Search Results

Search found 13011 results on 521 pages for 'catch block'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 43/521 | < Previous Page | 39 40 41 42 43 44 45 46 47 48 49 50  | Next Page >

  • Override properties block when including a psake script in an other psake script

    - by DanceAlot
    I am new to psake and I have this issue: I have 2 psake scripts: (1): base_tasks.ps1: properties{ $a = "hello" $b = "hi" } task One{ Write-Host $a } (2): install.ps1 Include .\base_tasks.ps1 properties{ $a = "Goodbye" $b = "Adjeu" } task default -depends One Now, is it possible to override the properties and variables from file 1? I want to use file 1 as "base tasks" and use the tasks in the install.ps1 and override the properties. Or do I have to do that an other way? I will invoke install.ps1 and use my $a and $b from install.ps1. DanceAlot

    Read the article

  • Jquery Block on my document .ready function not working

    - by kumar
    Hello Friens, I have this code, I added JS Script file to my Master page. <script src="/Scripts/Jquery.blockUI.js" type="text/javascript"></script> This Below code I have in my master page.on document.ready <script type="text/javascript"> $(document).ready(function () { $.blockUI({ message: $('#question'), css: { width: '275px'} }); }); </script> <div id="question" style="display:none; cursor: default"> <h2 class="padding"><br />An unexpected system error has occurred while processing your request.<br /></h2> <h3>We apologize for this inconvenience.<br /> Please report this error to your system administrator with the following information:<br /><br /> Session id is:</h3> <input type="button" id="OK" value="OK" /> </asp:Content> On my Document.ready Function my BlockUi is not working? can any body tell me why its not working? thanks

    Read the article

  • user buffer after doing 'write' to file opened with O_DIRECT

    - by user1868481
    I'm using the O_DIRECT flag to write to the disk directly from the user buffer. But as far as I understand, Linux doesn't guarantee that after this call, the data is written. It just writes directly from the user buffer to the physical device using DMA or anything else... Therefore, I don't understand if I can write to the user buffer after the call to 'write' function. I'm sure that example code will help to understand my question: char *user_buff = malloc(...); /* assume it is aligned as needed */ fd = open(..., O_DIRECT); write(fd, ...) memset(user_buff, 0, ...) Is the last line (memset) legal? Is writing to the user buffer valid that is maybe used by DMA to transfer data to the device?

    Read the article

  • Loop each x elements

    - by Cimm
    What's the beste way to show a list with 20 images in rows of 5? Or, in other words, how do I clean up this ugly snippet? <div class="row"> <% @images.each_with_index do |image, index| %> <%= image_tag image.url %> <% if index != 0 && index % 5 == 0 %> </div><div class="row"> <% end %> <% end %> </div>

    Read the article

  • SLRequest return nil before block complete

    - by jaytr0n
    I'm having a little trouble thinking through this and deciding if it's a design flaw on my behalf or if I'm missing a piece that could make this work. Basically I'm using the new SLRequest to make a Twitter API call. After the data is returned, I'd like to put it into an object and return that object: -(AUDSlide *) getFollowerSlide { SLRequest *getRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodGET URL:[NSURL URLWithString:[NSString stringWithFormat:@"https://api.twitter.com/1.1/followers/ids.json?user_id=%@", [[self.twitterAccount valueForKey:@"properties"] valueForKey:@"user_id"]]] parameters:nil]; getRequest.account = twitterAccount; AUDSlide *slide = [[AUDSlide alloc] init]; [getRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) { if ([urlResponse statusCode] == 200) { NSError *jsonError = nil; NSDictionary *list = [NSJSONSerialization JSONObjectWithData:responseData options:0 error:&jsonError]; NSLog(@"Number of Followers: %u", [[list objectForKey:@"ids"] count]); slide.title = @"Followers"; slide.number = [NSString stringWithFormat:@"%u",[[list objectForKey:@"ids"] count]]; } else{ slide.title = @"Error"; slide.number = [NSString stringWithFormat: @"E%u", [urlResponse statusCode]]; } }]; return slide; } Of course the slide is returned before the call is complete and returns a nil object. So I'm not sure if I should try to force this into a synchronous request (that seems like it could be a bad idea) or rethink the design. Does anyone have any advice?

    Read the article

  • Common block usage in Fortran

    - by Crystal
    I'm new to Fortran and just doing some simple things for work. And as a new programmer in general, not sure exactly how this works, so excuse me if my explanation or notation is not the best. At the top of the .F file there are common declarations. The person explaining it to me said think of it like a struct in C, and that they are global. Also in that same .F file, they have it declared with what type. So it's something like: COMMON SOMEVAR INTEGER*2 SOMEVAR And then when I actually see it being used in some other file, they declare local variables, (e.g. SOMEVAR_LOCAL) and depending on the condition, they set SOMEVAR_LOCAL = 1 or 0. Then there is another conditional later down the line that will say something like IF (SOMEVAR_LOCAL. eq. 1) SOMEVAR(PARAM) = 1; (Again I apologize if this is not proper Fortran, but I don't have access to the code right now). So it seems to me that there is a "struct" like variable called SOMEVAR that is of some length (2 bytes of data?), then there is a local variable that is used as a flag so that later down the line, the global struct SOMEVAR can be set to that value. But because there is (PARAM), it's like an array for that particular instance? Thanks. Sorry for my bad explanation, but hopefully you will understand what I am asking.

