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  • simple jQuery script not running

    - by romaer
    I just have copied a simple script from W3School and cannot get it running: Here it is: <!DOCTYPE html> <html> <head> <script type="text/javascript" src="http://Web Testing/js/jquery-1.8.0.min.js"> </script> <script> $(document).ready(function(){ $("p").click(function(){ $(this).hide(); }); }); </script> </head> <body> <p>If you click on me, I will disappear.</p> <p>Click me away!</p> <p>Click me too!</p> </body> </html> It works on their Tryit Editor with the following line but does not work even with this line on my Mac under BBEdit

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  • Applying jQuery attr value to new DOM elements (result of AJAX query)

    - by Daniel
    Hello everyone, I have a div on a page whose contents is replaced by an AJAX request when the user selects an option from a select list. When the page loads, I issue a command to disable the autocomplete feature for all of the pages text input elements: //Stop that pesky browser autocomplete $('input[type=text]').attr("autocomplete", "off"); However, when new elements appear in the div after an AJAX call, this line of code does not reference them because they were not part of the original DOM (when the page was loaded). I have tried appending the autocomplete line to the end of the post function: //AJAX Post request that changes the fields in the address div for each different country $("div#address select#country").live("change", function() { $.post("<?php print($_SERVER['PHP_SELF']); ?>", { country: $(this).val() }, function(data) { $('div#address').html(data); }, "text"); $('div#address input[type=text]').attr("autocomplete", "off"); }); But for some reason it does not work and the autocomplete pops up when text is entered into any of the address fields. As far as I am aware I cannot use .live() to select the input elements because changing an attribute is not classed as an event. So can anyone advise me how to modify the attributes of a newly created DOM element?

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  • How do I pause main() until all other threads have died?

    - by thechiman
    In my program, I am creating several threads in the main() method. The last line in the main method is a call to System.out.println(), which I don't want to call until all the threads have died. I have tried calling Thread.join() on each thread however that blocks each thread so that they execute sequentially instead of in parallel. Is there a way to block the main() thread until all other threads have finished executing? Here is the relevant part of my code: public static void main(String[] args) { //some other initialization code //Make array of Thread objects Thread[] racecars = new Thread[numberOfRaceCars]; //Fill array with RaceCar objects for(int i=0; i<numberOfRaceCars; i++) { racecars[i] = new RaceCar(laps, args[i]); } //Call start() on each Thread for(int i=0; i<numberOfRaceCars; i++) { racecars[i].start(); try { racecars[i].join(); //This is where I tried to using join() //It just blocks all other threads until the current //thread finishes. } catch(InterruptedException e) { e.printStackTrace(); } } //This is the line I want to execute after all other Threads have finished System.out.println("It's Over!"); } Thanks for the help guys! Eric

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  • printSoln module problem

    - by dingo_d
    Hi I found in book:Numerical Methods in engineering with Python the module run_kut5, but for that module I need module printSoln, all provided in the book. Now I cp the code, made necessary line adjustments and so. The code looks like: # -*- coding: cp1250 -*- ## module printSoln ''' printSoln(X,Y,freq). Prints X and Y returned from the differential equation solvers using printput frequency ’freq’. freq = n prints every nth step. freq = 0 prints initial and final values only. ''' def printSoln(X,Y,freq): def printHead(n): print "\n x ", for i in range (n): print " y[",i,"] ", print def printLine(x,y,n): print "%13.4e"% x,f for i in range (n): print "%13.4e"% y[i], print m = len(Y) try: n = len(Y[0]) except TypeError: n = 1 if freq == 0: freq = m printHead(n) for i in range(0,m,freq): printLine(X[i],Y[i],n) if i != m - 1: printLine(X[m - 1],Y[m - 1],n) Now, when I run the program it says: line 24, in <module> m = len(Y) NameError: name 'Y' is not defined But I cp'd from the book :\ So now when I call the run_kut module I get the same error, no Y defined in printSoln... I'm trying to figure this out but I suck :( Help, please...

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  • Rails 4 testing bug?

    - by Jamato
    Situation: if we add two identic line items into a cart, we update line item quantity instead of adding a duplicate.In browser everything works fine but in unit testing section something fails because of an empty cycle in code. Which I wanted to use to update all prices. Why? Is that a unit test engine bug? LineItem.all and cart.line_items in process of testing produce two DIFFERENT structures. #<LineItem id: 980190964, product_id: 1, cart_id: 999, created_at: "2014-06-01 00:21:28", updated_at: "2014-06-01 00:21:28", quantity: 2, price: #<BigDecimal:ba0fb544,'0.4E1',9(27)>> #<LineItem id: 980190964, product_id: 1, cart_id: 999, created_at: "2014-06-01 00:21:28", updated_at: "2014-06-01 00:21:28", quantity: 1, price: #<BigDecimal:ba0d1b04,'0.4E1',9(27)>> cart.line_items guy did not update quantity Code itself (produces LineItem which is then saved in line_item_controller which calls this method) class Cart < ActiveRecord::Base has_many :line_items, dependent: :destroy def add_product(product_id) # LOOK THIS CYCLE BREAKS UNIT TEST, SRSLY, I MEAN IT line_items.each do |item| end current_item = line_items.find_by(product_id: product_id) fresh_price = Product.find_by(id: product_id).price if current_item current_item.quantity += 1 else current_item = line_items.build(product_id: product_id, price: fresh_price) end return current_item end ... Unit test code test "non-unique item added" do cart = Cart.new(:id => 999) line_item0 = cart.add_product(2) line_item0.save line_item1 = cart.add_product(1) line_item1.save assert_equal 2, cart.line_items.size #success line_item2 = cart.add_product(1) line_item2.save assert_equal 2, cart.line_items.size, "what?" assert cart.total_price > 15 #fail, prices are not enough, quantity of product1 = 1 #we get total price from quantity, it's a simple method in model end And once again: IT DOES WORK in browser as it should. Even with cycle. I feel so dumb right now...

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  • getline with ints C++

    - by Mdjon26
    I have a file 0 3 2 1 2 3 4 5 6 6 8 1 Where the first number for each line is the row, the second number is the column, and the third number is the data contained in that row, column. This will be a given [8][8] array so I have already initialized everything to 0, but how can I store each of these data values? For example, I want [0][3] =2 and [1][2] = 3. I would like to keep track of the line on which I found that row, col, and data value. So, how can I correctly insert these values into my 2-D array? int rowcol[8][8]; for (int i=0; i < 9; i++) for (int j=0; j < 9; j++) { rowcol[i][j] =0; } ifstream myfile; int nums; myfile.open(text.c_str()); while (!myfile.eof()) { myfile >> nums; numbers.push_back(nums); } for (int i=0; i < numbers.size(); i++) { //Not sure what the best approach here would be and I'm not even sure if I should have done a vector... }

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  • CakePHP: Missing database table

    - by Justin
    I have a CakePHP application that is running fine locally. I uploaded it to a production server and the first page that uses a database connection gives the "Missing Database Table" error. When I look at the controller dump, it's complaining about the first table. I've tried a variety of things to fix this problem, with no luck: I've confirmed that at the command line I can login with the given MySQL credentials in database.php I've confirmed this table exists I've tried using the MySQL root credentials (temporarily) to see if the problem lies with permissions of the user. The same error appeared. My debug level is currently set to 3 I've deleted the entire contents of /app/tmp/cache I've set 777 permissions on /app/tmp* I've confirmed that I can run DESCRIBE commands at the commant line MySQL when logged in with the MySQL credentials used by by the application I've verified that the CakePHP log file only contains the error I'm setting in the browser window. I've tried all the suggestions I could find in similar postings on SO I've Googled around and didn't find any other ideas I think I've eliminating the obvious problems and my research isn't turning anything up. I feel like I'm missing something obvious. Any ideas?

