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  • How to set Minimum and Maximum Character limitation to EditText in Android?

    - by nishitpatel
    I am new to android here i have very silly problem i want to set my Edit text box minimum and maximum input value. Here I am creating one Simple validation for Edit text it only take A-Z and 0-9 value with minimum 5 and Maximum 8 character. I set the Maximum and other validation as follow. <EditText android:id="@+id/edittextKode_Listing" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginRight="5dp" android:layout_marginLeft="5dp" android:layout_alignTop="@+id/textKode_listing" android:layout_toRightOf="@+id/textKode_listing" android:maxLength="8" android:inputType="textCapCharacters" android:digits="0,1,2,3,4,5,6,7,8,9,ABCDEFGHIJKLMNOPQRSTVUWXYZ" /> but not able to set Minimum requirement. My Edit text is in alert dialog and i also apply the following code to solve this problem ` private void openInboxDialog() { LayoutInflater inflater = this.getLayoutInflater(); // declare dialog view final View dialogView = inflater.inflate(R.layout.kirim_layout, null); final EditText edittextKode = (EditText) dialogView.findViewById(R.id.edittextKode_Listing); final EditText edittextalamat = (EditText) dialogView.findViewById(R.id.edittextAlamat); edittextKode.setOnFocusChangeListener(new OnFocusChangeListener() { @Override public void onFocusChange(View v, boolean hasFocus) { // TODO Auto-generated method stub if(edittextKode.getText().toString().length() > 0){ if(edittextKode.getText().toString().length() < 5) { edittextKode.setError("Error"); Toast.makeText(GPSActivity.this, "Kode listing value not be less than 5", Toast.LENGTH_SHORT).show(); edittextKode.requestFocus(); } } } }); final AlertDialog.Builder builder = new AlertDialog.Builder(GPSActivity.this); builder.setTitle("Kirim").setView(dialogView) .setNeutralButton("OK", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub gpsCoordinates = (TextView) findViewById(R.id.text_GPS_Coordinates); kode = edittextKode.getText().toString(); alamat = edittextalamat.getText().toString(); catatan = edittextcatatan.getText().toString(); pengirim = edittextPengirim.getText().toString(); if (kode.length() > 0 && alamat.length() > 0 && catatan.length() > 0 && pengirim.length() > 0) { message = "Kode listing : " + kode + "\nAlamat : " + alamat + " \nCatatan : " + catatan + " \n Pengirim : " + pengirim + "\nKoordinat GPS : " + gpsCoordinates.getText().toString(); sendByGmail(); } else { Toast.makeText( getApplicationContext(), "Please fill all three fields to send mail", Toast.LENGTH_LONG).show(); } } }); builder.create(); builder.show(); }` in this alert dialog i have two edittext i want to apply my validation on first edittext i called the setOnFocusChangeListener to check its minimum length on focus change and if length is less than 5 request for focus but it still type in second edittext. please help me out.

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  • Why is my custom view not appearing?

    - by user351469
    When I comment out setContentView(boardView); in my Game.java my custom view in BoardView works fine and displays everything nicely... but onSizeChanged never gets called in BoardView.java... so I can't read the device width and height at runtime. If I leave setContentView uncommented onSizeChanged works... but the screen is blank! I want to be able to read the screen width and height at runtime and set the sizes of my ImageViews at creation so they are the optimal size. public class Game extends Activity implements OnClickListener{ private BoardView boardView; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); boardView = new BoardView(this); setContentView(boardView); // when this line disabled, it looks ok boardView.requestFocus(); } public class BoardView extends View { private final Game game; private float width; // width of one unit private float height; // height of one unit public BoardView(Context context){ super(context); this.game = (Game)context; setFocusable(true); setFocusableInTouchMode(true); LinearLayout maincontainer = new LinearLayout(game); maincontainer.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT)); maincontainer.setGravity(Gravity.CENTER); maincontainer.setOrientation(LinearLayout.VERTICAL); maincontainer.setBackgroundColor(Color.BLACK); LinearLayout innercontainer = new LinearLayout(game); innercontainer.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT)); innercontainer.setGravity(Gravity.CENTER); innercontainer.setOrientation(LinearLayout.HORIZONTAL); // declare a new table TableLayout layout = new TableLayout(game); layout.setLayoutParams(new TableLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT)); // build a grid of ImageViews in a TableLayout for (int f=1; f<=7; f++) { TableRow tr = new TableRow(game); for (int c=1; c<=7; c++) { ImageView b = new ImageView(game); b.setImageResource(R.drawable.neworb); b.setOnClickListener(game); tr.addView(b, 30,30); // I'd like to not use fixed values here } // for layout.addView(tr); } // for innercontainer.addView(layout); maincontainer.addView(innercontainer); game.setContentView(maincontainer); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh){ width = w/9f; height = width; super.onSizeChanged(w, h, oldw, oldh); } }

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  • Beginner Android Dev question navigating through intents, getting errors not sure how to fix it. I've tried rearranging and everything even tabbing.

    - by user554786
    /*I created this Sign-In page. I start by declaring variables for username/password & buttons. If user enters "test" as username & "test" as password and hits the login button, its supposed to go to the DrinksTwitter.class activity, else throw error message I created. To me the code and login makes perfect sense. I'm not sure why it wont go to the next activity I want it to go to */ package com.android.drinksonme; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class Screen2 extends Activity { // Declare our Views, so we can access them later private EditText etUsername; private EditText etPassword; private Button btnLogin; private Button btnSignUp; private TextView lblResult; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Get the EditText and Button References etUsername = (EditText)findViewById(R.id.username); etPassword = (EditText)findViewById(R.id.password); btnLogin = (Button)findViewById(R.id.login_button); btnSignUp = (Button)findViewById(R.id.signup_button); lblResult = (TextView)findViewById(R.id.result); // Check Login String username = etUsername.getText().toString(); String password = etPassword.getText().toString(); if(username.equals("test") && password.equals("test")){ final Intent i = new Intent(Screen2.this, DrinksTwitter.class); btnLogin.setOnClickListener(new OnClickListener() { public void onClick(View v) { startActivity(i); } // lblResult.setText("Login successful."); else { /* ERROR- Syntax error on token "else", { expected */ lblResult.setText("Invalid username or password."); } } }); final Intent k = new Intent(Screen2.this, SignUp.class); btnSignUp.setOnClickListener(new OnClickListener() { public void onClick(View v) { startActivity(k); } }); /* ERROR- Syntax error, insert "}" to complete Statement*/ } }

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  • dojo dgrid tree, subrows in wrong position

    - by Ventura
    I have a dgrid, working with tree column plugin. Every time that the user click on the tree, I call the server, catch the subrows(json) and bind it. But when it happens, these subrows are show in wrong position, like the image bellow. The most strange is when I change the pagination, after go back to first page, the subrows stay on the correct place. (please, tell me if is possible to understand my english, then I can try to improve the text) My dgrid code: var CustomGrid = declare([OnDemandGrid, Keyboard, Selection, Pagination]); var grid = new CustomGrid({ columns: [ selector({label: "#", disabled: function(object){ return object.type == 'DOCx'; }}, "radio"), {label:'Id', field:'id', sortable: false}, tree({label: "Title", field:"title", sortable: true, indentWidth:20, allowDuplicates:true}), //{label:'Title', field:'title', sortable: false}, {label:'Count', field:'count', sortable: false} ], store: this.memoryStore, collapseOnRefresh:true, pagingLinks: false, pagingTextBox: true, firstLastArrows: true, pageSizeOptions: [10, 15, 25], selectionMode: "single", // for Selection; only select a single row at a time cellNavigation: false // for Keyboard; allow only row-level keyboard navigation }, "grid"); My memory store: loadMemoryStore: function(items){ this.memoryStore = Observable(new Memory({ data: items, getChildren: function(parent, options){ return this.query({parent: parent.id}, options); }, mayHaveChildren: function(parent){ return (parent.count != 0) && (parent.type != 'DOC'); } })); }, This moment I am binding the subrows: success: function(data){ for(var i=0; i<data.report.length; i++){ this.memoryStore.put({id:data.report[i].id, title:data.report[i].created, type:'DOC', parent:this.designId}); } }, I was thinking, maybe every moment that I bind the subrows, I could do like a refresh on the grid, maybe works. I think that the pagination does the same thing. Thanks. edit: I forgot the question. Well, How can I correct this bug? If The refresh in dgrid works. How can I do it? Other thing that I was thinking, maybe my getChildren is wrong, but I could not identify it. thanks again.

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  • How do I defer execution of some Ruby code until later and run it on demand in this scenario?

    - by Kyle Kaitan
    I've got some code that looks like the following. First, there's a simple Parser class for parsing command-line arguments with options. class Parser def initialize(&b); ...; end # Create new parser. def parse(args = ARGV); ...; end # Consume command-line args. def opt(...); ...; end # Declare supported option. def die(...); ...; end # Validation handler. end Then I have my own Parsers module which holds some metadata about parsers that I want to track. module Parsers ParserMap = {} def self.make_parser(kind, desc, &b) b ||= lambda {} module_eval { ParserMap[kind] = {:desc => "", :validation => lambda {} } ParserMap[kind][:desc] = desc # Create new parser identified by `<Kind>Parser`. Making a Parser is very # expensive, so we defer its creation until it's actually needed later # by wrapping it in a lambda and calling it when we actually need it. const_set(name_for_parser(kind), lambda { Parser.new(&b) }) } end # ... end Now when you want to add a new parser, you can call make_parser like so: make_parser :db, "login to database" do # Options that this parser knows how to parse. opt :verbose, "be verbose with output messages" opt :uid, "user id" opt :pwd, "password" end Cool. But there's a problem. We want to optionally associate validation with each parser, so that we can write something like: validation = lambda { |parser, opts| parser.die unless opts[:uid] && opts[:pwd] # Must provide login. } The interface contract with Parser says that we can't do any validation until after Parser#parse has been called. So, we want to do the following: Associate an optional block with every Parser we make with make_parser. We also want to be able to run this block, ideally as a new method called Parser#validate. But any on-demand method is equally suitable. How do we do that?

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  • Why can't I reserve 1,000,000,000 in my vector ?

    - by vipersnake005
    When I type in the foll. code, I get the output as 1073741823. #include <iostream> #include <vector> using namespace std; int main() { vector <int> v; cout<<v.max_size(); return 0; } However when I try to resize the vector to 1,000,000,000, by v.resize(1000000000); the program stops executing. How can I enable the program to allocate the required memory, when it seems that it should be able to? I am using MinGW in Windows 7. I have 2 GB RAM. Should it not be possible? In case it is not possible, can't I declare it as an array of integers and get away? BUt even that doesn't work. Another thing is that, suppose I would use a file(which can easily handle so much data ). How can I let it read and write and the same time. Using fstream file("file.txt', ios::out | ios::in ); doesn't create a file, in the first place. But supposing the file exists, I am unable to use to do reading and writing simultaneously. WHat I mean is this : Let the contents of the file be 111111 Then if I run : - #include <fstream> #include <iostream> using namespace std; int main() { fstream file("file.txt",ios:in|ios::out); char x; while( file>>x) { file<<'0'; } return 0; } Shouldn't the file's contents now be 101010 ? Read one character and then overwrite the next one with 0 ? Or incase the entire contents were read at once into some buffer, should there not be atleast one 0 in the file ? 1111110 ? But the contents remain unaltered. Please explain. Thank you.