    Read the article

  • If I write a framework that gets information from the Internet, should I make a degelate or use blocks?

    - by Time Machine
    Say I'm writing a publicly available framework for the Vimeo API. This framework needs to get information from the Internet. Because this can take some time, I need to use threadin to prevent the UI from hanging. Foundation uses delegates for this, like NSURLConnectionDelegate. However, Game Kit uses blocks as callback functions. What is the recommended way of doing this? I know blocks aren't supported in standard GCC versions, but they require less, much less code for the one that uses my framework. Delegates, on the other hand, are real methods and when protocols are used, I'm sure the methods are implemented. Thanks.

    Read the article

  • How does this code block works?

    - by Justin John
    I can't understand how the following code works. $start = 1; while($start<10){ if ($start&1) { echo "ODD ".$start." <br/> "; } else { echo "EVEN ".$start." <br/> "; } $start++; } The $start&1 will return ODD and EVEN seperately. Output ODD 1 EVEN 2 ODD 3 EVEN 4 ODD 5 EVEN 6 ODD 7 EVEN 8 ODD 9 If we give $start&2 instead of $start&1, it returns with another order. How &1 &2 etc... works here?

    Read the article

  • Converting Java code block to Objective-C

    - by user1123688
    I am trying to convert my Android app to iOS. This will be my first iOS app. I can't seem to translate this code properly. If someone wouldn't mind showing me how its done, that would be greatly appreciated. //scrambBase20 is a Byte array String descramble(String input){ char[] ret; ret = input.toCharArray(); int offset = -scrambBase20.length; for(int i=0;i<input.length();i++){ if(i%scrambBase20.length==0) offset+=scrambBase20.length; ret[scrambBase20[i%scrambBase20.length]+offset]=(char) ((byte) (input.charAt(i))^0x45); } String realRet = ""; for (char x : ret){ realRet+=x; } realRet = realRet.trim(); return realRet; }

    Read the article

  • Chalk Talk, Glenn Block &ndash; Leith, Edinburgh 12th March 2011

    - by David Christiansen
    Exciting news. I am proud to announce that Glenn Block from Microsoft  will be coming all the way from Seattle to Scotland on the 12th March to talk to you!. Glenn is a PM on the WCF team working on Microsoft’s future HTTP and REST stack and has been involved in some pretty exciting and ground-breaking Microsoft development mind-shifts in recent times. Don’t miss the chance to hear him speak and ask him questions. Brief history of Glenn Prior to WCF he was a PM on the new Managed Extensibility Framework in .NET 4.0. Glenn has a breadth of experience both inside and outside Microsoft developing software solutions for ISVs and the enterprise. Glenn has also been very active in involving folks from the community in the development of software at Microsoft. This has included shipping several products under open source licenses, as well as assisting other teams looking to do so. Glenn is also a frequent speaker at local and international events and user groups.  When he's not working and playing with technology, he spends his time with his wife and daughter either at their home in Seattle or at one of the local coffee shops. Glenn Block on the web mvcConf 2 - Glenn Block: Take some REST with WCF (Feb 2011) @gblock on twitter My Technobabble - Glenn’s Blog Sponsored by Storm ID is an award winning full service digital agency in Edinburgh

    Read the article

  • Is there a command-line utility app which can find a specific block of lines in a text file, and replace it?

    - by fred.bear
    UPDATE (see end of question) The text "search and replace" utility programs I've seen, seem to only search on a line-by-line basis... Is there a command-line tool which can locate one block of lines (in a text file), and replace it with another block of lines.? For example: Does the test file file contain this exact group of lines: 'Twas brillig, and the slithy toves Did gyre and gimble in the wabe: All mimsy were the borogoves, And the mome raths outgrabe. 'Beware the Jabberwock, my son! The jaws that bite, the claws that catch! Beware the Jubjub bird, and shun The frumious Bandersnatch!' I want this, so that I can replace multiple lines of text in a file and know I'm not overwriting the wrong lines. I would never replace "The Jabberwocky" (Lewis Carroll), but it makes a novel example :) UPDATE: ..(sub-update) My following comment about reasons when not use sed are only in the context of; don't push any tool too far beyond its design intent (I use sed quite often, and consider it to be invaluable.) I just now found an interesting web page about sed and when not to use it. So, because of all the sed answers, I"ll post the link.. it is part of the sed FAQ on sourceforge Also, I'm pretty sure there is some way diff can do the job of locating the block of text (once it's located, the replacement is quite straight foward; using head and tail) ... 'diff' dumps all the necessary data, but I haven't yet worked out how to filter it , ... (I'm still working on it)

    Read the article

  • How To Initialize Object Which May Be Used In Catch Clause?

    - by Onorio Catenacci
    I've seen this sort of pattern in code before: //pseudo C# code var exInfo = null; //Line A try { var p = SomeProperty; //Line B exInfo = new ExceptionMessage("The property was " + p); //Line C } catch(Exception ex) { exInfo.SomeOtherProperty = SomeOtherValue; //Line D } Usually the code is structured in this fashion because exInfo has to be visible outside of the try clause. The problem is that if an exception occurs on Line B, then exInfo will be null at Line D. The issue arises when something happens on Line B that must occur before exInfo is constructed. But if I set exInfo to a new Object at line A then memory may get leaked at Line C (due to "new"-ing the object there). Is there a better pattern for handling this sort of code? Is there a name for this sort of initialization pattern? By the way I know I could check for exInfo == null before line D but that seems a bit clumsy and I'm looking for a better approach.

