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• Raid 1 array won't assemble after power outage. How do I fix this ext4 mirror?

  - by Forkrul Assail

  Two ext4 drives on Raid 1 with mdadm won't reassemble after the power went out for an extended period (UPS drained). After turning the machine back on, mdadm said that the array was degraded, after which it took about 2 days for a full resync, which completed without problems. On trying to remount the array I get: mount: you must specify the filesystem type cat /etc/fstab lines relevant to setup: /dev/md127 /media/mediapool ext4 defaults 0 0 dmesg | tail (on trying to mount) says: [ 1050.818782] EXT3-fs (md127): error: can't find ext3 filesystem on dev md127. [ 1050.849214] EXT4-fs (md127): VFS: Can't find ext4 filesystem [ 1050.944781] FAT-fs (md127): invalid media value (0x00) [ 1050.944782] FAT-fs (md127): Can't find a valid FAT filesystem [ 1058.272787] EXT2-fs (md127): error: can't find an ext2 filesystem on dev md127. cat /proc/mdstat says: Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md127 : active (auto-read-only) raid1 sdj[2] sdi[0] 2930135360 blocks super 1.2 [2/2] [UU] unused devices: <none> fsck /dev/md127 says: fsck from util-linux 2.20.1 e2fsck 1.42 (29-Nov-2011) fsck.ext2: Superblock invalid, trying backup blocks... fsck.ext2: Bad magic number in super-block while trying to open /dev/md127 The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 <device> mdadm -E /dev/sdi gives me: /dev/sdi: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 37ac1824:eb8a21f6:bd5afd6d:96da6394 Name : sojourn:33 Creation Time : Sat Nov 10 10:43:52 2012 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 5860271016 (2794.40 GiB 3000.46 GB) Array Size : 2930135360 (2794.39 GiB 3000.46 GB) Used Dev Size : 5860270720 (2794.39 GiB 3000.46 GB) Data Offset : 262144 sectors Super Offset : 8 sectors State : clean Device UUID : 3e6e9a4f:6c07ab3d:22d47fce:13cecfd0 Update Time : Tue Nov 13 20:34:18 2012 Checksum : f7d10db9 - correct Events : 27 Device Role : Active device 0 Array State : AA ('A' == active, '.' == missing) boot@boot ~ $ sudo mdadm -E /dev/sdj /dev/sdj: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 37ac1824:eb8a21f6:bd5afd6d:96da6394 Name : sojourn:33 Creation Time : Sat Nov 10 10:43:52 2012 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 5860271016 (2794.40 GiB 3000.46 GB) Array Size : 2930135360 (2794.39 GiB 3000.46 GB) Used Dev Size : 5860270720 (2794.39 GiB 3000.46 GB) Data Offset : 262144 sectors Super Offset : 8 sectors State : clean Device UUID : 7fb84af4:e9295f7b:ede61f27:bec0cb57 Update Time : Tue Nov 13 20:34:18 2012 Checksum : b9d17fef - correct Events : 27 Device Role : Active device 1 Array State : AA ('A' == active, '.' == missing) machine@user ~ dmesg | tail [ 61.785866] init: alsa-restore main process (2736) terminated with status 99 [ 68.433548] eth0: no IPv6 routers present [ 534.142511] EXT4-fs (sdi): ext4_check_descriptors: Block bitmap for group 0 not in group (block 2838187772)! [ 534.142518] EXT4-fs (sdi): group descriptors corrupted! [ 546.418780] EXT2-fs (sdi): error: couldn't mount because of unsupported optional features (240) [ 549.654127] EXT3-fs (sdi): error: couldn't mount because of unsupported optional features (240) Since this is Raid 1 it was suggested that I try and mount or fsck the drives separately. After a long fsck on one drive, it ended with this as tail: Illegal double indirect block (2298566437) in inode 39717736. CLEARED. Illegal block #4231180 (2611866932) in inode 39717736. CLEARED. Error storing directory block information (inode=39717736, block=0, num=1092368): Memory allocation failed Recreate journal? yes Creating journal (32768 blocks): Done. *** journal has been re-created - filesystem is now ext3 again *** The drive however still doesn't want to mount: dmesg | tail [ 170.674659] md: export_rdev(sdc) [ 170.675152] md: export_rdev(sdc) [ 195.275288] md: export_rdev(sdc) [ 195.275876] md: export_rdev(sdc) [ 1338.540092] CE: hpet increased min_delta_ns to 30169 nsec [26125.734105] EXT4-fs (sdc): ext4_check_descriptors: Checksum for group 0 failed (43502!=37987) [26125.734115] EXT4-fs (sdc): group descriptors corrupted! [26182.325371] EXT3-fs (sdc): error: couldn't mount because of unsupported optional features (240) [27083.316519] EXT4-fs (sdc): ext4_check_descriptors: Checksum for group 0 failed (43502!=37987) [27083.316530] EXT4-fs (sdc): group descriptors corrupted! Please help me fix this. I never in my wildest nightmares thought a complete mirror would die this badly. Am I missing something? Suggestions on fixing this? Could someone explain why it would resync after the powerout, only to seemingly nuke the drive? Thanks for reading. Any help much appreciated. I've tried everything I can think of, including booting and filesystem checking with SystemRescue and Ubuntu liveboot discs.

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• Foo f = Foo(); // no matching function for call to 'Foo::Foo(Foo)' ... huh?!

  - by Kyle

  class Foo { public: explicit Foo() {} explicit Foo(Foo&) {} }; Foo d = Foo(); error: no matching function for call to 'Foo::Foo(Foo)' I tried changing Foo(Foo&) to Foo(Foo) as the error suggests, which AFAIK is not a valid constructor, and sure enough I get: error: invalid constructor; you probably meant ‘Foo (const Foo&)’ What gives? How do I resolve this? (This is on GCC by the way)

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• How To? Use an Expression Tree to call a Generic Method when the Type is only known at runtime.

  - by David Williams

  Please bear with me; I am very new to expression trees and lambda expressions, but trying to learn. This is something that I solved using reflection, but would like to see how to do it using expression trees. I have a generic function: private void DoSomeThing<T>( param object[] args ) { // Some work is done here. } that I need to call from else where in my class. Now, normally, this would be be simple: DoSomeThing<int>( blah ); but only if I know, at design time that I am working with an int. When I do not know the type until runtime is where I need the help. Like I said, I know how to do it via reflection, but I would like to do it via expression trees, as my (very limited) understanding is that I can do so. Any suggestions or points to sites where I can get this understanding, preferably with sample code?

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• With XSLT, how can I use this if-test with an array, when search element is returned by a template call inside the for loop?

  - by codesforcoffee

  I think this simple example might ask the question a lot more clearly. I have an input file with multiple products. There are 10 types of product (2 product IDs is fine enough for this example), but the input will have 200 products, and I only want to output the info for the first product of each type. (Output info for the lowest priced one, so the first one will be the lowest price because I sort by Price first.) So I want to read in each product, but only output the product's info if I haven't already output a product with that same ID. I couldn't figure out how to get the processID template to return a value that I need to do my if-check on, that uses parameters from inside the for-each Product loop -then properly close the if tag in the right place so it won't output the open Product tag unless it passes the if test. I know the following code does not work, but it illustrates the idea and gives me a place to start: <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output method="xml" encoding="UTF-8" indent="yes" cdata-section-elements="prod_name adv_notes"/> <xsl:template match="/"> <List> <xsl:for-each select="ProductGroup"> <xsl:sort select="ActiveProducts/Product/Rate"/> <xsl:variable name="IDarray"> <xsl:for-each select="ActiveProducts/Product"> <xsl:variable name="CurrentID"> <xsl:call-template name="processID"> <xsl:with-param name="ProductCode" select="ProductCode" /> </xsl:call-template> </xsl:variable> <xsl:if test="not(contains($IDarray, $CurrentID))"> <child elem="{@elem}"> <xsl:select value-of="$CurrentID" /> </child> <Product> <xsl:attribute name="ID"> <xsl:select value-of="$CurrentID" /> </xsl:attribute> <prod_name> <xsl:value-of select="../ProductName"/> </prod_name> <rate> <xsl:value-of select="../Rate"/> </rate> </Product> </xsl:if> </xsl:for-each> </xsl:variable> </xsl:for-each> </List> </xsl:template> <xsl:template name="processID"> <xsl:param name="ProductCode"/> <xsl:choose> <xsl:when test="starts-with($ProductCode, '515')">5</xsl:when> <xsl:when test="starts-with($ProductCode, '205')">2</xsl:when> </xsl:choose> </xsl:template> Thanks so much in advance, I know some of the awesome programmers here can help! :) -Holly An input would look like this: <ProductGroup> <ActiveProducts> <Product> <ProductCode> 5155 </ProductCode> <ProductName> House </ProductName> <Rate> 3.99 </Rate> </Product> <Product> <ProductCode> 5158 </ProductCode> <ProductName> House </ProductName> <Rate> 4.99 </Rate> </Product> </ActiveProducts> </ProductGroup> <ProductGroup> <ActiveProducts> <Product> <ProductCode> 2058 </ProductCode> <ProductName> House </ProductName> <Rate> 2.99 </Rate> </Product> <Product> <ProductCode> 2055 </ProductCode> <ProductName> House </ProductName> <Rate> 7.99 </Rate> </Product> </ActiveProducts> </ProductGroup> 200 of those with different attributes. I have the translation working, just needed to add that array and if statement somehow. Output would be this for only that simple input file:

