", 1}, {"\0", 1}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 14 readv(3, [{"\1\0\0\0", 4}, {"\1\0\0\0", 4}, {"\0\0\0\0", 4}], 3) = 12 readv(3, [{"\0", 1}], 1) = 1 close(3) = 0 open("/usr/lib/locale/locale-archive", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=56413824, ...}) = 0 mmap(NULL, 56413824, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2b8582cd8000 close(3) = 0 ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0 ioctl(1, TIOCGWINSZ, {ws_row=65, ws_col=137, ws_xpixel=0, ws_ypixel=0}) = 0 open("/usr/share/locale/locale.alias", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=2528, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(3, "# Locale name alias data base.\n#"..., 4096) = 2528 read(3, "", 4096) = 0 close(3) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/usr/share/locale/en_US.UTF-8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en_US.utf8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en_US/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en.UTF-8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en.utf8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) lstat("/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=4096, ...}) = 0 getxattr("/tmp", "system.posix_acl_access", 0x0, 0) = -1 ENODATA (No data available) getxattr("/tmp", "system.posix_acl_default", 0x0, 0) = -1 ENODATA (No data available) socket(PF_FILE, SOCK_STREAM, 0) = 3 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(3) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 3 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(3) = 0 open("/etc/nsswitch.conf", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=1711, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(3, "#\n# /etc/nsswitch.conf\n#\n# An ex"..., 4096) = 1711 read(3, "", 4096) = 0 close(3) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=71746, ...}) = 0 mmap(NULL, 71746, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2b85862a5000 close(3) = 0 open("/lib64/libnss_files.so.2", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\37\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=53880, ...}) = 0 mmap(NULL, 2139432, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x2b85862b7000 mprotect(0x2b85862c1000, 2093056, PROT_NONE) = 0 mmap(0x2b85864c0000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x9000) = 0x2b85864c0000 close(3) = 0 mprotect(0x2b85864c0000, 4096, PROT_READ) = 0 munmap(0x2b85862a5000, 71746) = 0 open("/etc/passwd", O_RDONLY) = 3 fcntl(3, F_GETFD) = 0 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 fstat(3, {st_mode=S_IFREG|0644, st_size=1823, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(3, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 1823 close(3) = 0 munmap(0x2b85862a5000, 4096) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 3 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(3) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 3 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(3) = 0 open("/etc/group", O_RDONLY) = 3 fcntl(3, F_GETFD) = 0 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 fstat(3, {st_mode=S_IFREG|0644, st_size=743, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(3, "root:x:0:root\nbin:x:1:root,bin,d"..., 4096) = 743 close(3) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/tmp", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 3 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 getdents(3, /* 8 entries */, 32768) = 264 lstat("/tmp/librsync-0.9.7.tar.gz", {st_mode=S_IFREG|0644, st_size=453802, ...}) = 0 getxattr("/tmp/librsync-0.9.7.tar.gz", "system.posix_acl_access", 0x0, 0) = -1 ENODATA (No data available) getxattr("/tmp/librsync-0.9.7.tar.gz", "system.posix_acl_default", 0x0, 0) = -1 ENODATA (No data available) lstat("/tmp/librsync-0.9.7", {st_mode=S_IFDIR|0777, st_size=4096, ...}) = 0 getxattr("/tmp/librsync-0.9.7", "system.posix_acl_access", 0x0, 0) = -1 ENODATA (No data available) getxattr("/tmp/librsync-0.9.7", "system.posix_acl_default", 0x0, 0) = -1 ENODATA (No data available) open("/etc/passwd", O_RDONLY) = 4 fcntl(4, F_GETFD) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=1823, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 1823 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/etc/ld.so.cache", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=71746, ...}) = 0 mmap(NULL, 71746, PROT_READ, MAP_PRIVATE, 4, 0) = 0x2b85862a5000 close(4) = 0 open("/lib64/libnss_ldap.so.2", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\300r\4\0\0\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=3169960, ...}) = 0 mmap(NULL, 5329912, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x2b85864c2000 mprotect(0x2b858679e000, 2093056, PROT_NONE) = 0 mmap(0x2b858699d000, 176128, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x2db000) = 0x2b858699d000 mmap(0x2b85869c8000, 62456, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x2b85869c8000 close(4) = 0 open("/lib64/libcom_err.so.2", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\n\300\2770\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=10000, ...}) = 0 mmap(0x30bfc00000, 2103048, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x30bfc00000 mprotect(0x30bfc02000, 2093056, PROT_NONE) = 0 mmap(0x30bfe01000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x1000) = 0x30bfe01000 close(4) = 0 open("/lib64/libkeyutils.so.1", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\n@\2760\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=9472, ...}) = 0 mmap(0x30be400000, 2102416, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x30be400000 mprotect(0x30be402000, 2093056, PROT_NONE) = 0 mmap(0x30be601000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x1000) = 0x30be601000 close(4) = 0 open("/lib64/libresolv.so.2", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\2402\0\2760\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=92736, ...}) = 0 mmap(0x30be000000, 2181864, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x30be000000 mprotect(0x30be011000, 2097152, PROT_NONE) = 0 mmap(0x30be211000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x11000) = 0x30be211000 mmap(0x30be213000, 6888, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30be213000 close(4) = 0 mprotect(0x30be211000, 4096, PROT_READ) = 0 munmap(0x2b85862a5000, 71746) = 0 rt_sigaction(SIGPIPE, {0x1, [], SA_RESTORER, 0x30ba8302d0}, {SIG_DFL, [], 0}, 8) = 0 geteuid() = 0 futex(0x2b85869c7708, FUTEX_WAKE_PRIVATE, 2147483647) = 0 open("/etc/ldap.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=9119, ...}) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=9119, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "# @(#)$Id: ldap.conf,v 1.38 2006"..., 4096) = 4096 read(4, "Use the OpenLDAP password change"..., 4096) = 4096 read(4, " OpenLDAP 2.0 and earlier is \"no"..., 4096) = 927 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 uname({sys="Linux", node="massive.answeron.com", ...}) = 0 open("/etc/resolv.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=107, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "; generated by /sbin/dhclient-sc"..., 4096) = 107 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 4 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(4, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(4) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 4 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(4, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(4) = 0 open("/etc/host.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=17, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "order hosts,bind\n", 4096) = 17 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 futex(0x30bab54d44, FUTEX_WAKE_PRIVATE, 2147483647) = 0 open("/etc/hosts", O_RDONLY) = 4 fcntl(4, F_GETFD) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=187, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "# Do not remove the following li"..., 4096) = 187 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/etc/ld.so.cache", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=71746, ...}) = 0 mmap(NULL, 71746, PROT_READ, MAP_PRIVATE, 4, 0) = 0x2b85862a5000 close(4) = 0 open("/lib64/libnss_dns.so.2", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\17\0\0\0\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=23736, ...}) = 0 mmap(NULL, 2113792, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x2b85869d8000 mprotect(0x2b85869dc000, 2093056, PROT_NONE) = 0 mmap(0x2b8586bdb000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x3000) = 0x2b8586bdb000 close(4) = 0 mprotect(0x2b8586bdb000, 4096, PROT_READ) = 0 munmap(0x2b85862a5000, 71746) = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, 28) = 0 fcntl(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 gettimeofday({1276265920, 823870}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0) = 1 ([{fd=4, revents=POLLOUT}]) sendto(4, "C\v\1\0\0\1\0\0\0\0\0\0\7massive\10answeron\3co"..., 38, MSG_NOSIGNAL, NULL, 0) = 38 poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [122]) = 0 recvfrom(4, "C\v\205\200\0\1\0\1\0\2\0\2\7massive\10answeron\3co"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, [16]) = 122 close(4) = 0 open("/etc/openldap/ldap.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=335, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "#\n# LDAP Defaults\n#\n\n# See ldap."..., 4096) = 335 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 getuid() = 0 geteuid() = 0 getgid() = 0 getegid() = 0 open("/root/ldaprc", O_RDONLY) = -1 ENOENT (No such file or directory) open("/root/.ldaprc", O_RDONLY) = -1 ENOENT (No such file or directory) stat("/etc/ldap.conf", {st_mode=S_IFREG|0644, st_size=9119, ...}) = 0 geteuid() = 0 brk(0x1c566000) = 0x1c566000 open("/etc/hosts", O_RDONLY) = 4 fcntl(4, F_GETFD) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=187, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "# Do not remove the following li"..., 4096) = 187 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/etc/hosts", O_RDONLY) = 4 fcntl(4, F_GETFD) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=187, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "# Do not remove the following li"..., 4096) = 187 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, 28) = 0 fcntl(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 gettimeofday({1276265920, 855948}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0) = 1 ([{fd=4, revents=POLLOUT}]) sendto(4, "\32 \1\0\0\1\0\0\0\0\0\0\4ldap\10answeron\3com\0\0"..., 35, MSG_NOSIGNAL, NULL, 0) = 35 poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [104]) = 0 recvfrom(4, "\32 \205\200\0\1\0\1\0\1\0\0\4ldap\10answeron\3com\0\0"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, [16]) = 104 close(4) = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, 28) = 0 fcntl(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 gettimeofday({1276265920, 858536}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0) = 1 ([{fd=4, revents=POLLOUT}]) sendto(4, "I\375\1\0\0\1\0\0\0\0\0\0\4ldap\10answeron\3com\0\0"..., 35, MSG_NOSIGNAL, NULL, 0) = 35 poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [139]) = 0 recvfrom(4, "I\375\205\200\0\1\0\2\0\2\0\2\4ldap\10answeron\3com\0\0"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, [16]) = 139 close(4) = 0 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 4 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 setsockopt(4, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 fcntl(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(4, {sa_family=AF_INET, sin_port=htons(389), sin_addr=inet_addr("10.20.0.30")}, 16) = -1 EINPROGRESS (Operation now in progress) poll([{fd=4, events=POLLOUT|POLLERR|POLLHUP}], 1, 120000 And thats where it stops, right there after that last 120000.... Using strace, I can obviously CTRL+C to keep going. But like I said, normally the terminal completely freezes. Anyone have any clues?