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  • "The breakpoint will not currently be hit" error while debugging a mixed mode application (c# and unmanaged c++)

    - by user1678403
    While debugging a mixed mode application in VS2010, the breakpoint set on a line of code contained in an unmanaged c++ dll source file (called from a managed c# wrapper class) shows the infamous "The breakpoint will not currently be hit. No symbols have been loaded for this document" info message when hovering the mouse over the breakpoint on the line in question. The breakpoint itself is a red circle with a yellow info triangle instead of the usual solid red orb. Of course, the breakpoint isn't hit when the debugger is executed. Most answers I've found for this warning indicate the breakpoint hasn't been set properly, or that the expected dll is not being loaded, or that the associated pdb file is not located in the correct location, etc. etc. This is not the problem. The application does load and execute the referenced dll correctly. I've verified that the correct pdb file, with the same file date as its dll, is located in the executable's working directory along with the target dll itself. The debugger simply doesn't load the symbols for the dll, and the dll doesn't show in the Modules list. None of the solutions I've found online work for this problem. The dll doesn't show in the modules list available from 'Debug-Windows-Modules' menu selection... even though it is, in fact, loaded. Breakpoints set in the wrapper class work correctly. Deleting the bin and obj directories, cleaning and rebuilding the solution also doesn't help.

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  • MS SQL: How to get the newest date in a table with several equal keys

    - by Qohelet
    Unfortunately my knowledge related to statements like "group by" and "having" is quite limited, so hopefully you can help me: I have a view -here's an excerpt- (if we have some Europeans here - it's v021 of Winline/Mesonic): ID | Artikelbezeichnung1 | Bez2 | mesoyear _____________________________________________________________________ 1401MA70 | Marga ,Saracena grigio,1S,33,3/33,3 | Marazzi | 1344 1401MA70 | Marga ,Saracena grigio,1S,33,3/33,3 | Marazzi | 1356 1401MA70 | Marga ,Saracena grigio,1S,33,3/33,3 | Marazzi | 1356 1401MA71 | Marga ,Saracena beige,1S,33,3/33,3 | Marazzi | 1344 1401MA71 | Marga ,Saracena beige,1S,33,3/33,3 | Marazzi | 1356 1401MA71 | Marga ,Saracena beige,1S,33,3/33,3 | Marazzi | 1356 2401CR13 | Crista,Mahon rojo,1S,33,3/33,3 | Cristacer | 1332 2401CR13 | Crista,Mahon rojo,1S,33,3/33,3 | Cristacer | 1344 So the ID is not unique and I just need the one with the highest val in "mesoyear". My fist solution was: Select c015 as ID, c003 as Artikelbezeichnung1, c074 as Bez2, mesoyear from CWLDATEN_91.dbo.v021 group by c015 having mesoyear = max(mesoyear) But this doesn't work at all... Msg 8121, Level 16, State 1, Line 8 Column 'CWLDATEN_91.dbo.v021.mesoyear' is invalid in the HAVING clause because it is not contained in either an aggregate function or the GROUP BY clause. So I just removed the "having" statement and it went "better": Msg 8120, Level 16, State 1, Line 2 Column 'CWLDATEN_91.dbo.v021.c003' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. So I tried to remove the error just by adding things to the "group by". And it worked. Select c015 as ID, c003 as Artikelbezeichnung1, c074 as Bez2, max(mesoyear) from CWLDATEN_91.dbo.v021 group by c015,c003,c074 gives me exactly what I want. But the correct Select contains about 24 columns and some calculations as well. The problem can't be solved just by adding all the columns to the "group by"...? Can someone please help me to find a proper command? Thank you!

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  • document.getElementById('form_name').submit() not working properly

    - by Leahn Novash
    Ok, I will try to give the most details I can. The site is not suposed to work with IE6. It would be nice if it worked with IE8 and Chrome, but that can be done later. The site is in PHP. The form where the submit is in another PHP file that is included in position on the index.php inside of a DIV tag. If I open the form solely, the submit works correcly, but when I try to submit on the index page, the Firefox error console says that document is undefined. The form code is echoed line by line via PHP. Save the text fields for username and password, the form code is the following: <form id="entrar" action="entrar.php" method="post" onsubmit="javascript:checkvalues();"> <a href="javascript:document.getElementById('entrar').submit();">ENTRAR</a> </form> What's the big deal? What am I missing here? I know it is something very silly but I can't figure it out.

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  • Cannot Display Data from MySQL table

    - by MxmastaMills
    I've got a pretty standard call to a MySQL database and for some reason I can't get the code to work. Here's what I have: $mysqli = mysqli_connect("localhost","username","password"); if (!$mysqli) { die('Could not connect: ' . mysqli_error($mysqli)); } session_start(); $sql = "SELECT * FROM jobs ORDER BY id DESC"; $result = $mysqli->query($sql); $num_rows = mysqli_num_rows($result); Now, first, I know that it is connecting properly because I'm not getting the die method plus I added an else conditional in there previously and it checked out. Then the page displays but I get the errors: Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in blablabla/index.php on line 11 Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in blablabla/index.php on line 12 I've double-checked my database and there is a table called jobs with a row of "id" (it's the primary row). The thing that confuses me is this is code that I literally copied and pasted from another site I built and for some reason the code doesn't work on this one (I obviously copy and pasted it and then just changed the table name and rows accordingly). I saw the error and tried: $num_rows = $mysqli_result->num_rows; $row_array = $mysqli_result->fetch_array; and that fixed the errors but resulted in no data being passed (because obviously $mysqli_result has no value). I don't know why the error is calling for that (is it a difference in version of MySQL or PHP from the other site)? Can someone help me track down the problem? Thanks so much. Sorry if it's something super simple that I'm overlooking, I've been at it for a while.

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  • How to find "y" values of the already estimated monotone function of the non-monotone regression curve corresponding to the original "x" points?

