ajax pro - Page 57 - Developer IT

difference between ajax and submit

- by kawtousse

hey, I just want to know what is the difference between sending parameter with ajax(post/get) to a servlet and sending them with "submit" . Thanks for your help.

Unable to execute functions on elements loaded with AJAX (jQuery)

i am using .prepend() to load data after i POST a form with .ajax(). once the new elements are added, my functions won't work on them. if i link the js file directly in the prepended data, the functions work, but when i POST, i starts multiplying the events. i have a feeling it has something to do with binding, but i am not able to figure out exactly how to handle it. any ideas? thanks!

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Performance difference between MacBook Pro (2.8 GHz) vs Air (1.7 GHz)?

- by jonathanconway

I'm comparing these two Apple laptops: MacBook Pro (13", 2011 model): 2.8GHz dual-core Intel Core i7 processor with 4MB shared L3 cache 4GB (two 2GB SO-DIMMs) of 1333MHz DDR3 SDRAM AMD Radeon HD 6770M graphics processor with 1GB of GDDR5 memory on 2.4GHz configuration MacBook Air (13", 2011 model): 1.7GHz dual-core Intel Core i5 with 3MB shared L3 cache 4GB of 1333MHz DDR3 onboard memory Intel HD Graphics 3000 processor with 384MB of DDR3 SDRAM shared with main memory There's definitely a gap between them in terms of CPU speed and graphics, but what practical difference would this make on a day-to-day basis? On the one hand, I love the sleek, thin appearance of the Air. On the other hand, I don't want a machine that's going to be dog-slow when doing tasks such as running Virtual Machines, dual-booting to Windows and running multiple instances of Visual Studio, and maybe some light gaming. Is there going to be a major difference that makes the MacBook Pro a more attractive purchase?

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How do I type Home on a MacBook Pro?

- by Daryl Spitzer

What combination of keys (fn, control, option, command, arrow keys) is the equivalent of the Home key on a MacBook Pro?

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How to prepare and secure a Macbook Pro for work/office?

- by sunpech

I plan to use my Macbook Pro at work/office. Before I do so, I will need to speak to my manager on how to properly prepare and secure it since this is the first Mac that will be regularly used on the network in the office and company intranet. The intranet comprises mostly of PCs running Microsoft Windows XP, Server 2003, and Windows 7. So there's definitely a Microsoft-only culture in the office, and the infrastructure/networking team are mostly unfamiliar with non-Microsoft technology and software. What steps and software would I need to prepare and secure my Macbook Pro for work/office? Antivirus/Spyware software for Mac required/necessary? What options do I have to encrypt files, or possibly the whole drive/partition? What network/firewall settings should be enabled?

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Java Spotlight Episode 76: Pro Java FX2 - A Definative Guide to Rich Clients with Java Technology