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  • Deleting multiple objects in a AWS S3 bucket with s3curl.pl?

    - by user183394
    I have been trying to use the AWS "official" command line tool s3curl.pl to test out the recently announced multi-object delete. Here is what I have done: First, I tested out the s3curl.pl with a set of credentials without a hitch: $ s3curl.pl --id=s3 -- http://testbucket-0.s3.amazonaws.com/|xmllint --format - % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 884 0 884 0 0 4399 0 --:--:-- --:--:-- --:--:-- 5703 <?xml version="1.0" encoding="UTF-8"?> <ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"> <Name>testbucket-0</Name> <Prefix/> <Marker/> <MaxKeys>1000</MaxKeys> <IsTruncated>false</IsTruncated> <Contents> <Key>file_1</Key> <LastModified>2012-03-22T17:08:17.000Z</LastModified> <ETag>"ee0e521a76524034aaa5b331842a8b4e"</ETag> <Size>400000</Size> <Owner> <ID>e6d81ea69572270e58d3814ab674df8c8f1fd5d502669633a4951bdd5185f7f4</ID> <DisplayName>zackp</DisplayName> </Owner> <StorageClass>STANDARD</StorageClass> </Contents> <Contents> <Key>file_2</Key> <LastModified>2012-03-22T17:08:19.000Z</LastModified> <ETag>"6b32cbf8219a59690a9f69ba6ff3f590"</ETag> <Size>600000</Size> <Owner> <ID>e6d81ea69572270e58d3814ab674df8c8f1fd5d502669633a4951bdd5185f7f4</ID> <DisplayName>zackp</DisplayName> </Owner> <StorageClass>STANDARD</StorageClass> </Contents> </ListBucketResult> Then, I following the s3curl.pl's usage instructions: s3curl.pl --help Usage /usr/local/bin/s3curl.pl --id friendly-name (or AWSAccessKeyId) [options] -- [curl-options] [URL] options: --key SecretAccessKey id/key are AWSAcessKeyId and Secret (unsafe) --contentType text/plain set content-type header --acl public-read use a 'canned' ACL (x-amz-acl header) --contentMd5 content_md5 add x-amz-content-md5 header --put <filename> PUT request (from the provided local file) --post [<filename>] POST request (optional local file) --copySrc bucket/key Copy from this source key --createBucket [<region>] create-bucket with optional location constraint --head HEAD request --debug enable debug logging common curl options: -H 'x-amz-acl: public-read' another way of using canned ACLs -v verbose logging Then, I tried the following, and always got back error. I would appreciated it very much if someone could point out where I made a mistake? $ s3curl.pl --id=s3 --post multi_delete.xml -- http://testbucket-0.s3.amazonaws.com/?delete <?xml version="1.0" encoding="UTF-8"?> <Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your key and signing method.</Message><StringToSignBytes>50 4f 53 54 0a 0a 0a 54 68 75 2c 20 30 35 20 41 70 72 20 32 30 31 32 20 30 30 3a 35 30 3a 30 38 20 2b 30 30 30 30 0a 2f 7a 65 74 74 61 72 2d 74 2f 3f 64 65 6c 65 74 65</StringToSignBytes><RequestId>707FBE0EB4A571A8</RequestId><HostId>mP3ZwlPTcRqARQZd6gU4UvBrxGBNIVa0VVe5p0rqGmq5hM65RprwcG/qcXe+pmDT</HostId><SignatureProvided>edkNGuugiSFe0ku4eGzkh8kYgHw=</SignatureProvided><StringToSign>POST Thu, 05 Apr 2012 00:50:08 +0000 The file multi_delete.xml contains the following: cat multi_delete.xml <?xml version="1.0" encoding="UTF-8"?> <Delete> <Quiet>true</Quiet> <Object> <Key>file_1</Key> <VersionId> </VersionId>> </Object> <Object> <Key>file_2</Key> <VersionId> </VersionId> </Object> </Delete> Thanks for any help! --Zack

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  • How to prevent ‘Select *’ : The elegant way

