الصرفة والتطبیقیة 2009) 4 (22 المجلد مجلة ابن الھیثم للعلوم دون الحاجة ASP.NET غیر المتزامن في ال الملفاتحل مشكلة تحمیل مقترح ل الى استخدام تقنیة االجاكس سالم شاكر كتاب ابن الهیثم، جامعة بغداد–قسم علوم الحاسبات، كلیة التربیة الخالصة File Up ( ملفاتمحمل ال إن load( هو احد ال cont rols ط الموجودة ضمن في ال األدواتشری Visual Studio.N ET ال ولكن ال یمكن استخدام هذا control مع تقنیة الAjax ) ل في الوقت فیكاد یكون من المستحی ا من دون ان تكون مستن الحاضر ا كستهتم بتصمیم تطبیقات الوب او تطویره نیة االجا ال یدعم File Uploadالن ) خدما لتق از بشكل غیر مكتمل هذه التقنیه حیث یكون التنفیذ لال object is not عبارةتظهر أویع set على الرغم من الحاجة الماسة یر مع االجاكس لالcontrol الستخدام هذا ال س المتزامنستفادة من نقل البیانات غ ره االجاك File الن وذلك، الذي یوف Up load control عند حدوث عملیة إالال یعمل Post backمن ال client الى ال server یه لفلسفة اس عمل والفكرة االس XM( بل انشاء كائن برمجي serverالى ال Postbackاالجاكس هي عدم القیام بعملیة LHttpRequest( یتصل موقعفيالموسع وبعد البحث . )Web Site( من الصفحة للقیام بعملیة تحدیث جزئیة لقسم محددserver بال net.asp.www موقع توصل الى ان com.microsoft.msdn.wwwو lcont هذا التم ال ro سوف یقوم بدعم تقنیة ملیة ال ،VisualStudio.net 2008الحق لاالجاكس في االصدار ا ستمرة م Postback اال ان الحل لم یكن حقیقیا الن ع لحاجة الى اقتراح حل بدیل. Postback Trigger ال ب مایعرفافاضافو، یضاا عن استخدام تقنیة االجاكس من لذلك اقتضت ا Web Servخالل بناء ices بالكامل بعملیة التحمیل بشكل غیر متزامن و تجنب اعادة ت لتقوم Postback) حمیل الصفحة op eration) تعند . محاولة تحمیل الملفا IBN AL- H AITHAM J. FO R PURE & APPL. S CI VO L.22 (4) 2009 A Suggestion To Solve The Problem Of Asynchronous File Uploads In ASP.NET Without The Need To Use Ajax Technolo gy S. S. Kitab De partment of Com puter Science, College of Education - Ibn Al-haitham, Baghda d University, Abstrac t The file up load is one of the cont rols of t he tool bar of t he VisualStodio.NET, but it can’t be used with Ajax techno lo gy (It 's almost imp ossible today to be involved in web ap p lication design or develop ment and not be aware of Ajax) because the file upload cont rol don’t supp ort Ajax technology that the execution of t he inst ruction is not comp leted or t he (object is not set) message will ap p ear, although the ess ential ne ed to use this control with Ajax to gain the asynchronous data transfer that supp lied by Ajax, be cause the file up load don’t work without the Postback op eration from t he client to the server, and t he main idea of Ajax technolo gy is working without Postback op eration to the server. After the deep research in www.asp .net and www.msdn.microsoft.com sit es the result was that the solution will be in the next version VisualStodio.NET 2008, but it was not a real solution because the Postback op eration is continuous. So this p ap er suggests alternative solution to Ajax by building Web Services to up load files asy nchronously and avoid reload the whole web site (Postback operation) when file up loading process is lemented. Introductio n As the web grows and bandwidth increases, p eop le demand more fro m their online exp eriences. They want more cont ent and grap hics, smarter ap p lications, and instantaneous responses [1]. Until recently , web app lication develop ers and end users for that matter st ruggled with slow , unresponsive sy stems where entire p ages had to be reloaded to up date a single element. The web's architecture simply was not a convenient p latform for demanding app lications [2]. Many solutions, like Google M ap s, were not even p ossible until the wide-sp read adopt ion of Ajax occurred. AJAX is not a new p rogramming language, but a technique for creatin g better, faster, and more int eractive web app lications [3]. With AJAX, y our JavaScrip t can commun icate directly with the server, using the JavaScript XM LHttpRequest object. With this object, y our JavaScript can trade data with a web server, without reloading the page, but it not supp lied by the file up load control ability [4]. One of the most imp ortant things that should be transferred through the web are the files, so we discus sed an ap proach to uploading f iles to a web server directly through an ASPX p age, or through a web serv ice. The method is used to asy nchronously up load files rather than using Ajax to make Ajax sty le file up load ap p roach. IBN AL- H AITHAM