- by Roger Brinkley

Tweet An interview with the authors of Pro Java FX2: A Definative Guide to Rich Clients with Java Technology. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link: Java Spotlight Podcast in iTunes. Show Notes News Angela Caicedo has created 3 new Java FX screen cast videos on java UTube channel: Part 1: Building your First Java FX Application with Netbeans 7.1, Part 2: Building your First Java FX Application with Netbeans 7.1, and Getting Started with Scene Builder. Events March 26-29, EclipseCon, Reston, USA March 27, Virtual Developer Days - Java (Asia Pacific (English)),9:30 am to 2:00pm IST / 12:00pm to 4.30pm SGT / 3.00pm - 7.30pm AEDT April 4-5, JavaOne Japan, Tokyo, Japan April 12, GreenJUG, Greenville, SC April 17-18, JavaOne Russia, Moscow Russia April 18–20, Devoxx France, Paris, France April 26, Mix-IT, Lyon, France, May 3-4, JavaOne India, Hyderabad, India Feature InterviewPro JavaFX 2: A Definitive Guide to Rich Clients with Java Technology is available from Amazon.com in either paperback or on the Kindle.James L. (Jim) Weaver is a Java and JavaFX developer, author, and speaker with a passion for helping rich-client Java and JavaFX become preferred technologies for new application development. Books that Jim has authored include Inside Java, Beginning J2EE, and Pro JavaFX Platform, with the latter being updated to cover JavaFX 2.0. His professional background includes 15 years as a systems architect at EDS, and the same number of years as an independent developer. Jim is an international speaker at software technology conferences, including the JavaOne conferences in San Francisco and São Paulo. Jim blogs at http://javafxpert.com, tweets @javafxpert. Weiqi Gao is a principal software engineer with Object Computing, Inc., in St. Louis, MO. He has more than 18 years of software development experience and has been using Java technology since 1998. He is interested in programming languages, object-oriented systems, distributed computing, and graphical user interfaces. He is a presenter and a member of the steering committee of the St. Louis Java Users Group. Weiqi holds a PhD in mathematics. Stephen Chin is chief agile methodologist at GXS and a technical expert in client UI technologies. He is lead author on the Pro Android Flash title and coauthored the Pro JavaFX Platform title, which is the leading technical reference for JavaFX. In addition, Stephen runs the very successful Silicon Valley JavaFX User Group, which has hundreds of members and tens of thousands of online viewers. Finally, he is a Java Champion, chair of the OSCON Java conference, and an internationally recognized speaker featured at Devoxx, Codemash, AnDevCon, Jazoon, and JavaOne, where he received a Rock Star Award. Stephen can be followed on twitter @steveonjava and reached via his blog: http://steveonjava.com.Dean Iverson has been writing software professionally for more than 15 years. He is employed by the Virginia Tech Transportation Institute, where he is a rich client application developer. He also has a small software consultancy called Pleasing Software Solutions, which he cofounded with his wife. Johan Vos started to work with Java in 1995. As part of the Blackdown team, he helped port Java to Linux. With LodgON, the company he cofounded, he has been mainly working on Java-based solutions for social networking software. Because he can't make a choice between embedded development and enterprise development, his main focus is on end-to-end Java, combining the strengths of backend systems and embedded devices. His favorite technologies are currently Java EE/Glassfish at the backend and JavaFX at the frontend. Johan's blog can be followed at http://blogs.lodgon.com/johan, he tweets at http://twitter.com/johanvos. Mail Bag What’s Cool Gerrit Grunwald's SteelSeries FX Experience Tools Canned Animations ComboBox

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How can I boot Ubuntu 10.04 on my MacBook Pro from a USB hard drive?

- by Daniel Huckstep

I installed Ubuntu 10.04 to my MacBook Pro (not the latest gen with i7, but one before that) on an external, USB harddrive (GRUB installed to the external as well). When I hold down the option key to try to select the external, it doesn't show up. After some looking around, my understanding is that it won't boot 'unsupported' operating system from an external drive. I have ran OSX from an external when I upgraded my harddrive. What can I do (or is it even possible) to allow my MacBook Pro to boot the Ubuntu drive?

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Is there any Mac Pro hardware parts that can ONLY be purchased thru Apple?

- by bigp

I'd like to know if I need to be concerned about any hardware parts that I should include in a brand new Mac Pro purchase, instead of trying to hunt it down on 3rd party vendors (or whitelist vendors / hardware suppliers). The main components I'm interested for "upgradeability" are: Processors (If starting with Two 2.4GHz Quad-Core "Westmere"); RAM (If starting with the least possible, which seems to be 6 x 1GB); Video Cards (If starting with one ATI Radeon HD 5770, can a 2nd one be purchased elsewhere?) Hard-Drives (Since these are mounted in specialized trays [if I'm not mistaking], are they also sold elsewhere? And can they be bought as SSDs?) Power Supply (Do I need to be concerned about this at all, or does it auto-adjust depending on the new component upgrades?) I just want to be sure by choosing a Mac Pro with lower component specifications that I can in fact purchase upgrade parts cheaper elsewhere. Thanks!

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How to swap ctrl and fn key on a MacBook Pro running Windows 7 via Boot Camp?

- by hobbes3

There are sooooo many discussion on the internet about swapping the fn and ctrl key on a MacBook Pro. On the Mac side, a new software called ReMap4MacBook does a perfect job swapping the two key. But on the PC side (specifically Windows 7), I can't really find a definitive answer. Most post refer to this article but I read the loooong article and followed the instructions to no avail. I remember there used to be a program (maybe it was on XP) that not only swapped the two keys but it also controlled the fans on the MacBook Pro. But I can't remember the name and I also recall that that program stopped being updated like years ago. EDIT: It's called Input Remapper. So I am hoping there exist a simple program that I can simply run to swap those two keys.