    - by Dave Ballantyne
    I’ve been doing a lot of work with the “Microsoft SQL Server 2012 Transact-SQL Language Service” recently, see my post here and article here for more details on its use and some uses. An obvious use is to interrogate sql scripts to enforce our coding standards.  In the SQL world a no-brainer is SELECT *,  all apologies must now be given to Jorge Segarra and his post “How To Prevent SELECT * The Evil Way” as this is a blatant rip-off IMO, the only true way to check for this particular evilness is to parse the SQL as if we were SQL Server itself.  The parser mentioned above is ,pretty much, the best tool for doing this.  So without further ado lets have a look at a powershell script that does exactly that : cls #Load the assembly [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SqlServer.Management.SqlParser") | Out-Null $ParseOptions = New-Object Microsoft.SqlServer.Management.SqlParser.Parser.ParseOptions $ParseOptions.BatchSeparator = 'GO' #Create the object $Parser = new-object Microsoft.SqlServer.Management.SqlParser.Parser.Scanner($ParseOptions) $SqlArr = Get-Content "C:\scripts\myscript.sql" $Sql = "" foreach($Line in $SqlArr){ $Sql+=$Line $Sql+="`r`n" } $Parser.SetSource($Sql,0) $Token=[Microsoft.SqlServer.Management.SqlParser.Parser.Tokens]::TOKEN_SET $IsEndOfBatch = $false $IsMatched = $false $IsExecAutoParamHelp = $false $Batch = "" $BatchStart =0 $Start=0 $End=0 $State=0 $SelectColumns=@(); $InSelect = $false $InWith = $false; while(($Token = $Parser.GetNext([ref]$State ,[ref]$Start, [ref]$End, [ref]$IsMatched, [ref]$IsExecAutoParamHelp ))-ne [Microsoft.SqlServer.Management.SqlParser.Parser.Tokens]::EOF) { $Str = $Sql.Substring($Start,($End-$Start)+1) try{ ($TokenPrs =[Microsoft.SqlServer.Management.SqlParser.Parser.Tokens]$Token) | Out-Null #Write-Host $TokenPrs if($TokenPrs -eq [Microsoft.SqlServer.Management.SqlParser.Parser.Tokens]::TOKEN_SELECT){ $InSelect =$true $SelectColumns+="" } if($TokenPrs -eq [Microsoft.SqlServer.Management.SqlParser.Parser.Tokens]::TOKEN_FROM){ $InSelect =$false #Write-Host $SelectColumns -BackgroundColor Red foreach($Col in $SelectColumns){ if($Col.EndsWith("*")){ Write-Host "select * is not allowed" exit } } $SelectColumns =@() } }catch{ #$Error $TokenPrs = $null } if($InSelect -and $TokenPrs -ne [Microsoft.SqlServer.Management.SqlParser.Parser.Tokens]::TOKEN_SELECT){ if($Str -eq ","){ $SelectColumns+="" }else{ $SelectColumns[$SelectColumns.Length-1]+=$Str } } } OK, im not going to pretend that its the prettiest of powershell scripts,  but if our parsed script file “C:\Scripts\MyScript.SQL” contains SELECT * then “select * is not allowed” will be written to the host.  So, where can this go wrong ?  It cant ,or at least shouldn’t , go wrong, but it is lacking in functionality.  IMO, Select * should be allowed in CTEs, views and Inline table valued functions at least and as it stands they will be reported upon. Anyway, it is a start and is more reliable that other methods.

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  • Operator of the week - Assert

    - by Fabiano Amorim
    Well my friends, I was wondering how to help you in a practical way to understand execution plans. So I think I'll talk about the Showplan Operators. Showplan Operators are used by the Query Optimizer (QO) to build the query plan in order to perform a specified operation. A query plan will consist of many physical operators. The Query Optimizer uses a simple language that represents each physical operation by an operator, and each operator is represented in the graphical execution plan by an icon. I'll try to talk about one operator every week, but so as to avoid having to continue to write about these operators for years, I'll mention only of those that are more common: The first being the Assert. The Assert is used to verify a certain condition, it validates a Constraint on every row to ensure that the condition was met. If, for example, our DDL includes a check constraint which specifies only two valid values for a column, the Assert will, for every row, validate the value passed to the column to ensure that input is consistent with the check constraint. Assert  and Check Constraints: Let's see where the SQL Server uses that information in practice. Take the following T-SQL: IF OBJECT_ID('Tab1') IS NOT NULL   DROP TABLE Tab1 GO CREATE TABLE Tab1(ID Integer, Gender CHAR(1))  GO  ALTER TABLE TAB1 ADD CONSTRAINT ck_Gender_M_F CHECK(Gender IN('M','F'))  GO INSERT INTO Tab1(ID, Gender) VALUES(1,'X') GO To the command above the SQL Server has generated the following execution plan: As we can see, the execution plan uses the Assert operator to check that the inserted value doesn't violate the Check Constraint. In this specific case, the Assert applies the rule, 'if the value is different to "F" and different to "M" than return 0 otherwise returns NULL'. The Assert operator is programmed to show an error if the returned value is not NULL; in other words, the returned value is not a "M" or "F". Assert checking Foreign Keys Now let's take a look at an example where the Assert is used to validate a foreign key constraint. Suppose we have this  query: ALTER TABLE Tab1 ADD ID_Genders INT GO  IF OBJECT_ID('Tab2') IS NOT NULL   DROP TABLE Tab2 GO CREATE TABLE Tab2(ID Integer PRIMARY KEY, Gender CHAR(1))  GO  INSERT INTO Tab2(ID, Gender) VALUES(1, 'F') INSERT INTO Tab2(ID, Gender) VALUES(2, 'M') INSERT INTO Tab2(ID, Gender) VALUES(3, 'N') GO  ALTER TABLE Tab1 ADD CONSTRAINT fk_Tab2 FOREIGN KEY (ID_Genders) REFERENCES Tab2(ID) GO  INSERT INTO Tab1(ID, ID_Genders, Gender) VALUES(1, 4, 'X') Let's look at the text execution plan to see what these Assert operators were doing. To see the text execution plan just execute SET SHOWPLAN_TEXT ON before run the insert command. |--Assert(WHERE:(CASE WHEN NOT [Pass1008] AND [Expr1007] IS NULL THEN (0) ELSE NULL END))      |--Nested Loops(Left Semi Join, PASSTHRU:([Tab1].[ID_Genders] IS NULL), OUTER REFERENCES:([Tab1].[ID_Genders]), DEFINE:([Expr1007] = [PROBE VALUE]))           |--Assert(WHERE:(CASE WHEN [Tab1].[Gender]<>'F' AND [Tab1].[Gender]<>'M' THEN (0) ELSE NULL END))           |    |--Clustered Index Insert(OBJECT:([Tab1].[PK]), SET:([Tab1].[ID] = RaiseIfNullInsert([@1]),[Tab1].[ID_Genders] = [@2],[Tab1].[Gender] = [Expr1003]), DEFINE:([Expr1003]=CONVERT_IMPLICIT(char(1),[@3],0)))           |--Clustered Index Seek(OBJECT:([Tab2].[PK]), SEEK:([Tab2].[ID]=[Tab1].[ID_Genders]) ORDERED FORWARD) Here we can see the Assert operator twice, first (looking down to up in the text plan and the right to left in the graphical plan) validating the Check Constraint. The same concept showed above is used, if the exit value is "0" than keep running the query, but if NULL is returned shows an exception. The second Assert is validating the result of the Tab1 and Tab2 join. It is interesting to see the "[Expr1007] IS NULL". To understand that you need to know what this Expr1007 is, look at the Probe Value (green text) in the text plan and you will see that it is the result of the join. If the value passed to the INSERT at the column ID_Gender exists in the table Tab2, then that probe will return the join value; otherwise it will return NULL. So the Assert is checking the value of the search at the Tab2; if the value that is passed to the INSERT is not found  then Assert will show one exception. If the value passed to the column ID_Genders is NULL than the SQL can't show a exception, in that case it returns "0" and keeps running the query. If you run the INSERT above, the SQL will show an exception because of the "X" value, but if you change the "X" to "F" and run again, it will show an exception because of the value "4". If you change the value "4" to NULL, 1, 2 or 3 the insert will be executed without any error. Assert checking a SubQuery: The Assert operator is also used to check one subquery. As we know, one scalar subquery can't validly return more than one value: Sometimes, however, a  mistake happens, and a subquery attempts to return more than one value . Here the Assert comes into play by validating the condition that a scalar subquery returns just one value. Take the following query: INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1), 'F')    INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1), 'F')    |--Assert(WHERE:(CASE WHEN NOT [Pass1016] AND [Expr1015] IS NULL THEN (0) ELSE NULL END))        |--Nested Loops(Left Semi Join, PASSTHRU:([tempdb].[dbo].[Tab1].[ID_TipoSexo] IS NULL), OUTER REFERENCES:([tempdb].[dbo].[Tab1].[ID_TipoSexo]), DEFINE:([Expr1015] = [PROBE VALUE]))              |--Assert(WHERE:([Expr1017]))             |    |--Compute Scalar(DEFINE:([Expr1017]=CASE WHEN [tempdb].[dbo].[Tab1].[Sexo]<>'F' AND [tempdb].[dbo].[Tab1].[Sexo]<>'M' THEN (0) ELSE NULL END))              |         |--Clustered Index Insert(OBJECT:([tempdb].[dbo].[Tab1].[PK__Tab1__3214EC277097A3C8]), SET:([tempdb].[dbo].[Tab1].[ID_TipoSexo] = [Expr1008],[tempdb].[dbo].[Tab1].[Sexo] = [Expr1009],[tempdb].[dbo].[Tab1].[ID] = [Expr1003]))              |              |--Top(TOP EXPRESSION:((1)))              |                   |--Compute Scalar(DEFINE:([Expr1008]=[Expr1014], [Expr1009]='F'))              |                        |--Nested Loops(Left Outer Join)              |                             |--Compute Scalar(DEFINE:([Expr1003]=getidentity((1856985942),(2),NULL)))              |                             |    |--Constant Scan              |                             |--Assert(WHERE:(CASE WHEN [Expr1013]>(1) THEN (0) ELSE NULL END))              |                                  |--Stream Aggregate(DEFINE:([Expr1013]=Count(*), [Expr1014]=ANY([tempdb].[dbo].[Tab1].[ID_TipoSexo])))             |                                       |--Clustered Index Scan(OBJECT:([tempdb].[dbo].[Tab1].[PK__Tab1__3214EC277097A3C8]))              |--Clustered Index Seek(OBJECT:([tempdb].[dbo].[Tab2].[PK__Tab2__3214EC27755C58E5]), SEEK:([tempdb].[dbo].[Tab2].[ID]=[tempdb].[dbo].[Tab1].[ID_TipoSexo]) ORDERED FORWARD)  You can see from this text showplan that SQL Server as generated a Stream Aggregate to count how many rows the SubQuery will return, This value is then passed to the Assert which then does its job by checking its validity. Is very interesting to see that  the Query Optimizer is smart enough be able to avoid using assert operators when they are not necessary. For instance: INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1 WHERE ID = 1), 'F') INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT TOP 1 ID_TipoSexo FROM Tab1), 'F')  For both these INSERTs, the Query Optimiser is smart enough to know that only one row will ever be returned, so there is no need to use the Assert. Well, that's all folks, I see you next week with more "Operators". Cheers, Fabiano