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• That Escalated Quickly

  - by Jesse Taber

  Originally posted on: http://geekswithblogs.net/GruffCode/archive/2014/05/17/that-escalated-quickly.aspxI have been working remotely out of my home for over 4 years now. All of my coworkers during that time have also worked remotely. Lots of folks have written about the challenges inherent in facilitating communication on remote teams and strategies for overcoming them. A popular theme around this topic is the notion of “escalating communication”. In this context “escalating” means taking a conversation from one mode of communication to a different, higher fidelity mode of communication. Here are the five modes of communication I use at work in order of increasing fidelity: Email – This is the “lowest fidelity” mode of communication that I use. I usually only check it a few times a day (and I’m trying to check it even less frequently than that) and I only keep items in my inbox if they represent an item I need to take action on that I haven’t tracked anywhere else. Forums / Message boards – Being a developer, I’ve gotten into the habit of having other people look over my code before it becomes part of the product I’m working on. These code reviews often happen in “real time” via screen sharing, but I also always have someone else give all of the changes another look using pull requests. A pull request takes my code and lets someone else see the changes I’ve made side-by-side with the existing code so they can see if I did anything dumb. Pull requests can facilitate a conversation about the code changes in an online-forum like style. Some teams I’ve worked on also liked using tools like Trello or Google Groups to have on-going conversations about a topic or task that was being worked on. Chat & Instant Messaging  - Chat and instant messaging are the real workhorses for communication on the remote teams I’ve been a part of. I know some teams that are co-located that also use it pretty extensively for quick messages that don’t warrant walking across the office to talk with someone but reqire more immediacy than an e-mail. For the purposes of this post I think it’s important to note that the terms “chat” and “instant messaging” might insinuate that the conversation is happening in real time, but that’s not always true. Modern chat and IM applications maintain a searchable history so people can easily see what might have been discussed while they were away from their computers. Voice, Video and Screen sharing – Everyone’s got a camera and microphone on their computers now, and there are an abundance of services that will let you use them to talk to other people who have cameras and microphones on their computers. I’m including screen sharing here as well because, in my experience, these discussions typically involve one or more people showing the other participants something that’s happening on their screen. Obviously, this mode of communication is much higher-fidelity than any of the ones listed above. Scheduled meetings are typically conducted using this mode of communication. In Person – No matter how great communication tools become, there’s no substitute for meeting with someone face-to-face. However, opportunities for this kind of communcation are few and far between when you work on a remote team. When a conversation gets escalated that usually means it moves up one or more positions on this list. A lot of people advocate jumping to #4 sooner than later. Like them, I used to believe that, if it was possible, organizing a call with voice and video was automatically better than any kind of text-based communication could be. Lately, however, I’m becoming less convinced that escalating is always the right move. Working Asynchronously Last year I attended a talk at our local code camp given by Drew Miller. Drew works at GitHub and was talking about how they use GitHub internally. Many of the folks at GitHub work remotely, so communication was one of the main themes in Drew’s talk. During the talk Drew used the phrase, “asynchronous communication” to describe their use of chat and pull request comments. That phrase stuck in my head because I hadn’t heard it before but I think it perfectly describes the way in which remote teams often need to communicate. You don’t always know when your co-workers are at their computers or what hours (if any) they are working that day. In order to work this way you need to assume that the person you’re talking to might not respond right away. You can’t always afford to wait until everyone required is online and available to join a voice call, so you need to use text-based, persistent forms of communication so that people can receive and respond to messages when they are available. Going back to my list from the beginning of this post for a second, I characterize items #1-3 as being “asynchronous” modes of communication while we could call items #4 and #5 “synchronous”. When communication gets escalated it’s almost always moving from an asynchronous mode of communication to a synchronous one. Now, to the point of this post: I’ve become increasingly reluctant to escalate from asynchronous to synchronous communication for two primary reasons: 1 – You can often find a higher fidelity way to convey your message without holding a synchronous conversation 2 - Asynchronous modes of communication are (usually) persistent and searchable. You Don’t Have to Broadcast Live Let’s start with the first reason I’ve listed. A lot of times you feel like you need to escalate to synchronous communication because you’re having difficulty describing something that you’re seeing in words. You want to provide the people you’re conversing with some audio-visual aids to help them understand the point that you’re trying to make and you think that getting on Skype and sharing your screen with them is the best way to do that. Firing up a screen sharing session does work well, but you can usually accomplish the same thing in an asynchronous manner. For example, you could take a screenshot and annotate it with some text and drawings to illustrate what it is you’re seeing. If a screenshot won’t work, taking a short screen recording while your narrate over it and posting the video to your forum or chat system along with a text-based description of what’s in the recording that can be searched for later can be a great way to effectively communicate with your team asynchronously. I Said What?!? Now for the second reason I listed: most asynchronous modes of communication provide a transcript of what was said and what decisions might have been made during the conversation. There have been many occasions where I’ve used the search feature of my team’s chat application to find a conversation that happened several weeks or months ago to remember what was decided. Unfortunately, I think the benefits associated with the persistence of communicating asynchronously often get overlooked when people decide to escalate to a in-person meeting or voice/video call. I’m becoming much more reluctant to suggest a voice or video call if I suspect that it might lead to codifying some kind of design decision because everyone involved is going to hang up the call and immediately forget what was decided. I recognize that you can record and archive these types of interactions, but without being able to search them the recordings aren’t terribly useful. When and How To Escalate I don’t mean to imply that communicating via voice/video or in person is never a good idea. I probably jump on a Skype call with a co-worker at least once a day to quickly hash something out or show them a bit of code that I’m working on. Also, meeting in person periodically is really important for remote teams. There’s no way around the fact that sometimes it’s easier to jump on a call and show someone my screen so they can see what I’m seeing. So when is it right to escalate? I think the simplest way to answer that is when the communication starts to feel painful. Everyone’s tolerance for that pain is different, but I think you need to let it hurt a little bit before jumping to synchronous communication. When you do escalate from asynchronous to synchronous communication, there are a couple of things you can do to maximize the effectiveness of the communication: Takes notes – This is huge and yet I’ve found that a lot of teams don’t do this. If you’re holding a meeting with  > 2 people you should have someone taking notes. Taking notes while participating in a meeting can be difficult but there are a few strategies to deal with this challenge that probably deserve a short post of their own. After the meeting, make sure the notes are posted to a place where all concerned parties (including those that might not have attended the meeting) can review and search them. Persist decisions made ASAP – If any decisions were made during the meeting, persist those decisions to a searchable medium as soon as possible following the conversation. All the teams I’ve worked on used a web-based system for tracking the on-going work and a backlog of work to be done in the future. I always try to make sure that all of the cards/stories/tasks/whatever in these systems always reflect the latest decisions that were made as the work was being planned and executed. If held a quick call with your team lead and decided that it wasn’t worth the effort to build real-time validation into that new UI you were working on, go and codify that decision in the story associated with that work immediately after you hang up. Even better, write it up in the story while you are both still on the phone. That way when the folks from your QA team pick up the story to test a few days later they’ll know why the real-time validation isn’t there without having to invoke yet another conversation about the work. Communicating Well is Hard At this point you might be thinking that communicating asynchronously is more difficult than having a live conversation. You’re right: it is more difficult. In order to communicate effectively this way you need to very carefully think about the message that you’re trying to convey and craft it in a way that’s easy for your audience to understand. This is almost always harder than just talking through a problem in real time with someone; this is why escalating communication is such a popular idea. Why wouldn’t we want to do the thing that’s easier? Easier isn’t always better. If you and your team can get in the habit of communicating effectively in an asynchronous manner you’ll find that, over time, all of your communications get less painful because you don’t need to re-iterate previously made points over and over again. If you communicate right the first time, you often don’t need to rehash old conversations because you can go back and find the decisions that were made laid out in plain language. You’ll also find that you get better at doing things like writing useful comments in your code, creating written documentation about how the feature that you just built works, or persuading your team to do things in a certain way.

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• HTML5-MVC application using VS2010 SP1