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  • Pass Variables In Inheritance (Obj - C)

    - by Marmik Shah
    I working on a project in Obj-C where i have a base class (ViewController) and a Derived Class (MultiPlayer). Now i have declared certain variables and properties in the base class. My properties are getting accessed from the derived class but im not able to access the variables (int,char and bool type). I'm completely new to Obj-C so i have no clue whats wrong. I have used the data types which are used in C and C++. Is there some specific way to declare variables in Obj-C?? If so, How? Here are my files ViewController.h #import <UIKit/UIKit.h> @interface ViewController : UIViewController @property (weak,nonatomic) IBOutlet UIImageView* backGroungImage; @property (strong,nonatomic) IBOutlet UIImageView *blockView1; @property (strong,nonatomic) IBOutlet UIImageView *blockView2; @property (strong,nonatomic) IBOutlet UIImageView *blockView3; @property (strong,nonatomic) IBOutlet UIImageView *blockView4; @property (strong,nonatomic) IBOutlet UIImageView *blockView5; @property (strong,nonatomic) IBOutlet UIImageView *blockView6; @property (strong,nonatomic) IBOutlet UIImageView *blockView7; @property (strong,nonatomic) IBOutlet UIImageView *blockView8; @property (strong,nonatomic) IBOutlet UIImageView *blockView9; @property (strong,nonatomic) UIImage *x; @property (strong,nonatomic) UIImage *O; @property (strong,nonatomic) IBOutlet UIImageView* back1; @property (strong,nonatomic) IBOutlet UIImageView* back2; @end ViewController.m #import "ViewController.h" @interface ViewController () @end @implementation ViewController int chooseTheBackground = 0; int movesToDecideXorO = 0; int winningArrayX[3]; int winningArrayO[3]; int blocksTotal[9] = {8,3,4,1,5,9,6,7,2}; int checkIfContentInBlocks[9] = {0,0,0,0,0,0,0,0,0}; char determineContentInBlocks[9] = {' ',' ',' ',' ',' ',' ',' ',' ',' '}; bool player1Win = false; bool player2Win = false; bool playerWin = false; bool computerWin = false; - (void)viewDidLoad { [super viewDidLoad]; if(chooseTheBackground==0) { UIImage* backImage = [UIImage imageNamed:@"MainBack1.png"]; _backGroungImage.image=backImage; } if(chooseTheBackground==1) { UIImage* backImage = [UIImage imageNamed:@"MainBack2.png"]; _backGroungImage.image=backImage; } } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } @end I am not able to use the above declared variables in my derived classes!

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  • How to generate a script for changing a column of varchar to xml type with data being converted?

    - by user1323981
    Initially I have a column (partner_email) of varchar.Now a recent change has come where it needs to be changed to be changed to the XML type but the previous records needs to be reserve into the new column. I have applied the below algorithm to accomplish the work /*********************************************************************** Purpose: To change the partner_email column from Varchar Type To Xml Type and convert the existing records from varchar to xml types. Programmers Notes: 1. Create a new Column by the name partner_email_temp of type XML into the Partner Table 2. Copy the Email contents from partner_email to partner_email_temp column after proper conversion N.B.~ The format will be <PartnerEmails> <Email>[email protected]</Email> <Email /> <Email /> </PartnerEmails> 3. Drop the exisitng partner_email 4. Rename partner_email_temp column to partner_email ***********************************************************************/ USE [Test] GO --===== Create a partner_email_temp column of type xml into the Partner table IF NOT EXISTS ( SELECT * FROM INFORMATION_SCHEMA.columns WHERE table_name = 'Partner' AND column_name = 'partner_email_temp' ) BEGIN ALTER TABLE [dbo].[Partner] ADD partner_email_temp XML NULL END GO --===== Copy the Email contents from partner_email to partner_email_temp column -- after proper conversion to xml type UPDATE [dbo].[Partner] SET partner_email_temp = CAST('<PartnerEmails><Email>' + REPLACE(partner_email, '&', '&amp;') + '</Email><Email></Email><Email></Email></PartnerEmails>' AS XML) GO --===== Drop the exisitng partner_email ALTER TABLE [dbo].[Partner] DROP COLUMN partner_email GO --===== Rename partner_email_temp column to partner_email Exec sp_RENAME 'Partner.partner_email_temp','partner_email','COLUMN' GO I works fine for the first time I ran. Now if I ran it for the next time, it am getting an error Msg 8116, Level 16, State 1, Line 4 Argument data type xml is invalid for argument 1 of replace function. Caution: Changing any part of an object name could break scripts and stored procedures. The intention is that, if the partner_email column is varchar, the script will change it to xml type and will convert all the data in xml format . If I ran it second time, it should ignore the statement. How to achieve this? I am trying in a different way DECLARE @columnDataType VARCHAR(50) SELECT @columnDataType = DATA_TYPE FROM INFORMATION_SCHEMA.columns WHERE table_name = 'Partner' AND column_name = 'partner_email' print @columnDataType IF (@columnDataType = 'varchar') BEGIN --===== Create a partner_email_temp column of type xml into the Partner table IF NOT EXISTS ( SELECT * FROM INFORMATION_SCHEMA.columns WHERE table_name = 'Partner' AND column_name = 'partner_email_temp' ) BEGIN ALTER TABLE [dbo].[Partner] ADD partner_email_temp XML NULL --===== Copy the Email contents from partner_email to partner_email_temp column -- after proper conversion to xml type UPDATE [dbo].[Partner] SET partner_email_temp = CAST('<PartnerEmails><Email>' + REPLACE(partner_email, '&', '&amp;') + '</Email><Email></Email><Email></Email></PartnerEmails>' AS XML) --===== Drop the exisitng partner_email ALTER TABLE [dbo].[Partner] DROP COLUMN partner_email --===== Rename partner_email_temp column to partner_email EXEC sp_RENAME 'Partner.partner_email_temp','partner_email','COLUMN' END END but getting error Msg 207, Level 16, State 1, Line 29 Invalid column name 'partner_email_temp'. Help needed

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  • shell script over SSH ends unexpectedly after running 'ant build'

    - by YShin
    I wrote a shell script that runs on remote host to build source code with 'ant build' command, and then distribute the built binary to other servers. However, right after Ant build is over successfully(I can see the command line output saying Build was successful), the ssh session ends and whatever commands after 'ant build' does not get executed. I'm confused what might be cause of this behavior. I suspected that it might be because the 'ant build' command takes too long time, and SSH somehow quits itself after that long command. But I don't think that's correct since if I just do 'sleep 60' in place of 'ant build' command, it actually execute latter commands as intended. I'm new at shell programming, so I might have made some silly misassumption. Can someone provide a pointer to a possible cause of this problem? My shell script #!/bin/bash # Inject some variables ssh -T $SSH_USER@$SSH_URL "setenv REMOTE_BASE_DIR $REMOTE_BASE_DIR; setenv CASSANDRA_SRC_TAR_FILE $CASSANDRA_SRC_TAR_FILE; setenv CASSANDRA_SRC_DIR_NAME $CASSANDRA_SRC_DIR_NAME; setenv CLUSTER_SIZE $CLUSTER_SIZE; setenv REMOTE_REDEPLOY_SCRIPT $REMOTE_REDEPLOY_SCRIPT; /bin/bash" << 'EOF' export JAVA_HOME=/usr/lib/jvm/jdk1.7.0 cd $REMOTE_BASE_DIR/$CASSANDRA_SRC_DIR_NAME echo "## Building Cassandra source" ant clean build # Anything after this doesn't run echo "## Ant Build is over. Invoking redeploy script on remote nodes" # Invoke redeploy script for each node for (( i=0; i < CLUSTER_SIZE; i++)) do echo "## Invoking redeploy script on node-$i" done Command-line output ## Building Cassandra source Buildfile: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build.xml clean: [delete] Deleting directory /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/test [delete] Deleting directory /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/classes [delete] Deleting directory /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/src/gen-java [delete] Deleting directory /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/src/resources/org/apache/cassandra/config init: [mkdir] Created dir: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/classes/main [mkdir] Created dir: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/classes/thrift [mkdir] Created dir: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/test/lib [mkdir] Created dir: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/test/classes [mkdir] Created dir: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/src/gen-java maven-ant-tasks-localrepo: maven-ant-tasks-download: maven-ant-tasks-init: maven-declare-dependencies: maven-ant-tasks-retrieve-build: init-dependencies: [echo] Loading dependency paths from file: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/build-dependencies.xml check-gen-cli-grammar: gen-cli-grammar: [echo] Building Grammar /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/src/java/org/apache/cassandra/cli/Cli.g .... check-gen-cql2-grammar: gen-cql2-grammar: [echo] Building Grammar /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/src/java/org/apache/cassandra/cql/Cql.g ... check-gen-cql3-grammar: gen-cql3-grammar: [echo] Building Grammar /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/src/java/org/apache/cassandra/cql3/Cql.g ... build-project: [echo] apache-cassandra: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build.xml [javac] Compiling 43 source files to /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/classes/thrift [javac] Note: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/interface/thrift/gen-java/org/apache/cassandra/thrift/Cassandra.java uses or overrides a deprecated API. [javac] Note: Recompile with -Xlint:deprecation for details. [javac] Note: Some input files use unchecked or unsafe operations. [javac] Note: Recompile with -Xlint:unchecked for details. [javac] Compiling 865 source files to /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/classes/main [javac] Note: Some input files use or override a deprecated API. [javac] Note: Recompile with -Xlint:deprecation for details. [javac] Note: Some input files use unchecked or unsafe operations. [javac] Note: Recompile with -Xlint:unchecked for details. createVersionPropFile: [mkdir] Created dir: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/src/resources/org/apache/cassandra/config [propertyfile] Creating new property file: /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/src/resources/org/apache/cassandra/config/version.properties [copy] Copying 3 files to /scratch/ISS/shin14/repos/apache-cassandra-2.0.8-src-0713/build/classes/main build: BUILD SUCCESSFUL Total time: 32 seconds

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  • How to load the environment variables at boot time before X11 on Ubuntu Precise?

    - by Fnux
    Using Ubuntu Precise 64 bit, I'm facing a problem that I'm unable to solve and that I'll try to describe below: I'm using a console mode program (let's say abc) that uses Go, NodeJS, Java and Scala. In order for abc to work with these languages, I've to declare the following statements: a) within /etc/environment: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" CLASSPATH=$CLASSPATH:/usr/share/java/scala-library.jar b) within /etc/login.defs ENV_SUPATH PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin ENV_PATH PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin c) a) within /etc/sudoers: `# env_reset Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin"` Then, when I start abc from a terminal, all is fine and I can use any of the 4 languages described above. However, if I put a script within /etc/init.d that starts abc during the boot process (i.e. before to start the GUI), using Java from abc still is fine, but using Go, NodeJS or Scala doesn't work anymore. Then, I guess that during the boot process, the script within /etc/init.d that starts abc is executed before that the different environment variables set within /etc/sudoers, /etc/environment and /etc/login.defs are loaded. So, my question is: how to force the environment variables to be loaded before that my script starting abc is launched? Any help and advice on this topic would be trully appreciated. TIA. Cheers. Thanks again to Mark and Danila. Below is the current "abc" script file that I put within /etc/init.d `#! /bin/sh ### EDIT: ADD THIS VARS DEFINITIONS: PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" CLASSPATH=$CLASSPATH:/usr/share/java/scala-library.jar "ENV_SUPATH PATH"="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" "ENV_PATH PATH"="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" "Defaults secure_path"="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" ##### EXPORT this VARS so they are accessible to children:" export "PATH" "CLASSPATH" "ENV_SUPATH PATH" "ENV_PATH PATH" "Defaults secure_path" `### BEGIN INIT INFO `# Provides: abc `# Required-Start: $remote_fs $syslog `# Required-Stop: $remote_fs $syslog `# Default-Start: 2 3 4 5 `# Default-Stop: 0 1 6 `# Short-Description: abc initscript `# Description: This iniscript starts and stops abc `### END INIT INFO `# Author: Fnux, fnux.fl at gmail dot com `# Version: 1.2 `# Note: (edit ABC_PATH if abc isn't installed in /opt/abc) NAME=abc ABC_PATH=/opt/abc START="-d" STOP="-k" VERSION="-v" SCRIPTNAME=/etc/init.d/$NAME STARTMESG="\nStarting abc in deamon mode." UPMESG="\n$NAME is running." DOWNMESG="\n$NAME is not running." STATUS=`pidof $NAME` `# Exit if abc is not installed [ -x "$ABC_PATH/$NAME" ] || exit 0 case "$1" in start) echo $STARTMESG cd $ABC_PATH ./$NAME $START ;; stop) cd $ABC_PATH ./$NAME $STOP ;; status) if [ "$STATUS" > 0 ] ; then echo $UPMESG else echo $DOWNMESG fi ;; restart) cd $ABC_PATH ./$NAME $STOP echo $STARTMESG ./$NAME $START ;; version) cd $ABC_PATH ./$NAME $VERSION ;; *) echo "Usage: $SCRIPTNAME {start|status|restart|stop|version}" >&2 exit 3 ;; esac : So, where and how should I write the needed environment variables for: a) Go needs the following statements (ie: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" ENV_SUPATH PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin ENV_PATH PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin `# env_reset Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin") b) and Scala needs this one: (ie CLASSPATH=$CLASSPATH:/usr/share/java/scala-library.jar). TIA for an explanation how to do so. Cheers.