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  • Why do you need float/double?

    - by acidzombie24
    I was watching http://www.joelonsoftware.com/items/2011/06/27.html and laughed at Jon Skeet joke about 0.3 not being 0.3. I personally never had problems with floats/decimals/doubles but then I remember I learned 6502 very early and never needed floats in most of my programs. The only time I used it was for graphics and math where inaccurate numbers were ok and the output was for the screen and not to be stored (in a db, file) or dependent on. My question is, where are places were you typically use floats/decimals/double? So I know to watch out for these gotchas. With money I use longs and store values by the cent, for speed of an object in a game I add ints and divide (or bitshift) the value to know if I need to move a pixel or not. (I made object move in the 6502 days, we had no divide nor floats but had shifts). So I was mostly curious.

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  • International Radio Operators Alphabet in F# &amp; Silverlight &ndash; Part 2

    - by MarkPearl
    So the brunt of my my very complex F# code has been done. Now it’s just putting the Silverlight stuff in. The first thing I did was add a new project to my solution. I gave it a name and VS2010 did the rest of the magic in creating the .Web project etc. In this instance because I want to take the MVVM approach and make use of commanding I have decided to make the frontend a Silverlight4 project. I now need move my F# code into a proper Silverlight Library. Warning – when you create the Silverlight Library VS2010 will ask you whether you want it to be based on Silverlight3 or Silverlight4. I originally went for Silverlight4 only to discover when I tried to compile my solution that I was given an error… Error 12 F# runtime for Silverlight version v4.0 is not installed. Please go to http://go.microsoft.com/fwlink/?LinkId=177463 to download and install matching.. After asking around I discovered that the Silverlight4 F# runtime is not available yet. No problem, the suggestion was to change the F# Silverlight Library to a Silverlight3 project however when going to the properties of the project file – even though I changed it to Silverlight3, VS2010 did not like it and kept reverting it to a Silverlight4 project. After a few minutes of scratching my head I simply deleted Silverlight4 F# Library project and created a new F# Silverlight Library project in Silverlight3 and VS2010 was happy. Now that the project structure is set up, rest is fairly simple. You need to add the Silverlight Library as a reference to the C# Silverlight Front End. Then setup your views, since I was following the MVVM pattern I made a Views & ViewModel folder and set up the relevant View and ViewModels. The MainPageViewModel file looks as follows using System; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Ink; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using System.Collections.ObjectModel; namespace IROAFrontEnd.ViewModels { public class MainPageViewModel : ViewModelBase { private string _iroaString; private string _inputCharacters; public string InputCharacters { get { return _inputCharacters; } set { if (_inputCharacters != value) { _inputCharacters = value; OnPropertyChanged("InputCharacters"); } } } public string IROAString { get { return _iroaString; } set { if (_iroaString != value) { _iroaString = value; OnPropertyChanged("IROAString"); } } } public ICommand MySpecialCommand { get { return new MyCommand(this); } } public class MyCommand : ICommand { readonly MainPageViewModel _myViewModel; public MyCommand(MainPageViewModel myViewModel) { _myViewModel = myViewModel; } public event EventHandler CanExecuteChanged; public bool CanExecute(object parameter) { return true; } public void Execute(object parameter) { var result = ModuleMain.ConvertCharsToStrings(_myViewModel.InputCharacters); var newString = ""; foreach (var Item in result) { newString += Item + " "; } _myViewModel.IROAString = newString.Trim(); } } } } One of the features I like in Silverlight4 is the new commanding. You will notice in my I have put the code under the command execute to reference to my F# module. At the moment this could be cleaned up even more, but will suffice for now.. public void Execute(object parameter) { var result = ModuleMain.ConvertCharsToStrings(_myViewModel.InputCharacters); var newString = ""; foreach (var Item in result) { newString += Item + " "; } _myViewModel.IROAString = newString.Trim(); } I then needed to set the view up. If we have a look at the MainPageView.xaml the xaml code will look like the following…. Nothing to fancy, but battleship grey for now… take careful note of the binding of the command in the button to MySpecialCommand which was created in the ViewModel. <UserControl x:Class="IROAFrontEnd.Views.MainPageView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400"> <Grid x:Name="LayoutRoot" Background="White"> <Grid.RowDefinitions> <RowDefinition/> <RowDefinition/> <RowDefinition/> </Grid.RowDefinitions> <TextBox Grid.Row="0" Text="{Binding InputCharacters, Mode=TwoWay}"/> <Button Grid.Row="1" Command="{Binding MySpecialCommand}"> <TextBlock Text="Generate"/> </Button> <TextBlock Grid.Row="2" Text="{Binding IROAString}"/> </Grid> </UserControl> Finally in the App.xaml.cs file we need to set the View and link it to the ViewModel. private void Application_Startup(object sender, StartupEventArgs e) { var myView = new MainPageView(); var myViewModel = new MainPageViewModel(); myView.DataContext = myViewModel; this.RootVisual = myView; }   Once this is done – hey presto – it worked. I typed in some “Test Input” and clicked the generate button and the correct Radio Operators Alphabet was generated. And that’s the end of my first very basic F# Silverlight application.