  - by nmarun

  This is my first attempt at creating HTML5 pages. VS 2010 allows working with HTML5 now (you just need to make a small change after installing SP1). So my Razor view is now a HTML5 page. I call this application - 5Commerce – (an over-simplified) HTML5 ECommerce site. So here’s the flow of the application: home page renders user enters first and last name, chooses a product and the quantity can enter additional instructions for the order place the order user is then taken to another page showing the order details Off to the details. This is what my page looks in Google Chrome 10 beta (or later) soon after it renders. Here are some of the things to observe on this. Look a little closer and you’ll see a border around the first name textbox – this is ‘autofocus’ in action. I’ve set the autofocus attribute on this textbox. So as soon as the page loads, this control gets focus. 1: <input type="text" autofocus id="firstName" class="inputWidth" data_minlength="" 2: data_maxlength="" placeholder="first name" /> See a partially grayed out ‘last name’ text in the second textbox. This is set using a placeholder attribute (see above). It gets wiped out on-focus and improves the UI visuals in general. The quantity textbox is actually a numerical-only textbox. 1: <input type="number" id="quantity" data_mincount="" class="inputWidth" /> The last line is for additional instructions. This looks like a label but it’s content is editable. Just adding the ‘contenteditable’ attribute to the span allow the user to edit the text inside. 1: <span contenteditable id="additionalInstructions" data_texttype="" class="editableContent">select text and edit </span> All of the above is just plain HTML (no lurking javascript acting in here). Makes it real clean and simple. Going more into the HTML, I see that the _Layout.cshtml already is using some HTML5 content. I created my project before installing SP1, so that was the reason for my surprise. 1: <!DOCTYPE html> This is the doctype declaration in HTML5 and this is supported even by IE6 (just take my word on IE6 now, don’t go install it to test it, especially when MS is doing an IE6 countdown). That’s just amazing and extremely easy to read remember and talk about a few less bytes on every call! I modified the rest of my _Layout.cshtml to the below: 1: <!DOCTYPE html> 2: <html> 3: <head> 4: <title>5Commerce - HTML 5 Ecommerce site</title> 5: <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> 6: <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> 7: <script src="@Url.Content("~/Scripts/CustomScripts.js")" type="text/javascript"></script> 8: <script type="text/javascript"> 9: $(document).ready(function () { 10: WireupEvents(); 11: }); 12:</script> 13:  14: </head> 15:  16: <body role="document" class="bodybackground"> 17: <header role="heading"> 18: <h2>5Commerce - HTML 5 Ecommerce site!</h2> 19: </header> 20: <section id="mainForm"> 21: @RenderBody() 22: </section> 23: <footer id="page_footer" role="siteBaseInfo"> 24: <p>&copy; 2011 5Commerce Inc!</p> 25: </footer> 26: </body> 27: </html> I’m sure you’re seeing some of the new tags here. To give a brief intro about them: <header>, <footer>: Marks the header/footer region of a page or section. <section>: A logical grouping of content role attribute: Identifies the responsibility of an element. This attribute can be used by screen readers and can also be filtered through jQuery. SP1 also allows for some intellisense in HTML5. You see the other types of input fields – email, date, datetime, month, url and there are others as well. So once my page loads, i.e., ‘on document ready’, I’m wiring up the events following the principles of unobtrusive javascript. In the snippet below, I’m controlling the behavior of the input controls for specific events. 1: $("#productList").bind('change blur', function () { 2: IsSelectedProductValid(); 3: }); 4:  5: $("#quantity").bind('blur', function () { 6: IsQuantityValid(); 7: }); 8:  9: $("#placeOrderButton").click( 10: function () { 11: if (IsPageValid()) { 12: LoadProducts(); 13: } 14: }); This enables some client-side validation to occur before the data is sent to the server. These validation constraints are obtained through a JSON call to the WCF service and are set to the ‘data_’ attributes of the input controls. Have a look at the ‘GetValidators()’ function below: 1: function GetValidators() { 2: // the post to your webservice or page 3: $.ajax({ 4: type: "GET", //GET or POST or PUT or DELETE verb 5: url: "http://localhost:14805/OrderService.svc/GetValidators", // Location of the service 6: data: "{}", //Data sent to server 7: contentType: "application/json; charset=utf-8", // content type sent to server 8: dataType: "json", //Expected data format from server 9: processdata: true, //True or False 10: success: function (result) {//On Successfull service call 11: if (result.length > 0) { 12: for (i = 0; i < result.length; i++) { 13: if (result[i].PropertyName == "FirstName") { 14: if (result[i].MinLength > 0) { 15: $("#firstName").attr("data_minLength", result[i].MinLength); 16: } 17: if (result[i].MaxLength > 0) { 18: $("#firstName").attr("data_maxLength", result[i].MaxLength); 19: } 20: } 21: else if (result[i].PropertyName == "LastName") { 22: if (result[i].MinLength > 0) { 23: $("#lastName").attr("data_minLength", result[i].MinLength); 24: } 25: if (result[i].MaxLength > 0) { 26: $("#lastName").attr("data_maxLength", result[i].MaxLength); 27: } 28: } 29: else if (result[i].PropertyName == "Quantity") { 30: if (result[i].MinCount > 0) { 31: $("#quantity").attr("data_minCount", result[i].MinCount); 32: } 33: } 34: else if (result[i].PropertyName == "AdditionalInstructions") { 35: if (result[i].TextType.length > 0) { 36: $("#additionalInstructions").attr("data_textType", result[i].TextType); 37: } 38: } 39: } 40: } 41: }, 42: error: function (result) {// When Service call fails 43: alert('Service call failed: ' + result.status + ' ' + result.statusText); 44: } 45: }); 46:  47: //.... 48: } Just before the GetValidators() function runs and sets the validation constraints, this is what the html looks like (seen through the Dev tools of Chrome): After the function executes, you see the values in the ‘data_’  attributes. As and when we enter valid data into these fields, the error messages disappear, since the validation is bound to the blur event of the control. There you see… no error messages (well, the catch here is that once you enter THAT name, all errors disappear automatically). Clicking on ‘Place Order!’ runs the SaveOrder function. You can see the JSON for the order object that is getting constructed and passed to the WCF Service. 1: function SaveOrder() { 2: var addlInstructionsDefaultText = "select text and edit"; 3: var addlInstructions = $("span:first").text(); 4: if(addlInstructions == addlInstructionsDefaultText) 5: { 6: addlInstructions = ''; 7: } 8: var orderJson = { 9: AdditionalInstructions: addlInstructions, 10: Customer: { 11: FirstName: $("#firstName").val(), 12: LastName: $("#lastName").val() 13: }, 14: OrderedProduct: { 15: Id: $("#productList").val(), 16: Quantity: $("#quantity").val() 17: } 18: }; 19:  20: // the post to your webservice or page 21: $.ajax({ 22: type: "POST", //GET or POST or PUT or DELETE verb 23: url: "http://localhost:14805/OrderService.svc/SaveOrder", // Location of the service 24: data: JSON.stringify(orderJson), //Data sent to server 25: contentType: "application/json; charset=utf-8", // content type sent to server 26: dataType: "json", //Expected data format from server 27: processdata: false, //True or False 28: success: function (result) {//On Successfull service call 29: window.location.href = "http://localhost:14805/home/ShowOrderDetail/" + result; 30: }, 31: error: function (request, error) {// When Service call fails 32: alert('Service call failed: ' + request.status + ' ' + request.statusText); 33: } 34: }); 35: } The service saves this order into an XML file and returns the order id (a guid). On success, I redirect to the ShowOrderDetail action method passing the guid. This page will show all the details of the order. Although the back-end weightlifting is done by WCF, I did not show any of that plumbing-work as I wanted to concentrate more on the HTML5 and its associates. However, you can see it all in the source here. I do have one issue with HTML5 and this is an existing issue with HTML4 as well. If you see the snippet above where I’ve declared a textbox for first name, you’ll see the autofocus attribute just dangling by itself. It doesn’t follow the xml syntax of ‘key="value"’ allowing users to continue writing badly-formatted html even in the new version. You’ll see the same issue with the ‘contenteditable’ attribute as well. The work-around is that you can do ‘autofocus=”true”’ and it’ll work fine plus make it well-formatted. But unless the standards enforce this, there will be people (me included) who’ll get by, by just typing the bare minimum! Hoping this will get fixed in the coming version-updates. Source code here. Verdict: I think it’s time for us to embrace the new HTML5. Thank you HTML4 and Welcome HTML5.

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• Securing an ADF Application using OES11g: Part 2

  - by user12587121

  To validate the integration with OES we need a sample ADF Application that is rich enough to allow us to test securing the various ADF elements.  To achieve this we can add some items including bounded task flows to the application developed in this tutorial. A sample JDeveloper 11.1.1.6 project is available here. It depends on the Fusion Order Demo (FOD) database schema which is easily created using the FOD build scripts.In the deployment we have chosen to enable only ADF Authentication as we will delegate Authorization, mostly, to OES.The welcome page of the application with all the links exposed looks as follows: The Welcome, Browse Products, Browse Stock and System Administration links go to pages while the Supplier Registration and Update Stock are bounded task flows.  The Login link goes to a basic login page and once logged in a link is presented that goes to a logout page.  Only the Browse Products and Browse Stock pages are really connected to the database--the other pages and task flows do not really perform any operations on the database. Required Security Policies We make use of a set of test users and roles as decscribed on the welcome page of the application.  In order to exercise the different authorization possibilities we would like to enforce the following sample policies: Anonymous users can see the Login, Welcome and Supplier Registration links. They can also see the Welcome page, the Login page and follow the Supplier Registration task flow.  They can see the icon adjacent to the Login link indicating whether they have logged in or not. Authenticated users can see the Browse Product page. Only staff granted the right can see the Browse Product page cost price value returned from the database and then only if the value is below a configurable limit. Suppliers and staff can see the Browse Stock links and pages.  Customers cannot. Suppliers can see the Update Stock link but only those with the update permission are allowed to follow the task flow that it launches.  We could hide the link but leave it exposed here so we can easily demonstrate the method call activity protecting the task flow. Only staff granted the right can see the System Administration link and the System Administration page it accesses. Implementing the required policies In order to secure the application we will make use of the following techniques: EL Expressions and Java backing beans: JSF has the notion of EL expressions to reference data from backing Java classes.  We use these to control the presentation of links on the navigation page which respect the security contraints.  So a user will not see links that he is not allowed to click on into. These Java backing beans can call on to OES for an authorization decision.  Important Note: naturally we would configure the WLS domain where our ADF application is running as an OES WLS SM, which would allow us to efficiently query OES over the PEP API.  However versioning conflicts between OES 11.1.1.5 and ADF 11.1.1.6 mean that this is not possible.  Nevertheless, we can make use of the OES RESTful gateway technique from this posting in order to call into OES. You can easily create and manage backing beans in Jdeveloper as follows: Custom ADF Phase Listener: ADF extends the JSF page lifecycle flow and allows one to hook into the flow to intercept page rendering.  We use this to put a check prior to rendering any protected pages, again calling on to OES via the backing bean.  Phase listeners are configured in the adf-settings.xml file.  See the MyPageListener.java class in the project.  Here, for example,  is the code we use in the listener to check for allowed access to the sysadmin page, navigating back to the welcome page if authorization is not granted:                         if (page != null && (page.equals("/system.jspx") || page.equals("/system"))){                             System.out.println("MyPageListener: Checking Authorization for /system");                             if (getValue("#{oesBackingBean.UIAccessSysAdmin}").toString().equals("false") ){                                   System.out.println("MyPageListener: Forcing navigation away from system" +                                       "to welcome");                                 NavigationHandler nh = fc.getApplication().getNavigationHandler();                                   nh.handleNavigation(fc, null, "welcome");                               } else {                                 System.out.println("MyPageListener: access allowed");                              }                         } Method call activity: our app makes use of bounded task flows to implement the sequence of pages that update the stock or allow suppliers to self register.  ADF takes care of ensuring that a bounded task flow can be entered by only one page.  So a way to protect all those pages is to make a call to OES in the first activity and then either exit the task flow or continue depending on the authorization decision.  The method call returns a String which contains the name of the transition to effect. This is where we configure the method call activity in JDeveloper: We implement each of the policies using the above techniques as follows: Policies 1 and 2: as these policies concern the coarse grained notions of controlling access to anonymous and authenticated users we can make use of the container’s security constraints which can be defined in the web.xml file.  The allPages constraint is added automatically when we configure Authentication for the ADF application.  We have added the “anonymousss” constraint to allow access to the the required pages, task flows and icons: <security-constraint>    <web-resource-collection>      <web-resource-name>anonymousss</web-resource-name>      <url-pattern>/faces/welcome</url-pattern>      <url-pattern>/afr/*</url-pattern>      <url-pattern>/adf/*</url-pattern>      <url-pattern>/key.png</url-pattern>      <url-pattern>/faces/supplier-reg-btf/*</url-pattern>      <url-pattern>/faces/supplier_register_complete</url-pattern>    </web-resource-collection>  </security-constraint> Policy 3: we can place an EL expression on the element representing the cost price on the products.jspx page: #{oesBackingBean.dataAccessCostPrice}. This EL Expression references a method in a Java backing bean that will call on to OES for an authorization decision.  In OES we model the authorization requirement by requiring the view permission on the resource /MyADFApp/data/costprice and granting it only to the staff application role.  We recover any obligations to determine the limit.  Policy 4: is implemented by putting an EL expression on the Browse Stock link #{oesBackingBean.UIAccessBrowseStock} which checks for the view permission on the /MyADFApp/ui/stock resource. The stock.jspx page is protected by checking for the same permission in a custom phase listener—if the required permission is not satisfied then we force navigation back to the welcome page. Policy 5: the Update Stock link is protected with the same EL expression as the Browse Link: #{oesBackingBean.UIAccessBrowseStock}.  However the Update Stock link launches a bounded task flow and to protect it the first activity in the flow is a method call activity which will execute an EL expression #{oesBackingBean.isUIAccessSupplierUpdateTransition}  to check for the update permission on the /MyADFApp/ui/stock resource and either transition to the next step in the flow or terminate the flow with an authorization error. Policy 6: the System Administration link is protected with an EL Expression #{oesBackingBean.UIAccessSysAdmin} that checks for view access on the /MyADF/ui/sysadmin resource.  The system page is protected in the same way at the stock page—the custom phase listener checks for the same permission that protects the link and if not satisfied we navigate back to the welcome page. Testing the Application To test the application: deploy the OES11g Admin to a WLS domain deploy the OES gateway in a another domain configured to be a WLS SM. You must ensure that the jps-config.xml file therein is configured to allow access to the identity store, otherwise the gateway will not b eable to resolve the principals for the requested users.  To do this ensure that the following elements appear in the jps-config.xml file: <serviceProvider type="IDENTITY_STORE" name="idstore.ldap.provider" class="oracle.security.jps.internal.idstore.ldap.LdapIdentityStoreProvider">             <description>LDAP-based IdentityStore Provider</description>  </serviceProvider> <serviceInstance name="idstore.ldap" provider="idstore.ldap.provider">             <property name="idstore.config.provider" value="oracle.security.jps.wls.internal.idstore.WlsLdapIdStoreConfigProvider"/>             <property name="CONNECTION_POOL_CLASS" value="oracle.security.idm.providers.stdldap.JNDIPool"/></serviceInstance> <serviceInstanceRef ref="idstore.ldap"/> download the sample application and change the URL to the gateway in the MyADFApp OESBackingBean code to point to the OES Gateway and deploy the application to an 11.1.1.6 WLS domain that has been extended with the ADF JRF files. You will need to configure the FOD database connection to point your database which contains the FOD schema. populate the OES Admin and OES Gateway WLS LDAP stores with the sample set of users and groups.  If  you have configured the WLS domains to point to the same LDAP then it would only have to be done once.  To help with this there is a directory called ldap_scripts in the sample project with ldif files for the test users and groups. start the OES Admin console and configure the required OES authorization policies for the MyADFApp application and push them to the WLS SM containing the OES Gateway. Login to the MyADFApp as each of the users described on the login page to test that the security policy is correct. You will see informative logging from the OES Gateway and the ADF application to their respective WLS consoles. Congratulations, you may now login to the OES Admin console and change policies that will control the behaviour of your ADF application--change the limit value in the obligation for the cost price for example, or define Role Mapping policies to determine staff access to the system administration page based on user profile attributes. ADF Development Notes Some notes on ADF development which are probably typical gotchas: May need this on WLS startup in order to allow us to overwrite credentials for the database, the signal here is that there is an error trying to access the data base: -Djps.app.credential.overwrite.allowed=true Best to call Bounded Task flows via a CommandLink (as opposed to a go link) as you cannot seem to start them again from a go link, even having completed the task flow correctly with a return activity. Once a bounded task flow (BTF) is initated it must complete correctly  via a return activity—attempting to click on any other link whilst in the context of a  BTF has no effect.  See here for example: When using the ADF Authentication only security approach it seems to be awkward to allow anonymous access to the welcome and registration pages.  We can achieve anonymous access using the web.xml security constraint shown above (where no auth-constraint is specified) however it is not clear what needs to be listed in there….for example the /afr/* and /adf/* are in there by trial and error as sometimes the welcome page will not render if we omit those items.  I was not able to use the default allPages constraint with for example the anonymous-role or the everyone WLS group in order to be able to allow anonymous access to pages. The ADF security best practice advises placing all pages under the public_html/WEB-INF folder as then ADF will not allow any direct access to the .jspx pages but will only allow acces via a link of the form /faces/welcome rather than /faces/welcome.jspx.  This seems like a very good practice to follow as having multiple entry points to data is a source of confusion in a web application (particulary from a security point of view). In Authentication+Authorization mode only pages with a Page definition file are protected.  In order to add an emty one right click on the page and choose Go to Page Definition.  This will create an empty page definition and now the page will require explicit permission to be seen. It is advisable to give a unique context root via the weblogic.xml for the application, as otherwise the application will clash with any other application with the same context root and it will not deploy