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  • From Binary to Data Structures

    - by Cédric Menzi
    Table of Contents Introduction PE file format and COFF header COFF file header BaseCoffReader Byte4ByteCoffReader UnsafeCoffReader ManagedCoffReader Conclusion History This article is also available on CodeProject Introduction Sometimes, you want to parse well-formed binary data and bring it into your objects to do some dirty stuff with it. In the Windows world most data structures are stored in special binary format. Either we call a WinApi function or we want to read from special files like images, spool files, executables or may be the previously announced Outlook Personal Folders File. Most specifications for these files can be found on the MSDN Libarary: Open Specification In my example, we are going to get the COFF (Common Object File Format) file header from a PE (Portable Executable). The exact specification can be found here: PECOFF PE file format and COFF header Before we start we need to know how this file is formatted. The following figure shows an overview of the Microsoft PE executable format. Source: Microsoft Our goal is to get the PE header. As we can see, the image starts with a MS-DOS 2.0 header with is not important for us. From the documentation we can read "...After the MS DOS stub, at the file offset specified at offset 0x3c, is a 4-byte...". With this information we know our reader has to jump to location 0x3c and read the offset to the signature. The signature is always 4 bytes that ensures that the image is a PE file. The signature is: PE\0\0. To prove this we first seek to the offset 0x3c, read if the file consist the signature. So we need to declare some constants, because we do not want magic numbers.   private const int PeSignatureOffsetLocation = 0x3c; private const int PeSignatureSize = 4; private const string PeSignatureContent = "PE";   Then a method for moving the reader to the correct location to read the offset of signature. With this method we always move the underlining Stream of the BinaryReader to the start location of the PE signature.   private void SeekToPeSignature(BinaryReader br) { // seek to the offset for the PE signagure br.BaseStream.Seek(PeSignatureOffsetLocation, SeekOrigin.Begin); // read the offset int offsetToPeSig = br.ReadInt32(); // seek to the start of the PE signature br.BaseStream.Seek(offsetToPeSig, SeekOrigin.Begin); }   Now, we can check if it is a valid PE image by reading of the next 4 byte contains the content PE.   private bool IsValidPeSignature(BinaryReader br) { // read 4 bytes to get the PE signature byte[] peSigBytes = br.ReadBytes(PeSignatureSize); // convert it to a string and trim \0 at the end of the content string peContent = Encoding.Default.GetString(peSigBytes).TrimEnd('\0'); // check if PE is in the content return peContent.Equals(PeSignatureContent); }   With this basic functionality we have a good base reader class to try the different methods of parsing the COFF file header. COFF file header The COFF header has the following structure: Offset Size Field 0 2 Machine 2 2 NumberOfSections 4 4 TimeDateStamp 8 4 PointerToSymbolTable 12 4 NumberOfSymbols 16 2 SizeOfOptionalHeader 18 2 Characteristics If we translate this table to code, we get something like this:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public MachineType Machine; public ushort NumberOfSections; public uint TimeDateStamp; public uint PointerToSymbolTable; public uint NumberOfSymbols; public ushort SizeOfOptionalHeader; public Characteristic Characteristics; } BaseCoffReader All readers do the same thing, so we go to the patterns library in our head and see that Strategy pattern or Template method pattern is sticked out in the bookshelf. I have decided to take the template method pattern in this case, because the Parse() should handle the IO for all implementations and the concrete parsing should done in its derived classes.   public CoffHeader Parse() { using (var br = new BinaryReader(File.Open(_fileName, FileMode.Open, FileAccess.Read, FileShare.Read))) { SeekToPeSignature(br); if (!IsValidPeSignature(br)) { throw new BadImageFormatException(); } return ParseInternal(br); } } protected abstract CoffHeader ParseInternal(BinaryReader br);   First we open the BinaryReader, seek to the PE signature then we check if it contains a valid PE signature and rest is done by the derived implementations. Byte4ByteCoffReader The first solution is using the BinaryReader. It is the general way to get the data. We only need to know which order, which data-type and its size. If we read byte for byte we could comment out the first line in the CoffHeader structure, because we have control about the order of the member assignment.   protected override CoffHeader ParseInternal(BinaryReader br) { CoffHeader coff = new CoffHeader(); coff.Machine = (MachineType)br.ReadInt16(); coff.NumberOfSections = (ushort)br.ReadInt16(); coff.TimeDateStamp = br.ReadUInt32(); coff.PointerToSymbolTable = br.ReadUInt32(); coff.NumberOfSymbols = br.ReadUInt32(); coff.SizeOfOptionalHeader = (ushort)br.ReadInt16(); coff.Characteristics = (Characteristic)br.ReadInt16(); return coff; }   If the structure is as short as the COFF header here and the specification will never changed, there is probably no reason to change the strategy. But if a data-type will be changed, a new member will be added or ordering of member will be changed the maintenance costs of this method are very high. UnsafeCoffReader Another way to bring the data into this structure is using a "magically" unsafe trick. As above, we know the layout and order of the data structure. Now, we need the StructLayout attribute, because we have to ensure that the .NET Runtime allocates the structure in the same order as it is specified in the source code. We also need to enable "Allow unsafe code (/unsafe)" in the project's build properties. Then we need to add the following constructor to the CoffHeader structure.   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { unsafe { fixed (byte* packet = &data[0]) { this = *(CoffHeader*)packet; } } } }   The "magic" trick is in the statement: this = *(CoffHeader*)packet;. What happens here? We have a fixed size of data somewhere in the memory and because a struct in C# is a value-type, the assignment operator = copies the whole data of the structure and not only the reference. To fill the structure with data, we need to pass the data as bytes into the CoffHeader structure. This can be achieved by reading the exact size of the structure from the PE file.   protected override CoffHeader ParseInternal(BinaryReader br) { return new CoffHeader(br.ReadBytes(Marshal.SizeOf(typeof(CoffHeader)))); }   This solution is the fastest way to parse the data and bring it into the structure, but it is unsafe and it could introduce some security and stability risks. ManagedCoffReader In this solution we are using the same approach of the structure assignment as above. But we need to replace the unsafe part in the constructor with the following managed part:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { IntPtr coffPtr = IntPtr.Zero; try { int size = Marshal.SizeOf(typeof(CoffHeader)); coffPtr = Marshal.AllocHGlobal(size); Marshal.Copy(data, 0, coffPtr, size); this = (CoffHeader)Marshal.PtrToStructure(coffPtr, typeof(CoffHeader)); } finally { Marshal.FreeHGlobal(coffPtr); } } }     Conclusion We saw that we can parse well-formed binary data to our data structures using different approaches. The first is probably the clearest way, because we know each member and its size and ordering and we have control about the reading the data for each member. But if add member or the structure is going change by some reason, we need to change the reader. The two other solutions use the approach of the structure assignment. In the unsafe implementation we need to compile the project with the /unsafe option. We increase the performance, but we get some security risks.

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  • Oracle HRMS API – Rehire Employee

    - by PRajkumar
    API --  hr_employee_api.re_hire_ex_employee   Example -- Consider a Ex-Employee we will try to Rehire that employee using Rehire API     DECLARE      ln_per_object_version_number      PER_ALL_PEOPLE_F.OBJECT_VERSION_NUMBER%TYPE        := 5;      ln_assg_object_version_number    PER_ALL_ASSIGNMENTS_F.OBJECT_VERSION_NUMBER%TYPE;      ln_assignment_id                               PER_ALL_ASSIGNMENTS_F.ASSIGNMENT_ID%TYPE;      ld_per_effective_start_date              PER_ALL_PEOPLE_F.EFFECTIVE_START_DATE%TYPE;      ld_per_effective_end_date               PER_ALL_PEOPLE_F.EFFECTIVE_END_DATE%TYPE;      ln_assignment_sequence                  PER_ALL_ASSIGNMENTS_F.ASSIGNMENT_SEQUENCE%TYPE;      lb_assign_payroll_warning            BOOLEAN;      lc_assignment_number                     PER_ALL_ASSIGNMENTS_F.ASSIGNMENT_NUMBER%TYPE; BEGIN     -- Rehire Employee API      -- --------------------------------      hr_employee_api.re_hire_ex_employee      (    -- Input data elements           -- -----------------------------          p_hire_date                                          => TO_DATE('28-JUN-2011'),          p_person_id                                         => 32979,          p_rehire_reason                                  => NULL,          -- Output data elements          -- --------------------------------         p_assignment_id                                => ln_assignment_id,         p_per_object_version_number       => ln_per_object_version_number,         p_asg_object_version_number       => ln_assg_object_version_number,         p_per_effective_start_date               => ld_per_effective_start_date,         p_per_effective_end_date                => ld_per_effective_end_date,         p_assignment_sequence                  => ln_assignment_sequence,         p_assignment_number                     => lc_assignment_number,         p_assign_payroll_warning             => lb_assign_payroll_warning     );    COMMIT; EXCEPTION        WHEN OTHERS THEN                        ROLLBACK;                        dbms_output.put_line(SQLERRM); END; / SHOW ERR;  

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  • Creating an AJAX Accordion Menu

