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  • How to install Opera Browser?

    - by bruce
    I am trying to install opera browser from the terminal. I downloaded the 'debian' installer because it didn't show up in software center. It completely destroyed my software center - it is frozen and I have no idea how to fix (I have a different thread for that though). Can I use this thing called synaptic package manager to install Opera? or am I stuck with Firefox? How do I install Opera Browser?

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  • How to Customize the File Open/Save Dialog Box in Windows

    - by Lori Kaufman
    Generally, there are two kinds of Open/Save dialog boxes in Windows. One kind looks like Windows Explorer, with the tree on the left containing Favorites, Libraries, Computer, etc. The other kind contains a vertical toolbar, called the Places Bar. The Windows Explorer-style Open/Save dialog box can be customized by adding your own folders to the Favorites list. You can, then, click the arrows to the left of the main items, except the Favorites, to collapse them, leaving only the list of default and custom Favorites. The Places Bar is located along the left side of the File Open/Save dialog box and contains buttons providing access to frequently-used folders. The default buttons on the Places Bar are links to Recent Places, Desktop, Libraries, Computer, and Network. However, you change these links to be links to custom folders of your choice. We will show you how to customize the Places Bar using the registry and using a free tool in case you are not comfortable making changes in the registry. Use Your Android Phone to Comparison Shop: 4 Scanner Apps Reviewed How to Run Android Apps on Your Desktop the Easy Way HTG Explains: Do You Really Need to Defrag Your PC?

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  • Legal issues regarding embedding a toolbar into a browser [closed]

    - by OmarOthman
    We are in the process of developing a software that provides service to internet users and we would like to ask about the legal liabilities of some issues. Of course, everything is to be done with the consent of the user of our software but our concern is about third party tools and services that may be invoked/used by our product. In particular, these are the concerns: (1) Embedding a toolbar to an existing browser. This screenshot is an example, where the words in the highlighted toolbar are passed to www.google.com for searching, and the contents of the window are the results of the search. I want to know if any consent should be obtained before such a toolbar can be embedded in a web browser, whether there are any legal requirements by the web browser; whether different web browsers have different requirements (at least for Internet Explorer, Firefox, Chrome, Opera and Safari). (2) Invoking a free website from that toolbar (like Google’s search page). The screenshot above demonstrates such an existing toolbar. (3) Full ownership and unrestricted access to the data entered to this toolbar. In the screenshot above, I want to take the words (translation english to spanish) and own them, i.e. storing them in my database and do some processing on them. (4) Ability to track the pages entered by the user starting from that free website. In the screenshot above, you can notice that the user opted only for the third result, whose URL is translate.google.com. I want to have access to this and all URLs clicked from this page for some processing as well. This is a commercial application, so I need a very concrete, precise and reference-supported answer.

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  • Opening a file opens the folder the file is in, not the file itself

    - by Pepe Lebuntu
    Whenever I try to open a file (such as an .odt, or .doc) from say, the Dash or the Firefox Downloads, Ubuntu 11.10 opens Nautilus to the the folder where the file is, rather than just going to the application and loading the file straight away. In previous releases, when I clicked on a downloaded file, it just went straight to LibreOffice, and it was fine. This is adding a superfluous step in the process. How do I associate the correct extensions?

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  • Why not open a PDF file in the browser but first save it to the harddisk?

    - by Lernkurve
    Question Is it correct that saving a PDF to the harddisk first, and then opening it from there with some PDF reader (not the browser) is safer than opening it directly with the browser plugin? My current understanding I know that the PDF browser plugin might have a security leak and a manipulated PDF file might exploit it and get access to the user's computer. I recently heard that saving the PDF file frist and opening it then was safer. I don't understand why that should be safer. Can anyone explain? My logic would suggest that a manipulated file started from the harddisk can just as well exploit a security leak, say for instance, of Adobe Acrobat Reader.

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  • Most efficient arc for developing cross-browser support?