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• Recompiling an old fortran 2/4\66 program that was compiled for os\2 need it to run in dos

  - by Mike Hansen

  I am helping an old scientist with some problems and have 1 program that he found and modified about 20 yrs. ago, and runs fine as a 32 bit os\2 executable but i need it to run under dos! I am not a programmer but a good hardware & software man, so I'am pretty stupid about this problem, but here go's I have downloaded 6 different compilers watcom77,silverfrost ftn95,gfortran,2 versions of g77 and f80. Watcom says it is to old of program,find older compiler,silverfrost opens it,debugs, etc. but is changing all the subroutines from "real" to "complex" and vice-vesa,and the g77's seem to install perfectly (library links and etc.) but wont even compile the test.f programs.My problem is 1; to recompile "as is" or "upgrade" the code? PROGRAM xconvlv INTEGER N,N2,M PARAMETER (N=2048,N2=2048,M=128) INTEGER i,isign REAL data(n),respns(m),resp(n),ans(n2),t3(n),DUMMY OPEN(UNIT=1, FILE='C:\QKBAS20\FDATA1.DAT') DO 1 i=1,N READ(1,*) T3(i), data(i), DUMMY continue CLOSE(UNIT-1) do 12 i=1,N respns(i)=data(i) resp(i)=respns(i) continue isign=-1 call convlv(data,N,resp,M,isign,ans) OPEN(UNIT=1,FILE='C:\QKBAS20\FDATA9.DAT') DO 14 i=1,N WRITE(1,*) T3(i), ans(i) continue END SUBROUTINE CONVLV(data,n,respns,m,isign,ans) INTEGER isign,m,n,NMAX REAL data(n),respns(n) COMPLEX ans(n) PARAMETER (NMAX=4096) * uses realft, twofft INTEGER i,no2 COMPLEX fft (NMAX) do 11 i=1, (m-1)/2 respns(n+1-i)=respns(m+1-i) continue do 12 i=(m+3)/2,n-(m-1)/2 respns(i)=0.0 continue call twofft (data,respns,fft,ans,n) no2=n/2 do 13 i=1,no2+1 if (isign.eq.1) then ans(i)=fft(i)*ans(i)/no2 else if (isign.eq.-1) then if (abs(ans(i)) .eq.0.0) pause ans(i)=fft(i)/ans(i)/no2 else pause 'no meaning for isign in convlv' endif continue ans(1)=cmplx(real (ans(1)),real (ans(no2+1))) call realft(ans,n,-1) return END SUBROUTINE realft(data,n,isign) INTEGER isign,n REAL data(n) * uses four1 INTEGER i,i1,i2,i3,i4,n2p3 REAL c1,c2,hli,hir,h2i,h2r,wis,wrs DOUBLE PRECISION theta,wi,wpi,wpr,wr,wtemp theta=3.141592653589793d0/dble(n/2) cl=0.5 if (isign.eq.1) then c2=-0.5 call four1(data,n/2,+1) else c2=0.5 theta=-theta endif (etc.,etc., etc.) SUBROUTINE twofft(data,data2,fft1,fft2,n) INTEGER n REAL data1(n,data2(n) COMPLEX fft1(n), fft2(n) * uses four1 INTEGER j,n2 COMPLEX h1,h2,c1,c2 c1=cmplx(0.5,0.0) c2=cmplx(0.0,-0.5) do 11 j=1,n fft1(j)=cmplx(data1(j),data2(j) continue call four1 (fft1,n,1) fft2(1)=cmplx(aimag(fft1(1)),0.0) fft1(1)=cmplx(real(fft1(1)),0.0) n2=n+2 do 12 j=2,n/2+1 h1=c1*(fft1(j)+conjg(fft1(n2-j))) h2=c2*(fft1(j)-conjg(fft1(n2-j))) fft1(j)=h1 fft1(n2-j)=conjg(h1) fft2(j)=h2 fft2(n2-j)=conjg(h2) continue return END SUBROUTINE four1(data,nn,isign) INTEGER isign,nn REAL data(2*nn) INTEGER i,istep,j,m,mmax,n REAL tempi,tempr DOUBLE PRECISION theta, wi,wpi,wpr,wr,wtemp n=2*nn j=1 do 11 i=1,n,2 if(j.gt.i)then tempr=data(j) tempi=data(j+1) (etc.,etc.,etc.,) continue mmax=istep goto 2 endif return END There are 4 subroutines with this that are about 3 pages of code and whould be much easier to e-mail to someone if their able to help me with this.My e-mail is [email protected] , or if someone could tell me where to get a "working" compiler that could recompile this? THANK-YOU, THANK-YOU,and THANK-YOU for any help with this! The errors Iam getting are; 1.In a call to CONVLV from another procedure,the first argument was of a type REAL(kind=1), it is now a COMPLEX(kind=1) 2.In a call to REALFT from another procedure, ... COMPLEX(kind=1) it is now a REAL(kind=1) 3.In a call to TWOFFT from...COMPLEX(kind-1) it is now a REAL(kind=1) 4.In a previous call to FOUR1, the first argument was of a type REAL(kind=1) it is now a COMPLEX(kind=1).