    - by jaullo
    Introduction Ajax is a powerful addition to asp.net that provides new functionality in a simple and agile  way This post is dedicated to creating a menu with ajax accordion type. About the Control The basic idea of this control, is to provide a serie of panels and show and hide information inside these panels. The use is very simple, we have to set each panel inside accordion control and give to each panel a Header and of course, we have to set the content of each panel.  To use accordion control, u need the ajax control toolkit. know the basic propertyes of accordion control:  Before start developing an accordion control, we have to know the basic properties for this control Other accordion propertyes  FramesPerSecond - Number of frames per second used in the transition animations RequireOpenedPane - Prevent closing the currently opened pane when its header is clicked (which ensures one pane is always open). The default value is true. SuppressHeaderPostbacks - Prevent the client-side click handlers of elements inside a header from firing (this is especially useful when you want to include hyperlinks in your headers for accessibility) DataSource - The data source to use. DataBind() must be called. DataSourceID - The ID of the data source to use. DataMember - The member to bind to when using a DataSourceID  AJAX Accordion Control Extender DataSource  The Accordion Control extender of AJAX Control toolkit can also be used as DataBound control. You can bind the data retrieved from the database to the Accordion control. Accordion Control consists of properties such as DataSource and DataSourceID (we can se it above) that can be used to bind the data. HeaderTemplate can used to display the header or title for the pane generated by the Accordion control, a click on which will open or close the ContentTemplate generated by binding the data with Accordion extender. When DataSource is passed to the Accordion control, also use the DataBind method to bind the data. The Accordion control bound with data auto generates the expand/collapse panes along with their headers.  This code represents the basic steps to bind the Accordion to a Datasource Collapse Public Sub getCategories() Dim sqlConn As New SqlConnection(conString) sqlConn.Open() Dim sqlSelect As New SqlCommand("SELECT * FROM Categories", sqlConn) sqlSelect.CommandType = System.Data.CommandType.Text Dim sqlAdapter As New SqlDataAdapter(sqlSelect) Dim myDataset As New DataSet() sqlAdapter.Fill(myDataset) sqlConn.Close() Accordion1.DataSource = myDataset.Tables(0).DefaultView Accordion1.DataBind()End Sub Protected Sub Accordion1_ItemDataBound(sender As Object, _ e As AjaxControlToolkit.AccordionItemEventArgs) If e.ItemType = AjaxControlToolkit.AccordionItemType.Content Then Dim sqlConn As New SqlConnection(conString) sqlConn.Open() Dim sqlSelect As New SqlCommand("SELECT productName " & _ "FROM Products where categoryID = '" + _ DirectCast(e.AccordionItem.FindControl("txt_categoryID"),_ HiddenField).Value + "'", sqlConn) sqlSelect.CommandType = System.Data.CommandType.Text Dim sqlAdapter As New SqlDataAdapter(sqlSelect) Dim myDataset As New DataSet() sqlAdapter.Fill(myDataset) sqlConn.Close() Dim grd As New GridView() grd = DirectCast(e.AccordionItem.FindControl("GridView1"), GridView) grd.DataSource = myDataset grd.DataBind() End If End Sub In the above code, we made two things, first, we made a sql select to database to retrieve all data from categories table, this data will be used to set the header and columns of the accordion.  Collapse <asp:ScriptManager ID="ScriptManager1" runat="server"> </asp:ScriptManager> <ajaxToolkit:Accordion ID="Accordion1" runat="server" TransitionDuration="100" FramesPerSecond="200" FadeTransitions="true" RequireOpenedPane="false" OnItemDataBound="Accordion1_ItemDataBound" ContentCssClass="acc-content" HeaderCssClass="acc-header" HeaderSelectedCssClass="acc-selected"> <HeaderTemplate> <%#DataBinder.Eval(Container.DataItem,"categoryName") %> </HeaderTemplate> <ContentTemplate> <asp:HiddenField ID="txt_categoryID" runat="server" Value='<%#DataBinder.Eval(Container.DataItem,"categoryID") %>' /> <asp:GridView ID="GridView1" runat="server" RowStyle-BackColor="#ededed" RowStyle-HorizontalAlign="Left" AutoGenerateColumns="false" GridLines="None" CellPadding="2" CellSpacing="2" Width="300px"> <Columns> <asp:TemplateField HeaderStyle-HorizontalAlign="Left" HeaderText="Product Name" HeaderStyle-BackColor="#d1d1d1" HeaderStyle-ForeColor="#777777"> <ItemTemplate> <%#DataBinder.Eval(Container.DataItem,"productName") %> </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView> </ContentTemplate> </ajaxToolkit:Accordion>  Here, we use <%#DataBinder.Eval(Container.DataItem,"categoryName") %> to bind accordion header with categoryName, so we made on header for each element found on database.    Creating a basic accordion control As we know, to use any of the ajax components, there must be a registered ScriptManager on our site, which will be responsible for managing our controls. So the first thing we will do is create our script manager.     Collapse <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager> Then we define our accordion  element and establish some basic properties:    Collapse <cc1:Accordion ID="AccordionCtrl" runat="server" SelectedIndex="0" HeaderCssClass="accordionHeader" ContentCssClass="accordionContent" AutoSize="None" FadeTransitions="true" TransitionDuration="250" FramesPerSecond="40" For our work we must declare PANES accordion inside it, these breads will be responsible for contain information, links or information that we want to show.  Collapse <Panes> <cc1:AccordionPane ID="AccordionPane0" runat="server"> <Header>Matenimiento</Header> <Content> <li><a href="mypagina.aspx">My página de prueba</a></li> </Content> </cc1:AccordionPane> To end this work, we have to close all panels and our accordion Collapse </Panes> </cc1:Accordion> Finally complete our example should look like:  Collapse <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager> <cc1:Accordion ID="AccordionCtrl" runat="server" SelectedIndex="0" HeaderCssClass="accordionHeader" ContentCssClass="accordionContent" AutoSize="None" FadeTransitions="true" TransitionDuration="250" FramesPerSecond="40"> <Panes> <cc1:AccordionPane ID="AccordionPane0" runat="server"> <Header>Matenimiento</Header> <Content> <li><a href="mypagina.aspx">My página de prueba</a></li> </Content> </cc1:AccordionPane> </Panes> </cc1:Accordion>

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  • Using a "white list" for extracting terms for Text Mining

    - by [email protected]
    In Part 1 of my post on "Generating cluster names from a document clustering model" (part 1, part 2, part 3), I showed how to build a clustering model from text documents using Oracle Data Miner, which automates preparing data for text mining. In this process we specified a custom stoplist and lexer and relied on Oracle Text to identify important terms.  However, there is an alternative approach, the white list, which uses a thesaurus object with the Oracle Text CTXRULE index to allow you to specify the important terms. INTRODUCTIONA stoplist is used to exclude, i.e., black list, specific words in your documents from being indexed. For example, words like a, if, and, or, and but normally add no value when text mining. Other words can also be excluded if they do not help to differentiate documents, e.g., the word Oracle is ubiquitous in the Oracle product literature. One problem with stoplists is determining which words to specify. This usually requires inspecting the terms that are extracted, manually identifying which ones you don't want, and then re-indexing the documents to determine if you missed any. Since a corpus of documents could contain thousands of words, this could be a tedious exercise. Moreover, since every word is considered as an individual token, a term excluded in one context may be needed to help identify a term in another context. For example, in our Oracle product literature example, the words "Oracle Data Mining" taken individually are not particular helpful. The term "Oracle" may be found in nearly all documents, as with the term "Data." The term "Mining" is more unique, but could also refer to the Mining industry. If we exclude "Oracle" and "Data" by specifying them in the stoplist, we lose valuable information. But it we include them, they may introduce too much noise. Still, when you have a broad vocabulary or don't have a list of specific terms of interest, you rely on the text engine to identify important terms, often by computing the term frequency - inverse document frequency metric. (This is effectively a weight associated with each term indicating its relative importance in a document within a collection of documents. We'll revisit this later.) The results using this technique is often quite valuable. As noted above, an alternative to the subtractive nature of the stoplist is to specify a white list, or a list of terms--perhaps multi-word--that we want to extract and use for data mining. The obvious downside to this approach is the need to specify the set of terms of interest. However, this may not be as daunting a task as it seems. For example, in a given domain (Oracle product literature), there is often a recognized glossary, or a list of keywords and phrases (Oracle product names, industry names, product categories, etc.). Being able to identify multi-word terms, e.g., "Oracle Data Mining" or "Customer Relationship Management" as a single token can greatly increase the quality of the data mining results. The remainder of this post and subsequent posts will focus on how to produce a dataset that contains white list terms, suitable for mining. CREATING A WHITE LIST We'll leverage the thesaurus capability of Oracle Text. Using a thesaurus, we create a set of rules that are in effect our mapping from single and multi-word terms to the tokens used to represent those terms. For example, "Oracle Data Mining" becomes "ORACLEDATAMINING." First, we'll create and populate a mapping table called my_term_token_map. All text has been converted to upper case and values in the TERM column are intended to be mapped to the token in the TOKEN column. TERM                                TOKEN DATA MINING                         DATAMINING ORACLE DATA MINING                  ORACLEDATAMINING 11G                                 ORACLE11G JAVA                                JAVA CRM                                 CRM CUSTOMER RELATIONSHIP MANAGEMENT    CRM ... Next, we'll create a thesaurus object my_thesaurus and a rules table my_thesaurus_rules: CTX_THES.CREATE_THESAURUS('my_thesaurus', FALSE); CREATE TABLE my_thesaurus_rules (main_term     VARCHAR2(100),                                  query_string  VARCHAR2(400)); We next populate the thesaurus object and rules table using the term token map. A cursor is defined over my_term_token_map. As we iterate over  the rows, we insert a synonym relationship 'SYN' into the thesaurus. We also insert into the table my_thesaurus_rules the main term, and the corresponding query string, which specifies synonyms for the token in the thesaurus. DECLARE   cursor c2 is     select token, term     from my_term_token_map; BEGIN   for r_c2 in c2 loop     CTX_THES.CREATE_RELATION('my_thesaurus',r_c2.token,'SYN',r_c2.term);     EXECUTE IMMEDIATE 'insert into my_thesaurus_rules values                        (:1,''SYN(' || r_c2.token || ', my_thesaurus)'')'     using r_c2.token;   end loop; END; We are effectively inserting the token to return and the corresponding query that will look up synonyms in our thesaurus into the my_thesaurus_rules table, for example:     'ORACLEDATAMINING'        SYN ('ORACLEDATAMINING', my_thesaurus)At this point, we create a CTXRULE index on the my_thesaurus_rules table: create index my_thesaurus_rules_idx on        my_thesaurus_rules(query_string)        indextype is ctxsys.ctxrule; In my next post, this index will be used to extract the tokens that match each of the rules specified. We'll then compute the tf-idf weights for each of the terms and create a nested table suitable for mining.

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  • SharePoint 2010 Replaceable Parameter, some observations…