J. FO R PURE & APPL. S CI VO L.22 (4) 2009 Ajax te chnology AJAX is a browser technology indep endent of web server software. It is a way of developing Web ap p lications that combines [1]: - XHTM L (EXtensible HyperT ext M arkup Language) and CSS (Casc adin g Sty le Sheets) st andards based presentation. - Int eraction with t he p age through the DOM (Document Object Model). - Data interchange with XML (EXtensible M arkup Langua ge) and XSLT (EXt ensible Stylesheet Language T ransformations). - Asynchronous data retrieval with XM LHttp Request. - JavaScr ip t to t ie it all together. The Ajax en gine works wit hin the Web browser (t hrough Jav aScript and t he DO M) to render the Web ap plication and hand le any request s that the customer might have of the Web server [1]. The beauty of it is that because the Ajax engine is handling the requests, it can hold most information in the engine itself, while allowing the int eraction with the app lication and the customer t o happ en asy nchronously and indep endently of any interaction with the server [2]. Asynchronous interacti on This is the key . In st andard Web ap plications, the interaction between the cust omer and the server is synchronous. T his means that one has to happen after the ot her. If a customer clicks a link, the request is sent to the server, which then sends the results back [2]. With Ajax, the JavaScr ip t that is loaded when the p age loads handles most of the basic tasks such as data validation and manipulation, as well as disp lay rendering the Ajax en gine handl es without a trip to the server. At the same time that it is making d isp lay changes for the cust omer, it is sending data back and forth to the server. But the data transfer is not dep endent upon actions of the customer [3]. Web S ervices Web services are software system design ed to supp ort interop erable machine-to-ma chine interaction over a network [4]. Web services ar e frequently just Web APIs that can be accessed over a network, such as the Int ernet, and executed on a remote sy stem hosting the requested services. This definition encomp ass es many different sy stems, but in common usage the term refers to client s and servers that communicate over t he HTTP p rotocol used on the Web [5]. Postback operation A Postback is an action taken by an interactive webp age, when t he entire p age and its cont ent s are sent to t he server for processing some infor mation and then, the server p osts the same page back to t he brow ser [6]. T his is don e to verify p ass words for loggin g in, p rocess an on-line order form, or ot her such tasks that a client comp ut er cannot do on its own. This is not to be confused with refresh or back actions taken by the but tons on t he brow ser [7]. Post back in an event that is triggered when action is p erformed by a cont rol on an asp .net page. For example when y ou click on a but ton the data on t he p age is p osted back to the server for processing [8]. Upload Files The following su ggest ed app roach to up load files to a web server:  By using a web service (T o simulate Ajax sty le) Upload files asy nchronously . IBN AL- H AITHAM J. FO R PURE & APPL. S CI VO L.22 (4) 2009 Ajax st yle, this p ap er and included code describe and illustrate this app roach. The examp le will illust rate an approach to class ify files up on up load and direct the file to sp ecific folders based on t he typ e of file up loaded. - Programmin g Environment: Visual Studio 2005 - Langua ge: Visual Basic 2005, ASP.NET Algorithm [Upload File in AS P.NET withou t the N eed to use Ajax Te chnology] [1] Build a web service. 1.1. Call a library that is used to cut down the file extension from interior f ile up load. 1.2. Build a method used to save the interior file with its extension comp letely and int o folders used to hold different typ es of files (e.g., im ages or text). 1.2.1. Filter file op tions based up on the file typ e. [2] U se a web service (To simulate Ajax sty le) t o up load files asy nchronously . 2.1. Imp ort a library in order t o imp lement a p rocess involving the file extension. 2.2. Convert the file to bytes. 2.3. Do not use a postback and imp lement a wait handle to block the p age from loadin g unt il after the results are returned from t he web service. 