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• Asserting with JustMock

  - by mehfuzh

  In this post, i will be digging in a bit deep on Mock.Assert. This is the continuation from previous post and covers up the ways you can use assert for your mock expectations. I have used another traditional sample of Talisker that has a warehouse [Collaborator] and an order class [SUT] that will call upon the warehouse to see the stock and fill it up with items. Our sample, interface of warehouse and order looks similar to : public interface IWarehouse {     bool HasInventory(string productName, int quantity);     void Remove(string productName, int quantity); }   public class Order {     public string ProductName { get; private set; }     public int Quantity { get; private set; }     public bool IsFilled { get; private set; }       public Order(string productName, int quantity)     {         this.ProductName = productName;         this.Quantity = quantity;     }       public void Fill(IWarehouse warehouse)     {         if (warehouse.HasInventory(ProductName, Quantity))         {             warehouse.Remove(ProductName, Quantity);             IsFilled = true;         }     }   }   Our first example deals with mock object assertion [my take] / assert all scenario. This will only act on the setups that has this “MustBeCalled” flag associated. To be more specific , let first consider the following test code:    var order = new Order(TALISKER, 0);    var wareHouse = Mock.Create<IWarehouse>();      Mock.Arrange(() => wareHouse.HasInventory(Arg.Any<string>(), 0)).Returns(true).MustBeCalled();    Mock.Arrange(() => wareHouse.Remove(Arg.Any<string>(), 0)).Throws(new InvalidOperationException()).MustBeCalled();    Mock.Arrange(() => wareHouse.Remove(Arg.Any<string>(), 100)).Throws(new InvalidOperationException());      //exercise    Assert.Throws<InvalidOperationException>(() => order.Fill(wareHouse));    // it will assert first and second setup.    Mock.Assert(wareHouse); Here, we have created the order object, created the mock of IWarehouse , then I setup our HasInventory and Remove calls of IWarehouse with my expected, which is called by the order.Fill internally. Now both of these setups are marked as “MustBeCalled”. There is one additional IWarehouse.Remove that is invalid and is not marked.   On line 9 ,  as we do order.Fill , the first and second setups will be invoked internally where the third one is left  un-invoked. Here, Mock.Assert will pass successfully as  both of the required ones are called as expected. But, if we marked the third one as must then it would fail with an  proper exception. Here, we can also see that I have used the same call for two different setups, this feature is called sequential mocking and will be covered later on. Moving forward, let’s say, we don’t want this must call, when we want to do it specifically with lamda. For that let’s consider the following code: //setup - data var order = new Order(TALISKER, 50); var wareHouse = Mock.Create<IWarehouse>();   Mock.Arrange(() => wareHouse.HasInventory(TALISKER, 50)).Returns(true);   //exercise order.Fill(wareHouse);   //verify state Assert.True(order.IsFilled); //verify interaction Mock.Assert(()=> wareHouse.HasInventory(TALISKER, 50));   Here, the snippet shows a case for successful order, i haven’t used “MustBeCalled” rather i used lamda specifically to assert the call that I have made, which is more justified for the cases where we exactly know the user code will behave. But, here goes a question that how we are going assert a mock call if we don’t know what item a user code may request for. In that case, we can combine the matchers with our assert calls like we do it for arrange: //setup - data  var order = new Order(TALISKER, 50);  var wareHouse = Mock.Create<IWarehouse>();    Mock.Arrange(() => wareHouse.HasInventory(TALISKER, Arg.Matches<int>( x => x <= 50))).Returns(true);    //exercise  order.Fill(wareHouse);    //verify state  Assert.True(order.IsFilled);    //verify interaction  Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), Arg.Matches<int>(x => x <= 50)));   Here, i have asserted a mock call for which i don’t know the item name,  but i know that number of items that user will request is less than 50.  This kind of expression based assertion is now possible with JustMock. We can extent this sample for properties as well, which will be covered shortly [in other posts]. In addition to just simple assertion, we can also use filters to limit to times a call has occurred or if ever occurred. Like for the first test code, we have one setup that is never invoked. For such, it is always valid to use the following assert call: Mock.Assert(() => wareHouse.Remove(Arg.Any<string>(), 100), Occurs.Never()); Or ,for warehouse.HasInventory we can do the following: Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), 0), Occurs.Once()); Or,  to be more specific, it’s even better with: Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), 0), Occurs.Exactly(1));   There are other filters  that you can apply here using AtMost, AtLeast and AtLeastOnce but I left those to the readers. You can try the above sample that is provided in the examples shipped with JustMock.Please, do check it out and feel free to ping me for any issues.   Enjoy!!

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• wss4j: - Cannot find key for alias: monit

  - by feiroox

  Hi I'm using axis1.4 and wss4j. When I define in client-config.wsdd for WSDoAllSender and WSDoAllReceiver different signaturePropFiles where I have different key stores defined with different certificates, I'm able to have different certificates for sending and receiving. But when I use the same signaturePropFiles' with the same keystore. I get this message when I try to send a message: org.apache.ws.security.components.crypto.CryptoBase -- Cannot find key for alias: [monit] in keystore of type [jks] from provider [SUN version 1.5] with size [2] and aliases: {other, monit} - Error during Signature: ; nested exception is: org.apache.ws.security.WSSecurityException: Signature creation failed; nested exception is: java.lang.Exception: Cannot find key for alias: [monit] org.apache.ws.security.WSSecurityException: Error during Signature: ; nested exception is: org.apache.ws.security.WSSecurityException: Signature creation failed; nested exception is: java.lang.Exception: Cannot find key for alias: [monit] at org.apache.ws.security.action.SignatureAction.execute(SignatureAction.java:60) at org.apache.ws.security.handler.WSHandler.doSenderAction(WSHandler.java:202) at org.apache.ws.axis.security.WSDoAllSender.invoke(WSDoAllSender.java:168) at org.apache.axis.strategies.InvocationStrategy.visit(InvocationStrategy.java:32) at org.apache.axis.SimpleChain.doVisiting(SimpleChain.java:118) at org.apache.axis.SimpleChain.invoke(SimpleChain.java:83) at org.apache.axis.client.AxisClient.invoke(AxisClient.java:127) at org.apache.axis.client.Call.invokeEngine(Call.java:2784) at org.apache.axis.client.Call.invoke(Call.java:2767) at org.apache.axis.client.Call.invoke(Call.java:2443) at org.apache.axis.client.Call.invoke(Call.java:2366) at org.apache.axis.client.Call.invoke(Call.java:1812) at cz.ing.oopf.model.wsclient.ModelWebServiceSoapBindingStub.getStatus(ModelWebServiceSoapBindingStub.java:213) at cz.ing.oopf.wsgemonitor.monitor.util.MonitorUtil.checkStatus(MonitorUtil.java:18) at cz.ing.oopf.wsgemonitor.monitor.Test02WsMonitor.runTest(Test02WsMonitor.java:23) at cz.ing.oopf.wsgemonitor.Main.main(Main.java:75) Caused by: org.apache.ws.security.WSSecurityException: Signature creation failed; nested exception is: java.lang.Exception: Cannot find key for alias: [monit] at org.apache.ws.security.message.WSSecSignature.computeSignature(WSSecSignature.java:721) at org.apache.ws.security.message.WSSecSignature.build(WSSecSignature.java:780) at org.apache.ws.security.action.SignatureAction.execute(SignatureAction.java:57) ... 15 more Caused by: java.lang.Exception: Cannot find key for alias: [monit] at org.apache.ws.security.components.crypto.CryptoBase.getPrivateKey(CryptoBase.java:214) at org.apache.ws.security.message.WSSecSignature.computeSignature(WSSecSignature.java:713) ... 17 more How to have two certificates for wss4j in the same keystore? why it cannot find my certificate there when i have two certificates in one keystore. I have the same password for both certificates regarding PWCallback (CallbackHandler) My properties file: org.apache.ws.security.crypto.provider=org.apache.ws.security.components.crypto.Merlin org.apache.ws.security.crypto.merlin.keystore.type=jks org.apache.ws.security.crypto.merlin.keystore.password=keystore org.apache.ws.security.crypto.merlin.keystore.alias=monit org.apache.ws.security.crypto.merlin.alias.password=*** org.apache.ws.security.crypto.merlin.file=key.jks My client-config.wsdd: <deployment xmlns="http://xml.apache.org/axis/wsdd/" xmlns:java="http://xml.apache.org/axis/wsdd/providers/java"> <globalConfiguration> <requestFlow> <handler name="WSSecurity" type="java:org.apache.ws.axis.security.WSDoAllSender"> <parameter name="user" value="monit"/> <parameter name="passwordCallbackClass" value="cz.ing.oopf.common.ws.PWCallback"/> <parameter name="action" value="Signature"/> <parameter name="signaturePropFile" value="monit.properties"/> <parameter name="signatureKeyIdentifier" value="DirectReference" /> <parameter name="mustUnderstand" value="0"/> </handler> <handler type="java:org.apache.axis.handlers.JWSHandler"> <parameter name="scope" value="session"/> </handler> <handler type="java:org.apache.axis.handlers.JWSHandler"> <parameter name="scope" value="request"/> <parameter name="extension" value=".jwr"/> </handler> </requestFlow> <responseFlow> <handler name="DoSecurityReceiver" type="java:org.apache.ws.axis.security.WSDoAllReceiver"> <parameter name="user" value="other"/> <parameter name="passwordCallbackClass" value="cz.ing.oopf.common.ws.PWCallback"/> <parameter name="action" value="Signature"/> <parameter name="signaturePropFile" value="other.properties"/> <parameter name="signatureKeyIdentifier" value="DirectReference" /> </handler> </responseFlow> </globalConfiguration> <transport name="http" pivot="java:org.apache.axis.transport.http.HTTPSender"> </transport> </deployment> Listing from keytool: keytool -keystore monit-key.jks -v -list Enter keystore password: Keystore type: JKS Keystore provider: SUN Your keystore contains 2 entries Alias name: other Creation date: Jul 22, 2009 Entry type: PrivateKeyEntry Certificate chain length: 1 Certificate[1]: .... Alias name: monit Creation date: Oct 19, 2009 Entry type: trustedCertEntry

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• Static and Non Static Method Intercall in Java

  - by Vishal

  I am clearing my concepts on Java. My knowledge about Java is on far begineer side, so kindly bear with me. I am trying to understand static method and non static method intercalls. I know -- Static method can call another static method simply by its name within same class. Static method can call another non staic method of same class only after creating instance of the class. Non static method can call another static method of same class simply by way of classname.methodname - No sure if this correct ? My Question is about non static method call to another non staic method of same class. In class declaration, when we declare all methods, can we call another non static method of same class from a non static class ? Please explain with example. Thank you.

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• Calling javascript from objective-c code

  - by Infinity

  Hello! I found a lots of ways to call objective-c code from javascript, but I want to call the javascript code from objective-c. Last time I submitted a HTML FORM from objective-c, and now I wan't to call a javascript method. What do you think, is there any way to call it and get the response? I am interested in any solution, but I started to think and I think I need to send a html call or something like this, but I am not sure about this because the javascript is client side code, so maybe I need to process it from my objective-c code. What do you think about this?