    - by svdoever
    SharePoint Tools for Visual Studio 2010 provides a rudimentary mechanism for replaceable parameters that you can use in files that are not compiled, like ascx files and your project property settings. The basics on this can be found in the documentation at http://msdn.microsoft.com/en-us/library/ee231545.aspx. There are some quirks however. For example: My Package name is MacawMastSP2010Templates, as defined in my Package properties: I want to use the $SharePoint.Package.Name$ replaceable parameter in my feature properties. But this parameter does not work in the “Deployment Path” property, while other parameters work there, while it works in the “Image Url” property. It just does not get expanded. So I had to resort to explicitly naming the first path of the deployment path: : You also see a special property for the “Receiver Class” in the format $SharePoint.Type.<GUID>.FullName$. The documentation gives the following description:The full name of the type matching the GUID in the token. The format of the GUID is lowercase and corresponds to the Guid.ToString(“D”) format (that is, xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx). Not very clear. After some searching it happened to be the guid as declared in my feature receiver code: In other properties you see a different set of replaceable parameters: We use a similar mechanism for replaceable parameter for years in our Macaw Solutions Factory for SharePoint 2007 development, where each replaceable parameter is a PowerShell function. This provides so much more power. For example in a feature declaration we can say: Code Snippet <?xml version="1.0" encoding="utf-8" ?> <!-- Template expansion      [[ProductDependency]] -> Wss3 or Moss2007      [[FeatureReceiverAssemblySignature]] -> for example: Macaw.Mast.Wss3.Templates.SharePoint.Features, Version=1.0.0.0, Culture=neutral, PublicKeyToken=6e9d15db2e2a0be5      [[FeatureReceiverClass]] -> for example: Macaw.Mast.Wss3.Templates.SharePoint.Features.SampleFeature.FeatureReceiver.SampleFeatureFeatureReceiver --> <Feature Id="[[$Feature.SampleFeature.ID]]"   Title="MAST [[$MastSolutionName]] Sample Feature"   Description="The MAST [[$MastSolutionName]] Sample Feature, where all possible elements in a feature are showcased"   Version="1.0.0.0"   Scope="Site"   Hidden="FALSE"   ImageUrl="[[FeatureImage]]"   ReceiverAssembly="[[FeatureReceiverAssemblySignature]]"   ReceiverClass="[[FeatureReceiverClass]]"   xmlns="http://schemas.microsoft.com/sharepoint/">     <ElementManifests>         <ElementManifest Location="ExampleCustomActions.xml" />         <ElementManifest Location="ExampleSiteColumns.xml" />         <ElementManifest Location="ExampleContentTypes.xml" />         <ElementManifest Location="ExampleDocLib.xml" />         <ElementManifest Location="ExampleMasterPages.xml" />           <!-- Element files -->         [[GenerateXmlNodesForFiles -path 'ExampleDocLib\*.*' -node 'ElementFile' -attributes @{Location = { RelativePathToExpansionSourceFile -path $_ }}]]         [[GenerateXmlNodesForFiles -path 'ExampleMasterPages\*.*' -node 'ElementFile' -attributes @{Location = { RelativePathToExpansionSourceFile -path $_ }}]]         [[GenerateXmlNodesForFiles -path 'Resources\*.resx' -node 'ElementFile' -attributes @{Location = { RelativePathToExpansionSourceFile -path $_ }}]]     </ElementManifests> </Feature> We have a solution level PowerShell script file named TemplateExpansionConfiguration.ps1 where we declare our variables (starting with a $) and include helper functions: Code Snippet # ============================================================================================== # NAME: product:\src\Wss3\Templates\TemplateExpansionConfiguration.ps1 # # AUTHOR: Serge van den Oever, Macaw # DATE  : May 24, 2007 # # COMMENT: # Nota bene: define variable and function definitions global to be visible during template expansion. # # ============================================================================================== Set-PSDebug -strict -trace 0 #variables must have value before usage $global:ErrorActionPreference = 'Stop' # Stop on errors $global:VerbosePreference = 'Continue' # set to SilentlyContinue to get no verbose output   # Load template expansion utility functions . product:\tools\Wss3\MastDeploy\TemplateExpansionUtil.ps1   # If exists add solution expansion utility functions $solutionTemplateExpansionUtilFile = $MastSolutionDir + "\TemplateExpansionUtil.ps1" if ((Test-Path -Path $solutionTemplateExpansionUtilFile)) {     . $solutionTemplateExpansionUtilFile } # ==============================================================================================   # Expected: $Solution.ID; Unique GUID value identifying the solution (DON'T INCLUDE BRACKETS). # function: guid:UpperCaseWithoutCurlies -guid '{...}' ensures correct syntax $global:Solution = @{     ID = GuidUpperCaseWithoutCurlies -guid '{d366ced4-0b98-4fa8-b256-c5a35bcbc98b}'; }   #  DON'T INCLUDE BRACKETS for feature id's!!! # function: GuidUpperCaseWithoutCurlies -guid '{...}' ensures correct syntax $global:Feature = @{     SampleFeature = @{         ID = GuidUpperCaseWithoutCurlies -guid '{35de59f4-0c8e-405e-b760-15234fe6885c}';     } }   $global:SiteDefinition = @{     TemplateBlankSite = @{         ID = '12346';     } }   # To inherit from this content type add the delimiter (00) and then your own guid # ID: <base>00<newguid> $global:ContentType = @{     ExampleContentType = @{         ID = '0x01008e5e167ba2db4bfeb3810c4a7ff72913';     } }   #  INCLUDE BRACKETS for column id's and make them LOWER CASE!!! # function: GuidLowerCaseWithCurlies -guid '{...}' ensures correct syntax $global:SiteColumn = @{     ExampleChoiceField = @{         ID = GuidLowerCaseWithCurlies -guid '{69d38ce4-2771-43b4-a861-f14247885fe9}';     };     ExampleBooleanField = @{         ID = GuidLowerCaseWithCurlies -guid '{76f794e6-f7bd-490e-a53e-07efdf967169}';     };     ExampleDateTimeField = @{         ID = GuidLowerCaseWithCurlies -guid '{6f176e6e-22d2-453a-8dad-8ab17ac12387}';     };     ExampleNumberField = @{         ID = GuidLowerCaseWithCurlies -guid '{6026947f-f102-436b-abfd-fece49495788}';     };     ExampleTextField = @{         ID = GuidLowerCaseWithCurlies -guid '{23ca1c29-5ef0-4b3d-93cd-0d1d2b6ddbde}';     };     ExampleUserField = @{         ID = GuidLowerCaseWithCurlies -guid '{ee55b9f1-7b7c-4a7e-9892-3e35729bb1a5}';     };     ExampleNoteField = @{         ID = GuidLowerCaseWithCurlies -guid '{f9aa8da3-1f30-48a6-a0af-aa0a643d9ed4}';     }; } This gives so much more possibilities, like for example the elements file expansion where a PowerShell function iterates through a folder and generates the required XML nodes. I think I will bring back this mechanism, so it can work together with the built-in replaceable parameters, there are hooks to define you custom replacements as described by Waldek in this blog post.

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  • RSS feeds in Orchard

    - by Bertrand Le Roy
    When we added RSS to Orchard, we wanted to make it easy for any module to expose any contents as a feed. We also wanted the rendering of the feed to be handled by Orchard in order to minimize the amount of work from the module developer. A typical example of such feed exposition is of course blog feeds. We have an IFeedManager interface for which you can get the built-in implementation through dependency injection. Look at the BlogController constructor for an example: public BlogController( IOrchardServices services, IBlogService blogService, IBlogSlugConstraint blogSlugConstraint, IFeedManager feedManager, RouteCollection routeCollection) { If you look a little further in that same controller, in the Item action, you’ll see a call to the Register method of the feed manager: _feedManager.Register(blog); This in reality is a call into an extension method that is specialized for blogs, but we could have made the two calls to the actual generic Register directly in the action instead, that is just an implementation detail: feedManager.Register(blog.Name, "rss", new RouteValueDictionary { { "containerid", blog.Id } }); feedManager.Register(blog.Name + " - Comments", "rss", new RouteValueDictionary { { "commentedoncontainer", blog.Id } }); What those two effective calls are doing is to register two feeds: one for the blog itself and one for the comments on the blog. For each call, the name of the feed is provided, then we have the type of feed (“rss”) and some values to be injected into the generic RSS route that will be used later to route the feed to the right providers. This is all you have to do to expose a new feed. If you’re only interested in exposing feeds, you can stop right there. If on the other hand you want to know what happens after that under the hood, carry on. What happens after that is that the feedmanager will take care of formatting the link tag for the feed (see FeedManager.GetRegisteredLinks). The GetRegisteredLinks method itself will be called from a specialized filter, FeedFilter. FeedFilter is an MVC filter and the event we’re interested in hooking into is OnResultExecuting, which happens after the controller action has returned an ActionResult and just before MVC executes that action result. In other words, our feed registration has already been called but the view is not yet rendered. Here’s the code for OnResultExecuting: model.Zones.AddAction("head:after", html => html.ViewContext.Writer.Write( _feedManager.GetRegisteredLinks(html))); This is another piece of code whose execution is differed. It is saying that whenever comes time to render the “head” zone, this code should be called right after. The code itself is rendering the link tags. As a result of all that, here’s what can be found in an Orchard blog’s head section: <link rel="alternate" type="application/rss+xml"     title="Tales from the Evil Empire"     href="/rss?containerid=5" /> <link rel="alternate" type="application/rss+xml"     title="Tales from the Evil Empire - Comments"     href="/rss?commentedoncontainer=5" /> The generic action that these two feeds point to is Index on FeedController. That controller has three important dependencies: an IFeedBuilderProvider, an IFeedQueryProvider and an IFeedItemProvider. Different implementations of these interfaces can provide different formats of feeds, such as RSS and Atom. The Match method enables each of the competing providers to provide a priority for themselves based on arbitrary criteria that can be found on the FeedContext. This means that a provider can be selected based not only on the desired format, but also on the nature of the objects being exposed as a feed or on something even more arbitrary such as the destination device (you could imagine for example giving shorter text only excerpts of posts on mobile devices, and full HTML on desktop). The key here is extensibility and dynamic competition and collaboration from unknown and loosely coupled parts. You’ll find this pattern pretty much everywhere in the Orchard architecture. The RssFeedBuilder implementation of IFeedBuilderProvider is also a regular controller with a Process action that builds a RssResult, which is itself a thin ActionResult wrapper around an XDocument. Let’s get back to the FeedController’s Index action. After having called into each known feed builder to get its priority on the currently requested feed, it will select the one with the highest priority. The next thing it needs to do is to actually fetch the data for the feed. This again is a collaborative effort from a priori unknown providers, the implementations of IFeedQueryProvider. There are several implementations by default in Orchard, the choice of which is again done through a Match method. ContainerFeedQuery for example chimes in when a “containerid” parameter is found in the context (see URL in the link tag above): public FeedQueryMatch Match(FeedContext context) { var containerIdValue = context.ValueProvider.GetValue("containerid"); if (containerIdValue == null) return null; return new FeedQueryMatch { FeedQuery = this, Priority = -5 }; } The actual work is done in the Execute method, which finds the right container content item in the Orchard database and adds elements for each of them. In other words, the feed query provider knows how to retrieve the list of content items to add to the feed. The last step is to translate each of the content items into feed entries, which is done by implementations of IFeedItemBuilder. There is no Match method this time. Instead, all providers are called with the collection of items (or more accurately with the FeedContext, but this contains the list of items, which is what’s relevant in most cases). Each provider can then choose to pick those items that it knows how to treat and transform them into the format requested. This enables the construction of heterogeneous feeds that expose content items of various types into a single feed. That will be extremely important when you’ll want to expose a single feed for all your site. So here are feeds in Orchard in a nutshell. The main point here is that there is a fair number of components involved, with some complexity in implementation in order to allow for extreme flexibility, but the part that you use to expose a new feed is extremely simple and light: declare that you want your content exposed as a feed and you’re done. There are cases where you’ll have to dive in and provide new implementations for some or all of the interfaces involved, but that requirement will only arise as needed. For example, you might need to create a new feed item builder to include your custom content type but that effort will be extremely focused on the specialized task at hand. The rest of the system won’t need to change. So what do you think?

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  • Anti-Forgery Request Helpers for ASP.NET MVC and jQuery AJAX