    Read the article

  • TechDays TV : la Catch TV gratuite des TechDays 2011 pour revivre les moments forts du rendez-vous des professionnels informatiques

    TechDays TV : la Catch TV gratuite des TechDays 2011 Pour revivre les moments forts du rendez?vous des professionnels informatiques de Microsoft La cinquième édition des TechDays, l'évènement de Microsoft réunissant les développeurs, professionnels et décideurs IT, s'est achevée la semaine dernière. Cette édition a été marquée par une actualité riche et de nombreuses innovations. TechDays TV permettait ainsi aux personnes n'ayant pas eu l'occasion de se rendre sur place d'assister à plusieurs sessions et de suivre l'événement en direct. Aujourd'hui, Microsoft propose la rediffusion intégrale et gratuite des contenus de cette WebTV (conférences plénières, sélections des meil...

    Read the article

  • Google Apps - Can I configure a wildcard MX record and and catch all emai address for a domain

    - by Rohit
    I am using Google Apps Premier Edition. I want to create a disposable email address service and I want to catch all emails for a domain. This means that I should be able to catch all mails sent to an arbitrary userid and/or arbitrary domain and store them into a single Google Apps account. For example, in a single account I want to get all mails sent to: 1) [email protected] 2) [email protected] without requiring to do any extra configuration in Google Apps for abc or xyz. My app will download mails from this account and process accordingly. I have figured out that I could do (1) by specifying a catch all email address. Is the combination of both (1) and (2) possible?

    Read the article

  • Is there a better strategy than relying on the compiler to catch errors?

    - by koan
    I've been programming in C and C++ for some time, although I would say I'm far from being an expert. For some time, I've been using various strategies to develop my code such as unit tests, test driven design, code reviews and so on. When I wrote my first programs in BASIC, I typed in long blocks before finding they would not run and they were a nightmare to debug. So I learned to write a small bit and then test it. These days, I often find myself repeatedly writing a small bit of code then using the compiler to find all the mistakes. That's OK if it picks up a typo but when you start adjusting the parameters types etc just to make it compile you can screw up the design. It also seems that the compiler is creeping into the design process when it should only be used for checking syntax. There's a danger here of over reliance on the compiler to make my programs better. Are there better strategies than this? I vaguely remember some time ago an article on a company developing a type of C compiler where an extra header file also specified the prototypes. The idea was that inconsistencies in the API definition would be easier to catch if you had to define it twice in different ways.

    Read the article

  • Upload File to Windows Azure Blob in Chunks through ASP.NET MVC, JavaScript and HTML5