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• Passing events in JMS

  - by sam

  I'm new in JMS. In my program, My Problem is that , I want to pass 4 events(classes) (callEvent, agentEvent, featureEvent, eventListenerExit) from the JMSQueue Program , who i m mention below. How can I do this? // (JmsSender.java) package com.apac.control.helper; import java.util.Calendar; import javax.jms.Queue; import javax.jms.QueueConnection; import javax.jms.QueueConnectionFactory; import javax.jms.QueueSender; import javax.jms.QueueSession; import javax.jms.Session; import javax.jms.TextMessage; import javax.naming.InitialContext; import com.apac.control.api.CallData; import com.apac.control.exception.CtiException; import library.cti.CtiEventDocument; import library.cti.impl.CtiEventDocumentImpl; public final class JmsSender { private QueueConnectionFactory factory; private Queue queue; private QueueConnection connection; private QueueSession session; private QueueSender sender; private String sessionId; private String deviceId; private String centerId; private String switchId; public JmsSender(String queueJndiName, String sessionId, String deviceId, String centerId, String switchId) throws CtiException { this.sessionId = sessionId; this.deviceId = deviceId; this.centerId = centerId; this.switchId = switchId; try { InitialContext ic = new InitialContext(); factory = (QueueConnectionFactory) ic.lookup("javax/jms/QueueConnectionFactory"); queue = (Queue) ic.lookup(queueJndiName); } catch (Exception e) { throw new CtiException("CTI. Error creating JmsSender.", e); } } public String getCenterId() { return centerId; } public String getDeviceId() { return deviceId; } public String getSwitchId() { return switchId; } public void connect() throws CtiException { try { connection = factory.createQueueConnection(); } catch (Exception e) { throw new CtiException("CTI000. Error connecting to cti queue."); } } public void close() throws CtiException { try { connection.close(); } catch (Exception e) { throw new CtiException("CTI000. Error closing queue."); } } public void send(String eventType, CallData call, long seqId) throws CtiException { // prepare the message CtiEventDocument ced = this.createBaseCtiDocument(); CtiEventDocument ce = ced.getCtiEvent(); ce.setSequenceId(seqId); ce.setCallId("" + call.getCallId()); ce.setUcid(call.getUCID()); ce.setEventType(eventType); ce.setDnisNumber(call.getDnisNumber()); ce.setAniNumber(call.getAniNumber()); ce.setApplicationData(call.getApplicationData()); ce.setQueueNumber(call.getQueueNumber()); ce.setCallingNumber(call.getCallingNumber()); if (call instanceof ManualCall) { ce.setManual("yes"); } try { sendMessage(ced.toString()); } catch (Exception e) { throw new CtiException("CTI051. Error sending message.", e); } } public void send(String eventType, String agentId, String agentMode, long seqId) throws CtiException { CtiEventDocument ced = this.createBaseCtiDocument(); CtiEventDocument ce = ced.getCtiEvent(); ce.setSequenceId(seqId); ce.setEventType(eventType); ce.setAgentId(agentId); ce.setAgentMode(agentMode); try { sendMessage(ced.toString()); } catch (Exception e) { throw new CtiException("CTI051. Error sending message.", e); } } public void sendError(String errCode, String errMsg) throws CtiException { CtiEventDocument ced = this.createBaseCtiDocument(); CtiEventDocument ce = ced.getCtiEvent(); ce.setEventType("Error"); ce.setErrorCode(errCode); ce.setErrorMessage(errMsg); try { sendMessage(ced.toString()); } catch (Exception e) { throw new CtiException("CTI051. Error sending message.", e); } } private CtiEventDocument createBaseCtiDocument() { CtiEventDocument ced = CtiEventDocument.Factory.newInstance(); CtiEventDocument ce = ced.addNewCtiEvent(); ce.setSessionId(sessionId); ce.setSwitchId(switchId); ce.setCenterId(centerId); ce.setDeviceId(deviceId); ce.setTime(Calendar.getInstance()); return ced; } // Synchronization protects session, which cannot be // accessed by more than one thread. We may more than // one thread here from Cti in some cases (for example // when customer is being transfered out and hangs the call // at the same time. synchronized void sendMessage(String msg) throws Exception { session = connection.createQueueSession(true, Session.AUTO_ACKNOWLEDGE); sender = session.createSender(queue); TextMessage txtMsg = session.createTextMessage(msg); sender.send(txtMsg); sender.close(); session.commit(); } }

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• Why isn't pyinstaller making me an .exe file?

  - by Matt Miller

  I am attempting to follow this guide to make a simple Hello World script into an .exe file. I have Windows Vista with an AMD 64-bit processor I have installed Python 2.6.5 (Windows AMD64 version) I have set the PATH (if that's the right word) so that the command line recognizes Python I have installed UPX (there only seems to be a 32-bit version for Windows) and pasted a copy of upx.exe into the Python26 folder as instructed. I have installed Pywin (Windows AMD 64 Python 2.6 version) I have run Pyinstaller's Configure.py. It gives some error messages but seems to complete. I don't know if this is what's causing the problem, so the following is what it says when I run it: C:\Python26\Pyinstaller\branches\py26winConfigure.py I: read old config from C:\Python26\Pyinstaller\branches\py26win\config.dat I: computing EXE_dependencies I: Finding TCL/TK... I: Analyzing C:\Python26\DLLs_tkinter.pyd W: Cannot get binary dependencies for file: W: C:\Python26\DLLs_tkinter.pyd W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: Analyzing C:\Python26\DLLs_ctypes.pyd W: Cannot get binary dependencies for file: W: C:\Python26\DLLs_ctypes.pyd W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: Analyzing C:\Python26\DLLs\select.pyd W: Cannot get binary dependencies for file: W: C:\Python26\DLLs\select.pyd W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: Analyzing C:\Python26\DLLs\unicodedata.pyd W: Cannot get binary dependencies for file: W: C:\Python26\DLLs\unicodedata.pyd W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: Analyzing C:\Python26\DLLs\bz2.pyd W: Cannot get binary dependencies for file: W: C:\Python26\DLLs\bz2.pyd W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: Analyzing C:\Python26\python.exe I: Dependent assemblies of C:\Python26\python.exe: I: amd64_Microsoft.VC90.CRT_1fc8b3b9a1e18e3b_9.0.21022.8_none I: Searching for assembly amd64_Microsoft.VC90.CRT_1fc8b3b9a1e18e3b_9.0.21022.8_ none... I: Found manifest C:\Windows\WinSxS\Manifests\amd64_microsoft.vc90.crt_1fc8b3b9a 1e18e3b_9.0.21022.8_none_750b37ff97f4f68b.manifest I: Searching for file msvcr90.dll I: Found file C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.21 022.8_none_750b37ff97f4f68b\msvcr90.dll I: Searching for file msvcp90.dll I: Found file C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.21 022.8_none_750b37ff97f4f68b\msvcp90.dll I: Searching for file msvcm90.dll I: Found file C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.21 022.8_none_750b37ff97f4f68b\msvcm90.dll I: Adding Microsoft.VC90.CRT\Microsoft.VC90.CRT.manifest I: Adding Microsoft.VC90.CRT\msvcr90.dll I: Adding Microsoft.VC90.CRT\msvcp90.dll I: Adding Microsoft.VC90.CRT\msvcm90.dll W: Cannot get binary dependencies for file: W: C:\Python26\python.exe W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: Analyzing C:\Windows\WinSxS\Manifests\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e 3b_9.0.21022.8_none_750b37ff97f4f68b.manifest I: Analyzing C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.210 22.8_none_750b37ff97f4f68b\msvcr90.dll W: Cannot get binary dependencies for file: W: C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.21022.8_none_ 750b37ff97f4f68b\msvcr90.dll W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: Analyzing C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.210 22.8_none_750b37ff97f4f68b\msvcp90.dll W: Cannot get binary dependencies for file: W: C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.21022.8_none_ 750b37ff97f4f68b\msvcp90.dll W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: Analyzing C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.210 22.8_none_750b37ff97f4f68b\msvcm90.dll W: Cannot get binary dependencies for file: W: C:\Windows\WinSxS\amd64_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.21022.8_none_ 750b37ff97f4f68b\msvcm90.dll W: Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 608, in get Imports return _getImports_pe(pth) File "C:\Python26\Pyinstaller\branches\py26win\bindepend.py", line 275, in _ge tImports_pe importva, importsz = datadirs[1] IndexError: list index out of range I: could not find TCL/TK I: testing for Zlib... I: ... Zlib available I: Testing for ability to set icons, version resources... I: ... resource update available I: Testing for Unicode support... I: ... Unicode available I: testing for UPX... I: ...UPX available I: computing PYZ dependencies... I: done generating C:\Python26\Pyinstaller\branches\py26win\config.dat My Python script (named Hello.py) is the same as the example: #!/usr/bin/env python for i in xrange(10000): print "Hello, World!" This is my BAT file, in the same directory: set PIP=C:\Python26\Pyinstaller\branches\py26win\ python %PIP%Makespec.py --onefile --console --upx --tk Hello.py python %PIP%Build.py Hello.spec When I run Hello.bat in the command prompt several files are made, none of which are an .exe file, and the following is displayed: C:\My Filesset PIP=C:\Python26\Pyinstaller\branches\py26win\ C:\My Filespython C:\Python26\Pyinstaller\branches\py26win\Makespec.py --onefil e --console --upx --tk Hello.py wrote C:\My Files\Hello.spec now run Build.py to build the executable C:\My Filespython C:\Python26\Pyinstaller\branches\py26win\Build.py Hello.spec I: Dependent assemblies of C:\Python26\python.exe: I: amd64_Microsoft.VC90.CRT_1fc8b3b9a1e18e3b_9.0.21022.8_none Traceback (most recent call last): File "C:\Python26\Pyinstaller\branches\py26win\Build.py", line 1359, in main(args[0], configfilename=opts.configfile) File "C:\Python26\Pyinstaller\branches\py26win\Build.py", line 1337, in main build(specfile) File "C:\Python26\Pyinstaller\branches\py26win\Build.py", line 1297, in build execfile(spec) File "Hello.spec", line 3, in pathex=['C:\My Files']) File "C:\Python26\Pyinstaller\branches\py26win\Build.py", line 292, in _init _ raise ValueError, "script '%s' not found" % script ValueError: script 'C:\Python26\Pyinstaller\branches\py26win\support\useTK.py' n ot found I have limited knowledge with the command prompt, so please take baby steps with me if I need to do something there.

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• Integration with Multiple Versions of BizTalk HL7 Accelerator Schemas