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  • Pure Front end JavaScript with Web API versus MVC views with ajax

    - by eyeballpaul
    This was more a discussion for what peoples thoughts are these days on how to split a web application. I am used to creating an MVC application with all its views and controllers. I would normally create a full view and pass this back to the browser on a full page request, unless there were specific areas that I did not want to populate straight away and would then use DOM page load events to call the server to load other areas using AJAX. Also, when it came to partial page refreshing, I would call an MVC action method which would return the HTML fragment which I could then use to populate parts of the page. This would be for areas that I did not want to slow down initial page load, or areas that fitted better with AJAX calls. One example would be for table paging. If you want to move on to the next page, I would prefer it if an AJAX call got that info rather than using a full page refresh. But the AJAX call would still return an HTML fragment. My question is. Are my thoughts on this archaic because I come from a .net background rather than a pure front end background? An intelligent front end developer that I work with, prefers to do more or less nothing in the MVC views, and would rather do everything on the front end. Right down to web API calls populating the page. So that rather than calling an MVC action method, which returns HTML, he would prefer to return a standard object and use javascript to create all the elements of the page. The front end developer way means that any benefits that I normally get with MVC model validation, including client side validation, would be gone. It also means that any benefits that I get with creating the views, with strongly typed html templates etc would be gone. I believe this would mean I would need to write the same validation for front end and back end validation. The javascript would also need to have lots of methods for creating all the different parts of the DOM. For example, when adding a new row to a table, I would normally use the MVC partial view for creating the row, and then return this as part of the AJAX call, which then gets injected into the table. By using a pure front end way, the javascript would would take in an object (for, say, a product) for the row from the api call, and then create a row from that object. Creating each individual part of the table row. The website in question will have lots of different areas, from administration, forms, product searching etc. A website that I don't think requires to be architected in a single page application way. What are everyone's thoughts on this? I am interested to hear from front end devs and back end devs.

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  • SQL SERVER – Replace a Column Name in Multiple Stored Procedure all together

    - by pinaldave
    I receive a lot of emails every day. I try to answer each and every email and comments on Facebook and Twitter. I prefer communication on social media as this gives opportunities to others to read the questions and participate along with me. There is always some question which everyone likes to read and remember. Here is one of the questions which I received in email. I believe the same question will be there any many developers who are beginning with SQL Server. I decided to blog about it so everyone can read it and participate. “I am beginner in SQL Server. I have a very interesting situation and need your help. I am beginner to SQL Server and that is why I do not have access to the production server and I work entirely on the development server. The project I am working on is also in the infant stage as well. In product I had to create a multiple tables and every table had few columns. Later on I have written Stored Procedures using those tables. During a code review my manager has requested to change one of the column which I have used in the table. As per him the naming convention was not accurate. Now changing the columname in the table is not a big issue. I figured out that I can do it very quickly either using T-SQL script or SQL Server Management Studio. The real problem is that I have used this column in nearly 50+ stored procedure. This looks like a very mechanical task. I believe I can go and change it in nearly 50+ stored procedure but is there a better solution I can use. Someone suggested that I should just go ahead and find the text in system table and update it there. Is that safe solution? If not, what is your solution. In simple words, How to replace a column name in multiple stored procedure efficiently and quickly? Please help me here with keeping my experience and non-production server in mind.” Well, I found this question very interesting. Honestly I would have preferred if this question was asked on my social media handles (Facebook and Twitter) as I am very active there and quite often before I reach there other experts have already answered this question. Anyway I am now answering the same question on the blog so all of us can participate here and come up with an appropriate answer. Here is my answer - “My Friend, I do not advice to touch system table. Please do not go that route. It can be dangerous and not appropriate. The issue which you faced today is what I used to face in early career as well I still face it often. There are two sets of argument I have observed – there are people who see no value in the name of the object and name objects like obj1, obj2 etc. There are sets of people who carefully chose the name of the object where object name is self-explanatory and almost tells a story. I am not here to take any side in this blog post – so let me go to a quick solution for your problem. Note: Following should not be directly practiced on Production Server. It should be properly tested on development server and once it is validated they should be pushed to your production server with your existing deployment practice. The answer is here assuming you have regular stored procedures and you are working on the Development NON Production Server. Go to Server Note >> Databases >> DatabaseName >> Programmability >> Stored Procedure Now make sure that Object Explorer Details are open (if not open it by clicking F7). You will see the list of all the stored procedures there. Now you will see a list of all the stored procedures on the right side list. Select either all of them or the one which you believe are relevant to your query. Now… Right click on the stored procedures >> SELECT DROP and CREATE to >> Now select New Query Editor Window or Clipboard. Paste the complete script to a new window if you have selected Clipboard option. Now press Control+H which will bring up the Find and Replace Screen. In this screen insert the column to be replaced in the “Find What”box and new column name into “Replace With” box. Now execute the whole script. As we have selected DROP and CREATE to, it will created drop the old procedure and create the new one. Another method would do all the same procedure but instead of DROP and CREATE manually replace the CREATE word with ALTER world. There is a small advantage in doing this is that if due to any reason the error comes up which prevents the new stored procedure to be created you will have your old stored procedure in the system as it is. “ Well, this was my answer to the question which I have received. Do you see any other workaround or solution? Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Stored Procedure, SQL Tips and Tricks, T SQL, Technology

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  • Search and Browse Database Objects with Oracle SQL Developer

    - by thatjeffsmith
    I was tempted to throw in another Dora the Explorer Map reference here, but I came to my senses.Having trouble finding something? Maybe you’re just getting older? I know I am. But still, it’d be nice if my favorite database tool could help me out a bit. Hmmm, what’s this ‘Find Database Object‘ thing over here…sounds like a search mechanism of some sort? You can access this panel from the ‘View‘ menu. It’s a good bit down the screen, so I don’t blame you if you haven’t seen it before. It makes finding ‘stuff’ in your database so much easier. Let’s say I want to find my ‘beer’ objects. I simply need to type my search string and the context (in this case I want it to search EVERYTHING), and hit enter. The search results are listed below and clicking on an object automatically opens it! I know it seems very simple, but I get asked this question a LOT. It will even search through your PL/SQL code! Finding too much? Be sure to toggle off the ‘%’ wildcard check box before doing a search. Working on a Project? I bet you use common column names, or codes, throughout your tables. You could take advantage of this knowledge and use the Find Database Object panel as a substitute connection tree or schema browser. Working on your HR project and want to look at your employee objects? Do a column search for your column ID/key. Sometimes thinking outside the box actually works! Don’t be afraid to tackle a problem from a weird angle, or re-purpose your tools. I do it all the time And I drive the developers nuts trying to do things with the tools they were never designed to do. But I digress. Back to your coding!