    - by parenthesis
    The title sounds complicated but that is what I am looking for. Focus on the picture. ## data x <- c(1.009648,1.017896,1.021773,1.043659,1.060277,1.074578,1.075495,1.097086,1.106268,1.110550,1.117795,1.143573,1.166305,1.177850,1.188795,1.198032,1.200526,1.223329,1.235814,1.239068,1.243189,1.260003,1.262732,1.266907,1.269932,1.284472,1.307483,1.323714,1.326705,1.328625,1.372419,1.398703,1.404474,1.414360,1.415909,1.418254,1.430865,1.431476,1.437642,1.438682,1.447056,1.456152,1.457934,1.457993,1.465968,1.478041,1.478076,1.485995,1.486357,1.490379,1.490719) y <- c(0.5102649,0.0000000,0.6360097,0.0000000,0.8692671,0.0000000,1.0000000,0.0000000,0.4183691,0.8953987,0.3442624,0.0000000,0.7513169,0.0000000,0.0000000,0.0000000,0.0000000,0.1291901,0.4936121,0.7565551,1.0085108,0.0000000,0.0000000,0.1655482,0.0000000,0.1473168,0.0000000,0.0000000,0.0000000,0.1875293,0.4918018,0.0000000,0.0000000,0.8101771,0.6853480,0.0000000,0.0000000,0.0000000,0.0000000,0.4068802,1.1061434,0.0000000,0.0000000,0.0000000,0.0000000,0.0000000,0.0000000,0.0000000,0.0000000,0.0000000,0.6391678) fit1 <- c(0.5102649100,0.5153380934,0.5177234836,0.5255544980,0.5307668662,0.5068087080,0.5071001179,0.4825657520,0.4832969250,0.4836378194,0.4842147729,0.5004039310,0.4987301366,0.4978800742,0.4978042478,0.4969807064,0.5086987191,0.4989497612,0.4936121200,0.4922210302,0.4904593166,0.4775197108,0.4757040857,0.4729265271,0.4709141776,0.4612406896,0.4459316517,0.4351338346,0.4331439717,0.4318664278,0.3235179189,0.2907908968,0.1665721429,0.1474035158,0.1443999345,0.1398517097,0.1153991839,0.1142140393,0.1022584672,0.1002410843,0.0840033244,0.0663669309,0.0629119398,0.0627979240,0.0473336492,0.0239237481,0.0238556876,0.0084990298,0.0077970954,0.0000000000,-0.0006598571) fit2 <- c(-0.0006598571,0.0153328298,0.0228511733,0.0652889427,0.0975108758,0.1252414661,0.1270195143,0.1922510501,0.2965234797,0.3018551305,0.3108761043,0.3621749370,0.4184150225,0.4359301495,0.4432114081,0.4493565757,0.4510158144,0.4661865431,0.4744926045,0.4766574718,0.4796937554,0.4834718810,0.4836125426,0.4839450098,0.4841092849,0.4877317306,0.4930561638,0.4964939389,0.4970089201,0.4971376528,0.4990394601,0.5005881678,0.5023814257,0.5052125977,0.5056691690,0.5064254338,0.5115481820,0.5117259449,0.5146054557,0.5149729419,0.5184178197,0.5211542908,0.5216215426,0.5216426533,0.5239797875,0.5273573222,0.5273683002,0.5293994824,0.5295130266,0.5306236672,0.5307303109) ## picture plot(x, y) ## red regression curve points(x, fit1, col=2); lines(x, fit1, col=2) ## blue monotonic curve to the regression points(min(x) + cumsum(c(0, rev(diff(x)))), rev(fit2), col="blue"); lines(min(x) + cumsum(c(0, rev(diff(x)))), rev(fit2), col="blue") ## "x" original point matches with the regression estimated point ## but not with the estimated (fit2=estimate) monotonic curve abline(v=1.223329, lty=2, col="grey") Focus on the dashed grey line. The idea is to get y value of the monotonic blue curve corresponding to x original value. The grey line should cross three points (the original one "black", the regression estimate "red", the adjusted regression estimate "blue"). Can we do this? Methodology: The object "fit2" is the output of the function rearrangement(). It is always monotonically increasing. library(Rearrangement) fit2 <- rearrangement(x=as.data.frame(x), y=fit1)

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  • Reading/Writing/Modifying a struct in C

    - by user1016401
    I am taking some information from a user (name, address, contact number) and store it in a struct. I then store this in a file which is opened in "r+" mode. I try reading it line by line and see if the entry I am trying to enter already exists, in which case I exit. Otherwise I append this entry at the end of the file. The problem is that when I open the file in "r+" mode, it gives me Segmentation fault! Here is the code: struct cust{ char *frstnam; char *lastnam; char *cntact; char *add; }; Now consider this function. I am passing a struct of information in this function. Its job is to check if this struct already exists else append it to end of file. void check(struct cust c) { struct cust cpy; FILE *f; f=fopen("Customer.txt","r+"); int num=0; if (f!= NULL){ while (!feof(f)) { num++; fread(&cpy,sizeof(struct cust),1,f); if ((cpy.frstnam==c.frstnam)&(cpy.lastnam==c.lastnam)&(cpy.cntact==c.cntact)&(cpy.add==c.add)) { printf("Hi %s %s. Nice to meet you again. You live at %s and your contact number is %s\n", cpy.frstnam,cpy.lastnam,cpy.add,cpy.cntact); return; } } fwrite(&c,sizeof(struct cust),1,f); fclose (f); } printf("number of lines read is %d\n",num); }

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  • Getting a Script Error Every Time I Click a Link

    - by Flip4Life
    I have everything working perfectly on my site, but for some reason, I get an error message in console whenever I click a link anywhere on my site. The error has to do with this line of coding here: jQuery(function($){ $('.navbar a, .scroll a, .smoothscroll a').bind('click',function(event){ var $anchor = $(this); $('html, body').stop().animate({ scrollTop: $($anchor.attr('href')).offset().top }, 850,'easeInOutExpo'); event.preventDefault(); }); }); And the error I am getting is this: "SCRIPT5007: Unable to get value of the property 'top': object is null or undefined custom.min.js, line 6 character 197" The exact code it is highlighting is this part of the above code: $('html, body').stop().animate({ scrollTop: $($anchor.attr('href')).offset().top }, 850,'easeInOutExpo') All I know is that when I remove the above code, my scroll-to links stop working on pages such as these: http://www.northtownsremodeling.com/things-to-know.php You can see the popup error happen and stay in the console easily by going to a page with a filter like this: http://www.northtownsremodeling.com/bathroom/ And clicking one of the filter buttons. Ultimately, I am trying to make it so my scroll-to setting still works, but not have that error come up anymore. I made this script a long time ago, and I'm really confused as to what could be causing this error when everything is functioning perfectly otherwise? Thanks!

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  • How to identify end of InputStream in java

    - by Vardhaman
    I am trying to read bytes from server using Socket program, ie I am using InputStream to read the bytes. If I pass the length size I am able to read the bytes, but I am not sure what may be the length. So I am not able initialize the byte array. Also I tried while (in.read() !=-1), I observered it loop works fine when the data is sent , but the next line after the loop is not executable , I feel its still looking for the data in the stream but there is no ata. If I close the Server connection , then my client will execute the next line followed to the loop. I am not sure where I am going wrong? this.in = socket.getInputStream(); int dataInt = this.in.read(); while(dataInt != -1){ System.out.print(","+i+"--"+dataInt); i++; dataInt = this.in.read(); } System.out.print("End Of loop"); I get the output as:- ,1--0,2--62,3--96,4--131,5--142,6--1,7--133,8--2,9--16,10--48,11--56,12--1,13--0,14--14,15--128,16--0,17--0,18--0,19--48,20--0,21--0,22--0,23--0,24--0,25--1,26--0,27--0,28--38,29--114,30--23,31--20,32--70,33--3,34--20,35--1,36--133,37--48,38--51,39--49,40--52,41--49,42--55,43--49,44--52,45--52,46--54,47--55,48--50,49--51,50--52,51--48,52--53,53--56,54--51,55--48,56--48,57--57,58--57,59--57,60--57,61--57,62--57,63--57,64--56 But no output for :- End Of loop Please guide how shall I close the loop? Looking forward for you response. Thanking you all in advance.

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  • php mysql_fetch_array() error

    - by user1877823
    I am getting this error while i am trying to delete a record the query is working but this line remains on the page. i want to echo "Deleted" written in the while should show up but the while loop is not working, i have tried and searched alot nothing helps! mysql_fetch_array() expects parameter 1 to be resource, boolean given in delete.php on line 27 delete.php <html> <body> <form method="post"> Id : <input type="text" name="id"> Name : <input type="text" name="name"> Description : <input type="text" name="des"> <input type="submit" value="delete" name="delete"> </form> <?php include("connect.php"); $id = $_POST['id']; $name = $_POST['name']; $des = $_POST['des']; $result = mysql_query("DELETE FROM fact WHERE id='$id'") or die(mysql_error()); while($row = mysql_fetch_array($result)) { echo "Deleted"; } mysql_close($con); ?> </body> </html> connect.php <?php $con = mysql_connect("localhost","root",""); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("Dataentry", $con); ?> How should i make the while loop work..