    - by Dixin
    Background To secure websites from cross-site request forgery (CSRF, or XSRF) attack, ASP.NET MVC provides an excellent mechanism: The server prints tokens to cookie and inside the form; When the form is submitted to server, token in cookie and token inside the form are sent in the HTTP request; Server validates the tokens. To print tokens to browser, just invoke HtmlHelper.AntiForgeryToken():<% using (Html.BeginForm()) { %> <%: this.Html.AntiForgeryToken(Constants.AntiForgeryTokenSalt)%> <%-- Other fields. --%> <input type="submit" value="Submit" /> <% } %> This invocation generates a token then writes inside the form:<form action="..." method="post"> <input name="__RequestVerificationToken" type="hidden" value="J56khgCvbE3bVcsCSZkNVuH9Cclm9SSIT/ywruFsXEgmV8CL2eW5C/gGsQUf/YuP" /> <!-- Other fields. --> <input type="submit" value="Submit" /> </form> and also writes into the cookie: __RequestVerificationToken_Lw__= J56khgCvbE3bVcsCSZkNVuH9Cclm9SSIT/ywruFsXEgmV8CL2eW5C/gGsQUf/YuP When the above form is submitted, they are both sent to server. In the server side, [ValidateAntiForgeryToken] attribute is used to specify the controllers or actions to validate them:[HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult Action(/* ... */) { // ... } This is very productive for form scenarios. But recently, when resolving security vulnerabilities for Web products, some problems are encountered. Specify validation on controller (not on each action) The server side problem is, It is expected to declare [ValidateAntiForgeryToken] on controller, but actually it has be to declared on each POST actions. Because POST actions are usually much more then controllers, this is a little crazy Problem Usually a controller contains actions for HTTP GET and actions for HTTP POST requests, and usually validations are expected for HTTP POST requests. So, if the [ValidateAntiForgeryToken] is declared on the controller, the HTTP GET requests become invalid:[ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public class SomeController : Controller // One [ValidateAntiForgeryToken] attribute. { [HttpGet] public ActionResult Index() // Index() cannot work. { // ... } [HttpPost] public ActionResult PostAction1(/* ... */) { // ... } [HttpPost] public ActionResult PostAction2(/* ... */) { // ... } // ... } If browser sends an HTTP GET request by clicking a link: http://Site/Some/Index, validation definitely fails, because no token is provided. So the result is, [ValidateAntiForgeryToken] attribute must be distributed to each POST action:public class SomeController : Controller // Many [ValidateAntiForgeryToken] attributes. { [HttpGet] public ActionResult Index() // Works. { // ... } [HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult PostAction1(/* ... */) { // ... } [HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult PostAction2(/* ... */) { // ... } // ... } This is a little bit crazy, because one application can have a lot of POST actions. Solution To avoid a large number of [ValidateAntiForgeryToken] attributes (one for each POST action), the following ValidateAntiForgeryTokenAttribute wrapper class can be helpful, where HTTP verbs can be specified:[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)] public class ValidateAntiForgeryTokenWrapperAttribute : FilterAttribute, IAuthorizationFilter { private readonly ValidateAntiForgeryTokenAttribute _validator; private readonly AcceptVerbsAttribute _verbs; public ValidateAntiForgeryTokenWrapperAttribute(HttpVerbs verbs) : this(verbs, null) { } public ValidateAntiForgeryTokenWrapperAttribute(HttpVerbs verbs, string salt) { this._verbs = new AcceptVerbsAttribute(verbs); this._validator = new ValidateAntiForgeryTokenAttribute() { Salt = salt }; } public void OnAuthorization(AuthorizationContext filterContext) { string httpMethodOverride = filterContext.HttpContext.Request.GetHttpMethodOverride(); if (this._verbs.Verbs.Contains(httpMethodOverride, StringComparer.OrdinalIgnoreCase)) { this._validator.OnAuthorization(filterContext); } } } When this attribute is declared on controller, only HTTP requests with the specified verbs are validated:[ValidateAntiForgeryTokenWrapper(HttpVerbs.Post, Constants.AntiForgeryTokenSalt)] public class SomeController : Controller { // GET actions are not affected. // Only HTTP POST requests are validated. } Now one single attribute on controller turns on validation for all POST actions. Maybe it would be nice if HTTP verbs can be specified on the built-in [ValidateAntiForgeryToken] attribute, which is easy to implemented. Submit token via AJAX The browser side problem is, if server side turns on anti-forgery validation for POST, then AJAX POST requests will fail be default. Problem For AJAX scenarios, when request is sent by jQuery instead of form:$.post(url, { productName: "Tofu", categoryId: 1 // Token is not posted. }, callback); This kind of AJAX POST requests will always be invalid, because server side code cannot see the token in the posted data. Solution The tokens are printed to browser then sent back to server. So first of all, HtmlHelper.AntiForgeryToken() must be called somewhere. Now the browser has token in HTML and cookie. Then jQuery must find the printed token in the HTML, and append token to the data before sending:$.post(url, { productName: "Tofu", categoryId: 1, __RequestVerificationToken: getToken() // Token is posted. }, callback); To be reusable, this can be encapsulated into a tiny jQuery plugin:/// <reference path="jquery-1.4.2.js" /> (function ($) { $.getAntiForgeryToken = function (tokenWindow, appPath) { // HtmlHelper.AntiForgeryToken() must be invoked to print the token. tokenWindow = tokenWindow && typeof tokenWindow === typeof window ? tokenWindow : window; appPath = appPath && typeof appPath === "string" ? "_" + appPath.toString() : ""; // The name attribute is either __RequestVerificationToken, // or __RequestVerificationToken_{appPath}. tokenName = "__RequestVerificationToken" + appPath; // Finds the <input type="hidden" name={tokenName} value="..." /> from the specified. // var inputElements = $("input[type='hidden'][name='__RequestVerificationToken" + appPath + "']"); var inputElements = tokenWindow.document.getElementsByTagName("input"); for (var i = 0; i < inputElements.length; i++) { var inputElement = inputElements[i]; if (inputElement.type === "hidden" && inputElement.name === tokenName) { return { name: tokenName, value: inputElement.value }; } } return null; }; $.appendAntiForgeryToken = function (data, token) { // Converts data if not already a string. if (data && typeof data !== "string") { data = $.param(data); } // Gets token from current window by default. token = token ? token : $.getAntiForgeryToken(); // $.getAntiForgeryToken(window). data = data ? data + "&" : ""; // If token exists, appends {token.name}={token.value} to data. return token ? data + encodeURIComponent(token.name) + "=" + encodeURIComponent(token.value) : data; }; // Wraps $.post(url, data, callback, type). $.postAntiForgery = function (url, data, callback, type) { return $.post(url, $.appendAntiForgeryToken(data), callback, type); }; // Wraps $.ajax(settings). $.ajaxAntiForgery = function (settings) { settings.data = $.appendAntiForgeryToken(settings.data); return $.ajax(settings); }; })(jQuery); In most of the scenarios, it is Ok to just replace $.post() invocation with $.postAntiForgery(), and replace $.ajax() with $.ajaxAntiForgery():$.postAntiForgery(url, { productName: "Tofu", categoryId: 1 }, callback); // Token is posted. There might be some scenarios of custom token. Here $.appendAntiForgeryToken() is provided:data = $.appendAntiForgeryToken(data, token); // Token is already in data. No need to invoke $.postAntiForgery(). $.post(url, data, callback); And there are scenarios that the token is not in the current window. For example, an HTTP POST request can be sent by iframe, while the token is in the parent window. Here window can be specified for $.getAntiForgeryToken():data = $.appendAntiForgeryToken(data, $.getAntiForgeryToken(window.parent)); // Token is already in data. No need to invoke $.postAntiForgery(). $.post(url, data, callback); If you have better solution, please do tell me.

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  • A simple Dynamic Proxy

    - by Abhijeet Patel
    Frameworks such as EF4 and MOQ do what most developers consider "dark magic". For instance in EF4, when you use a POCO for an entity you can opt-in to get behaviors such as "lazy-loading" and "change tracking" at runtime merely by ensuring that your type has the following characteristics: The class must be public and not sealed. The class must have a public or protected parameter-less constructor. The class must have public or protected properties Adhere to this and your type is magically endowed with these behaviors without any additional programming on your part. Behind the scenes the framework subclasses your type at runtime and creates a "dynamic proxy" which has these additional behaviors and when you navigate properties of your POCO, the framework replaces the POCO type with derived type instances. The MOQ framework does simlar magic. Let's say you have a simple interface:   public interface IFoo      {          int GetNum();      }   We can verify that the GetNum() was invoked on a mock like so:   var mock = new Mock<IFoo>(MockBehavior.Default);   mock.Setup(f => f.GetNum());   var num = mock.Object.GetNum();   mock.Verify(f => f.GetNum());   Beind the scenes the MOQ framework is generating a dynamic proxy by implementing IFoo at runtime. the call to moq.Object returns the dynamic proxy on which we then call "GetNum" and then verify that this method was invoked. No dark magic at all, just clever programming is what's going on here, just not visible and hence appears magical! Let's create a simple dynamic proxy generator which accepts an interface type and dynamically creates a proxy implementing the interface type specified at runtime.     public static class DynamicProxyGenerator   {       public static T GetInstanceFor<T>()       {           Type typeOfT = typeof(T);           var methodInfos = typeOfT.GetMethods();           AssemblyName assName = new AssemblyName("testAssembly");           var assBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assName, AssemblyBuilderAccess.RunAndSave);           var moduleBuilder = assBuilder.DefineDynamicModule("testModule", "test.dll");           var typeBuilder = moduleBuilder.DefineType(typeOfT.Name + "Proxy", TypeAttributes.Public);              typeBuilder.AddInterfaceImplementation(typeOfT);           var ctorBuilder = typeBuilder.DefineConstructor(                     MethodAttributes.Public,                     CallingConventions.Standard,                     new Type[] { });           var ilGenerator = ctorBuilder.GetILGenerator();           ilGenerator.EmitWriteLine("Creating Proxy instance");           ilGenerator.Emit(OpCodes.Ret);           foreach (var methodInfo in methodInfos)           {               var methodBuilder = typeBuilder.DefineMethod(                   methodInfo.Name,                   MethodAttributes.Public | MethodAttributes.Virtual,                   methodInfo.ReturnType,                   methodInfo.GetParameters().Select(p => p.GetType()).ToArray()                   );               var methodILGen = methodBuilder.GetILGenerator();               methodILGen.EmitWriteLine("I'm a proxy");               if (methodInfo.ReturnType == typeof(void))               {                   methodILGen.Emit(OpCodes.Ret);               }               else               {                   if (methodInfo.ReturnType.IsValueType || methodInfo.ReturnType.IsEnum)                   {                       MethodInfo getMethod = typeof(Activator).GetMethod(/span>"CreateInstance",new Type[]{typeof((Type)});                                               LocalBuilder lb = methodILGen.DeclareLocal(methodInfo.ReturnType);                       methodILGen.Emit(OpCodes.Ldtoken, lb.LocalType);                       methodILGen.Emit(OpCodes.Call, typeofype).GetMethod("GetTypeFromHandle"));  ));                       methodILGen.Emit(OpCodes.Callvirt, getMethod);                       methodILGen.Emit(OpCodes.Unbox_Any, lb.LocalType);                                                              }                 else                   {                       methodILGen.Emit(OpCodes.Ldnull);                   }                   methodILGen.Emit(OpCodes.Ret);               }               typeBuilder.DefineMethodOverride(methodBuilder, methodInfo);           }                     Type constructedType = typeBuilder.CreateType();           var instance = Activator.CreateInstance(constructedType);           return (T)instance;       }   }   Dynamic proxies are created by calling into the following main types: AssemblyBuilder, TypeBuilder, Modulebuilder and ILGenerator. These types enable dynamically creating an assembly and emitting .NET modules and types in that assembly, all using IL instructions. Let's break down the code above a bit and examine it piece by piece                Type typeOfT = typeof(T);              var methodInfos = typeOfT.GetMethods();              AssemblyName assName = new AssemblyName("testAssembly");              var assBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assName, AssemblyBuilderAccess.RunAndSave);              var moduleBuilder = assBuilder.DefineDynamicModule("testModule", "test.dll");              var typeBuilder = moduleBuilder.DefineType(typeOfT.Name + "Proxy", TypeAttributes.Public);   We are instructing the runtime to create an assembly caled "test.dll"and in this assembly we then emit a new module called "testModule". We then emit a new type definition of name "typeName"Proxy into this new module. This is the definition for the "dynamic proxy" for type T                 typeBuilder.AddInterfaceImplementation(typeOfT);               var ctorBuilder = typeBuilder.DefineConstructor(                         MethodAttributes.Public,                         CallingConventions.Standard,                         new Type[] { });               var ilGenerator = ctorBuilder.GetILGenerator();               ilGenerator.EmitWriteLine("Creating Proxy instance");               ilGenerator.Emit(OpCodes.Ret);   The newly created type implements type T and defines a default parameterless constructor in which we emit a call to Console.WriteLine. This call is not necessary but we do this so that we can see first hand that when the proxy is constructed, when our default constructor is invoked.   var methodBuilder = typeBuilder.DefineMethod(                      methodInfo.Name,                      MethodAttributes.Public | MethodAttributes.Virtual,                      methodInfo.ReturnType,                      methodInfo.GetParameters().Select(p => p.GetType()).ToArray()                      );   We then iterate over each method declared on type T and add a method definition of the same name into our "dynamic proxy" definition     if (methodInfo.ReturnType == typeof(void))   {       methodILGen.Emit(OpCodes.Ret);   }   If the return type specified in the method declaration of T is void we simply return.     if (methodInfo.ReturnType.IsValueType || methodInfo.ReturnType.IsEnum)   {                               MethodInfo getMethod = typeof(Activator).GetMethod("CreateInstance",                                                         new Type[]{typeof(Type)});                               LocalBuilder lb = methodILGen.DeclareLocal(methodInfo.ReturnType);                                                     methodILGen.Emit(OpCodes.Ldtoken, lb.LocalType);       methodILGen.Emit(OpCodes.Call, typeof(Type).GetMethod("GetTypeFromHandle"));       methodILGen.Emit(OpCodes.Callvirt, getMethod);       methodILGen.Emit(OpCodes.Unbox_Any, lb.LocalType);   }   If the return type in the method declaration of T is either a value type or an enum, then we need to create an instance of the value type and return that instance the caller. In order to accomplish that we need to do the following: 1) Get a handle to the Activator.CreateInstance method 2) Declare a local variable which represents the Type of the return type(i.e the type object of the return type) specified on the method declaration of T(obtained from the MethodInfo) and push this Type object onto the evaluation stack. In reality a RuntimeTypeHandle is what is pushed onto the stack. 3) Invoke the "GetTypeFromHandle" method(a static method in the Type class) passing in the RuntimeTypeHandle pushed onto the stack previously as an argument, the result of this invocation is a Type object (representing the method's return type) which is pushed onto the top of the evaluation stack. 4) Invoke Activator.CreateInstance passing in the Type object from step 3, the result of this invocation is an instance of the value type boxed as a reference type and pushed onto the top of the evaluation stack. 5) Unbox the result and place it into the local variable of the return type defined in step 2   methodILGen.Emit(OpCodes.Ldnull);   If the return type is a reference type then we just load a null onto the evaluation stack   methodILGen.Emit(OpCodes.Ret);   Emit a a return statement to return whatever is on top of the evaluation stack(null or an instance of a value type) back to the caller     Type constructedType = typeBuilder.CreateType();   var instance = Activator.CreateInstance(constructedType);   return (T)instance;   Now that we have a definition of the "dynamic proxy" implementing all the methods declared on T, we can now create an instance of the proxy type and return that out typed as T. The caller can now invoke the generator and request a dynamic proxy for any type T. In our example when the client invokes GetNum() we get back "0". Lets add a new method on the interface called DayOfWeek GetDay()   public interface IFoo      {          int GetNum();          DayOfWeek GetDay();      }   When GetDay() is invoked, the "dynamic proxy" returns "Sunday" since that is the default value for the DayOfWeek enum This is a very trivial example of dynammic proxies, frameworks like MOQ have a way more sophisticated implementation of this paradigm where in you can instruct the framework to create proxies which return specified values for a method implementation.