    - by Chris Hasbrouck
    I'm curious to hear what approach people take to planning for cross-browser support when developing a website. There are generally two approaches I've seen developers take in their workflow: -optimize for webkit then apply hacks for IE7-9, or -optimize for IE7-8 then apply newer features for IE9/webkit Basically starting at the front of technology and working toward the back, or starting at the back of technology and working toward the front. How do you do things? What advantages or disadvantage do you perceive in the different way of doing things wrt to developing cross-browser support?

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  • Browser testing - Ideas on how to tackle it efficiently

    - by Rob
    Browser testing, the bane of any web designers life! Are there any tools and/or ways in which I can efficiently test different browsers on both Mac and PC? I not only want to test different browsers but also different versions of each browser. My current setup is on a Mac running VirtualBox with Windows Vista installed. This allows me to test both Mac and PC but the complications arise when trying to test different versions of browsers. Any one have any ideas?

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  • How relevant is PHP today for browser games?

    - by Bitgarden
    I was the lead developer of 2 moderately successful browser games quite a few years back, and plan on working on a new game soon. At the time, I wrote them in pure PHP (no template engine or anything of the sort). I'd like to start working on a new game, but have been out of the web development world for a while. Reading around, I hear a lot of good about Rails, Django, Node.js, etc., with which I have no experience (although I know my way around Python, Javascript, and the others quite well). So my question is the following- if I were to go in my old ways and go with PHP again, would I be making things hard for myself? Would picking something more "trendy" have a real impact on my development? In addition, does anyone have any pointers relating to specifically developing browser games with these more modern tools?

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  • No sound in any web browser(s)

    - by shaneo
    Hello I recently tried to compile and update alsa from source via this guide http://www.stchman.com/alsa_update.html. Afterwards the sound in any web browser I open Firefox, Opera, Chrome, Chromium, Iron there is no sound on any pages. I went back through the script listed on the site and found where it had installed the drivers and deleted it and than re-installed alsa via synaptic. Though I still have no sound in my browser(s). All system sounds work as they are supposed to only web sounds don't work. Here is my alsabase.conf http://paste.ubuntu.com/1073135/ also a snapshot of alsamixer Any assistance would be greatly appreciated. Thank You and let me know if any more information is required.

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  • How to create browser based software?

    - by erkant
    I have recently used some software, which come as a regular setup file, where you install your software, and then when you run it, opens the browser, uses the localhost with some specific port number to connect to the software, and runs it from there. I find it quite useful and interesting. But I even don't know whether this kind of software and programming methodology have a name or not. Therefore, I would like to learn which programming languages, APIs, and frameworks are specifically designed for this purpose? One example to this is Metasploit. You can download its setup file, and install it casually like any other software, then when everything finishes, and you want to use the software. It will open the browser and connect to, http://localhost:3790/ where Metasploit will load and start.

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  • Check to see if file transfer is complete

    - by Cymon
    We have a daily job that processes files delivered from an external source. The process usually runs fine without any issues but every once in a while we have an issue of attempting to process a file that is not completely transferred. The external source SCPs these files from a UNIX server to our Windows server. From there we try to process the files. Is there a way to check to see if a file is still being transferred? Does UNIX put a lock on a file while SCPing it that we could check on the Windows side?

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  • cross browser compatibility

    - by Mayur
    HI All, I m a web designer and working in html and css so i m using linux machine as our company provide us, The problem is that when i am going for compatibility with windows it gets very problematic to me so plz tell me is there any site where i can check my web site in all browser of windows and mac where i get a good result as expected ......... Thanks

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  • How to change the default browser from the registry? [closed]

    - by msbg
    Possible Duplicate: Which registry keys need to be edited to change the default browser? I am trying to change the default browser opened from start ? run or win + r. I have set both HKEY_CLASSES_ROOT\http\shell\open\command and HKEY_LOCAL_MACHINE\SOFTWARE\Classes\http\shell\open\command From "C:\Program Files\Internet Explorer\iexplore.exe" %1 To "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" %1 But running an http address still opens Internet Explorer not Firefox. How do I change this?