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  • java:25: '.class' expected error while merging arrays

    - by user3677712
    Here is my code, it is asking me to call a class, I am confused as to do this. Noob to java, so any help would be greatly appreciated. line 25 is where the error occurs. This program is merging two arrays together into a new array. public class Merge{ public static void main(String[] args){ int[] a = {1, 1, 4, 5, 7}; int[] b = {2, 4, 6, 8}; int[] mergedArray = merge(a, b); for(int i = 0; i < mergedArray.length; i++){ System.out.print(mergedArray[i] + " "); } } public static int[] merge(int[] a, int[] b){ // WRITE CODE HERE int[] mergedArray = new int[a.length[] + b.length[]]; int i = 0, j = 0, k = 0; while (i < a.length() && j < b.length()) //error occurs at this line { if (a[i] < b[j]) { mergedArray[k] = a[i]; i++; } else { mergedArray[k] = b[j]; j++; } k++; } while (i < a.length()) { mergedArray[k] = a[i]; i++; k++; } while (j < b.length()) { mergedArray[k] = b[j]; j++; k++; } return mergedArray; } } This program is merging two arrays together into a new array.

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  • linux find the command invoked

    - by Subbu
    I am writing a C program which determines the number of bytes read from the standard input . I found out there are ways to give input to the program piped input redirection entering into command line while the program is waiting for input How to find the exact command by which the program was executed from the shell . I tried using command-line arguments but failed . #include <stdio.h> int main(int argc,char *argv[]) { char buffer[100]; int n; for(n=1;n<argc;n++) printf("argument: %s\t",argv[n]); printf("\n"); if(argc==1) printf("waiting for input :"); else if (argc==3) printf("Not waiting for input . Got the source from command itself ."); n = read(0,buffer,100); if(n==-1) printf("\nError occured in reading"); printf("\nReading successfully done\n"); return 0; } Also ,

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  • Why does this while terminate before receiving a value? (java)

    - by David
    Here's the relevant code snippet. public static Territory[] assignTerri (Territory[] board, String[] colors) { for (int i = 0; i<board.length; i++) { // so a problem is that Territory.translate is void fix this. System.out.print ("What team controls ") ; Territory.translate (i) ; System.out.println (" ?") ; boolean a = false ; while (a = false) { String s = getIns () ; if ((checkColor (s, colors))) { board[i].team = (returnIndex (s, colors)) ; a =true ; } else System.out.println ("error try again") ; } System.out.print ("How many unites are on ") ; Territory.translate (i) ; System.out.println (" ?") ; int n = getInt () ; board[i].population = n ; } return board ; } As an additional piece of information, checkColor just checks to make sure that its first argument, a string, is a string in one of the indexes of its second argument, an array. It seems to me that when the while the method gets a string from the keyboard and then only if that string checks out is a true and the while allowed to terminate. The output I get though is this: What team controls Alaska ? How many unites are on Alaska ? (there is space at the end to type in an input) This would seem to suggest that the while terminates before an input is ever typed in since the first line of text is within the while while the second line of text comes after it outside of it. Why is this happening?

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  • Pulling Data out of an object in Javascript

    - by PerryCS
    I am having a problem retreiving data out of an object passed back from PHP. I've tried many different ways to access this data and none work. In Firebug I see the following... (it looks nicer in Firebug) - I tried to make this look as close to Firebug as possible results Object { data="{"formName":"form3","formData":"data goes here"}", phpLiveDebug="<...s: 198.91.215.227"} data "{"formName":"form3","formData":"data goes here"}" phpLiveDebug "<...s: 198.91.215.227" I can access phpLiveDebug no problem, but the data portion is an object. I have tried the following... success: function(results) { //$("#formName").val(results.data.formName); //$("#formName").val(results.data[0].formName); //$("#formName").val(results.data[0]); //$("#formName").val(results.data[1]); //$("#formName").val(results.data[0]["formName"]); var tmp = results.data[formName]; alert("!" + tmp + "!"); $("#formName").val(tmp); $("#jqueryPHPDebug").val(results.phpLiveDebug); } This line works in the example above... $("#jqueryPHPDebug").val(results.phpLiveDebug); but... I can't figure out how to get at the data inside the results.data portion... as you can see above, I have been trying different things and more not even listed there. I was really hoping this line would work :) var tmp = results.data[formName]; But it doesn't. So, after many days of reading, tinkering, my solution was to re-write it to return data similar to the phpLiveDebug but then I thought... it's gotta be something simple I'm overlooking... Thank you for your time. Please try and explain why my logic (my horrible attempts at trying to figure out the proper method) above is wrong if you can?

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  • Why does this while terminate before recieving a value? (java)

    - by David
    here's the relevant code snippet. public static Territory[] assignTerri (Territory[] board, String[] colors) { for (int i = 0; i<board.length; i++) { // so a problem is that Territory.translate is void fix this. System.out.print ("What team controls ") ; Territory.translate (i) ; System.out.println (" ?") ; boolean a = false ; while (a = false) { String s = getIns () ; if ((checkColor (s, colors))) { board[i].team = (returnIndex (s, colors)) ; a =true ; } else System.out.println ("error try again") ; } System.out.print ("How many unites are on ") ; Territory.translate (i) ; System.out.println (" ?") ; int n = getInt () ; board[i].population = n ; } return board ; } as an additional piece of information, checkColor just checks to make sure that its first argument, a string, is a string in one of the indexes of its second argument, an array. it seems to me that when the while the method gets a string from the keyboard and then only if that string checks out is a true and the while allowed to terminate. The output i get though is this: What team controls Alaska ? How many unites are on Alaska ? (there is space at the end to type in an input) This would seem to suggest that the while terminates before an input is ever typed in since the first line of text is within the while while the second line of text comes after it outside of it. why is this happening?

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  • Java: Incompatible Types

    - by user2922081
    import java.text.*; import java.util.*; public class Proj3 { public static void main(String[]args){ // DecimalFormat df = new DecimalFormat("#0.00”); Scanner s = new Scanner(System.in); int TotalHours = 0; int TotalGrade = 0; System.out.print("How many courses did you take? "); int Courses = Integer.parseInt(s.nextLine()); System.out.println(""); int CourseNumber = Courses - (Courses - 1); while (Courses > 0){ System.out.print("Course (" + CourseNumber +"): How many hours? "); int Hours = Integer.parseInt(s.nextLine()); TotalHours = TotalHours + Hours; System.out.print("Course (" + CourseNumber +"): Letter grade? "); char Grade = s.nextLine().charAt(0); if (Grade == 'A'){ TotalGrade = TotalGrade + (4 * Hours); } if (Grade == 'B'){ TotalGrade = TotalGrade + (3 * Hours); } if (Grade == 'C'){ TotalGrade = TotalGrade + (2 * Hours); } if (Grade == 'D'){ TotalGrade = TotalGrade + (1 * Hours); } Courses = Courses - 1; CourseNumber = CourseNumber + 1; } Double GPA = TotalGrade / TotalHours; System.out.println(df.format(GPA)); } } This is for an assignment and I don't know how to fix my problem. The Double GPA = TotalGrade / ToutalHours; line is coming up with the Incompatible Types error. Also I'm supposed to include the DecimalFormat df = new DecimalFormat("#0.00”);line at the beginning of the main but its not working. Anything is very helpful. Thanks

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  • ASP.Net MVC 2 Auto Complete Textbox With Custom View Model Attribute & EditorTemplate