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  • June 2013 Release of the Ajax Control Toolkit

    - by Stephen.Walther
    I’m happy to announce the June 2013 release of the Ajax Control Toolkit. For this release, we enhanced the AjaxFileUpload control to support uploading files directly to Windows Azure. We also improved the SlideShow control by adding support for CSS3 animations. You can get the latest release of the Ajax Control Toolkit by visiting the project page at CodePlex (http://AjaxControlToolkit.CodePlex.com). Alternatively, you can execute the following NuGet command from the Visual Studio Library Package Manager window: Uploading Files to Azure The AjaxFileUpload control enables you to efficiently upload large files and display progress while uploading. With this release, we’ve added support for uploading large files directly to Windows Azure Blob Storage (You can continue to upload to your server hard drive if you prefer). Imagine, for example, that you have created an Azure Blob Storage container named pictures. In that case, you can use the following AjaxFileUpload control to upload to the container: <toolkit:ToolkitScriptManager runat="server" /> <toolkit:AjaxFileUpload ID="AjaxFileUpload1" StoreToAzure="true" AzureContainerName="pictures" runat="server" /> Notice that the AjaxFileUpload control is declared with two properties related to Azure. The StoreToAzure property causes the AjaxFileUpload control to upload a file to Azure instead of the local computer. The AzureContainerName property points to the blob container where the file is uploaded. .int3{position:absolute;clip:rect(487px,auto,auto,444px);}SMALL cash advance VERY CHEAP To use the AjaxFileUpload control, you need to modify your web.config file so it contains some additional settings. You need to configure the AjaxFileUpload handler and you need to point your Windows Azure connection string to your Blob Storage account. <configuration> <appSettings> <!--<add key="AjaxFileUploadAzureConnectionString" value="UseDevelopmentStorage=true"/>--> <add key="AjaxFileUploadAzureConnectionString" value="DefaultEndpointsProtocol=https;AccountName=testact;AccountKey=RvqL89Iw4npvPlAAtpOIPzrinHkhkb6rtRZmD0+ojZupUWuuAVJRyyF/LIVzzkoN38I4LSr8qvvl68sZtA152A=="/> </appSettings> <system.web> <compilation debug="true" targetFramework="4.5" /> <httpRuntime targetFramework="4.5" /> <httpHandlers> <add verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/> </httpHandlers> </system.web> <system.webServer> <validation validateIntegratedModeConfiguration="false" /> <handlers> <add name="AjaxFileUploadHandler" verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/> </handlers> <security> <requestFiltering> <requestLimits maxAllowedContentLength="4294967295"/> </requestFiltering> </security> </system.webServer> </configuration> You supply the connection string for your Azure Blob Storage account with the AjaxFileUploadAzureConnectionString property. If you set the value “UseDevelopmentStorage=true” then the AjaxFileUpload will upload to the simulated Blob Storage on your local machine. After you create the necessary configuration settings, you can use the AjaxFileUpload control to upload files directly to Azure (even very large files). Here’s a screen capture of how the AjaxFileUpload control appears in Google Chrome: After the files are uploaded, you can view the uploaded files in the Windows Azure Portal. You can see that all 5 files were uploaded successfully: New AjaxFileUpload Events In response to user feedback, we added two new events to the AjaxFileUpload control (on both the server and the client): · UploadStart – Raised on the server before any files have been uploaded. · UploadCompleteAll – Raised on the server when all files have been uploaded. · OnClientUploadStart – The name of a function on the client which is called before any files have been uploaded. · OnClientUploadCompleteAll – The name of a function on the client which is called after all files have been uploaded. These new events are most useful when uploading multiple files at a time. The updated AjaxFileUpload sample page demonstrates how to use these events to show the total amount of time required to upload multiple files (see the AjaxFileUpload.aspx file in the Ajax Control Toolkit sample site). SlideShow Animated Slide Transitions With this release of the Ajax Control Toolkit, we also added support for CSS3 animations to the SlideShow control. The animation is used when transitioning from one slide to another. Here’s the complete list of animations: · FadeInFadeOut · ScaleX · ScaleY · ZoomInOut · Rotate · SlideLeft · SlideDown You specify the animation which you want to use by setting the SlideShowAnimationType property. For example, here is how you would use the Rotate animation when displaying a set of slides: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowSlideShow.aspx.cs" Inherits="TestACTJune2013.ShowSlideShow" %> <%@ Register TagPrefix="toolkit" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit" %> <script runat="Server" type="text/C#"> [System.Web.Services.WebMethod] [System.Web.Script.Services.ScriptMethod] public static AjaxControlToolkit.Slide[] GetSlides() { return new AjaxControlToolkit.Slide[] { new AjaxControlToolkit.Slide("slides/Blue hills.jpg", "Blue Hills", "Go Blue"), new AjaxControlToolkit.Slide("slides/Sunset.jpg", "Sunset", "Setting sun"), new AjaxControlToolkit.Slide("slides/Winter.jpg", "Winter", "Wintery..."), new AjaxControlToolkit.Slide("slides/Water lilies.jpg", "Water lillies", "Lillies in the water"), new AjaxControlToolkit.Slide("slides/VerticalPicture.jpg", "Sedona", "Portrait style picture") }; } </script> <!DOCTYPE html> <html > <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <div> <toolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server" /> <asp:Image ID="Image1" Height="300" Runat="server" /> <toolkit:SlideShowExtender ID="SlideShowExtender1" TargetControlID="Image1" SlideShowServiceMethod="GetSlides" AutoPlay="true" Loop="true" SlideShowAnimationType="Rotate" runat="server" /> </div> </form> </body> </html> In the code above, the set of slides is exposed by a page method named GetSlides(). The SlideShowAnimationType property is set to the value Rotate. The following animated GIF gives you an idea of the resulting slideshow: If you want to use either the SlideDown or SlideRight animations, then you must supply both an explicit width and height for the Image control which is the target of the SlideShow extender. For example, here is how you would declare an Image and SlideShow control to use a SlideRight animation: <toolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server" /> <asp:Image ID="Image1" Height="300" Width="300" Runat="server" /> <toolkit:SlideShowExtender ID="SlideShowExtender1" TargetControlID="Image1" SlideShowServiceMethod="GetSlides" AutoPlay="true" Loop="true" SlideShowAnimationType="SlideRight" runat="server" /> Notice that the Image control includes both a Height and Width property. Here’s an approximation of this animation using an animated GIF: Summary The Superexpert team worked hard on this release. We hope you like the new improvements to both the AjaxFileUpload and the SlideShow controls. We’d love to hear your feedback in the comments. On to the next sprint!

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  • Premature-Optimization and Performance Anxiety

    - by James Michael Hare
    While writing my post analyzing the new .NET 4 ConcurrentDictionary class (here), I fell into one of the classic blunders that I myself always love to warn about.  After analyzing the differences of time between a Dictionary with locking versus the new ConcurrentDictionary class, I noted that the ConcurrentDictionary was faster with read-heavy multi-threaded operations.  Then, I made the classic blunder of thinking that because the original Dictionary with locking was faster for those write-heavy uses, it was the best choice for those types of tasks.  In short, I fell into the premature-optimization anti-pattern. Basically, the premature-optimization anti-pattern is when a developer is coding very early for a perceived (whether rightly-or-wrongly) performance gain and sacrificing good design and maintainability in the process.  At best, the performance gains are usually negligible and at worst, can either negatively impact performance, or can degrade maintainability so much that time to market suffers or the code becomes very fragile due to the complexity. Keep in mind the distinction above.  I'm not talking about valid performance decisions.  There are decisions one should make when designing and writing an application that are valid performance decisions.  Examples of this are knowing the best data structures for a given situation (Dictionary versus List, for example) and choosing performance algorithms (linear search vs. binary search).  But these in my mind are macro optimizations.  The error is not in deciding to use a better data structure or algorithm, the anti-pattern as stated above is when you attempt to over-optimize early on in such a way that it sacrifices maintainability. In my case, I was actually considering trading the safety and maintainability gains of the ConcurrentDictionary (no locking required) for a slight performance gain by using the Dictionary with locking.  This would have been a mistake as I would be trading maintainability (ConcurrentDictionary requires no locking which helps readability) and safety (ConcurrentDictionary is safe for iteration even while being modified and you don't risk the developer locking incorrectly) -- and I fell for it even when I knew to watch out for it.  I think in my case, and it may be true for others as well, a large part of it was due to the time I was trained as a developer.  I began college in in the 90s when C and C++ was king and hardware speed and memory were still relatively priceless commodities and not to be squandered.  In those days, using a long instead of a short could waste precious resources, and as such, we were taught to try to minimize space and favor performance.  This is why in many cases such early code-bases were very hard to maintain.  I don't know how many times I heard back then to avoid too many function calls because of the overhead -- and in fact just last year I heard a new hire in the company where I work declare that she didn't want to refactor a long method because of function call overhead.  Now back then, that may have been a valid concern, but with today's modern hardware even if you're calling a trivial method in an extremely tight loop (which chances are the JIT compiler would optimize anyway) the results of removing method calls to speed up performance are negligible for the great majority of applications.  Now, obviously, there are those coding applications where speed is absolutely king (for example drivers, computer games, operating systems) where such sacrifices may be made.  But I would strongly advice against such optimization because of it's cost.  Many folks that are performing an optimization think it's always a win-win.  That they're simply adding speed to the application, what could possibly be wrong with that?  What they don't realize is the cost of their choice.  For every piece of straight-forward code that you obfuscate with performance enhancements, you risk the introduction of bugs in the long term technical debt of the application.  It will become so fragile over time that maintenance will become a nightmare.  I've seen such applications in places I have worked.  There are times I've seen applications where the designer was so obsessed with performance that they even designed their own memory management system for their application to try to squeeze out every ounce of performance.  Unfortunately, the application stability often suffers as a result and it is very difficult for anyone other than the original designer to maintain. I've even seen this recently where I heard a C++ developer bemoaning that in VS2010 the iterators are about twice as slow as they used to be because Microsoft added range checking (probably as part of the 0x standard implementation).  To me this was almost a joke.  Twice as slow sounds bad, but it almost never as bad as you think -- especially if you're gaining safety.  The only time twice is really that much slower is when once was too slow to begin with.  Think about it.  2 minutes is slow as a response time because 1 minute is slow.  But if an iterator takes 1 microsecond to move one position and a new, safer iterator takes 2 microseconds, this is trivial!  The only way you'd ever really notice this would be in iterating a collection just for the sake of iterating (i.e. no other operations).  To my mind, the added safety makes the extra time worth it. Always favor safety and maintainability when you can.  I know it can be a hard habit to break, especially if you started out your career early or in a language such as C where they are very performance conscious.  But in reality, these type of micro-optimizations only end up hurting you in the long run. Remember the two laws of optimization.  I'm not sure where I first heard these, but they are so true: For beginners: Do not optimize. For experts: Do not optimize yet. This is so true.  If you're a beginner, resist the urge to optimize at all costs.  And if you are an expert, delay that decision.  As long as you have chosen the right data structures and algorithms for your task, your performance will probably be more than sufficient.  Chances are it will be network, database, or disk hits that will be your slow-down, not your code.  As they say, 98% of your code's bottleneck is in 2% of your code so premature-optimization may add maintenance and safety debt that won't have any measurable impact.  Instead, code for maintainability and safety, and then, and only then, when you find a true bottleneck, then you should go back and optimize further.