2.4. Check comp lete up load or not. The Code: The first p roject is the web site, and t he second one is a web service that would be used to up load files. T he solution should cont ain bot h of them as show n in figure (1). 1- Web S ervice The st art cont ains all the declarations, the extension of the file would b e cut dow n from the interior file by System.IO library . Imports System.Web Imports System.Web.Services Imports System.Web.Services.P rotocols Imports System.IO ' F I L E S T O R A G E W E B S E R V I C E ' This service contains one web method: ' 1. SFAT - Saves file to folder with e xtension _ _ _ Public Class FileStora ge Inherits Sy stem.Web.Services.Web Servi ce IBN AL- H AITHAM J. FO R PURE & APPL. S CI VOL.22 (4) 2009 The file st orage class (“ FS” for short) p resents the save file as typ e method (“SFAT” for short) t hat used to save the comp lete interior file with the extension, these files could be variety kinds such pictures, text, web p ages. Etc. _ Public Function SFAT(By Val sFN As String, _ ByVal bFBA As Byt e()) As Integer ' Saves a f ile as a sp ecific type with an extension ' Cap ture the file typ e through its extension Dim sFT As String sFT = Sy stem.IO.Path.GetExtension(sF N) sFT = sFT.ToLower() ' filter file op tions based up on the file typ e Select Case sFT Case ".doc" ' Get the file name and set anot her p ath to the storage fold er Dim sF As String = _ Syst em.IO.Path.GetFileNameWithout Extension(sFN) sF = System.Web.Hosting.HostingEnvironment.M apPath _ ("~/StoredText/" & sF & sFT) 'write the file out to the storage location Try Dim stream As New FileStream(sF , FileM ode.OpenOrCreate) st ream.Write(bFBA, 0, bFBA.Length) st ream.Close() Return 0 Catch ex As E xception Return 1 End Try The same code will cont inue for t he followin g extensions: Case ".docx",". xml",".rt f",".lic",".txt",".ht ml",".ht m",".bmp ",".jp g",".gif",".p ng",".tif",".ico",".w mf". Case Else ' we don't know what kind of file it is, so we p ut in into ' this folder, then Get the file name and set a new p ath to ' the local storage folder Dim sF As String = _ Syst em.IO.Path.GetFileNameWithout Extension(sFN) sF = System.Web.Hosting.HostingEnvirnment .M apPath _ ("~/StorageStuff/" & sF & sF T) 'write the file out to the storage location Try Dim stream As New FileStream(sF , FileM ode.OpenOrCreate) st ream.Write(bFBA, 0, bFBA.Length) st ream.Close() Return 0 Catch ex As E xception IBN AL- H AITHAM J. FO R PURE & APPL. S CI VO L.22 (4) 2009 Return 1 End Try End Select End Function The extension of the interior file is cut dow n and the case body uses it. The case categorizes the files accordin g to the extension and the file kind (p ictures, document s, or unknown file); the case will p ut the file into related folder. The name of the file and its information create a st ring that could be receipted by the method which eliminates the extension from the file then decide a new path. The unknown file would be sent to a rubbish folder called storage st uff. According to a try block, the method sends ba ck (returns) zero if the file was written successfully and sends back one if not . That zeros and ones used by anot her method to sp ecify the success or failure of t he op eration. NOTE: A fail message will r eturn if y ou try to upload a file that up loaded p reviously . 2- Web S ite. As shown in figure (2), the web site will lead the user to up load the files asy nchronously to web service with its extension. The p age class produces inheritance to the declared object (t he solitary one) that represents the p roxy described p reviously. The p roxy page doesn’t need vast scop e but it’s not damage if it takes that scop e, so it could keep the code inside its own methods. The initial code p art of t he sit e is: Imports System.IO ' D E F A U L T A S P X P A G E ' ' This web page offers user fi le up load op tion: ' Use a web service (T o simulate Ajax style) to upload files asy nchronously Partial Class _Default Inherits Sy stem.Web.UI.Page Private webs As New FileStora ge.Fil eStora ge() The code in the main page class is used to imp lement the up load files asy nchronous ly and keep the extension (T o simulate Ajax sty le). The code will not use a p ostback and ap p ly a wait handler to p revent (freeze) the sit e load while the result comeback from the web service; and the rout