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How can I format a USB drive as FAT from a MacBook Pro?

- by Edward Tanguay

I plugged in a 250GB USB hard drive into my MacBook Pro and want to format it in FAT so I can transfer files back and forth between a windows machine. (My windows7 machine only formats in exFAT which my Snow Leopard 2.6.4 doesn't support until I do the update). So I want to format it on the mac. but when I right click on the drive, it gives me the options to eject, copy, but not to format. I can go into Disk Utilities, click on Partition, but the only option is the "Mac Journaled format". How can I Format my USB drive as FAT from my MacBook Pro?

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How should I handle a redirect to an identity provider during a web api data request

- by Erds

Scenario I have a single-page web app consisting purely of html, css, and javascript. After initial load and during use, it updates various views with data from one or more RESTful apis via ajax calls. The api calls return data in a json format. Each web api may be hosted on independent domains. Question During the ajax callout, if my authorization token is not deemed valid by the web api, the web api will redirect me (302) to the identity provider for that particular api. Since this is an ajax callout for data and not necessarily for display, i need to find a way to display the identity provider's authentication page. It seems that I should trap that redirect, and open up another view to display the identity provider's login page. Once the oauth series of redirects is complete, i need to grab the token and retrigger my ajax data call with the token attached. Is this a valid approach, and if so are there any examples showing the ajax handling of the redirects?

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How can Perl interact with an ajax form

- by Jeff

I'm writing a perl program that was doing a simple get command to retrieve results and process them. But the site has been updated and now has a java component that handles the results (so the actual data is not in the source code anymore). This is the site: http://wro.westchesterclerk.com/legalsearch.aspx Try putting in: Index Number: 11103 Year: 2009 I want to be able to pro grammatically enter the "index number" and "year" at the bottom of the form where it says "search by number" and then retrieve the results listed next to it. I've written many programs in Perl that simply pass variables via the URL and the results are listed in the source code, so it's easy to parse. (Using LWP:Simple) Like: $html = get("http://www.url.com?id=$somenum&year=$someyear") But this is totally new to me and I don't know where to begin. I'm somewhat familiar with LWP:UserAgent and Mechanize. I'd really appreciate any help. Thanks!

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Why updatepanel triggers another updatepanel?

- by HasanGursoy

I have two update panels at my ajax page. This is first time I'm using updatepanel and I don't know what is wrong. I think only btnFilter's Click event must trigger the second update panel's content but changing combo values (which also hides/unhides btnFilter button) makes second updatepanel change content (at least I see transferred data with firebug & second updatepanel blinks sometimes). Online here. <asp:UpdatePanel ID="upComparison" runat="server"> <ContentTemplate> Brand: <asp:DropDownList ID="ddlBrands" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlBrands_SelectedIndexChanged" AppendDataBoundItems="true"> <asp:ListItem Value="" Text="Please select a brand..." /> </asp:DropDownList> <asp:Panel ID="pModels" runat="server" Visible="false"> Model: <asp:DropDownList ID="ddlModels" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlModels_SelectedIndexChanged" /> </asp:Panel> <asp:Panel ID="pButton" runat="server" Visible="false"> <asp:UpdateProgress ID="upMain" runat="server" DisplayAfter="100"> <ProgressTemplate><img src="/Assets/Images/loader.gif" /> </ProgressTemplate> </asp:UpdateProgress> <asp:Button ID="btnFilter" runat="server" Text="Filter" OnClick="btnFilter_Click" /> </asp:Panel> </ContentTemplate> </asp:UpdatePanel> <asp:UpdatePanel ID="upList" runat="server"> <ContentTemplate> <asp:Repeater ID="rProducts" runat="server"> <ItemTemplate>some code here</ItemTemplate> </asp:Repeater> </ContentTemplate> <Triggers> <asp:AsyncPostBackTrigger ControlID="btnFilter" EventName="Click" /> </Triggers> </asp:UpdatePanel>

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UpdatePanel not working in IE or Chrome