    - by SeanMcAlinden
    In this post I’m going to show how to create a generic, ajax driven Auto Complete text box using the new MVC 2 Templates and the jQuery UI library. The template will be automatically displayed when a property is decorated with a custom attribute within the view model. The AutoComplete text box in action will look like the following:   The first thing to do is to do is visit my previous blog post to put the custom model metadata provider in place, this is necessary when using custom attributes on the view model. http://weblogs.asp.net/seanmcalinden/archive/2010/06/11/custom-asp-net-mvc-2-modelmetadataprovider-for-using-custom-view-model-attributes.aspx Once this is in place, make sure you visit the jQuery UI and download the latest stable release – in this example I’m using version 1.8.2. You can download it here. Add the jQuery scripts and css theme to your project and add references to them in your master page. Should look something like the following: Site.Master <head runat="server">     <title><asp:ContentPlaceHolder ID="TitleContent" runat="server" /></title>     <link href="../../Content/Site.css" rel="stylesheet" type="text/css" />     <link href="../../css/ui-lightness/jquery-ui-1.8.2.custom.css" rel="stylesheet" type="text/css" />     <script src="../../Scripts/jquery-1.4.2.min.js" type="text/javascript"></script>     <script src="../../Scripts/jquery-ui-1.8.2.custom.min.js" type="text/javascript"></script> </head> Once this is place we can get started. Creating the AutoComplete Custom Attribute The auto complete attribute will derive from the abstract MetadataAttribute created in my previous post. It will look like the following: AutoCompleteAttribute using System.Collections.Generic; using System.Web.Mvc; using System.Web.Routing; namespace Mvc2Templates.Attributes {     public class AutoCompleteAttribute : MetadataAttribute     {         public RouteValueDictionary RouteValueDictionary;         public AutoCompleteAttribute(string controller, string action, string parameterName)         {             this.RouteValueDictionary = new RouteValueDictionary();             this.RouteValueDictionary.Add("Controller", controller);             this.RouteValueDictionary.Add("Action", action);             this.RouteValueDictionary.Add(parameterName, string.Empty);         }         public override void Process(ModelMetadata modelMetaData)         {             modelMetaData.AdditionalValues.Add("AutoCompleteUrlData", this.RouteValueDictionary);             modelMetaData.TemplateHint = "AutoComplete";         }     } } As you can see, the constructor takes in strings for the controller, action and parameter name. The parameter name will be used for passing the search text within the auto complete text box. The constructor then creates a new RouteValueDictionary which we will use later to construct the url for getting the auto complete results via ajax. The main interesting method is the method override called Process. With the process method, the route value dictionary is added to the modelMetaData AdditionalValues collection. The TemplateHint is also set to AutoComplete, this means that when the view model is parsed for display, the MVC 2 framework will look for a view user control template called AutoComplete, if it finds one, it uses that template to display the property. The View Model To show you how the attribute will look, this is the view model I have used in my example which can be downloaded at the end of this post. View Model using System.ComponentModel; using Mvc2Templates.Attributes; namespace Mvc2Templates.Models {     public class TemplateDemoViewModel     {         [AutoComplete("Home", "AutoCompleteResult", "searchText")]         [DisplayName("European Country Search")]         public string SearchText { get; set; }     } } As you can see, the auto complete attribute is called with the controller name, action name and the name of the action parameter that the search text will be passed into. The AutoComplete Template Now all of this is in place, it’s time to create the AutoComplete template. Create a ViewUserControl called AutoComplete.ascx at the following location within your application – Views/Shared/EditorTemplates/AutoComplete.ascx Add the following code: AutoComplete.ascx <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl" %> <%     var propertyName = ViewData.ModelMetadata.PropertyName;     var propertyValue = ViewData.ModelMetadata.Model;     var id = Guid.NewGuid().ToString();     RouteValueDictionary urlData =         (RouteValueDictionary)ViewData.ModelMetadata.AdditionalValues.Where(x => x.Key == "AutoCompleteUrlData").Single().Value;     var url = Mvc2Templates.Views.Shared.Helpers.RouteHelper.GetUrl(this.ViewContext.RequestContext, urlData); %> <input type="text" name="<%= propertyName %>" value="<%= propertyValue %>" id="<%= id %>" class="autoComplete" /> <script type="text/javascript">     $(function () {         $("#<%= id %>").autocomplete({             source: function (request, response) {                 $.ajax({                     url: "<%= url %>" + request.term,                     dataType: "json",                     success: function (data) {                         response(data);                     }                 });             },             minLength: 2         });     }); </script> There is a lot going on in here but when you break it down it’s quite simple. Firstly, the property name and property value are retrieved through the model meta data. These are required to ensure that the text box input has the correct name and data to allow for model binding. If you look at line 14 you can see them being used in the text box input creation. The interesting bit is on line 8 and 9, this is the code to retrieve the route value dictionary we added into the model metada via the custom attribute. Line 11 is used to create the url, in order to do this I created a quick helper class which looks like the code below titled RouteHelper. The last bit of script is the code to initialise the jQuery UI AutoComplete control with the correct url for calling back to our controller action. RouteHelper using System.Web.Mvc; using System.Web.Routing; namespace Mvc2Templates.Views.Shared.Helpers {     public static class RouteHelper     {         const string Controller = "Controller";         const string Action = "Action";         const string ReplaceFormatString = "REPLACE{0}";         public static string GetUrl(RequestContext requestContext, RouteValueDictionary routeValueDictionary)         {             RouteValueDictionary urlData = new RouteValueDictionary();             UrlHelper urlHelper = new UrlHelper(requestContext);                          int i = 0;             foreach(var item in routeValueDictionary)             {                 if (item.Value == string.Empty)                 {                     i++;                     urlData.Add(item.Key, string.Format(ReplaceFormatString, i.ToString()));                 }                 else                 {                     urlData.Add(item.Key, item.Value);                 }             }             var url = urlHelper.RouteUrl(urlData);             for (int index = 1; index <= i; index++)             {                 url = url.Replace(string.Format(ReplaceFormatString, index.ToString()), string.Empty);             }             return url;         }     } } See it in action All you need to do to see it in action is pass a view model from your controller with the new AutoComplete attribute attached and call the following within your view: <%= this.Html.EditorForModel() %> NOTE: The jQuery UI auto complete control expects a JSON string returned from your controller action method… as you can’t use the JsonResult to perform GET requests, use a normal action result, convert your data into json and return it as a string via a ContentResult. If you download the solution it will be very clear how to handle the controller and action for this demo. The full source code for this post can be downloaded here. It has been developed using MVC 2 and Visual Studio 2010. As always, I hope this has been interesting/useful. Kind Regards, Sean McAlinden.

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  • .NET HTML Sanitation for rich HTML Input