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  • C# Performance Pitfall – Interop Scenarios Change the Rules

    - by Reed
    C# and .NET, overall, really do have fantastic performance in my opinion.  That being said, the performance characteristics dramatically differ from native programming, and take some relearning if you’re used to doing performance optimization in most other languages, especially C, C++, and similar.  However, there are times when revisiting tricks learned in native code play a critical role in performance optimization in C#. I recently ran across a nasty scenario that illustrated to me how dangerous following any fixed rules for optimization can be… The rules in C# when optimizing code are very different than C or C++.  Often, they’re exactly backwards.  For example, in C and C++, lifting a variable out of loops in order to avoid memory allocations often can have huge advantages.  If some function within a call graph is allocating memory dynamically, and that gets called in a loop, it can dramatically slow down a routine. This can be a tricky bottleneck to track down, even with a profiler.  Looking at the memory allocation graph is usually the key for spotting this routine, as it’s often “hidden” deep in call graph.  For example, while optimizing some of my scientific routines, I ran into a situation where I had a loop similar to: for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i]); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This loop was at a fairly high level in the call graph, and often could take many hours to complete, depending on the input data.  As such, any performance optimization we could achieve would be greatly appreciated by our users. After a fair bit of profiling, I noticed that a couple of function calls down the call graph (inside of ProcessElement), there was some code that effectively was doing: // Allocate some data required DataStructure* data = new DataStructure(num); // Call into a subroutine that passed around and manipulated this data highly CallSubroutine(data); // Read and use some values from here double values = data->Foo; // Cleanup delete data; // ... return bar; Normally, if “DataStructure” was a simple data type, I could just allocate it on the stack.  However, it’s constructor, internally, allocated it’s own memory using new, so this wouldn’t eliminate the problem.  In this case, however, I could change the call signatures to allow the pointer to the data structure to be passed into ProcessElement and through the call graph, allowing the inner routine to reuse the same “data” memory instead of allocating.  At the highest level, my code effectively changed to something like: DataStructure* data = new DataStructure(numberToProcess); for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i], data); } delete data; Granted, this dramatically reduced the maintainability of the code, so it wasn’t something I wanted to do unless there was a significant benefit.  In this case, after profiling the new version, I found that it increased the overall performance dramatically – my main test case went from 35 minutes runtime down to 21 minutes.  This was such a significant improvement, I felt it was worth the reduction in maintainability. In C and C++, it’s generally a good idea (for performance) to: Reduce the number of memory allocations as much as possible, Use fewer, larger memory allocations instead of many smaller ones, and Allocate as high up the call stack as possible, and reuse memory I’ve seen many people try to make similar optimizations in C# code.  For good or bad, this is typically not a good idea.  The garbage collector in .NET completely changes the rules here. In C#, reallocating memory in a loop is not always a bad idea.  In this scenario, for example, I may have been much better off leaving the original code alone.  The reason for this is the garbage collector.  The GC in .NET is incredibly effective, and leaving the allocation deep inside the call stack has some huge advantages.  First and foremost, it tends to make the code more maintainable – passing around object references tends to couple the methods together more than necessary, and overall increase the complexity of the code.  This is something that should be avoided unless there is a significant reason.  Second, (unlike C and C++) memory allocation of a single object in C# is normally cheap and fast.  Finally, and most critically, there is a large advantage to having short lived objects.  If you lift a variable out of the loop and reuse the memory, its much more likely that object will get promoted to Gen1 (or worse, Gen2).  This can cause expensive compaction operations to be required, and also lead to (at least temporary) memory fragmentation as well as more costly collections later. As such, I’ve found that it’s often (though not always) faster to leave memory allocations where you’d naturally place them – deep inside of the call graph, inside of the loops.  This causes the objects to stay very short lived, which in turn increases the efficiency of the garbage collector, and can dramatically improve the overall performance of the routine as a whole. In C#, I tend to: Keep variable declarations in the tightest scope possible Declare and allocate objects at usage While this tends to cause some of the same goals (reducing unnecessary allocations, etc), the goal here is a bit different – it’s about keeping the objects rooted for as little time as possible in order to (attempt) to keep them completely in Gen0, or worst case, Gen1.  It also has the huge advantage of keeping the code very maintainable – objects are used and “released” as soon as possible, which keeps the code very clean.  It does, however, often have the side effect of causing more allocations to occur, but keeping the objects rooted for a much shorter time. Now – nowhere here am I suggesting that these rules are hard, fast rules that are always true.  That being said, my time spent optimizing over the years encourages me to naturally write code that follows the above guidelines, then profile and adjust as necessary.  In my current project, however, I ran across one of those nasty little pitfalls that’s something to keep in mind – interop changes the rules. In this case, I was dealing with an API that, internally, used some COM objects.  In this case, these COM objects were leading to native allocations (most likely C++) occurring in a loop deep in my call graph.  Even though I was writing nice, clean managed code, the normal managed code rules for performance no longer apply.  After profiling to find the bottleneck in my code, I realized that my inner loop, a innocuous looking block of C# code, was effectively causing a set of native memory allocations in every iteration.  This required going back to a “native programming” mindset for optimization.  Lifting these variables and reusing them took a 1:10 routine down to 0:20 – again, a very worthwhile improvement. Overall, the lessons here are: Always profile if you suspect a performance problem – don’t assume any rule is correct, or any code is efficient just because it looks like it should be Remember to check memory allocations when profiling, not just CPU cycles Interop scenarios often cause managed code to act very differently than “normal” managed code. Native code can be hidden very cleverly inside of managed wrappers

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  • PostSharp, Obfuscation, and IL

    - by Simon Cooper
    Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day!

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  • PostSharp, Obfuscation, and IL

    - by Simon Cooper
    Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day!

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  • PostSharp, Obfuscation, and IL

    - by simonc
    Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day! Cross posted from Simple Talk.

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  • Execution plan warnings–The final chapter

    - by Dave Ballantyne
    In my previous posts (here and here), I showed examples of some of the execution plan warnings that have been added to SQL Server 2012.  There is one other warning that is of interest to me : “Unmatched Indexes”. Firstly, how do I know this is the final one ?  The plan is an XML document, right ? So that means that it can have an accompanying XSD.  As an XSD is a schema definition, we can poke around inside it to find interesting things that *could* be in the final XML file. The showplan schema is stored in the folder Microsoft SQL Server\110\Tools\Binn\schemas\sqlserver\2004\07\showplan and by comparing schemas over releases you can get a really good idea of any new functionality that has been added. Here is the section of the Sql Server 2012 showplan schema that has been interesting me so far : <xsd:complexType name="AffectingConvertWarningType"> <xsd:annotation> <xsd:documentation>Warning information for plan-affecting type conversion</xsd:documentation> </xsd:annotation> <xsd:sequence> <!-- Additional information may go here when available --> </xsd:sequence> <xsd:attribute name="ConvertIssue" use="required"> <xsd:simpleType> <xsd:restriction base="xsd:string"> <xsd:enumeration value="Cardinality Estimate" /> <xsd:enumeration value="Seek Plan" /> <!-- to be extended here --> </xsd:restriction> </xsd:simpleType> </xsd:attribute> <xsd:attribute name="Expression" type ="xsd:string" use="required" /></xsd:complexType><xsd:complexType name="WarningsType"> <xsd:annotation> <xsd:documentation>List of all possible iterator or query specific warnings (e.g. hash spilling, no join predicate)</xsd:documentation> </xsd:annotation> <xsd:choice minOccurs="1" maxOccurs="unbounded"> <xsd:element name="ColumnsWithNoStatistics" type="shp:ColumnReferenceListType" minOccurs="0" maxOccurs="1" /> <xsd:element name="SpillToTempDb" type="shp:SpillToTempDbType" minOccurs="0" maxOccurs="unbounded" /> <xsd:element name="Wait" type="shp:WaitWarningType" minOccurs="0" maxOccurs="unbounded" /> <xsd:element name="PlanAffectingConvert" type="shp:AffectingConvertWarningType" minOccurs="0" maxOccurs="unbounded" /> </xsd:choice> <xsd:attribute name="NoJoinPredicate" type="xsd:boolean" use="optional" /> <xsd:attribute name="SpatialGuess" type="xsd:boolean" use="optional" /> <xsd:attribute name="UnmatchedIndexes" type="xsd:boolean" use="optional" /> <xsd:attribute name="FullUpdateForOnlineIndexBuild" type="xsd:boolean" use="optional" /></xsd:complexType> I especially like the “to be extended here” comment,  high hopes that we will see more of these in the future.   So “Unmatched Indexes” was a warning that I couldn’t get and many thanks must go to Fabiano Amorim (b|t) for showing me the way.   Filtered indexes were introduced in Sql Server 2008 and are really useful if you only need to index only a portion of the data within a table.  However,  if your SQL code uses a variable as a predicate on the filtered data that matches the filtered condition, then the filtered index cannot be used as, naturally,  the value in the variable may ( and probably will ) change and therefore will need to read data outside the index.  As an aside,  you could use option(recompile) here , in which case the optimizer will build a plan specific to the variable values and use the filtered index,  but that can bring about other problems.   To demonstrate this warning, we need to generate some test data :   DROP TABLE #TestTab1GOCREATE TABLE #TestTab1 (Col1 Int not null, Col2 Char(7500) not null, Quantity Int not null)GOINSERT INTO #TestTab1 VALUES (1,1,1),(1,2,5),(1,2,10),(1,3,20), (2,1,101),(2,2,105),(2,2,110),(2,3,120)GO and then add a filtered index CREATE INDEX ixFilter ON #TestTab1 (Col1)WHERE Quantity = 122 Now if we execute SELECT COUNT(*) FROM #TestTab1 WHERE Quantity = 122 We will see the filtered index being scanned But if we parameterize the query DECLARE @i INT = 122SELECT COUNT(*) FROM #TestTab1 WHERE Quantity = @i The plan is very different a table scan, as the value of the variable used in the predicate can change at run time, and also we see the familiar warning triangle. If we now look at the properties pane, we will see two pieces of information “Warnings” and “UnmatchedIndexes”. So, handily, we are being told which filtered index is not being used due to parameterization.

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