- by gevjen

I have an updatepanel on my masterpage. Within the contentplace holder I have my update progress control. When a user clicks on the button I load some data into a gridview. This works perfectly in FireFox. User clicks the button, the loading image in my updateprogress fires and loads the gridview. When I test this in IE 6 or 7 or in Chrome. It does a full postback and the updateprogress is never shown. So the updatepanel doesnt seem to be working in these two browsers. Code is below. Again...it works perfect in FireFox. ***From Masterpage *** <asp:UpdatePanel ID="UpdatePanel" runat="server"> <contenttemplate> <asp:contentplaceholder id="holder" runat="server" /> </contenttemplate> </asp:UpdatePanel> **From aspx page **** <asp:UpdateProgress ID="UpdateProgress1" runat="server"> <ProgressTemplate> <img src="ajax-loader.gif" /> </ProgressTemplate> </asp:UpdateProgress>

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Internet Explorer ajax request not returning anything

- by Ryan Giglio

At the end of my registration process you get to a payment screen where you can enter a coupon code, and there is an AJAX call which fetches the coupon from the database and returns it to the page so it can be applied to your total before it is submitted to paypal. It works great in Firefox, Chrome, and Safari, but in Internet Explorer, nothing happens. The (data) being returned to the jQuery function appears to be null. jQuery Post function applyPromo() { var enteredCode = $("#promoCode").val(); $(".promoDiscountContainer").css("display", "block"); $(".promoDiscount").html("<img src='/images/loading.gif' alt='Loading...' title='Loading...' height='18' width='18' />"); $.post("/ajax/lookup-promo.php", { promoCode : enteredCode }, function(data){ if ( data != "error" ) { var promoType = data.getElementsByTagName('promoType').item(0).childNodes.item(0).data; var promoAmount = data.getElementsByTagName('promoAmount').item(0).childNodes.item(0).data; $(".promoDiscountContainer").css("display", "block"); $(".totalWithPromoContainer").css("display", "block"); if (promoType == "percent") { $("#promoDiscount").html("-" + promoAmount + "%"); var newPrice = (originalPrice - (originalPrice * (promoAmount / 100))); $("#totalWithPromo").html(" $" + newPrice); if ( promoAmount == 100 ) { skipPayment(); } } else { $("#promoDiscount").html("-$" + promoAmount); var newPrice = originalPrice - promoAmount; $("#totalWithPromo").html(" $" + newPrice); } $("#paypalPrice").val(newPrice + ".00"); $("#promoConfirm").css("display", "none"); $("#promoConfirm").html("Promotion Found"); finalPrice = newPrice; } else { $(".promoDiscountContainer").css("display", "none"); $(".totalWithPromoContainer").css("display", "none"); $("#promoDiscount").html(""); $("#totalWithPromo").html(""); $("#paypalPrice").val(originalPrice + ".00"); $("#promoConfirm").css("display", "block"); $("#promoConfirm").html("Promotion Not Found"); finalPrice = originalPrice; } }, "xml"); } Corresponding PHP Page include '../includes/dbConn.php'; $enteredCode = $_POST['promoCode']; $result = mysql_query( "SELECT * FROM promotion WHERE promo_code = '" . $enteredCode . "' LIMIT 1"); $currPromo = mysql_fetch_array( $result ); if ( $currPromo ) { if ( $currPromo['percent_off'] != "" ) { header("content-type:application/xml;charset=utf-8"); echo "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>"; echo "<promo>"; echo "<promoType>percent</promoType>"; echo "<promoAmount>" . $currPromo['percent_off'] . "</promoAmount>"; echo "</promo>"; } else if ( $currPromo['fixed_off'] != "") { header("content-type:application/xml;charset=utf-8"); echo "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>"; echo "<promo>"; echo "<promoType>fixed</promoType>"; echo "<promoAmount>" . $currPromo['fixed_off'] . "</promoAmount>"; echo "</promo>"; } } else { echo "error"; } When I run the code in IE, I get a javascript error on the Javascript line that says var promoType = data.getElementsByTagName('promoType').item(0).childNodes.item(0).data; Here's a screenshot of the IE debugger

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Sys.WebForms.PageRequestManagerServerErrorException: .... The status code returned from the server w

- by webnoob

Hi All, I have seen a few posts regarding this issue but not one specific to my problem and I have no ideas as to what I need to do to debug this. I have some combo boxes on an aspx pages, when I select a value from the first one, it fills the second with value and so on with the third and fourth. This works with no problems until I wrap an asp.net UpdatePanel around the combo boxes and try to "ajaxify" the whole process so the page isn't dancing around. The exact error I get is: Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 404 Some things to note: I am using URL rewriting - This is what I think is causing the problem The error will occur whenever I choose a selection for a SECOND time. This means that I could select a value from the first combo box and get the same error (so it is happening on the second postback - No matter which combo box it's from). I have tried setting the EnablePartialRendering="false" on teh scriptmanager but as I said, it works when not using ajax, so I don't know how to debug the issue. My server is Windows 2008 running IIS& with ASP.NET 2.0. I would really appreciate your help Thanks in advance.