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  • C#: Why Decorate When You Can Intercept

    - by James Michael Hare
    We've all heard of the old Decorator Design Pattern (here) or used it at one time or another either directly or indirectly.  A decorator is a class that wraps a given abstract class or interface and presents the same (or a superset) public interface but "decorated" with additional functionality.   As a really simplistic example, consider the System.IO.BufferedStream, it itself is a descendent of System.IO.Stream and wraps the given stream with buffering logic while still presenting System.IO.Stream's public interface:   1: Stream buffStream = new BufferedStream(rawStream); Now, let's take a look at a custom-code example.  Let's say that we have a class in our data access layer that retrieves a list of products from a database:  1: // a class that handles our CRUD operations for products 2: public class ProductDao 3: { 4: ... 5:  6: // a method that would retrieve all available products 7: public IEnumerable<Product> GetAvailableProducts() 8: { 9: var results = new List<Product>(); 10:  11: // must create the connection 12: using (var con = _factory.CreateConnection()) 13: { 14: con.ConnectionString = _productsConnectionString; 15: con.Open(); 16:  17: // create the command 18: using (var cmd = _factory.CreateCommand()) 19: { 20: cmd.Connection = con; 21: cmd.CommandText = _getAllProductsStoredProc; 22: cmd.CommandType = CommandType.StoredProcedure; 23:  24: // get a reader and pass back all results 25: using (var reader = cmd.ExecuteReader()) 26: { 27: while(reader.Read()) 28: { 29: results.Add(new Product 30: { 31: Name = reader["product_name"].ToString(), 32: ... 33: }); 34: } 35: } 36: } 37: }            38:  39: return results; 40: } 41: } Yes, you could use EF or any myriad other choices for this sort of thing, but the germaine point is that you have some operation that takes a non-trivial amount of time.  What if, during the production day I notice that my application is performing slowly and I want to see how much of that slowness is in the query versus my code.  Well, I could easily wrap the logic block in a System.Diagnostics.Stopwatch and log the results to log4net or other logging flavor of choice: 1:     // a class that handles our CRUD operations for products 2:     public class ProductDao 3:     { 4:         private static readonly ILog _log = LogManager.GetLogger(typeof(ProductDao)); 5:         ... 6:         7:         // a method that would retrieve all available products 8:         public IEnumerable<Product> GetAvailableProducts() 9:         { 10:             var results = new List<Product>(); 11:             var timer = Stopwatch.StartNew(); 12:             13:             // must create the connection 14:             using (var con = _factory.CreateConnection()) 15:             { 16:                 con.ConnectionString = _productsConnectionString; 17:                 18:                 // and all that other DB code... 19:                 ... 20:             } 21:             22:             timer.Stop(); 23:             24:             if (timer.ElapsedMilliseconds > 5000) 25:             { 26:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 27:                     timer.ElapsedMillseconds); 28:             } 29:             30:             return results; 31:         } 32:     } In my eye, this is very ugly.  It violates Single Responsibility Principle (SRP), which says that a class should only ever have one responsibility, where responsibility is often defined as a reason to change.  This class (and in particular this method) has two reasons to change: If the method of retrieving products changes. If the method of logging changes. Well, we could “simplify” this using the Decorator Design Pattern (here).  If we followed the pattern to the letter, we'd need to create a base decorator that implements the DAOs public interface and forwards to the wrapped instance.  So let's assume we break out the ProductDAO interface into IProductDAO using your refactoring tool of choice (Resharper is great for this). Now, ProductDao will implement IProductDao and get rid of all logging logic: 1:     public class ProductDao : IProductDao 2:     { 3:         // this reverts back to original version except for the interface added 4:     } 5:  And we create the base Decorator that also implements the interface and forwards all calls: 1:     public class ProductDaoDecorator : IProductDao 2:     { 3:         private readonly IProductDao _wrappedDao; 4:         5:         // constructor takes the dao to wrap 6:         public ProductDaoDecorator(IProductDao wrappedDao) 7:         { 8:             _wrappedDao = wrappedDao; 9:         } 10:         11:         ... 12:         13:         // and then all methods just forward their calls 14:         public IEnumerable<Product> GetAvailableProducts() 15:         { 16:             return _wrappedDao.GetAvailableProducts(); 17:         } 18:     } This defines our base decorator, then we can create decorators that add items of interest, and for any methods we don't decorate, we'll get the default behavior which just forwards the call to the wrapper in the base decorator: 1:     public class TimedThresholdProductDaoDecorator : ProductDaoDecorator 2:     { 3:         private static readonly ILog _log = LogManager.GetLogger(typeof(TimedThresholdProductDaoDecorator)); 4:         5:         public TimedThresholdProductDaoDecorator(IProductDao wrappedDao) : 6:             base(wrappedDao) 7:         { 8:         } 9:         10:         ... 11:         12:         public IEnumerable<Product> GetAvailableProducts() 13:         { 14:             var timer = Stopwatch.StartNew(); 15:             16:             var results = _wrapped.GetAvailableProducts(); 17:             18:             timer.Stop(); 19:             20:             if (timer.ElapsedMilliseconds > 5000) 21:             { 22:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 23:                     timer.ElapsedMillseconds); 24:             } 25:             26:             return results; 27:         } 28:     } Well, it's a bit better.  Now the logging is in its own class, and the database logic is in its own class.  But we've essentially multiplied the number of classes.  We now have 3 classes and one interface!  Now if you want to do that same logging decorating on all your DAOs, imagine the code bloat!  Sure, you can simplify and avoid creating the base decorator, or chuck it all and just inherit directly.  But regardless all of these have the problem of tying the logging logic into the code itself. Enter the Interceptors.  Things like this to me are a perfect example of when it's good to write an Interceptor using your class library of choice.  Sure, you could design your own perfectly generic decorator with delegates and all that, but personally I'm a big fan of Castle's Dynamic Proxy (here) which is actually used by many projects including Moq. What DynamicProxy allows you to do is intercept calls into any object by wrapping it with a proxy on the fly that intercepts the method and allows you to add functionality.  Essentially, the code would now look like this using DynamicProxy: 1: // Note: I like hiding DynamicProxy behind the scenes so users 2: // don't have to explicitly add reference to Castle's libraries. 3: public static class TimeThresholdInterceptor 4: { 5: // Our logging handle 6: private static readonly ILog _log = LogManager.GetLogger(typeof(TimeThresholdInterceptor)); 7:  8: // Handle to Castle's proxy generator 9: private static readonly ProxyGenerator _generator = new ProxyGenerator(); 10:  11: // generic form for those who prefer it 12: public static object Create<TInterface>(object target, TimeSpan threshold) 13: { 14: return Create(typeof(TInterface), target, threshold); 15: } 16:  17: // Form that uses type instead 18: public static object Create(Type interfaceType, object target, TimeSpan threshold) 19: { 20: return _generator.CreateInterfaceProxyWithTarget(interfaceType, target, 21: new TimedThreshold(threshold, level)); 22: } 23:  24: // The interceptor that is created to intercept the interface calls. 25: // Hidden as a private inner class so not exposing Castle libraries. 26: private class TimedThreshold : IInterceptor 27: { 28: // The threshold as a positive timespan that triggers a log message. 29: private readonly TimeSpan _threshold; 30:  31: // interceptor constructor 32: public TimedThreshold(TimeSpan threshold) 33: { 34: _threshold = threshold; 35: } 36:  37: // Intercept functor for each method invokation 38: public void Intercept(IInvocation invocation) 39: { 40: // time the method invocation 41: var timer = Stopwatch.StartNew(); 42:  43: // the Castle magic that tells the method to go ahead 44: invocation.Proceed(); 45:  46: timer.Stop(); 47:  48: // check if threshold is exceeded 49: if (timer.Elapsed > _threshold) 50: { 51: _log.WarnFormat("Long execution in {0} took {1} ms", 52: invocation.Method.Name, 53: timer.ElapsedMillseconds); 54: } 55: } 56: } 57: } Yes, it's a bit longer, but notice that: This class ONLY deals with logging long method calls, no DAO interface leftovers. This class can be used to time ANY class that has an interface or virtual methods. Personally, I like to wrap and hide the usage of DynamicProxy and IInterceptor so that anyone who uses this class doesn't need to know to add a Castle library reference.  As far as they are concerned, they're using my interceptor.  If I change to a new library if a better one comes along, they're insulated. Now, all we have to do to use this is to tell it to wrap our ProductDao and it does the rest: 1: // wraps a new ProductDao with a timing interceptor with a threshold of 5 seconds 2: IProductDao dao = TimeThresholdInterceptor.Create<IProductDao>(new ProductDao(), 5000); Automatic decoration of all methods!  You can even refine the proxy so that it only intercepts certain methods. This is ideal for so many things.  These are just some of the interceptors we've dreamed up and use: Log parameters and returns of methods to XML for auditing. Block invocations to methods and return default value (stubbing). Throw exception if certain methods are called (good for blocking access to deprecated methods). Log entrance and exit of a method and the duration. Log a message if a method takes more than a given time threshold to execute. Whether you use DynamicProxy or some other technology, I hope you see the benefits this adds.  Does it completely eliminate all need for the Decorator pattern?  No, there may still be cases where you want to decorate a particular class with functionality that doesn't apply to the world at large. But for all those cases where you are using Decorator to add functionality that's truly generic.  I strongly suggest you give this a try!