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  • PHP File Downloading Questions

    - by nsearle
    Hey All! I am currently running into some problems with user's downloading a file stored on my server. I have code set up to auto download a file once the user hits the download button. It is working for all files, but when the size get's larger than 30 MB it is having issues. Is there a limit on user download? Also, I have supplied my example code and am wondering if there is a better practice than using the PHP function 'file_get_contents'. Thank You all for the help! $path = $_SERVER['DOCUMENT_ROOT'] . '../path/to/file/'; $filename = 'filename.zip'; $filesize = filesize($path . $filename); @header("Content-type: application/zip"); @header("Content-Disposition: attachment; filename=$filename"); @header("Content-Length: $filesize") echo file_get_contents($path . $filename);

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  • Using Multiple File Handles for Single File

    - by Ryan Rosario
    I have an O(n^2) operation that requires me to read line i from a file, and then compare line i to every line in the file. This repeats for all i. I wrote the following code to do this with 2 file handles, but it does not yield the result I am looking for. I imagine this is a simple error on my part. IN1 = open("myfile.dat","r") IN2 = open("myfile.dat","r") for line1 in IN1: for line2 in IN2: print line1.strip(), line2.strip() IN1.close() IN2.close() The result: Hello Hello Hello World Hello This Hello is Hello an Hello Example Hello of Hello Using Hello Two Hello File Hello Pointers Hello to Hello Read Hello One Hello File The output should contain 15^2 lines.

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  • Browser download file prompt using javascript

    - by aix
    hi, I was wondering if there was any method to implement browser's download file prompt using javascript. My reason - well users will be uploading files to a local fileserver which cannot be accessed from the webserver. In other words, both will be on different domains! e.g. let’s say websites hosted on www.xyz.com, but files would reside on local file server with address like \10.10.10.01\Files\file.txt. How am I uploading/transferring file to local fileserver... using ACTIVEX(yikes) & VBscript!!!! (don’t ask :-) so i am storing local file path in my database and binding that data to a grid. So when the user clicks on that link, the file opens in a window (using javascript). Problem is certain file types like text, jpg, pdf, etc open inside browser window. How would i be able to implement content-type or content-disposition using client side scripting? Is that even possible? hoping my description was clear. Any ideas? EDIT: the local file server has a window's shared folder on which the files are saved.

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  • SWT Browser Drag and Drop

    - by scottalas
    I'm trying to use drag-n-drop with an embedded SWT Browser, so that my application can drag hyperlinks from the Browser to another Control. I've been able to set up the destination to receive data from an external browser, but the internal does not seem to participate in the drag-n-drop. Any ideas? I would guess that I need something like a selection listener to track when something is grabbed in the browser, or some way to ask the browser what is currently selected, perhaps using javascript. My current setup of the Browser is simplistic, looking like this: browser = new Browser(top, SWT.NONE); // MOZILLA createDragSource(browser); // below // a selection listener never receives events: browser.addListener(SWT.Selection, new Listener() { @Override public void handleEvent(Event event) { System.out.println("Selection listener event"); } }); ... private void createDragSource(final Browser browser) { Transfer[] types = new Transfer[] { URLTransfer.getInstance(), HTMLTransfer.getInstance(), TextTransfer.getInstance(), ImageTransfer.getInstance(), }; int mode = DND.DROP_COPY | DND.DROP_LINK | DND.DROP_MOVE; DragSource dragSource = new DragSource(browser, mode); dragSource.setTransfer(types); dragSource.addDragListener(new DragSourceListener() { public void dragStart(DragSourceEvent event) { System.out.println("source.dragStart"); } public void dragSetData(DragSourceEvent event) { System.out.println("source.dragSetData"); // Is there a way to get the Browser's drag item here? } public void dragFinished(DragSourceEvent event) { System.out.println("source.dragFinished"); //do nothing } }); } Thanks for any help!