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Rails destroy confirm with Jquery AJAX

- by Mike

I have got this working for the most part. My rails link is: <%= link_to(image_tag('/images/bin.png', :alt => 'Remove'), @business, :class => 'delete', :confirm => 'Are you sure?', :id => 'trash') %> :class = "delete" is calling an ajax function so that it is deleted and the page isn't refreshed that works great. But because the page doesn't refresh, it is still there. So my id trash is calling this jquery function: $('[id^=trash]').click(function(){ var row = $(this).closest("tr").get(0); $(row).hide(); return false; }); Which is hiding the row of whatever trash icon i clicked on. This also works great. I thought I had it all worked out and then I hit this problem. When you click on my trash can I have this confirm box pop up to ask you if you are sure. Regardless of whether you choose cancel or accept, the jquery fires and it hides the row. It isn't deleted, only hidden till you refresh the page. I tried changing it so that the prompt is done through jquery, but then rails was deleteing the row regardless of what i choose in my prompt because the .destroy function was being called when the prompt was being called. My question really is how can i get the value to cancel or accept from the rails confirm pop up so that in my jquery I can have an if statement that hides if they click accept and does nothing if they click cancel. EDIT: Answering Question below. That did not work. I tried changing my link to: <%= link_to(image_tag('/images/bin.png', :alt => 'Remove'), @business, :class => "delete", :onclick => "trash") %> and putting this in my jquery function trash(){ if(confirm("Are you sure?")){ var row = $(this).closest("tr").get(0); $(row).hide(); return false; } else { //they clicked no. } } But the function was never called. It just deletes it with no prompt and doesn't hide it. But that gave me an idea. I took the delete function that ajax was calling $('a.delete').click (function(){ $.post(this.href, {_method:'delete'}, null, "script"); $(row).hide(); }); And modified it implementing your code: remove :confirm = 'Are you sure?' $('a.delete').click (function(){ if(confirm("Are you sure?")){ var row = $(this).closest("tr").get(0); $.post(this.href, {_method:'delete'}, null, "script"); $(row).hide(); return false; } else { //they clicked no. return false; } }); Which does the trick.

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Dual AJAX Requests at different times