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  • GNU Smalltalk package

    - by Peter
    I've installed the GNU Smalltalk package and can get to the SmallTalk command line with the command 'gst'. However, I can't start the visual gst browser using the command: $ gst-browser When I try, this is what I get: peter@peredur:~$ gst-browser Object: CFunctionDescriptor new: 1 "<0x40488720>" error: Invalid C call-out gdk_colormap_get_type SystemExceptions.CInterfaceError(Smalltalk.Exception)>>signal (ExcHandling.st:254) SystemExceptions.CInterfaceError class(Smalltalk.Exception class)>>signal: (ExcHandling.st:161) Smalltalk.CFunctionDescriptor(Smalltalk.CCallable)>>callInto: (CCallable.st:165) GdkColormap class>>getType (GTK.star#VFS.ZipFile/Funcs.st:1) optimized [] in GLib class>>registerAllTypes (GTK.star#VFS.ZipFile/GtkDecl.st:78) Smalltalk.OrderedCollection>>do: (OrderColl.st:68) GLib class>>registerAllTypes (GTK.star#VFS.ZipFile/GtkDecl.st:78) Smalltalk.UndefinedObject>>executeStatements (GTK.star#VFS.ZipFile/GtkImpl.st:1078) Object: CFunctionDescriptor new: 1 "<0x404a7c28>" error: Invalid C call-out gtk_window_new SystemExceptions.CInterfaceError(Exception)>>signal (ExcHandling.st:254) SystemExceptions.CInterfaceError class(Exception class)>>signal: (ExcHandling.st:161) CFunctionDescriptor(CCallable)>>callInto: (CCallable.st:165) GTK.GtkWindow class>>new: (GTK.star#VFS.ZipFile/Funcs.st:1) VisualGST.GtkDebugger(VisualGST.GtkMainWindow)>>initialize (VisualGST.star#VFS.ZipFile/GtkMainWindow.st:131) VisualGST.GtkDebugger class(VisualGST.GtkMainWindow class)>>openSized: (VisualGST.star#VFS.ZipFile/GtkMainWindow.st:19) [] in VisualGST.GtkDebugger class>>open: (VisualGST.star#VFS.ZipFile/Debugger/GtkDebugger.st:16) [] in BlockClosure>>forkDebugger (DebugTools.star#VFS.ZipFile/DebugTools.st:380) [] in Process>>onBlock:at:suspend: (Process.st:392) BlockClosure>>on:do: (BlkClosure.st:193) [] in Process>>onBlock:at:suspend: (Process.st:393) BlockClosure>>ensure: (BlkClosure.st:269) [] in Process>>onBlock:at:suspend: (Process.st:370) [] in BlockClosure>>asContext: (BlkClosure.st:179) BlockContext class>>fromClosure:parent: (BlkContext.st:68) Everything hangs at this point until I hit ^C, after which, I get: Object: CFunctionDescriptor new: 1 "<0x404a7c28>" error: Invalid C call-out gtk_window_new SystemExceptions.CInterfaceError(Exception)>>signal (ExcHandling.st:254) SystemExceptions.CInterfaceError class(Exception class)>>signal: (ExcHandling.st:161) CFunctionDescriptor(CCallable)>>callInto: (CCallable.st:165) GTK.GtkWindow class>>new: (GTK.star#VFS.ZipFile/Funcs.st:1) VisualGST.GtkDebugger(VisualGST.GtkMainWindow)>>initialize (VisualGST.star#VFS.ZipFile/GtkMainWindow.st:131) VisualGST.GtkDebugger class(VisualGST.GtkMainWindow class)>>openSized: (VisualGST.star#VFS.ZipFile/GtkMainWindow.st:19) [] in VisualGST.GtkDebugger class>>open: (VisualGST.star#VFS.ZipFile/Debugger/GtkDebugger.st:16) [] in BlockClosure>>forkDebugger (DebugTools.star#VFS.ZipFile/DebugTools.st:380) [] in Process>>onBlock:at:suspend: (Process.st:392) BlockClosure>>on:do: (BlkClosure.st:193) [] in Process>>onBlock:at:suspend: (Process.st:393) BlockClosure>>ensure: (BlkClosure.st:269) [] in Process>>onBlock:at:suspend: (Process.st:370) [] in BlockClosure>>asContext: (BlkClosure.st:179) BlockContext class>>fromClosure:parent: (BlkContext.st:68) peter@peredur:~$ Is there a problem with this package?

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  • Shadow-mapping xna

    - by Kurt Ricci
    I've been trying to implement shadows in my game and I've been following quite a few tutorials online, mainly Riemers, but I'm always getting the same 2 errors when I'm drawing my models and setting the parameters from the effect file. The errors are: This method does not accept null for this parameter. Parameter name: value and Object reference not set to an instance of an object. So I've then downloaded a sample and just replaced my model with the one found in the sample and the same errors occur. I this find very strange as it works with his model. I'm wondering if the problem is with my models (I made them myself). Here's the code where the errors occur (they start to occur after the second foreach loop). Any help would be greatly appreciated, thanks.

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  • How to make and render a simple game just with 3d max?

    - by Sina
    I want to make a simple EXE file, where there is one object in the scene and the user can rotate that object by using arrow keys (or mouse). Is there any way in which I don't have to use a game engine and do it only using 3dsmax script? Cause there is a special renderer I want to use, which is V-Ray a kind of renderer which provides 3D images for 3D glasses. I am not good at making games and engines so I want to know if I can do it only with 3dsmax scripts?

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  • Guest Post: Using IronRuby and .NET to produce the &lsquo;Hello World of WPF&rsquo;