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  • Browser-based GUI for a python application

    - by ack__
    I want to create a web/browser-based GUI for a command-line python application. The goal is to make use of HTML/JS technologies to create this GUI. As the application itself, it needs to run on Linux and Windows, and the interface will be accessible only from localhost (not exposed to internet). The GUI will contain 5 to 10 pages. I don't want a traditional desktop GUI that includes HTML/JS, but just a bunch of html files and some kind of controller between those and the application. I also want to make use of asynchronous programming (ajax like) so I can load and print data in the GUI without refreshing the whole page. I'd probably use jQuery for that and a couple other things. How would you recommend to design this? Performance is not the key here, I'm rather looking at reliability, portability and simplicity. I'm thinking of using a lightweight python HTTP server / framework (like CherryPy) and maybe later a Python templating system (at the begining it will just be a couple pages). EDIT: I'm looking for ideas/recommendations how to build this, not for alternatives to browser/web-based GUI.

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  • A good tool for browser automation/client-side Web scripting

    - by hardmath
    I'm interested in adopting a tool/scripting language to automate some daily tasks connected with fighting forum spammers. A brief overview of these tasks: analyze new registrations and posts on a phpBB forum, and delete or deactivate spammers using a website/community that collects such spam reports. Typically such automation is integrated into the phpBB installation itself, which certainly has its advantages. My approach has the advantage of independent operation, etc. One way to think about this is in terms of browser automation. I've used iOpus iMacros for Firefox (the free version) in the past to respond to individual spammers, but current attacks are highly distributed. My "logic" for pigeonholing spammers vs. nonspammers seems beyond the easy reach of the free version of iMacros. From a more technical perspective one can think about dispensing with the browser altogether and programming GET/POST requests directed to my forum and other Web-based resources. I'm familiar with some scripting languages like Ruby and Lua, but I could be persuaded that a compiled application is better suited for these tasks. However in my experience the dynamic flexibility of interpreted environments is very useful in prototyping and debugging the application logic. So I'm leaning in the direction of scripting languages. Among browsers I favor Firefox and Chrome. I use both Windows and Linux platforms, and if the tool can adapt to an Android platform, it would make a neat demonstration of skills, yes? Thanks in advance for your suggestions!

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  • proxychained browser unable to open files

    - by Cocoro Cara
    Ubuntu 10.10, Midori 0.3.2 browser (same problem with Epiphany 2.30.2, Chrome 11.0.686.1 dev; haven't tried with Firefox as yet) Proxychains-3.1 installed, working fine. Here is the deal: when NOT proxychained, Midori or Epiphany can download and open a file (e.g. PDFs from a Google search) in Evince without problem. But when proxychained, neither browser can open PDF files. The message is, "file xxx downloaded". Then it tries to open the file, an indication appears in the status bar, the turning wheel appears, and then nothing. Evince doesn't open. Whats going on here? In both cases (with and without proxychains) files are downloaded to the /tmp folder. They have the same file permissions and ownership. Whats different when proxychained? Why can't the files be opened and why are there no error messages or notifications. Why the silent failure? I don't want to use FF or Chrome. Chrome does not follow my GTK2 customizations and FF is just too resource heavy. Please help.

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  • Most suited technology for browser games?

    - by Tingle
    I was thinking about making a 2D MMO which I would in the long run support on various plattforms like desktop, mac, browser, android and ios. The server will be c++/linux based and the first client would go in the browser. So I have done some research and found that webgl and flash 11 support hardware accelerated rendering, I saw some other things like normal HTML5 painting. So my question is, which technology should I use for such a project? My main goal would be that the users have a hassle free experience using what there hardware can give them with hardware acceleration. And the client should work on the most basic out-of-the-box pc's that any casual pc or mac user has. And another criteria would be that it should be developer friendly. I've messed with webgl abit for example and that would require writing a engine from scratch - which is acceptable but not preferred. Also, in case of non-actionscript, which kind language is most prefered in terms of speed and flexability. I'm not to fond of javascript due to the garbage collector but have learned to work around it. Thank you for you time.

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  • 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.

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