- by Nik

Alright, I'm trying to make an AJAX Chat system that polls the chat database every 400ms. That part is working, the part of which isn't is the Active User List. When I try to combine the two requests, the first two requests are made, then the whole thing snowballs and the usually timed (12 second) Active User List request starts updating every 1ms and the first request NEVER happens again. Displayed is the entire AJAX code for both requests: var waittime=400;chatmsg=document.getElementById("chatmsg"); room = document.getElementById("roomid").value; chatmsg.focus() document.getElementById("chatwindow").innerHTML = "loading..."; document.getElementById("userwindow").innerHTML = "Loading User List..."; var xmlhttp = false; var xmlhttp2 = false; var xmlhttp3 = false; function ajax_read(url) { if(window.XMLHttpRequest){ xmlhttp=new XMLHttpRequest(); if(xmlhttp.overrideMimeType){ xmlhttp.overrideMimeType('text/xml'); } } else if(window.ActiveXObject){ try{ xmlhttp=new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) { try{ xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } catch(e){ } } } if(!xmlhttp) { alert('Giving up :( Cannot create an XMLHTTP instance'); return false; } xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState==4) { document.getElementById("chatwindow").innerHTML = xmlhttp.responseText; setTimeout("ajax_read('methods.php?method=r&room=" + room +"')", waittime); } } xmlhttp.open('GET',url,true); xmlhttp.send(null); } function user_read(url) { if(window.XMLHttpRequest){ xmlhttp3=new XMLHttpRequest(); if(xmlhttp3.overrideMimeType){ xmlhttp3.overrideMimeType('text/xml'); } } else if(window.ActiveXObject){ try{ xmlhttp3=new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) { try{ xmlhttp3=new ActiveXObject("Microsoft.XMLHTTP"); } catch(e){ } } } if(!xmlhttp3) { alert('Giving up :( Cannot create an XMLHTTP instance'); return false; } xmlhttp3.onreadystatechange = function() { if (xmlhttp3.readyState==4) { document.getElementById("userwindow").innerHTML = xmlhttp3.responseText; setTimeout("ajax_read('methods.php?method=u&room=" + room +"')", 12000); } } xmlhttp3.open('GET',url,true); xmlhttp3.send(null); } function ajax_write(url){ if(window.XMLHttpRequest){ xmlhttp2=new XMLHttpRequest(); if(xmlhttp2.overrideMimeType){ xmlhttp2.overrideMimeType('text/xml'); } } else if(window.ActiveXObject){ try{ xmlhttp2=new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) { try{ xmlhttp2=new ActiveXObject("Microsoft.XMLHTTP"); } catch(e){ } } } if(!xmlhttp2) { alert('Giving up :( Cannot create an XMLHTTP instance'); return false; } xmlhttp2.open('GET',url,true); xmlhttp2.send(null); } function submit_msg(){ nick = document.getElementById("chatnick").value; msg = document.getElementById("chatmsg").value; document.getElementById("chatmsg").value = ""; ajax_write("methods.php?method=w&m=" + msg + "&n=" + nick + "&room=" + room + ""); } function keyup(arg1) { if (arg1 == 13) submit_msg(); } var intUpdate = setTimeout("ajax_read('methods.php')", waittime); var intUpdate = setTimeout("user_read('methods.php')", waittime);

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using JQuery and Ajax to post a form

- by hopes

Hi there, I want to use ajax to post my form I want radiobuttons to do this(there is no submit buton) so clicking a radiobutton will cause a form to be submitted or be post my php page needs to know the name of the radio button clicked is my code correct? cuz it doesn't work and I don't know why? <div id="Q1"> <form id="Question1" method='post'> <br /> <P> The sky color is.. </P><img border="0" src="images/wonder.png" width="94" height="134"/><br /><br /><br /> <input type="radio" id="option1" name="answer[1]" value="correct!"/> blue <br /> <input type="radio" id="option1" name="answer[1]" value="false!"/> red <br /> <input type="radio" id="option1" name="answer[1]" value="false!"/> green <br /> <input type="radio" id="option1" name="answer[1]" value="false!"/> white <br /> <br /> </Form>  <img border="0" src="images/welldone3.png" width="230" height="182" id="greatp" style="display: none;"/>  <img border="0" src="images/failed3.png" width="230" height="182" id="sorryp" style="display: none;"/> <img src="images/false2.png"id="myImage1"style="display: none;"/> <img src="images/correct2.png"id="myImage2"style="display: none;"/>  <input type="image" src="images/next.png" name="image" width="80" height="30" onclick="Next1()"> </div> jquery cod: <script> $(document).ready(function(){ $("#option1").click(function() { var answer= $("#option1").value; var fff= $("#option1").name; $.ajax({ type: "POST", url: "page2.php", data: fff, success: function(){ if(answer=='correct!') { $('#greatp').show(); $('#myImage2').show(); $('#Question1').hide(); } else { $('#sorryp').show(); $('#myImage1').show(); $('#Question1').hide(); } } }); return false; }); }); </script>

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REST WCF service locks thread when called using AJAX in an ASP.Net site