    - by Shaun
    Originally posted on: http://geekswithblogs.net/shaunxu/archive/2013/07/01/upload-file-to-windows-azure-blob-in-chunks-through-asp.net.aspxMany people are using Windows Azure Blob Storage to store their data in the cloud. Blob storage provides 99.9% availability with easy-to-use API through .NET SDK and HTTP REST. For example, we can store JavaScript files, images, documents in blob storage when we are building an ASP.NET web application on a Web Role in Windows Azure. Or we can store our VHD files in blob and mount it as a hard drive in our cloud service. If you are familiar with Windows Azure, you should know that there are two kinds of blob: page blob and block blob. The page blob is optimized for random read and write, which is very useful when you need to store VHD files. The block blob is optimized for sequential/chunk read and write, which has more common usage. Since we can upload block blob in blocks through BlockBlob.PutBlock, and them commit them as a whole blob with invoking the BlockBlob.PutBlockList, it is very powerful to upload large files, as we can upload blocks in parallel, and provide pause-resume feature. There are many documents, articles and blog posts described on how to upload a block blob. Most of them are focus on the server side, which means when you had received a big file, stream or binaries, how to upload them into blob storage in blocks through .NET SDK.  But the problem is, how can we upload these large files from client side, for example, a browser. This questioned to me when I was working with a Chinese customer to help them build a network disk production on top of azure. The end users upload their files from the web portal, and then the files will be stored in blob storage from the Web Role. My goal is to find the best way to transform the file from client (end user’s machine) to the server (Web Role) through browser. In this post I will demonstrate and describe what I had done, to upload large file in chunks with high speed, and save them as blocks into Windows Azure Blob Storage.   Traditional Upload, Works with Limitation The simplest way to implement this requirement is to create a web page with a form that contains a file input element and a submit button. 1: @using (Html.BeginForm("About", "Index", FormMethod.Post, new { enctype = "multipart/form-data" })) 2: { 3: <input type="file" name="file" /> 4: <input type="submit" value="upload" /> 5: } And then in the backend controller, we retrieve the whole content of this file and upload it in to the blob storage through .NET SDK. We can split the file in blocks and upload them in parallel and commit. The code had been well blogged in the community. 1: [HttpPost] 2: public ActionResult About(HttpPostedFileBase file) 3: { 4: var container = _client.GetContainerReference("test"); 5: container.CreateIfNotExists(); 6: var blob = container.GetBlockBlobReference(file.FileName); 7: var blockDataList = new Dictionary<string, byte[]>(); 8: using (var stream = file.InputStream) 9: { 10: var blockSizeInKB = 1024; 11: var offset = 0; 12: var index = 0; 13: while (offset < stream.Length) 14: { 15: var readLength = Math.Min(1024 * blockSizeInKB, (int)stream.Length - offset); 16: var blockData = new byte[readLength]; 17: offset += stream.Read(blockData, 0, readLength); 18: blockDataList.Add(Convert.ToBase64String(BitConverter.GetBytes(index)), blockData); 19:  20: index++; 21: } 22: } 23:  24: Parallel.ForEach(blockDataList, (bi) => 25: { 26: blob.PutBlock(bi.Key, new MemoryStream(bi.Value), null); 27: }); 28: blob.PutBlockList(blockDataList.Select(b => b.Key).ToArray()); 29:  30: return RedirectToAction("About"); 31: } This works perfect if we selected an image, a music or a small video to upload. But if I selected a large file, let’s say a 6GB HD-movie, after upload for about few minutes the page will be shown as below and the upload will be terminated. In ASP.NET there is a limitation of request length and the maximized request length is defined in the web.config file. It’s a number which less than about 4GB. So if we want to upload a really big file, we cannot simply implement in this way. Also, in Windows Azure, a cloud service network load balancer will terminate the connection if exceed the timeout period. From my test the timeout looks like 2 - 3 minutes. Hence, when we need to upload a large file we cannot just use the basic HTML elements. Besides the limitation mentioned above, the simple HTML file upload cannot provide rich upload experience such as chunk upload, pause and pause-resume. So we need to find a better way to upload large file from the client to the server.   Upload in Chunks through HTML5 and JavaScript In order to break those limitation mentioned above we will try to upload the large file in chunks. This takes some benefit to us such as - No request size limitation: Since we upload in chunks, we can define the request size for each chunks regardless how big the entire file is. - No timeout problem: The size of chunks are controlled by us, which means we should be able to make sure request for each chunk upload will not exceed the timeout period of both ASP.NET and Windows Azure load balancer. It was a big challenge to upload big file in chunks until we have HTML5. There are some new features and improvements introduced in HTML5 and we will use them to implement our solution.   In HTML5, the File interface had been improved with a new method called “slice”. It can be used to read part of the file by specifying the start byte index and the end byte index. For example if the entire file was 1024 bytes, file.slice(512, 768) will read the part of this file from the 512nd byte to 768th byte, and return a new object of interface called "Blob”, which you can treat as an array of bytes. In fact,  a Blob object represents a file-like object of immutable, raw data. The File interface is based on Blob, inheriting blob functionality and expanding it to support files on the user's system. For more information about the Blob please refer here. File and Blob is very useful to implement the chunk upload. We will use File interface to represent the file the user selected from the browser and then use File.slice to read the file in chunks in the size we wanted. For example, if we wanted to upload a 10MB file with 512KB chunks, then we can read it in 512KB blobs by using File.slice in a loop.   Assuming we have a web page as below. User can select a file, an input box to specify the block size in KB and a button to start upload. 1: <div> 2: <input type="file" id="upload_files" name="files[]" /><br /> 3: Block Size: <input type="number" id="block_size" value="512" name="block_size" />KB<br /> 4: <input type="button" id="upload_button_blob" name="upload" value="upload (blob)" /> 5: </div> Then we can have the JavaScript function to upload the file in chunks when user clicked the button. 1: <script type="text/javascript"> 1: 2: $(function () { 3: $("#upload_button_blob").click(function () { 4: }); 5: });</script> Firstly we need to ensure the client browser supports the interfaces we are going to use. Just try to invoke the File, Blob and FormData from the “window” object. If any of them is “undefined” the condition result will be “false” which means your browser doesn’t support these premium feature and it’s time for you to get your browser updated. FormData is another new feature we are going to use in the future. It could generate a temporary form for us. We will use this interface to create a form with chunk and associated metadata when invoked the service through ajax. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: if (window.File && window.Blob && window.FormData) { 4: alert("Your brwoser is awesome, let's rock!"); 5: } 6: else { 7: alert("Oh man plz update to a modern browser before try is cool stuff out."); 8: return; 9: } 10: }); Each browser supports these interfaces by their own implementation and currently the Blob, File and File.slice are supported by Chrome 21, FireFox 13, IE 10, Opera 12 and Safari 5.1 or higher. After that we worked on the files the user selected one by one since in HTML5, user can select multiple files in one file input box. 1: var files = $("#upload_files")[0].files; 2: for (var i = 0; i < files.length; i++) { 3: var file = files[i]; 4: var fileSize = file.size; 5: var fileName = file.name; 6: } Next, we calculated the start index and end index for each chunks based on the size the user specified from the browser. We put them into an array with the file name and the index, which will be used when we upload chunks into Windows Azure Blob Storage as blocks since we need to specify the target blob name and the block index. At the same time we will store the list of all indexes into another variant which will be used to commit blocks into blob in Azure Storage once all chunks had been uploaded successfully. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10:  11: // calculate the start and end byte index for each blocks(chunks) 12: // with the index, file name and index list for future using 13: var blockSizeInKB = $("#block_size").val(); 14: var blockSize = blockSizeInKB * 1024; 15: var blocks = []; 16: var offset = 0; 17: var index = 0; 18: var list = ""; 19: while (offset < fileSize) { 20: var start = offset; 21: var end = Math.min(offset + blockSize, fileSize); 22:  23: blocks.push({ 24: name: fileName, 25: index: index, 26: start: start, 27: end: end 28: }); 29: list += index + ","; 30:  31: offset = end; 32: index++; 33: } 34: } 35: }); Now we have all chunks’ information ready. The next step should be upload them one by one to the server side, and at the server side when received a chunk it will upload as a block into Blob Storage, and finally commit them with the index list through BlockBlobClient.PutBlockList. But since all these invokes are ajax calling, which means not synchronized call. So we need to introduce a new JavaScript library to help us coordinate the asynchronize operation, which named “async.js”. You can download this JavaScript library here, and you can find the document here. I will not explain this library too much in this post. We will put all procedures we want to execute as a function array, and pass into the proper function defined in async.js to let it help us to control the execution sequence, in series or in parallel. Hence we will define an array and put the function for chunk upload into this array. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4:  5: // start to upload each files in chunks 6: var files = $("#upload_files")[0].files; 7: for (var i = 0; i < files.length; i++) { 8: var file = files[i]; 9: var fileSize = file.size; 10: var fileName = file.name; 11: // calculate the start and end byte index for each blocks(chunks) 12: // with the index, file name and index list for future using 13: ... ... 14:  15: // define the function array and push all chunk upload operation into this array 16: blocks.forEach(function (block) { 17: putBlocks.push(function (callback) { 18: }); 19: }); 20: } 21: }); 22: }); As you can see, I used File.slice method to read each chunks based on the start and end byte index we calculated previously, and constructed a temporary HTML form with the file name, chunk index and chunk data through another new feature in HTML5 named FormData. Then post this form to the backend server through jQuery.ajax. This is the key part of our solution. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: blocks.forEach(function (block) { 15: putBlocks.push(function (callback) { 16: // load blob based on the start and end index for each chunks 17: var blob = file.slice(block.start, block.end); 18: // put the file name, index and blob into a temporary from 19: var fd = new FormData(); 20: fd.append("name", block.name); 21: fd.append("index", block.index); 22: fd.append("file", blob); 23: // post the form to backend service (asp.net mvc controller action) 24: $.ajax({ 25: url: "/Home/UploadInFormData", 26: data: fd, 27: processData: false, 28: contentType: "multipart/form-data", 29: type: "POST", 30: success: function (result) { 31: if (!result.success) { 32: alert(result.error); 33: } 34: callback(null, block.index); 35: } 36: }); 37: }); 38: }); 39: } 40: }); Then we will invoke these functions one by one by using the async.js. And once all functions had been executed successfully I invoked another ajax call to the backend service to commit all these chunks (blocks) as the blob in Windows Azure Storage. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.series(putBlocks, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: }); That’s all in the client side. The outline of our logic would be - Calculate the start and end byte index for each chunks based on the block size. - Defined the functions of reading the chunk form file and upload the content to the backend service through ajax. - Execute the functions defined in previous step with “async.js”. - Commit the chunks by invoking the backend service in Windows Azure Storage finally.   Save Chunks as Blocks into Blob Storage In above we finished the client size JavaScript code. It uploaded the file in chunks to the backend service which we are going to implement in this step. We will use ASP.NET MVC as our backend service, and it will receive the chunks, upload into Windows Azure Bob Storage in blocks, then finally commit as one blob. As in the client side we uploaded chunks by invoking the ajax call to the URL "/Home/UploadInFormData", I created a new action under the Index controller and it only accepts HTTP POST request. 1: [HttpPost] 2: public JsonResult UploadInFormData() 3: { 4: var error = string.Empty; 5: try 6: { 7: } 8: catch (Exception e) 9: { 10: error = e.ToString(); 11: } 12:  13: return new JsonResult() 14: { 15: Data = new 16: { 17: success = string.IsNullOrWhiteSpace(error), 18: error = error 19: } 20: }; 21: } Then I retrieved the file name, index and the chunk content from the Request.Form object, which was passed from our client side. And then, used the Windows Azure SDK to create a blob container (in this case we will use the container named “test”.) and create a blob reference with the blob name (same as the file name). Then uploaded the chunk as a block of this blob with the index, since in Blob Storage each block must have an index (ID) associated with so that finally we can put all blocks as one blob by specifying their block ID list. 1: [HttpPost] 2: public JsonResult UploadInFormData() 3: { 4: var error = string.Empty; 5: try 6: { 7: var name = Request.Form["name"]; 8: var index = int.Parse(Request.Form["index"]); 9: var file = Request.Files[0]; 10: var id = Convert.ToBase64String(BitConverter.GetBytes(index)); 11:  12: var container = _client.GetContainerReference("test"); 13: container.CreateIfNotExists(); 14: var blob = container.GetBlockBlobReference(name); 15: blob.PutBlock(id, file.InputStream, null); 16: } 17: catch (Exception e) 18: { 19: error = e.ToString(); 20: } 21:  22: return new JsonResult() 23: { 24: Data = new 25: { 26: success = string.IsNullOrWhiteSpace(error), 27: error = error 28: } 29: }; 30: } Next, I created another action to commit the blocks into blob once all chunks had been uploaded. Similarly, I retrieved the blob name from the Request.Form. I also retrieved the chunks ID list, which is the block ID list from the Request.Form in a string format, split them as a list, then invoked the BlockBlob.PutBlockList method. After that our blob will be shown in the container and ready to be download. 