  - by Paul Petrov

  Microsoft BizTalk Accelerator for HL7 comes with multiple versions of the HL7 implementation. One of the typical integration tasks is to receive one format and transmit another. For example, system A works HL7 v2.4 messages, system B with v2.3, and system C with v2.2. The system A is exchanging messages with B and C. The logical solution is to create schemas in separate namespaces for each system and assign maps on send ports. Schematic diagram of the messaging solution is shown below:   Nothing is complex about that conceptually. On the implementation level things can get nasty though because of the elaborate nature of HL7 schemas and sheer amount of message types involved. If trying to implement maps directly in BizTalk Map Editor one would quickly get buried by thousands of links between subfields of HL7 segments. Since task is repetitive because HL7 segments are reused between message types it's natural to take advantage of such modular structure and reduce amount of work through reuse. Here's where it makes sense to switch from visual map editor to old plain XSLT. The implementation is done in three steps. First, create XSL templates to map from segments of one version to another. This can be done using BizTalk Map Editor subsequently copying and modifying generated XSL code to create one xsl:template per segment. Group all segments for format mapping in one XSL file (we call it SegmentTemplates.xsl). Here's how template for the PID segment (Patient Identification) would look like this: <xsl:template name="PID"> <PID_PatientIdentification> <xsl:if test="PID_PatientIdentification/PID_1_SetIdPatientId"> <PID_1_SetIdPid> <xsl:value-of select="PID_PatientIdentification/PID_1_SetIdPatientId/text()" /> </PID_1_SetIdPid> </xsl:if> <xsl:for-each select="PID_PatientIdentification/PID_2_PatientIdExternalId"> <PID_2_PatientId> <xsl:if test="CX_0_Id"> <CX_0_Id> <xsl:value-of select="CX_0_Id/text()" /> </CX_0_Id> </xsl:if> <xsl:if test="CX_1_CheckDigit"> <CX_1_CheckDigitSt> <xsl:value-of select="CX_1_CheckDigit/text()" /> </CX_1_CheckDigitSt> </xsl:if> <xsl:if test="CX_2_CodeIdentifyingTheCheckDigitSchemeEmployed"> <CX_2_CodeIdentifyingTheCheckDigitSchemeEmployed> <xsl:value-of select="CX_2_CodeIdentifyingTheCheckDigitSchemeEmployed/text()" /> </CX_2_CodeIdentifyingTheCheckDigitSchemeEmployed> . . . // skipped for brevity This is the most tedious and time consuming part. Templates can be created for only those segments that are used in message interchange. Once this is done the rest goes much easier. The next step is to create message type specific XSL that references (imports) segment templates XSL file. Inside this file simple call segment templates in appropriate places. For example, beginning of the mapping XSL for ADT_A01 message would look like this:   <xsl:import href="SegmentTemplates_23_to_24.xslt" />  <xsl:output omit-xml-declaration="yes" method="xml" version="1.0" />   <xsl:template match="/">    <xsl:apply-templates select="s0:ADT_A01_23_GLO_DEF" />  </xsl:template>   <xsl:template match="s0:ADT_A01_23_GLO_DEF">    <ns0:ADT_A01_24_GLO_DEF>      <xsl:call-template name="EVN" />      <xsl:call-template name="PID" />      <xsl:for-each select="PD1_PatientDemographic">        <xsl:call-template name="PD1" />      </xsl:for-each>      <xsl:call-template name="PV1" />      <xsl:for-each select="PV2_PatientVisitAdditionalInformation">        <xsl:call-template name="PV2" />      </xsl:for-each> This code simply calls segment template directly for required singular elements and in for-each loop for optional/repeating elements. And lastly, create BizTalk map (btm) that references message type specific XSL. It is essentially empty map with Custom XSL Path set to appropriate XSL: In the end, you will end up with one segment templates file that is referenced by many message type specific XSL files which in turn used by BizTalk maps. Once all segment maps are created they are widely reusable and all the rest work is very simple and clean.

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• .NET Security Part 3

  - by Simon Cooper

  You write a security-related application that allows addins to be used. These addins (as dlls) can be downloaded from anywhere, and, if allowed to run full-trust, could open a security hole in your application. So you want to restrict what the addin dlls can do, using a sandboxed appdomain, as explained in my previous posts. But there needs to be an interaction between the code running in the sandbox and the code that created the sandbox, so the sandboxed code can control or react to things that happen in the controlling application. Sandboxed code needs to be able to call code outside the sandbox. Now, there are various methods of allowing cross-appdomain calls, the two main ones being .NET Remoting with MarshalByRefObject, and WCF named pipes. I’m not going to cover the details of setting up such mechanisms here, or which you should choose for your specific situation; there are plenty of blogs and tutorials covering such issues elsewhere. What I’m going to concentrate on here is the more general problem of running fully-trusted code within a sandbox, which is required in most methods of app-domain communication and control. Defining assemblies as fully-trusted In my last post, I mentioned that when you create a sandboxed appdomain, you can pass in a list of assembly strongnames that run as full-trust within the appdomain: // get the Assembly object for the assembly Assembly assemblyWithApi = ... // get the StrongName from the assembly's collection of evidence StrongName apiStrongName = assemblyWithApi.Evidence.GetHostEvidence<StrongName>(); // create the sandbox AppDomain sandbox = AppDomain.CreateDomain( "Sandbox", null, appDomainSetup, restrictedPerms, apiStrongName); Any assembly that is loaded into the sandbox with a strong name the same as one in the list of full-trust strong names is unconditionally given full-trust permissions within the sandbox, irregardless of permissions and sandbox setup. This is very powerful! You should only use this for assemblies that you trust as much as the code creating the sandbox. So now you have a class that you want the sandboxed code to call: // within assemblyWithApi public class MyApi { public static void MethodToDoThings() { ... } } // within the sandboxed dll public class UntrustedSandboxedClass { public void DodgyMethod() { ... MyApi.MethodToDoThings(); ... } } However, if you try to do this, you get quite an ugly exception: MethodAccessException: Attempt by security transparent method ‘UntrustedSandboxedClass.DodgyMethod()’ to access security critical method ‘MyApi.MethodToDoThings()’ failed. Security transparency, which I covered in my first post in the series, has entered the picture. Partially-trusted code runs at the Transparent security level, fully-trusted code runs at the Critical security level, and Transparent code cannot under any circumstances call Critical code. Security transparency and AllowPartiallyTrustedCallersAttribute So the solution is easy, right? Make MethodToDoThings SafeCritical, then the transparent code running in the sandbox can call the api: [SecuritySafeCritical] public static void MethodToDoThings() { ... } However, this doesn’t solve the problem. When you try again, exactly the same exception is thrown; MethodToDoThings is still running as Critical code. What’s going on? By default, a fully-trusted assembly always runs Critical code, irregardless of any security attributes on its types and methods. This is because it may not have been designed in a secure way when called from transparent code – as we’ll see in the next post, it is easy to open a security hole despite all the security protections .NET 4 offers. When exposing an assembly to be called from partially-trusted code, the entire assembly needs a security audit to decide what should be transparent, safe critical, or critical, and close any potential security holes. This is where AllowPartiallyTrustedCallersAttribute (APTCA) comes in. Without this attribute, fully-trusted assemblies run Critical code, and partially-trusted assemblies run Transparent code. When this attribute is applied to an assembly, it confirms that the assembly has had a full security audit, and it is safe to be called from untrusted code. All code in that assembly runs as Transparent, but SecurityCriticalAttribute and SecuritySafeCriticalAttribute can be applied to individual types and methods to make those run at the Critical or SafeCritical levels, with all the restrictions that entails. So, to allow the sandboxed assembly to call the full-trust API assembly, simply add APCTA to the API assembly: [assembly: AllowPartiallyTrustedCallers] and everything works as you expect. The sandboxed dll can call your API dll, and from there communicate with the rest of the application. Conclusion That’s the basics of running a full-trust assembly in a sandboxed appdomain, and allowing a sandboxed assembly to access it. The key is AllowPartiallyTrustedCallersAttribute, which is what lets partially-trusted code call a fully-trusted assembly. However, an assembly with APTCA applied to it means that you have run a full security audit of every type and member in the assembly. If you don’t, then you could inadvertently open a security hole. I’ll be looking at ways this can happen in my next post.

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• Subterranean IL: Constructor constraints

  - by Simon Cooper

  The constructor generic constraint is a slightly wierd one. The ECMA specification simply states that it: constrains [the type] to being a concrete reference type (i.e., not abstract) that has a public constructor taking no arguments (the default constructor), or to being a value type. There seems to be no reference within the spec to how you actually create an instance of a generic type with such a constraint. In non-generic methods, the normal way of creating an instance of a class is quite different to initializing an instance of a value type. For a reference type, you use newobj: newobj instance void IncrementableClass::.ctor() and for value types, you need to use initobj: .locals init ( valuetype IncrementableStruct s1 ) ldloca 0 initobj IncrementableStruct But, for a generic method, we need a consistent method that would work equally well for reference or value types. Activator.CreateInstance<T> To solve this problem the CLR designers could have chosen to create something similar to the constrained. prefix; if T is a value type, call initobj, and if it is a reference type, call newobj instance void !!0::.ctor(). However, this solution is much more heavyweight than constrained callvirt. The newobj call is encoded in the assembly using a simple reference to a row in a metadata table. This encoding is no longer valid for a call to !!0::.ctor(), as different constructor methods occupy different rows in the metadata tables. Furthermore, constructors aren't virtual, so we would have to somehow do a dynamic lookup to the correct method at runtime without using a MethodTable, something which is completely new to the CLR. Trying to do this in IL results in the following verification error: newobj instance void !!0::.ctor() [IL]: Error: Unable to resolve token. This is where Activator.CreateInstance<T> comes in. We can call this method to return us a new T, and make the whole issue Somebody Else's Problem. CreateInstance does all the dynamic method lookup for us, and returns us a new instance of the correct reference or value type (strangely enough, Activator.CreateInstance<T> does not itself have a .ctor constraint on its generic parameter): .method private static !!0 CreateInstance<.ctor T>() { call !!0 [mscorlib]System.Activator::CreateInstance<!!0>() ret } Going further: compiler enhancements Although this method works perfectly well for solving the problem, the C# compiler goes one step further. If you decompile the C# version of the CreateInstance method above: private static T CreateInstance() where T : new() { return new T(); } what you actually get is this (edited slightly for space & clarity): .method private static !!T CreateInstance<.ctor T>() { .locals init ( [0] !!T CS$0$0000, [1] !!T CS$0$0001 ) DetectValueType: ldloca.s 0 initobj !!T ldloc.0 box !!T brfalse.s CreateInstance CreateValueType: ldloca.s 1 initobj !!T ldloc.1 ret CreateInstance: call !!0 [mscorlib]System.Activator::CreateInstance<T>() ret } What on earth is going on here? Looking closer, it's actually quite a clever performance optimization around value types. So, lets dissect this code to see what it does. The CreateValueType and CreateInstance sections should be fairly self-explanatory; using initobj for value types, and Activator.CreateInstance for reference types. How does the DetectValueType section work? First, the stack transition for value types: ldloca.s 0 // &[!!T(uninitialized)] initobj !!T // ldloc.0 // !!T box !!T // O[!!T] brfalse.s // branch not taken When the brfalse.s is hit, the top stack entry is a non-null reference to a boxed !!T, so execution continues to to the CreateValueType section. What about when !!T is a reference type? Remember, the 'default' value of an object reference (type O) is zero, or null. ldloca.s 0 // &[!!T(null)] initobj !!T // ldloc.0 // null box !!T // null brfalse.s // branch taken Because box on a reference type is a no-op, the top of the stack at the brfalse.s is null, and so the branch to CreateInstance is taken. For reference types, Activator.CreateInstance is called which does the full dynamic lookup using reflection. For value types, a simple initobj is called, which is far faster, and also eliminates the unboxing that Activator.CreateInstance has to perform for value types. However, this is strictly a performance optimization; Activator.CreateInstance<T> works for value types as well as reference types. Next... That concludes the initial premise of the Subterranean IL series; to cover the details of generic methods and generic code in IL. I've got a few other ideas about where to go next; however, if anyone has any itching questions, suggestions, or things you've always wondered about IL, do let me know.