- by Jupaol

I have a WCF REST service consumed in an ASP.Net site, from a page, using AJAX. I want to be able to call methods from my service async, which means I will have callback handlers in my javascript code and when the methods finish, the output will be updated. The methods should run in different threads, because each method will take different time to complete their task I have the code semi-working, but something strange is happening because the first time I execute the code after compiling, it works, running each call in a different threads but subsequent calls blocs the service, in such a way that each method call has to wait until the last call ends in order to execute the next one. And they are running on the same thread. I have had the same problem before when I was using Page Methods, and I solved it by disabling the session in the page but I have not figured it out how to do the same when consuming WCF REST services Note: Methods complete time (running them async should take only 7 sec and the result should be: Execute1 - Execute3 - Execute2) Execute1 -- 2 sec Execute2 -- 7 sec Execute3 -- 4 sec Output After compiling Output subsequent calls (this is the problem) I will post the code...I'll try to simplify it as much as I can Service Contract [ServiceContract( SessionMode = SessionMode.NotAllowed )] public interface IMyService { // I have other 3 methods like these: Execute2 and Execute3 [OperationContract] [WebInvoke( RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, UriTemplate = "/Execute1", Method = "POST")] string Execute1(string param); } [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] [ServiceBehavior( InstanceContextMode = InstanceContextMode.PerCall )] public class MyService : IMyService { // I have other 3 methods like these: Execute2 (7 sec) and Execute3(4 sec) public string Execute1(string param) { var t = Observable.Start(() => Thread.Sleep(2000), Scheduler.NewThread); t.First(); return string.Format("Execute1 on: {0} count: {1} at: {2} thread: {3}", param, "0", DateTime.Now.ToString(), Thread.CurrentThread.ManagedThreadId.ToString()); } } ASPX page <%@ Page EnableSessionState="False" Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="RestService._Default" %> <asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent"> <script type="text/javascript"> function callMethodAsync(url, data) { $("#message").append("<br/>" + new Date()); $.ajax({ cache: false, type: "POST", async: true, url: url, data: '"de"', contentType: "application/json", dataType: "json", success: function (msg) { $("#message").append("<br/>   " + msg); }, error: function (xhr) { alert(xhr.responseText); } }); } $(function () { $("#callMany").click(function () { $("#message").html(""); callMethodAsync("/Execute1", "hello"); callMethodAsync("/Execute2", "crazy"); callMethodAsync("/Execute3", "world"); }); }); </script> </asp:Content> <asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent"> <input type="button" id="callMany" value="Post Many" /> <div id="message"> </div> </asp:Content> Web.config (relevant) <system.webServer> <modules runAllManagedModulesForAllRequests="true" /> </system.webServer> <system.serviceModel> <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" /> <standardEndpoints> <webHttpEndpoint> <standardEndpoint name="" helpEnabled="true" automaticFormatSelectionEnabled="true" /> </webHttpEndpoint> </standardEndpoints> </system.serviceModel> Global.asax void Application_Start(object sender, EventArgs e) { RouteTable.Routes.Ignore("{resource}.axd/{*pathInfo}"); RouteTable.Routes.Add(new ServiceRoute("", new WebServiceHostFactory(), typeof(MyService))); }

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Ajax Calendar Date Range with JavaScript