1: [HttpPost] 2: public JsonResult Commit() 3: { 4: var error = string.Empty; 5: try 6: { 7: var name = Request.Form["name"]; 8: var list = Request.Form["list"]; 9: var ids = list 10: .Split(',') 11: .Where(id => !string.IsNullOrWhiteSpace(id)) 12: .Select(id => Convert.ToBase64String(BitConverter.GetBytes(int.Parse(id)))) 13: .ToArray(); 14:  15: var container = _client.GetContainerReference("test"); 16: container.CreateIfNotExists(); 17: var blob = container.GetBlockBlobReference(name); 18: blob.PutBlockList(ids); 19: } 20: catch (Exception e) 21: { 22: error = e.ToString(); 23: } 24:  25: return new JsonResult() 26: { 27: Data = new 28: { 29: success = string.IsNullOrWhiteSpace(error), 30: error = error 31: } 32: }; 33: } Now we finished all code we need. The whole process of uploading would be like this below. Below is the full client side JavaScript code. 1: <script type="text/javascript" src="~/Scripts/async.js"></script> 2: <script type="text/javascript"> 3: $(function () { 4: $("#upload_button_blob").click(function () { 5: // assert the browser support html5 6: if (window.File && window.Blob && window.FormData) { 7: alert("Your brwoser is awesome, let's rock!"); 8: } 9: else { 10: alert("Oh man plz update to a modern browser before try is cool stuff out."); 11: return; 12: } 13:  14: // start to upload each files in chunks 15: var files = $("#upload_files")[0].files; 16: for (var i = 0; i < files.length; i++) { 17: var file = files[i]; 18: var fileSize = file.size; 19: var fileName = file.name; 20:  21: // calculate the start and end byte index for each blocks(chunks) 22: // with the index, file name and index list for future using 23: var blockSizeInKB = $("#block_size").val(); 24: var blockSize = blockSizeInKB * 1024; 25: var blocks = []; 26: var offset = 0; 27: var index = 0; 28: var list = ""; 29: while (offset < fileSize) { 30: var start = offset; 31: var end = Math.min(offset + blockSize, fileSize); 32:  33: blocks.push({ 34: name: fileName, 35: index: index, 36: start: start, 37: end: end 38: }); 39: list += index + ","; 40:  41: offset = end; 42: index++; 43: } 44:  45: // define the function array and push all chunk upload operation into this array 46: var putBlocks = []; 47: blocks.forEach(function (block) { 48: putBlocks.push(function (callback) { 49: // load blob based on the start and end index for each chunks 50: var blob = file.slice(block.start, block.end); 51: // put the file name, index and blob into a temporary from 52: var fd = new FormData(); 53: fd.append("name", block.name); 54: fd.append("index", block.index); 55: fd.append("file", blob); 56: // post the form to backend service (asp.net mvc controller action) 57: $.ajax({ 58: url: "/Home/UploadInFormData", 59: data: fd, 60: processData: false, 61: contentType: "multipart/form-data", 62: type: "POST", 63: success: function (result) { 64: if (!result.success) { 65: alert(result.error); 66: } 67: callback(null, block.index); 68: } 69: }); 70: }); 71: }); 72:  73: // invoke the functions one by one 74: // then invoke the commit ajax call to put blocks into blob in azure storage 75: async.series(putBlocks, function (error, result) { 76: var data = { 77: name: fileName, 78: list: list 79: }; 80: $.post("/Home/Commit", data, function (result) { 81: if (!result.success) { 82: alert(result.error); 83: } 84: else { 85: alert("done!"); 86: } 87: }); 88: }); 89: } 90: }); 91: }); 92: </script> And below is the full ASP.NET MVC controller code. 1: public class HomeController : Controller 2: { 3: private CloudStorageAccount _account; 4: private CloudBlobClient _client; 5:  6: public HomeController() 7: : base() 8: { 9: _account = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("DataConnectionString")); 10: _client = _account.CreateCloudBlobClient(); 11: } 12:  13: public ActionResult Index() 14: { 15: ViewBag.Message = "Modify this template to jump-start your ASP.NET MVC application."; 16:  17: return View(); 18: } 19:  20: [HttpPost] 21: public JsonResult UploadInFormData() 22: { 23: var error = string.Empty; 24: try 25: { 26: var name = Request.Form["name"]; 27: var index = int.Parse(Request.Form["index"]); 28: var file = Request.Files[0]; 29: var id = Convert.ToBase64String(BitConverter.GetBytes(index)); 30:  31: var container = _client.GetContainerReference("test"); 32: container.CreateIfNotExists(); 33: var blob = container.GetBlockBlobReference(name); 34: blob.PutBlock(id, file.InputStream, null); 35: } 36: catch (Exception e) 37: { 38: error = e.ToString(); 39: } 40:  41: return new JsonResult() 42: { 43: Data = new 44: { 45: success = string.IsNullOrWhiteSpace(error), 46: error = error 47: } 48: }; 49: } 50:  51: [HttpPost] 52: public JsonResult Commit() 53: { 54: var error = string.Empty; 55: try 56: { 57: var name = Request.Form["name"]; 58: var list = Request.Form["list"]; 59: var ids = list 60: .Split(',') 61: .Where(id => !string.IsNullOrWhiteSpace(id)) 62: .Select(id => Convert.ToBase64String(BitConverter.GetBytes(int.Parse(id)))) 63: .ToArray(); 64:  65: var container = _client.GetContainerReference("test"); 66: container.CreateIfNotExists(); 67: var blob = container.GetBlockBlobReference(name); 68: blob.PutBlockList(ids); 69: } 70: catch (Exception e) 71: { 72: error = e.ToString(); 73: } 74:  75: return new JsonResult() 76: { 77: Data = new 78: { 79: success = string.IsNullOrWhiteSpace(error), 80: error = error 81: } 82: }; 83: } 84: } And if we selected a file from the browser we will see our application will upload chunks in the size we specified to the server through ajax call in background, and then commit all chunks in one blob. Then we can find the blob in our Windows Azure Blob Storage.   Optimized by Parallel Upload In previous example we just uploaded our file in chunks. This solved the problem that ASP.NET MVC request content size limitation as well as the Windows Azure load balancer timeout. But it might introduce the performance problem since we uploaded chunks in sequence. In order to improve the upload performance we could modify our client side code a bit to make the upload operation invoked in parallel. The good news is that, “async.js” library provides the parallel execution function. If you remembered the code we invoke the service to upload chunks, it utilized “async.series” which means all functions will be executed in sequence. Now we will change this code to “async.parallel”. This will invoke all functions in parallel. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.parallel(putBlocks, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: }); In this way all chunks will be uploaded to the server side at the same time to maximize the bandwidth usage. This should work if the file was not very large and the chunk size was not very small. But for large file this might introduce another problem that too many ajax calls are sent to the server at the same time. So the best solution should be, upload the chunks in parallel with maximum concurrency limitation. The code below specified the concurrency limitation to 4, which means at the most only 4 ajax calls could be invoked at the same time. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.parallelLimit(putBlocks, 4, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: });   Summary In this post we discussed how to upload files in chunks to the backend service and then upload them into Windows Azure Blob Storage in blocks. We focused on the frontend side and leverage three new feature introduced in HTML 5 which are - File.slice: Read part of the file by specifying the start and end byte index. - Blob: File-like interface which contains the part of the file content. - FormData: Temporary form element that we can pass the chunk alone with some metadata to the backend service. Then we discussed the performance consideration of chunk uploading. Sequence upload cannot provide maximized upload speed, but the unlimited parallel upload might crash the browser and server if too many chunks. So we finally came up with the solution to upload chunks in parallel with the concurrency limitation. We also demonstrated how to utilize “async.js” JavaScript library to help us control the asynchronize call and the parallel limitation.   Regarding the chunk size and the parallel limitation value there is no “best” value. You need to test vary composition and find out the best one for your particular scenario. It depends on the local bandwidth, client machine cores and the server side (Windows Azure Cloud Service Virtual Machine) cores, memory and bandwidth. Below is one of my performance test result. The client machine was Windows 8 IE 10 with 4 cores. I was using Microsoft Cooperation Network. The web site was hosted on Windows Azure China North data center (in Beijing) with one small web role (1.7GB 1 core CPU, 1.75GB memory with 100Mbps bandwidth). The test cases were - Chunk size: 512KB, 1MB, 2MB, 4MB. - Upload Mode: Sequence, parallel (unlimited), parallel with limit (4 threads, 8 threads). - Chunk Format: base64 string, binaries. - Target file: 100MB. - Each case was tested 3 times. Below is the test result chart. Some thoughts, but not guidance or best practice: - Parallel gets better performance than series. - No significant performance improvement between parallel 4 threads and 8 threads. - Transform with binaries provides better performance than base64. - In all cases, chunk size in 1MB - 2MB gets better performance.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