    - by Rick Strahl
    Recently I was working on updating a legacy application to MVC 4 that included free form text input. When I set up the new site my initial approach was to not allow any rich HTML input, only simple text formatting that would respect a few simple HTML commands for bold, lists etc. and automatically handles line break processing for new lines and paragraphs. This is typical for what I do with most multi-line text input in my apps and it works very well with very little development effort involved. Then the client sprung another note: Oh by the way we have a bunch of customers (real estate agents) who need to post complete HTML documents. Oh uh! There goes the simple theory. After some discussion and pleading on my part (<snicker>) to try and avoid this type of raw HTML input because of potential XSS issues, the client decided to go ahead and allow raw HTML input anyway. There has been lots of discussions on this subject on StackOverFlow (and here and here) but to after reading through some of the solutions I didn't really find anything that would work even closely for what I needed. Specifically we need to be able to allow just about any HTML markup, with the exception of script code. Remote CSS and Images need to be loaded, links need to work and so. While the 'legit' HTML posted by these agents is basic in nature it does span most of the full gamut of HTML (4). Most of the solutions XSS prevention/sanitizer solutions I found were way to aggressive and rendered the posted output unusable mostly because they tend to strip any externally loaded content. In short I needed a custom solution. I thought the best solution to this would be to use an HTML parser - in this case the Html Agility Pack - and then to run through all the HTML markup provided and remove any of the blacklisted tags and a number of attributes that are prone to JavaScript injection. There's much discussion on whether to use blacklists vs. whitelists in the discussions mentioned above, but I found that whitelists can make sense in simple scenarios where you might allow manual HTML input, but when you need to allow a larger array of HTML functionality a blacklist is probably easier to manage as the vast majority of elements and attributes could be allowed. Also white listing gets a bit more complex with HTML5 and the new proliferation of new HTML tags and most new tags generally don't affect XSS issues directly. Pure whitelisting based on elements and attributes also doesn't capture many edge cases (see some of the XSS cheat sheets listed below) so even with a white list, custom logic is still required to handle many of those edge cases. The Microsoft Web Protection Library (AntiXSS) My first thought was to check out the Microsoft AntiXSS library. Microsoft has an HTML Encoding and Sanitation library in the Microsoft Web Protection Library (formerly AntiXSS Library) on CodePlex, which provides stricter functions for whitelist encoding and sanitation. Initially I thought the Sanitation class and its static members would do the trick for me,but I found that this library is way too restrictive for my needs. Specifically the Sanitation class strips out images and links which rendered the full HTML from our real estate clients completely useless. I didn't spend much time with it, but apparently I'm not alone if feeling this library is not really useful without some way to configure operation. To give you an example of what didn't work for me with the library here's a small and simple HTML fragment that includes script, img and anchor tags. I would expect the script to be stripped and everything else to be left intact. Here's the original HTML:var value = "<b>Here</b> <script>alert('hello')</script> we go. Visit the " + "<a href='http://west-wind.com'>West Wind</a> site. " + "<img src='http://west-wind.com/images/new.gif' /> " ; and the code to sanitize it with the AntiXSS Sanitize class:@Html.Raw(Microsoft.Security.Application.Sanitizer.GetSafeHtmlFragment(value)) This produced a not so useful sanitized string: Here we go. Visit the <a>West Wind</a> site. While it removed the <script> tag (good) it also removed the href from the link and the image tag altogether (bad). In some situations this might be useful, but for most tasks I doubt this is the desired behavior. While links can contain javascript: references and images can 'broadcast' information to a server, without configuration to tell the library what to restrict this becomes useless to me. I couldn't find any way to customize the white list, nor is there code available in this 'open source' library on CodePlex. Using Html Agility Pack for HTML Parsing The WPL library wasn't going to cut it. After doing a bit of research I decided the best approach for a custom solution would be to use an HTML parser and inspect the HTML fragment/document I'm trying to import. I've used the HTML Agility Pack before for a number of apps where I needed an HTML parser without requiring an instance of a full browser like the Internet Explorer Application object which is inadequate in Web apps. In case you haven't checked out the Html Agility Pack before, it's a powerful HTML parser library that you can use from your .NET code. It provides a simple, parsable HTML DOM model to full HTML documents or HTML fragments that let you walk through each of the elements in your document. If you've used the HTML or XML DOM in a browser before you'll feel right at home with the Agility Pack. Blacklist based HTML Parsing to strip XSS Code For my purposes of HTML sanitation, the process involved is to walk the HTML document one element at a time and then check each element and attribute against a blacklist. There's quite a bit of argument of what's better: A whitelist of allowed items or a blacklist of denied items. While whitelists tend to be more secure, they also require a lot more configuration. In the case of HTML5 a whitelist could be very extensive. For what I need, I only want to ensure that no JavaScript is executed, so a blacklist includes the obvious <script> tag plus any tag that allows loading of external content including <iframe>, <object>, <embed> and <link> etc. <form>  is also excluded to avoid posting content to a different location. I also disallow <head> and <meta> tags in particular for my case, since I'm only allowing posting of HTML fragments. There is also some internal logic to exclude some attributes or attributes that include references to JavaScript or CSS expressions. The default tag blacklist reflects my use case, but is customizable and can be added to. Here's my HtmlSanitizer implementation:using System.Collections.Generic; using System.IO; using System.Xml; using HtmlAgilityPack; namespace Westwind.Web.Utilities { public class HtmlSanitizer { public HashSet<string> BlackList = new HashSet<string>() { { "script" }, { "iframe" }, { "form" }, { "object" }, { "embed" }, { "link" }, { "head" }, { "meta" } }; /// <summary> /// Cleans up an HTML string and removes HTML tags in blacklist /// </summary> /// <param name="html"></param> /// <returns></returns> public static string SanitizeHtml(string html, params string[] blackList) { var sanitizer = new HtmlSanitizer(); if (blackList != null && blackList.Length > 0) { sanitizer.BlackList.Clear(); foreach (string item in blackList) sanitizer.BlackList.Add(item); } return sanitizer.Sanitize(html); } /// <summary> /// Cleans up an HTML string by removing elements /// on the blacklist and all elements that start /// with onXXX . /// </summary> /// <param name="html"></param> /// <returns></returns> public string Sanitize(string html) { var doc = new HtmlDocument(); doc.LoadHtml(html); SanitizeHtmlNode(doc.DocumentNode); //return doc.DocumentNode.WriteTo(); string output = null; // Use an XmlTextWriter to create self-closing tags using (StringWriter sw = new StringWriter()) { XmlWriter writer = new XmlTextWriter(sw); doc.DocumentNode.WriteTo(writer); output = sw.ToString(); // strip off XML doc header if (!string.IsNullOrEmpty(output)) { int at = output.IndexOf("?>"); output = output.Substring(at + 2); } writer.Close(); } doc = null; return output; } private void SanitizeHtmlNode(HtmlNode node) { if (node.NodeType == HtmlNodeType.Element) { // check for blacklist items and remove if (BlackList.Contains(node.Name)) { node.Remove(); return; } // remove CSS Expressions and embedded script links if (node.Name == "style") { if (string.IsNullOrEmpty(node.InnerText)) { if (node.InnerHtml.Contains("expression") || node.InnerHtml.Contains("javascript:")) node.ParentNode.RemoveChild(node); } } // remove script attributes if (node.HasAttributes) { for (int i = node.Attributes.Count - 1; i >= 0; i--) { HtmlAttribute currentAttribute = node.Attributes[i]; var attr = currentAttribute.Name.ToLower(); var val = currentAttribute.Value.ToLower(); span style="background: white; color: green">// remove event handlers if (attr.StartsWith("on")) node.Attributes.Remove(currentAttribute); // remove script links else if ( //(attr == "href" || attr== "src" || attr == "dynsrc" || attr == "lowsrc") && val != null && val.Contains("javascript:")) node.Attributes.Remove(currentAttribute); // Remove CSS Expressions else if (attr == "style" && val != null && val.Contains("expression") || val.Contains("javascript:") || val.Contains("vbscript:")) node.Attributes.Remove(currentAttribute); } } } // Look through child nodes recursively if (node.HasChildNodes) { for (int i = node.ChildNodes.Count - 1; i >= 0; i--) { SanitizeHtmlNode(node.ChildNodes[i]); } } } } } Please note: Use this as a starting point only for your own parsing and review the code for your specific use case! If your needs are less lenient than mine were you can you can make this much stricter by not allowing src and href attributes or CSS links if your HTML doesn't allow it. You can also check links for external URLs and disallow those - lots of options.  The code is simple enough to make it easy to extend to fit your use cases more specifically. It's also quite easy to make this code work using a WhiteList approach if you want to go that route. The code above is semi-generic for allowing full featured HTML fragments that only disallow script related content. The Sanitize method walks through each node of the document and then recursively drills into all of its children until the entire document has been traversed. Note that the code here uses an XmlTextWriter to write output - this is done to preserve XHTML style self-closing tags which are otherwise left as non-self-closing tags. The sanitizer code scans for blacklist elements and removes those elements not allowed. Note that the blacklist is configurable either in the instance class as a property or in the static method via the string parameter list. Additionally the code goes through each element's attributes and looks for a host of rules gleaned from some of the XSS cheat sheets listed at the end of the post. Clearly there are a lot more XSS vulnerabilities, but a lot of them apply to ancient browsers (IE6 and versions of Netscape) - many of these glaring holes (like CSS expressions - WTF IE?) have been removed in modern browsers. What a Pain To be honest this is NOT a piece of code that I wanted to write. I think building anything related to XSS is better left to people who have far more knowledge of the topic than I do. Unfortunately, I was unable to find a tool that worked even closely for me, or even provided a working base. For the project I was working on I had no choice and I'm sharing the code here merely as a base line to start with and potentially expand on for specific needs. It's sad that Microsoft Web Protection Library is currently such a train wreck - this is really something that should come from Microsoft as the systems vendor or possibly a third party that provides security tools. Luckily for my application we are dealing with a authenticated and validated users so the user base is fairly well known, and relatively small - this is not a wide open Internet application that's directly public facing. As I mentioned earlier in the post, if I had my way I would simply not allow this type of raw HTML input in the first place, and instead rely on a more controlled HTML input mechanism like MarkDown or even a good HTML Edit control that can provide some limits on what types of input are allowed. Alas in this case I was overridden and we had to go forward and allow *any* raw HTML posted. Sometimes I really feel sad that it's come this far - how many good applications and tools have been thwarted by fear of XSS (or worse) attacks? So many things that could be done *if* we had a more secure browser experience and didn't have to deal with every little script twerp trying to hack into Web pages and obscure browser bugs. So much time wasted building secure apps, so much time wasted by others trying to hack apps… We're a funny species - no other species manages to waste as much time, effort and resources as we humans do :-) Resources Code on GitHub Html Agility Pack XSS Cheat Sheet XSS Prevention Cheat Sheet Microsoft Web Protection Library (AntiXss) StackOverflow Links: http://stackoverflow.com/questions/341872/html-sanitizer-for-net http://blog.stackoverflow.com/2008/06/safe-html-and-xss/ http://code.google.com/p/subsonicforums/source/browse/trunk/SubSonic.Forums.Data/HtmlScrubber.cs?r=61© Rick Strahl, West Wind Technologies, 2005-2012Posted in Security  HTML  ASP.NET  JavaScript   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Use IIS Application Initialization for keeping ASP.NET Apps alive