- by hungrycoder

I have the following code to compare two dates with the following conditions Scenario: On load there are two text boxes (FromDate, ToDate) with Ajax calendar extenders. On load From Date shows today's date. when date less than today was selected in both text boxes(FromDate, ToDate), it alerts user saying "You cannot select a day earlier than today!" When ToDate's Selected date < FromDate's Selected Date, alerts user saying "To Date must be Greater than From date." and at the same time it clears the selected Date in ToDate Text box. Codeblock: ASP.NET , AJAX <asp:TextBox ID="txtFrom" runat="server" ReadOnly="true"></asp:TextBox> <asp:ImageButton ID="imgBtnFrom" runat="server" ImageUrl="~/images/Cal20x20.png" Width="20" Height="20" ImageAlign="TextTop" /> <asp:CalendarExtender ID="txtFrom_CalendarExtender" PopupButtonID="imgBtnFrom" runat="server" Enabled="True" OnClientDateSelectionChanged="checkDate" TargetControlID="txtFrom" Format="MMM d, yyyy"> </asp:CalendarExtender> <asp:TextBox ID="txtTo" runat="server" ReadOnly="true"></asp:TextBox> <asp:ImageButton ID="imgBtnTo" runat="server" ImageUrl="~/images/Cal20x20.png" Width="20" Height="20" ImageAlign="TextTop" /> <asp:CalendarExtender ID="txtTo_CalendarExtender" OnClientDateSelectionChanged="compareDateRange" PopupButtonID="imgBtnTo" runat="server" Enabled="True" TargetControlID="txtTo" Format="MMM d, yyyy"> </asp:CalendarExtender> <asp:HiddenField ID="hdnFrom" runat="server" /> <asp:HiddenField ID="hdnTo" runat="server" /> C# Code protected void Page_Load(object sender, EventArgs e) { txtFrom.Text = string.Format("{0: MMM d, yyyy}", DateTime.Today); if (Page.IsPostBack) { if (!String.IsNullOrEmpty(hdnFrom.Value as string)) { txtFrom.Text = hdnFrom.Value; } if (!String.IsNullOrEmpty(hdnTo.Value as string)) { txtTo.Text = hdnTo.Value; } } } JavaScript Code <script type="text/javascript"> function checkDate(sender, args) { document.getElementById('<%=txtTo.ClientID %>').value = ""; if (sender._selectedDate < new Date()) { alert("You cannot select a day earlier than today!"); sender._selectedDate = new Date(); // set the date back to the current date sender._textbox.set_Value(sender._selectedDate.format(sender._format)); //assign the value to the hidden field. document.getElementById('<%=hdnFrom.ClientID %>').value = sender._selectedDate.format(sender._format); //reset the to date to blank. document.getElementById('<%=txtTo.ClientID %>').value = ""; } else { document.getElementById('<%=hdnFrom.ClientID %>').value = sender._selectedDate.format(sender._format); } } function compareDateRange(sender, args) { var fromDateString = document.getElementById('<%=txtFrom.ClientID %>').value; var fromDate = new Date(fromDateString); if (sender._selectedDate < new Date()) { alert("You cannot select a Date earlier than today!"); sender._selectedDate = ""; sender._textbox.set_Value(sender._selectedDate) } if (sender._selectedDate <= fromDate) { alert("To Date must be Greater than From date."); sender._selectedDate = ""; sender._textbox.set_Value(sender._selectedDate) } else { document.getElementById('<%=hdnTo.ClientID %>').value = sender._selectedDate.format(sender._format); } } </script> Error Screen(Hmmm :X) Now in ToDate, when you select Date Earlier than today or Date less than FromDate, ToDate Calendar shows NaN for Every Date and ,0NaN for Year

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Introduction to the ASP.NET Web API

- by Stephen.Walther

I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html> Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "\n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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Introduction to the ASP.NET Web API

- by Stephen.Walther

I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html> Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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Can I output/flush data to screen while processing ajax page?

- by Bee

I need to display on my page a list of records pulled from a table. Ajax works fine (I query the database and put all the data inside a on the main page) but if I have lots of records (say 500+) it will hang until data is fully loaded, THEN it will be sent back to the page and correctly displayed. I would like to be able to display the records on the page while getting them, instead of being forced to wait until completion. I am trying with flush(); inside the remote (ajax) page but it still waits until full data is loaded. This is what I currently have inside the ajax page: At the very beginning: @apache_setenv('no-gzip', 1); @ini_set('zlib.output_compression', 0); @ini_set('implicit_flush', 1); for ($i = 0; $i < ob_get_level(); $i++) { ob_end_flush(); } ob_implicit_flush(1); Then whenever I have a echo call: ob_flush(); Now if I load the ajax page alone... it will list the records while reading them from the database. But if I call the same page via Ajax, it will hang and send all the data at once. Any idea? This is the function I use to get the ajax content ('id' is the target , 'url' refers to the ajax page that runs the database query to list the records): function ajax(id,url) { xmlhttp=new XMLHttpRequest(); xmlhttp.open("GET",url,false); xmlhttp.send(null); document.getElementById(id).innerHTML = parseScript(xmlhttp.responseText); }

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ASP.NET AJAX ToolkitScriptManager Issue With Combining Scripts

- by Kumar

I have an ASP.NET 3.5 web application in which i am using the ToolkitScriptManager as below: <ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager1" EnablePageMethods="true" ScriptMode="Release" LoadScriptsBeforeUI="false" runat="server" CombineScripts="false"> <CompositeScript> <Scripts> <asp:ScriptReference Path="~/JavaScript/jquery-1.4.1.min.js" /> <asp:ScriptReference Path="~/JavaScript/Validators.js" /> </Scripts> </CompositeScript> </ajaxToolkit:ToolkitScriptManager> This works fine but from a performance standpoint this is not good as the pages are making a lot of requests to the webresources.axd and scriptresource.axd files. When I changed the CombineScripts property to true my ASP.NET AJAX control extenders are no longer working. What is the reason for this weired behavior and is there a fix for this?

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