    Read the article

  • Error Handling Examples(C#)

    “The purpose of reviewing the Error Handling code is to assure that the application fails safely under all possible error conditions, expected and unexpected. No sensitive information is presented to the user when an error occurs.” (OWASP, 2011) No Error Handling The absence of error handling is still a form of error handling. Based on the code in Figure 1, if an error occurred and was not handled within either the ReadXml or BuildRequest methods the error would bubble up to the Search method. Since this method does not handle any acceptations the error will then bubble up the stack trace. If this continues and the error is not handled within the application then the environment in which the application is running will notify the user running the application that an error occurred based on what type of application. Figure 1: No Error Handling public DataSet Search(string searchTerm, int resultCount) { DataSet dt = new DataSet(); dt.ReadXml(BuildRequest(searchTerm, resultCount)); return dt; } Generic Error Handling One simple way to add error handling is to catch all errors by default. If you examine the code in Figure 2, you will see a try-catch block. On April 6th 2010 Louis Lazaris clearly describes a Try Catch statement by defining both the Try and Catch aspects of the statement. “The try portion is where you would put any code that might throw an error. In other words, all significant code should go in the try section. The catch section will also hold code, but that section is not vital to the running of the application. So, if you removed the try-catch statement altogether, the section of code inside the try part would still be the same, but all the code inside the catch would be removed.” (Lazaris, 2010) He also states that all errors that occur in the try section cause it to stops the execution of the try section and redirects all execution to the catch section. The catch section receives an object containing information about the error that occurred so that they system can gracefully handle the error properly. When errors occur they commonly log them in some form. This form could be an email, database entry, web service call, log file, or just an error massage displayed to the user.  Depending on the error sometimes applications can recover, while others force an application to close. Figure 2: Generic Error Handling public DataSet Search(string searchTerm, int resultCount) { DataSet dt = new DataSet(); try { dt.ReadXml(BuildRequest(searchTerm, resultCount)); } catch (Exception ex) { // Handle all Exceptions } return dt; } Error Specific Error Handling Like the Generic Error Handling, Error Specific error handling allows for the catching of specific known errors that may occur. For example wrapping a try catch statement around a soap web service call would allow the application to handle any error that was generated by the soap web service. Now, if the systems wanted to send a message to the web service provider every time a soap error occurred but did not want to notify them if any other type of error occurred like a network time out issue. This would be varying tedious to accomplish using the General Error Handling methodology. This brings us to the use case for using the Error Specific error handling methodology.  The Error Specific Error handling methodology allows for the TryCatch statement to catch various types of errors depending on the type of error that occurred. In Figure 3, the code attempts to handle DataException differently compared to how it potentially handles all other errors. This allows for specific error handling for each type of known error, and still allows for error handling of any unknown error that my occur during the execution of the TryCatch statement. Figure 5: Error Specific Error Handling public DataSet Search(string searchTerm, int resultCount) { DataSet dt = new DataSet(); try { dt.ReadXml(BuildRequest(searchTerm, resultCount)); } catch (TimeoutException ex) { // Handle Timeout TimeoutException Only } catch (Exception) { // Handle all Exceptions } return dt; }