    - by Rick Strahl
    I've been working quite a bit with Windows Services in the recent months, and well, it turns out that Windows Services are quite a bear to debug, deploy, update and maintain. The process of getting services set up,  debugged and updated is a major chore that has to be extensively documented and or automated specifically. On most projects when a service is built, people end up scrambling for the right 'process' to use for administration. Web app deployment and maintenance on the other hand are common and well understood today, as we are constantly dealing with Web apps. There's plenty of infrastructure and tooling built into Web Tools like Visual Studio to facilitate the process. By comparison Windows Services or anything self-hosted for that matter seems convoluted.In fact, in a recent blog post I mentioned that on a recent project I'd been using self-hosting for SignalR inside of a Windows service, because the application is in fact a 'service' that also needs to send out lots of messages via SignalR. But the reality is that it could just as well be an IIS application with a service component that runs in the background. Either way you look at it, it's either a Windows Service with a built in Web Server, or an IIS application running a Service application, neither of which follows the standard Service or Web App template.Personally I much prefer Web applications. Running inside of IIS I get all the benefits of the IIS platform including service lifetime management (crash and restart), controlled shutdowns, the whole security infrastructure including easy certificate support, hot-swapping of code and the the ability to publish directly to IIS from within Visual Studio with ease.Because of these benefits we set out to move from the self hosted service into an ASP.NET Web app instead.The Missing Link for ASP.NET as a Service: Auto-LoadingI've had moments in the past where I wanted to run a 'service like' application in ASP.NET because when you think about it, it's so much easier to control a Web application remotely. Services are locked into start/stop operations, but if you host inside of a Web app you can write your own ticket and control it from anywhere. In fact nearly 10 years ago I built a background scheduling application that ran inside of ASP.NET and it worked great and it's still running doing its job today.The tricky part for running an app as a service inside of IIS then and now, is how to get IIS and ASP.NET launched so your 'service' stays alive even after an Application Pool reset. 7 years ago I faked it by using a web monitor (my own West Wind Web Monitor app) I was running anyway to monitor my various web sites for uptime, and having the monitor ping my 'service' every 20 seconds to effectively keep ASP.NET alive or fire it back up after a reload. I used a simple scheduler class that also includes some logic for 'self-reloading'. Hacky for sure, but it worked reliably.Luckily today it's much easier and more integrated to get IIS to launch ASP.NET as soon as an Application Pool is started by using the Application Initialization Module. The Application Initialization Module basically allows you to turn on Preloading on the Application Pool and the Site/IIS App, which essentially fires a request through the IIS pipeline as soon as the Application Pool has been launched. This means that effectively your ASP.NET app becomes active immediately, Application_Start is fired making sure your app stays up and running at all times. All the other features like Application Pool recycling and auto-shutdown after idle time still work, but IIS will then always immediately re-launch the application.Getting started with Application InitializationAs of IIS 8 Application Initialization is part of the IIS feature set. For IIS 7 and 7.5 there's a separate download available via Web Platform Installer. Using IIS 8 Application Initialization is an optional install component in Windows or the Windows Server Role Manager: This is an optional component so make sure you explicitly select it.IIS Configuration for Application InitializationInitialization needs to be applied on the Application Pool as well as the IIS Application level. As of IIS 8 these settings can be made through the IIS Administration console.Start with the Application Pool:Here you need to set both the Start Automatically which is always set, and the StartMode which should be set to AlwaysRunning. Both have to be set - the Start Automatically flag is set true by default and controls the starting of the application pool itself while Always Running flag is required in order to launch the application. Without the latter flag set the site settings have no effect.Now on the Site/Application level you can specify whether the site should pre load: Set the Preload Enabled flag to true.At this point ASP.NET apps should auto-load. This is all that's needed to pre-load the site if all you want is to get your site launched automatically.If you want a little more control over the load process you can add a few more settings to your web.config file that allow you to show a static page while the App is starting up. This can be useful if startup is really slow, so rather than displaying blank screen while the user is fiddling their thumbs you can display a static HTML page instead: <system.webServer> <applicationInitialization remapManagedRequestsTo="Startup.htm" skipManagedModules="true"> <add initializationPage="ping.ashx" /> </applicationInitialization> </system.webServer>This allows you to specify a page to execute in a dry run. IIS basically fakes request and pushes it directly into the IIS pipeline without hitting the network. You specify a page and IIS will fake a request to that page in this case ping.ashx which just returns a simple OK string - ie. a fast pipeline request. This request is run immediately after Application Pool restart, and while this request is running and your app is warming up, IIS can display an alternate static page - Startup.htm above. So instead of showing users an empty loading page when clicking a link on your site you can optionally show some sort of static status page that says, "we'll be right back".  I'm not sure if that's such a brilliant idea since this can be pretty disruptive in some cases. Personally I think I prefer letting people wait, but at least get the response they were supposed to get back rather than a random page. But it's there if you need it.Note that the web.config stuff is optional. If you don't provide it IIS hits the default site link (/) and even if there's no matching request at the end of that request it'll still fire the request through the IIS pipeline. Ideally though you want to make sure that an ASP.NET endpoint is hit either with your default page, or by specify the initializationPage to ensure ASP.NET actually gets hit since it's possible for IIS fire unmanaged requests only for static pages (depending how your pipeline is configured).What about AppDomain Restarts?In addition to full Worker Process recycles at the IIS level, ASP.NET also has to deal with AppDomain shutdowns which can occur for a variety of reasons:Files are updated in the BIN folderWeb Deploy to your siteweb.config is changedHard application crashThese operations don't cause the worker process to restart, but they do cause ASP.NET to unload the current AppDomain and start up a new one. Because the features above only apply to Application Pool restarts, AppDomain restarts could also cause your 'ASP.NET service' to stop processing in the background.In order to keep the app running on AppDomain recycles, you can resort to a simple ping in the Application_End event:protected void Application_End() { var client = new WebClient(); var url = App.AdminConfiguration.MonitorHostUrl + "ping.aspx"; client.DownloadString(url); Trace.WriteLine("Application Shut Down Ping: " + url); }which fires any ASP.NET url to the current site at the very end of the pipeline shutdown which in turn ensures that the site immediately starts back up.Manual Configuration in ApplicationHost.configThe above UI corresponds to the following ApplicationHost.config settings. If you're using IIS 7, there's no UI for these flags so you'll have to manually edit them.When you install the Application Initialization component into IIS it should auto-configure the module into ApplicationHost.config. Unfortunately for me, with Mr. Murphy in his best form for me, the module registration did not occur and I had to manually add it.