    - by Eric Nelson
    [You might want to also read other GuestPosts on my blog – or contribute one?] On the 26th and 27th of March (2010) myself and Edd Morgan of Microsoft will be popping along to the Scottish Ruby Conference. I dabble with Ruby and I am a huge fan whilst Edd is a “proper Ruby developer”. Hence I asked Edd if he was interested in creating a guest post or two for my blog on IronRuby. This is the second of those posts. If you should stumble across this post and happen to be attending the Scottish Ruby Conference, then please do keep a look out for myself and Edd. We would both love to chat about all things Ruby and IronRuby. And… we should have (if Amazon is kind) a few books on IronRuby with us at the conference which will need to find a good home. This is me and Edd and … the book: Order on Amazon: http://bit.ly/ironrubyunleashed Using IronRuby and .NET to produce the ‘Hello World of WPF’ In my previous post I introduced, to a minor extent, IronRuby. I expanded a little on the basics of by getting a Rails app up-and-running on this .NET implementation of the Ruby language — but there wasn't much to it! So now I would like to go from simply running a pre-existing project under IronRuby to developing a whole new application demonstrating the seamless interoperability between IronRuby and .NET. In particular, we'll be using WPF (Windows Presentation Foundation) — the component of the .NET Framework stack used to create rich media and graphical interfaces. Foundations of WPF To reiterate, WPF is the engine in the .NET Framework responsible for rendering rich user interfaces and other media. It's not the only collection of libraries in the framework with the power to do this — Windows Forms does the trick, too — but it is the most powerful and flexible. Put simply, WPF really excels when you need to employ eye candy. It's all about creating impact. Whether you're presenting a document, video, a data entry form, some kind of data visualisation (which I am most hopeful for, especially in terms of IronRuby - more on that later) or chaining all of the above with some flashy animations, you're likely to find that WPF gives you the most power when developing any of these for a Windows target. Let's demonstrate this with an example. I give you what I like to consider the 'hello, world' of WPF applications: the analogue clock. Today, over my lunch break, I created a WPF-based analogue clock using IronRuby... Any normal person would have just looked at their watch. - Twitter The Sample Application: Click here to see this sample in full on GitHub. Using Windows Presentation Foundation from IronRuby to create a Clock class Invoking the Clock class   Gives you The above is by no means perfect (it was a lunch break), but I think it does the job of illustrating IronRuby's interoperability with WPF using a familiar data visualisation. I'm sure you'll want to dissect the code yourself, but allow me to step through the important bits. (By the way, feel free to run this through ir first to see what actually happens). Now we're using IronRuby - unlike my previous post where we took pure Ruby code and ran it through ir, the IronRuby interpreter, to demonstrate compatibility. The main thing of note is the very distinct parallels between .NET namespaces and Ruby modules, .NET classes and Ruby classes. I guess there's not much to say about it other than at this point, you may as well be working with a purely Ruby graphics-drawing library. You're instantiating .NET objects, but you're doing it with the standard Ruby .new method you know from Ruby as Object#new — although, the root object of all your IronRuby objects isn't actually Object, it's System.Object. You're calling methods on these objects (and classes, for example in the call to System.Windows.Controls.Canvas.SetZIndex()) using the underscored, lowercase convention established for the Ruby language. The integration is so seamless. The fact that you're using a dynamic language on top of .NET's CLR is completely abstracted from you, allowing you to just build your software. A Brief Note on Events Events are a big part of developing client applications in .NET as well as under every other environment I can think of. In case you aren't aware, event-driven programming is essentially the practice of telling your code to call a particular method, or other chunk of code (a delegate) when something happens at an unpredictable time. You can never predict when a user is going to click a button, move their mouse or perform any other kind of input, so the advent of the GUI is what necessitated event-driven programming. This is where one of my favourite aspects of the Ruby language, blocks, can really help us. In traditional C#, for instance, you may subscribe to an event (assign a block of code to execute when an event occurs) in one of two ways: by passing a reference to a named method, or by providing an anonymous code block. You'd be right for seeing the parallel here with Ruby's concept of blocks, Procs and lambdas. As demonstrated at the very end of this rather basic script, we are using .NET's System.Timers.Timer to (attempt to) update the clock every second (I know it's probably not the best way of doing this, but for example's sake). Note: Diverting a little from what I said above, the ticking of a clock is very predictable, yet we still use the event our Timer throws to do this updating as one of many ways to perform that task outside of the main thread. You'll see that all that's needed to assign a block of code to be triggered on an event is to provide that block to the method of the name of the event as it is known to the CLR. This drawback to this is that it only allows the delegation of one code block to each event. You may use the add method to subscribe multiple handlers to that event - pushing that to the end of a queue. Like so: def tick puts "tick tock" end timer.elapsed.add method(:tick) timer.elapsed.add proc { puts "tick tock" } tick_handler = lambda { puts "tick tock" } timer.elapsed.add(tick_handler)   The ability to just provide a block of code as an event handler helps IronRuby towards that very important term I keep throwing around; low ceremony. Anonymous methods are, of course, available in other more conventional .NET languages such as C# and VB but, as usual, feel ever so much more elegant and natural in IronRuby. Note: Whether it's a named method or an anonymous chunk o' code, the block you delegate to the handling of an event can take arguments - commonly, a sender object and some args. Another Brief Note on Verbosity Personally, I don't mind verbose chaining of references in my code as long as it doesn't interfere with performance - as evidenced in the example above. While I love clean code, there's a certain feeling of safety that comes with the terse explicitness of long-winded addressing and the describing of objects as opposed to ambiguity (not unlike this sentence). However, when working with IronRuby, even I grow tired of typing System::Whatever::Something. Some people enjoy simply assuming namespaces and forgetting about them, regardless of the language they're using. Don't worry, IronRuby has you covered. It is completely possible to, with a call to include, bring the contents of a .NET-converted module into context of your IronRuby code - just as you would if you wanted to bring in an 'organic' Ruby module. To refactor the style of the above example, I could place the following at the top of my Clock class: class Clock include System::Windows::Shape include System::Windows::Media include System::Windows::Threading # and so on...   And by doing so, reduce calls to System::Windows::Shapes::Ellipse.new to simply Ellipse.new or references to System::Windows::Threading::DispatcherPriority.Render to a friendlier DispatcherPriority.Render. Conclusion I hope by now you can understand better how IronRuby interoperates with .NET and how you can harness the power of the .NET framework with the dynamic nature and elegant idioms of the Ruby language. The manner and parlance of Ruby that makes it a joy to work with sets of data is, of course, present in IronRuby — couple that with WPF's capability to produce great graphics quickly and easily, and I hope you can visualise the possibilities of data visualisation using these two things. Using IronRuby and WPF together to create visual representations of data and infographics is very exciting to me. Although today, with this project, we're only presenting one simple piece of information - the time - the potential is much grander. My day-to-day job is centred around software development and UI design, specifically in the realm of healthcare, and if you were to pay a visit to our office you would behold, directly above my desk, a large plasma TV with a constantly rotating, animated slideshow of charts and infographics to help members of our team do their jobs. It's an app powered by WPF which never fails to spark some conversation with visitors whose gaze has been hooked. If only it was written in IronRuby, the pleasantly low ceremony and reduced pre-processing time for my brain would have helped greatly. Edd Morgan blog Related Links: Getting PhP and Ruby working on Windows Azure and SQL Azure

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  • Why is String Templating Better Than String Concatenation from an Engineering Perspective?

    - by stephen
    I once read (I think it was in "Programming Pearls") that one should use templates instead of building the string through the use of concatenation. For example, consider the template below (using C# razor library) <in a properties file> Browser Capabilities Type = @Model.Type Name = @Model.Browser Version = @Model.Version Supports Frames = @Model.Frames Supports Tables = @Model.Tables Supports Cookies = @Model.Cookies Supports VBScript = @Model.VBScript Supports Java Applets = @Model.JavaApplets Supports ActiveX Controls = @Model.ActiveXControls and later, in a separate code file private void Button1_Click(object sender, System.EventArgs e) { BrowserInfoTemplate = Properties.Resources.browserInfoTemplate; // see above string browserInfo = RazorEngine.Razor.Parse(BrowserInfoTemplate, browser); ... } From a software engineering perspective, how is this better than an equivalent string concatentation, like below: private void Button1_Click(object sender, System.EventArgs e) { System.Web.HttpBrowserCapabilities browser = Request.Browser; string s = "Browser Capabilities\n" + "Type = " + browser.Type + "\n" + "Name = " + browser.Browser + "\n" + "Version = " + browser.Version + "\n" + "Supports Frames = " + browser.Frames + "\n" + "Supports Tables = " + browser.Tables + "\n" + "Supports Cookies = " + browser.Cookies + "\n" + "Supports VBScript = " + browser.VBScript + "\n" + "Supports JavaScript = " + browser.EcmaScriptVersion.ToString() + "\n" + "Supports Java Applets = " + browser.JavaApplets + "\n" + "Supports ActiveX Controls = " + browser.ActiveXControls + "\n" ... }

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