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• JQuery UI sortable: restore position based on some condition

  - by dafi

  I call sortable.stop() to make an ajax call to store some data after drag&drop operation. When the ajax call returns an error (application logic error or net problem) I want to move the dragged element to its original/start position, how can I achieve it? The scenario should be user drags A to B the sortable.stop() event is called, it triggers an ajax call the ajax call returns an error inside the stop() event we get the ajax error move A to its original position user again move A to B everything is ok A remains in its new position in B Steps 6-8 are shown to clarify a successive drag can be done and previous error must be forgotten

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• More Quick Interview Tips

  - by Ajarn Mark Caldwell

  In the last couple of years I have conducted a lot of interviews for application and database developers for my company, and I can tell you that the little things can mean a lot.  Here are a few quick tips to help you make a good first impression. A year ago I gave you my #1 interview tip: Do some basic research!  And a year later, I am still stunned by how few technical people do the most basic of research.  I can only guess that it is because it is so engrained in our psyche that technical competence is everything (see How to Manage Technical Employees for more on this idea) that we forget or ignore the importance of soft skills and the art of the interview.  Or maybe it is because we have heard the stories of the uber-geek who has zero personal skills but still makes a fortune working for Microsoft.  Well, here’s another quick tip:  You’re probably not as good as he is; and a large number of companies actually run small to medium sized teams and can’t really afford to have the social outcast in the group.  In a small team, everyone has to get along well, and that’s an important part of what I’m evaluating during the interview process. My #2 tip is to act alive!  I typically conduct screening interviews by phone before I bring someone in for an in-person.  I don’t care how laid-back you are or if you have a “quiet personality”, when we are talking, ACT like you are happy I called and you are interested in getting the job.  If you sound like you are bored-to-death and that you would be perfectly happy to never work again, I am perfectly happy to help you attain that goal, and I’ll move on to the next candidate. And closely related to #2, perhaps we’ll call it #2.1 is this tip:  When I call you on the phone for the interview, don’t answer your phone by just saying, “Hello”.  You know that the odds are about 999-to-1 that it is me calling for the interview because we have specifically arranged this time slot for the call.  And you can see on the caller ID that it is not one of your buddies calling, so identify yourself.  Don’t make me question whether I dialed the right number.  Answer your phone with a, “Hello, this is ___<your full name preferred, but at least your first name>___.”.  And when I say, “Hi, <your name>, this is Mark from <my company>” it would be really nice to hear you say, “Hi, Mark, I have been expecting your call.”  This sets the perfect tone for our conversation.  I know I have the right person; you are professional enough and interested enough in the job or contract to remember your appointments; and now we can move on to a little intro segment and get on with the reason for our call. As crazy as it sounds, I’ve actually had phone interviews that went like this: <Ring…> You:  “Hello?” Me:  “Hi, this is Mark from _______” You:  “Yeah?” Me:  “Is this <your name>?” You:  “Yeah.” Me:  “I had this time in my calendar for us to talk…were you expecting my call?” You:  “Oh, yeah, sure…” I used to be nice and would try to go ahead with the interview even after this bad start, thinking I was giving the candidate the benefit of the doubt…a second chance…but more often than not it was a struggle and 10 minutes into what was supposed to be a 45-minute call, I’m looking for a way to hang up without being rude myself.  It never worked out.  I never brought that person in for an in-person interview, much less offered them the job or contract.  Who knows, maybe they were some sort of wunderkind that we missed out on.  What I know is that they would never fit in with the rest of the team, and around here that is absolutely critical. So, in conclusion… Act alive!  Identify yourself!  And do at least the very basic of research.

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• "The usage of semaphores is subtly wrong"

  - by Hoonose

  This past semester I was taking an OS practicum in C, in which the first project involved making a threads package, then writing a multiple producer-consumer program to demonstrate the functionality. However, after getting grading feedback, I lost points for "The usage of semaphores is subtly wrong" and "The program assumes preemption (e.g. uses yield to change control)" (We started with a non-preemptive threads package then added preemption later. Note that the comment and example contradict each other. I believe it doesn't assume either, and would work in both environments). This has been bugging me for a long time - the course staff was kind of overwhelmed, so I couldn't ask them what's wrong with this over the semester. I've spent a long time thinking about this and I can't see the issues. If anyone could take a look and point out the error, or reassure me that there actually isn't a problem, I'd really appreciate it. I believe the syntax should be pretty standard in terms of the thread package functions (minithreads and semaphores), but let me know if anything is confusing. #include <stdio.h> #include <stdlib.h> #include "minithread.h" #include "synch.h" #define BUFFER_SIZE 16 #define MAXCOUNT 100 int buffer[BUFFER_SIZE]; int size, head, tail; int count = 1; int out = 0; int toadd = 0; int toremove = 0; semaphore_t empty; semaphore_t full; semaphore_t count_lock; // Semaphore to keep a lock on the // global variables for maintaining the counts /* Method to handle the working of a student * The ID of a student is the corresponding minithread_id */ int student(int total_burgers) { int n, i; semaphore_P(count_lock); while ((out+toremove) < arg) { n = genintrand(BUFFER_SIZE); n = (n <= total_burgers - (out + toremove)) ? n : total_burgers - (out + toremove); printf("Student %d wants to get %d burgers ...\n", minithread_id(), n); toremove += n; semaphore_V(count_lock); for (i=0; i<n; i++) { semaphore_P(empty); out = buffer[tail]; printf("Student %d is taking burger %d.\n", minithread_id(), out); tail = (tail + 1) % BUFFER_SIZE; size--; toremove--; semaphore_V(full); } semaphore_P(count_lock); } semaphore_V(count_lock); printf("Student %d is done.\n", minithread_id()); return 0; } /* Method to handle the working of a cook * The ID of a cook is the corresponding minithread_id */ int cook(int total_burgers) { int n, i; printf("Creating Cook %d\n",minithread_id()); semaphore_P(count_lock); while ((count+toadd) <= arg) { n = genintrand(BUFFER_SIZE); n = (n <= total_burgers - (count + toadd) + 1) ? n : total_burgers - (count + toadd) + 1; printf("Cook %d wants to put %d burgers into the burger stack ...\n", minithread_id(),n); toadd += n; semaphore_V(count_lock); for (i=0; i<n; i++) { semaphore_P(full); printf("Cook %d is putting burger %d into the burger stack.\n", minithread_id(), count); buffer[head] = count++; head = (head + 1) % BUFFER_SIZE; size++; toadd--; semaphore_V(empty); } semaphore_P(count_lock); } semaphore_V(count_lock); printf("Cook %d is done.\n", minithread_id()); return 0; } /* Method to create our multiple producers and consumers * and start their respective threads by fork */ void starter(int* c){ int i; for (i=0;i<c[2];i++){ minithread_fork(cook, c[0]); } for (i=0;i<c[1];i++){ minithread_fork(student, c[0]); } } /* The arguments are passed as command line parameters * argv[1] is the no of students * argv[2] is the no of cooks */ void main(int argc, char *argv[]) { int pass_args[3]; pass_args[0] = MAXCOUNT; pass_args[1] = atoi(argv[1]); pass_args[2] = atoi(argv[2]); size = head = tail = 0; empty = semaphore_create(); semaphore_initialize(empty, 0); full = semaphore_create(); semaphore_initialize(full, BUFFER_SIZE); count_lock = semaphore_create(); semaphore_initialize(count_lock, 1); minithread_system_initialize(starter, pass_args); }

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• Segmentation Fault when using "mov" in Assembly

  - by quithakay207

  I am working on a simple assembly program for a class, and am encountering an odd segmentation fault. It's a pretty simple program to convert bytes into kilobytes. However, within the function that does the conversion, I get a segmentation fault when I try to move the value 1024 into the ebx register. I've never had this kind of problem before when working with registers. Does someone know what could be causing this? I imagine it is something simple that I'm overlooking. Thank you! asm_main: enter 0,0 pusha mov eax, 0 mov ebx, 0 call read_int push eax call functionA popa mov leave ret functionA: mov eax, [esp + 4] call print_int call print_nl mov ebx, 1024 ;segmentation fault occurs here div ebx call print_int ret UPDATE: One interesting discovery is that if I delete the lines interacting with the stack, push eax and mov eax, [esp + 4], there is no longer a segmentation fault. However, I get a crazy result in eax after performing div ebx.

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• Python: re-initialize a function's default value for subsequent calls to the function.

  - by Peter Stewart

  I have a function that calls itself to increment and decrement a stack. I need to call it a number of times, and I'd like it to work the same way in subsequent calls but, as expected, it doesn't re-use the default value. I've read that this is a newbie trap and I've seen suggested solutions, but I haven't been able to make any solution work. It would be nice to be able to "fun.reset" def a(x, stack = [None]): print x,' ', stack if x > 5: temp = stack.pop() if x <=5: stack.append(1) if stack == []: return a(x + 1) print a(0) print a(2) #second call print a(3) #third call I expected this to work, but it doesn't. print a(0, [None]) print a(2, [None]) #second call print a(3, [None]) #third call Can I reset the function to it's initial state? Any help would be appreciated.

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• Transfer of control and data between C and C#

  - by Prithvi

  C# main program needs to call a C program GA.c This C code executes many functions and one function initialize() calls objective() function. But this objective function needs to be written in C#.This call is in a loop in the C code and the C code needs to continue execution after the return from objective() until its main is over and return control to C# main program. C# main() { //code call to GA in C; //remaining code; } GA in C: Ga Main() { //code call to initialize function(); //remaining code } initialize funtion() in GA { for(some condition) { //code call to objective(parameter) function in C#; //code } } How do we do this?

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• calling a function without knowing the number of parameters in advance

  - by Sourabh Bose

  suppose i have a dll with 2 functions.name of dll="dll1" f1(int a, int b, int c); f2(int a); my program would take the funtion name ,the dll name and a "list" of parameters as input. how would i call the appropriate function with its appropriate parameters. i.e, if input is dll1 f1 list(5,8,9) this would require me to call f1 with 3 parameters if input was dll1 f2 list(8) it would require me to call f2 with one parameter how would i call the function without knowing the number of parameters in advance. further clarification: how do I write code that will call any function with all its arguments by building the argument list dynamically using some other source of information

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• SQLBindParameter is working fine but SQLExecute gives error in Windows 2008 Server 64bit.

  - by rajugkgp

  Dear All, I am migrating my application from 32bit(Windows 2003 Server) to 64bit (Windows 2008 Server R2).I am getting the following while trying to execute a SQL command Encountered ODBC error -1: S1010, 0, [Microsoft][ODBC Driver Manager] Function sequence error . Basically internal function call is SQLExecute() function call. This works perfectly for Windows 2003 Server 32bit. I tried the command execute at the background from the command prompt and it is working. Any help or suggestion would be very much appreciated. I checked the squence of call.We have two consecutive SQLBindParameter function call and then we call SQLExecute. Is this sequence incorrect in case of 64bit? I also checked the return code given by SQLExecute which is 99. Any pointers or suggestions would be very helpful. The above sequence is working fine with 32bit Windows. Thanks in advance. -R

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