ine will manip ulate the results and demonstrates success or failure to the user accordin g to the result that comeback from the web service. If you wish to manip ulate the result with anot her way, y ou have to execute a p ostback op eration in case that y ou don’t warry about p reventing (block ing) t he page form loadin g. A wait handle is also set and the results are only p rocessed after the method returns. The code is as follows: Protected Sub bUp loadWithExAsy n_Click(ByVal sender As Object, _ By Val e As System.Event Args) Handles bUp loadWithExAsyn.Click ' Asy nchronous file upload (keep extension) Try ' validate that a file h as been selected into the ' file up load cont rol IBN AL- H AITHAM J. FO R PURE & APPL. S CI VO L.22 (4) 2009 If FUp .HasFile Then ' convert the file to bytes Dim by tes As Byte() = FUp .FileBy tes ' to catch the return value, set up an IA sy ncResult object from ' the web service call - we are not using a p ostback here so ' the p ost back argument is set to not hing Dim iarst As IAsy ncResult iarst = webs.BeginSFAT(FUp .FileName.ToString(), _ bytes, Nothing, Nothing) ' Wait for the call to finish iarst.Asy ncWaitHandle.WaitO ne() ' the asy nc call is comp lete, p rocess the results Dim rV As String rV = webs.EndSFAT(iarst ) If rV = "0" Then M essageBo x("The file up loaded") Else ' this message will appear M essageBo x("The file is not up loaded") End If End If Catch ex As Excep tion M essageBox(e x.M ess age.ToStrin g()) End Try End Sub Conclusions 1- "Web Serv ices" is the umbrella term of group of loosely related Web-based resources and comp onents that may be used by other Web app lications over HTTP. T hese resources could include any thing from phone directory data to weather dat a to sp orts results. 2- With asynchronous interaction between the customer and the server, Internet app lications can be made r icher، smaller, f ast er and more user-fri endly. 3- The t raditional methods to imp lement file up loadin g to server involves Postback operation but only the use of asy nchronous file up load through web services st rategy satisfies the simulation of Ajax technolo gy (w ithout Post back). 4- The suggest ed method of up loadin g fi les through web services will imp lement asy nchronously the thing that enabled the web p age to st ay in front of the client who can implement any desired chan ges to t he rest controls in the same web page in asy nchronously manner while the up loading fi le op eration incessant . 5- The file should be converted into by tes then up loaded, and t he up loading period dep ends on the size of t he file. IBN AL- H AITHAM J. FO R PURE & APPL. S CI VO L.22 (4) 2009 References 1. Edmond Woy chowsky , (2006). “Ajax: Cr eating Web Pages with Asynchronous JavaScript and XM L”, Prentice Hall, Government Sales, August 08, 2. Ry an Asleson; Nathaniel Schut ta, (2006), “Beginnin g Ajax with ASP.NET”, Wiley Publishing, In c.10475 Crossp oint Boulevard, 3. Andy Budd; Cameron M oll; Simon Co llison, CSS M astery : (2006), “Advanced Web Standards Solutions”, P rentice Hall, U.S. Corp orate & Government Sales, 4. Ingo Rammer; Mario Szp uszta, (2005), (M icrosoft), “Advanced .NET Remoting”, 1st Edition, Apress, M arch,. 5. Ralf West p hal, (2004), Christ ian Wey er, “Programming ASP.NET: Building Web App lications & Services Using C# and VB.NET”, Addison Wesley , July . 6. Christian Nagel., (2003), “ ASP to ASP.NET Migration Handbook”, Wrox, February 18,. 7. Christian Nagel, (2004) “Professional .NET Network Programm in g”, 1st Edition, Wro x, Sep tember 30,. 8. Ingo Rammer, (2002), “ Advanced .N ET Remoting in VB.N ET”, Ap ress , July 29,. IBN AL- H AITHAM J. FO R PURE & APPL. S CI VO L.22 (4) 2009 Start Build a web service Import librarie s Build containe r method Write the fil e out to storage loc ation Capture fil e type No Save a file as a spe cific type with an extension Set anothe r path to the storage folde r Set another path to the storage folder (StorageStuff ) Yes Fil te ring Offer u ser to upl oad fil es asynchronously Use the web service Convert the fil e to byte s Set up an IAsyncResult object Wait for the call to finish Ye s No Fil e uploaded completely? IBN AL- H AITHAM J. FO R PURE & APPL. S CI VO L.22 (4) 2009 Fig. (2) :The web site for the suggested Asynchronous File Upload in ASP.NET.