<globalModules> <add name="ApplicationInitializationModule" image="%windir%\System32\inetsrv\warmup.dll" /> </globalModules>Most likely you won't need ever need to add this, but if things are not working it's worth to check if the module is actually registered.Next you need to configure the ApplicationPool and the Web site. The following are the two relevant entries in ApplicationHost.config.<system.applicationHost> <applicationPools> <add name="West Wind West Wind Web Connection" autoStart="true" startMode="AlwaysRunning" managedRuntimeVersion="v4.0" managedPipelineMode="Integrated"> <processModel identityType="LocalSystem" setProfileEnvironment="true" /> </add> </applicationPools> <sites> <site name="Default Web Site" id="1"> <application path="/MPress.Workflow.WebQueueMessageManager" applicationPool="West Wind West Wind Web Connection" preloadEnabled="true"> <virtualDirectory path="/" physicalPath="C:\Clients\…" /> </application> </site> </sites> </system.applicationHost>On the Application Pool make sure to set the autoStart and startMode flags to true and AlwaysRunning respectively. On the site make sure to set the preloadEnabled flag to true.And that's all you should need. You can still set the web.config settings described above as well.ASP.NET as a Service?In the particular application I'm working on currently, we have a queue manager that runs as standalone service that polls a database queue and picks out jobs and processes them on several threads. The service can spin up any number of threads and keep these threads alive in the background while IIS is running doing its own thing. These threads are newly created threads, so they sit completely outside of the IIS thread pool. In order for this service to work all it needs is a long running reference that keeps it alive for the life time of the application.In this particular app there are two components that run in the background on their own threads: A scheduler that runs various scheduled tasks and handles things like picking up emails to send out outside of IIS's scope and the QueueManager. Here's what this looks like in global.asax:public class Global : System.Web.HttpApplication { private static ApplicationScheduler scheduler; private static ServiceLauncher launcher; protected void Application_Start(object sender, EventArgs e) { // Pings the service and ensures it stays alive scheduler = new ApplicationScheduler() { CheckFrequency = 600000 }; scheduler.Start(); launcher = new ServiceLauncher(); launcher.Start(); // register so shutdown is controlled HostingEnvironment.RegisterObject(launcher); }}By keeping these objects around as static instances that are set only once on startup, they survive the lifetime of the application. The code in these classes is essentially unchanged from the Windows Service code except that I could remove the various overrides required for the Windows Service interface (OnStart,OnStop,OnResume etc.). Otherwise the behavior and operation is very similar.In this application ASP.NET serves two purposes: It acts as the host for SignalR and provides the administration interface which allows remote management of the 'service'. I can start and stop the service remotely by shutting down the ApplicationScheduler very easily. I can also very easily feed stats from the queue out directly via a couple of Web requests or (as we do now) through the SignalR service.Registering a Background Object with ASP.NETNotice also the use of the HostingEnvironment.RegisterObject(). This function registers an object with ASP.NET to let it know that it's a background task that should be notified if the AppDomain shuts down. RegisterObject() requires an interface with a Stop() method that's fired and allows your code to respond to a shutdown request. Here's what the IRegisteredObject::Stop() method looks like on the launcher:public void Stop(bool immediate = false) { LogManager.Current.LogInfo("QueueManager Controller Stopped."); Controller.StopProcessing(); Controller.Dispose(); Thread.Sleep(1500); // give background threads some time HostingEnvironment.UnregisterObject(this); }Implementing IRegisterObject should help with reliability on AppDomain shutdowns. Thanks to Justin Van Patten for pointing this out to me on Twitter.RegisterObject() is not required but I would highly recommend implementing it on whatever object controls your background processing to all clean shutdowns when the AppDomain shuts down.Testing it outI'm still in the testing phase with this particular service to see if there are any side effects. But so far it doesn't look like it. With about 50 lines of code I was able to replace the Windows service startup to Web start up - everything else just worked as is. An honorable mention goes to SignalR 2.0's oWin hosting, because with the new oWin based hosting no code changes at all were required, merely a couple of configuration file settings and an assembly directive needed, to point at the SignalR startup class. Sweet!It also seems like SignalR is noticeably faster running inside of IIS compared to self-host. Startup feels faster because of the preload.Starting and Stopping the 'Service'Because the application is running as a Web Server, it's easy to have a Web interface for starting and stopping the services running inside of the service. For our queue manager the SignalR service and front monitoring app has a play and stop button for toggling the queue.If you want more administrative control and have it work more like a Windows Service you can also stop the application pool explicitly from the command line which would be equivalent to stopping and restarting a service.To start and stop from the command line you can use the IIS appCmd tool. To stop:> %windir%\system32\inetsrv\appcmd stop apppool /apppool.name:"Weblog"and to start> %windir%\system32\inetsrv\appcmd start apppool /apppool.name:"Weblog"Note that when you explicitly force the AppPool to stop running either in the UI (on the ApplicationPools page use Start/Stop) or via command line tools, the application pool will not auto-restart immediately. You have to manually start it back up.What's not to like?There are certainly a lot of benefits to running a background service in IIS, but… ASP.NET applications do have more overhead in terms of memory footprint and startup time is a little slower, but generally for server applications this is not a big deal. If the application is stable the service should fire up and stay running indefinitely. A lot of times this kind of service interface can simply be attached to an existing Web application, or if scalability requires be offloaded to its own Web server.Easier to work withBut the ultimate benefit here is that it's much easier to work with a Web app as opposed to a service. While developing I can simply turn off the auto-launch features and launch the service on demand through IIS simply by hitting a page on the site. If I want to shut down an IISRESET -stop will shut down the service easily enough. I can then attach a debugger anywhere I want and this works like any other ASP.NET application. Yes you end up on a background thread for debugging but Visual Studio handles that just fine and if you stay on a single thread this is no different than debugging any other code.SummaryUsing ASP.NET to run background service operations is probably not a super common scenario, but it probably should be something that is considered carefully when building services. Many applications have service like features and with the auto-start functionality of the Application Initialization module, it's easy to build this functionality into ASP.NET. Especially when combined with the notification features of SignalR it becomes very, very easy to create rich services that can also communicate their status easily to the outside world.Whether it's existing applications that need some background processing for scheduling related tasks, or whether you just create a separate site altogether just to host your service it's easy to do and you can leverage the same tool chain you're already using for other Web projects. If you have lots of service projects it's worth considering… give it some thought…© Rick Strahl, West Wind Technologies, 2005-2013Posted in ASP.NET  SignalR  IIS   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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