    Read the article

  • What is the quickest way to indent a block of text with spaces for use within a web browser?

    - by ændrük
    I occasionally have the need to indent a block of text with spaces for use within a web browser, for example, when formatting a code block on this site or in a post on Launchpad. So far I've just done it by hand by copying four spaces to the clipboard and then mashing keys really fast: ?, Home, Ctrl+V (repeat) What is the quickest way to accomplish this? Copying and pasting to another program? (Which?) A Firefox or Chrome browser extension? A command to directly modify the clipboard contents? An auto-typing program?

    Read the article

  • How do I easily repair a single unreadable block on a Linux disk?

    - by Nelson
    My Linux system has started throwing SMART errors in the syslog. I tracked it down and believe the problem is a single block on the disk. How do I go about easily getting the disk to reallocate that one block? I'd like to know what file got destroyed in the process. (I'm aware that if one block fails on a disk others are likely to follow; I have a good ongoing backup and just want to try to keep this disk working.) Searching the web leads to the Bad block HOWTO, which describes a manual process on an unmounted disk. It seems complicated and error-prone. Is there a tool to automate this process in Linux? My only other option is the manufacturer's diagnostic tool, but I presume that'll clobber the bad block without any reporting on what got destroyed. Worst case, it might be filesystem metadata. The disk in question is the primary system partition. Using ext3fs and LVM. Here's the error log from syslog and the relevant bit from smartctl. smartd[5226]: Device: /dev/hda, 1 Currently unreadable (pending) sectors Error 1 occurred at disk power-on lifetime: 17449 hours (727 days + 1 hours) ... Error: UNC at LBA = 0x00d39eee = 13868782 There's a full smartctl dump on pastebin.

    Read the article

  • What is a quick way to indent a block of text with spaces for use within a web browser?

    - by ændrük
    I occasionally have the need to indent a block of text with spaces for use within a web browser, for example, when formatting a code block on this site or in a post on Launchpad. So far I've just done it by hand by copying four spaces to the clipboard and then mashing keys really fast: ?, Home, Ctrl+V (repeat) What is a quicker way to accomplish this, e.g. copying and pasting to another program? a Firefox or Chrome browser extension? a command to directly modify the clipboard contents? an auto-typing program?

    Read the article

  • Game actions that take multiple frames to complete

    - by CantTetris
    I've never really done much game programming before, pretty straightforward question. Imagine I'm building a Tetris game, with the main loop looking something like this. for every frame handle input if it's time to make the current block move down a row if we can move the block move the block else remove all complete rows move rows down so there are no gaps if we can spawn a new block spawn a new current block else game over Everything in the game so far happens instantly - things are spawned instantly, rows are removed instantly etc. But what if I don't want things to happen instantly (i.e animate things)? for every frame handle input if it's time to make the current block move down a row if we can move the block move the block else ?? animate complete rows disappearing (somehow, wait over multiple frames until the animation is done) ?? animate rows moving downwards (and again, wait over multiple frames) if we can spawn a new block spawn a new current block else game over In my Pong clone this wasn't an issue, as every frame I was just moving the ball and checking for collisions. How can I wrap my head around this issue? Surely most games involves some action that takes more than a frame, and other things halt until the action is done.

    Read the article

  • Block elements vs inline elements in HTML: why the distinction?

    - by EpsilonVector
    The distinction between block and inline elements always seemed strange to me. The whole difference is that a block element takes up the entire width thus forcing a line break before and after the element, and an inline element only takes up as much as the content. Why not just have one type of element- an inline element where you can also apply custom height/width, and use that? You want line breaks? Insert a <br />, or maybe add a special tag in the CSS for that behavior. The way it's now, I don't see it solving any problem, and instead it only forces a property that in my opinion should be decided by a designer. So why the two types?

    Read the article

  • Is it safe to block redirected (but still linked) URLs with robots.txt?

    - by Edgar Quintero
    I have a website that has all URLs optimized and 301 redirected from nasty URLs to clean ones. However, everywhere throughout the site the unclean URLs are linked in menus, content, products, etc. Google currently has all clean URLs indexed, along with a few unclean URLs too. So the site still has linked everywhere the old URLs (ideally this wouldn't be the case but this is how it is ATM). I would like to block the unclean URLs with robots.txt. The question: if I block these unclean URLs with the robots.txt, when the entire website is linked with them (but they all redirect to the clean version), will this affect the indexing status at all?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 39 40 41 42 43 44 45 46 47 48 49 50  | Next Page >