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Advanced ASP Uploader

, 28 Aug 2001
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An advanced COM component that provides file upload capabilities for your ASP pages.
<!-- Add the rest of your HTML here -->

Introduction

Browser-based (HTTP) file uploading is a great way to transfer arbitrary files from a client machine to the Web server which adds another dimension to Web-based applications. However, to enable this feature the client form should be submitted using "multipart/form-data" encoding.

Unfortunately, the ASP Request.Form object cannot be used with this encoding type (currently). For this reason, many solutions have been provided by third party components to solve this problem. However, most of these third party components suffer from one or more of the following problems:

  1. Discarding other important form data which are not related to the uploaded file.
  2. No support for multiple file uploading.
  3. Inconsistent interface to the existing Request.Form interface.
  4. No support for chunk data reading from the uploaded file (helpful on uploading a large. file into a BLOB field in a database using AppendChunk in an ADO Recordset object).

For these reasons, I have developed a COM object that users can use instead of Request.Form in case of a "multipart/form-data" encoding.

While developing this COM object, I have tried to avoid falling into any of the previous mentioned problems. However, the solution that I am providing will not totally replace Request.Form, rather it will be a complementary solution that users can use incase of a "multipart/form-data" encoding as I mentioned earlier. Users can still use Request.Form for other encoding types, however.

What is multipart/form-data?

This "multipart/form-data" type of encoding is described in RFC1867 which describes how file uploading should be implemented over HTTP protocol. To enable file uploading the form enctype should be set to multipart/form-data and the method should be set to post. Then the input tag should be of type file.

For the previous form here is the required code

<form method=post action=upload.asp enctype="multipart/form-data">
<input name=name value="Al-Mutairi, Fayez">
<input name=email value="fayezmm@yahoo.com">
<input name=file type=file>
<input name=submit type=submit value=Submit>
</form>

When the user clicks the submit button the web server will receive the following:

-----------------------------7d1f5a80420
Content-Disposition: form-data; name="name"

Al-Mutairi, Fayez
-----------------------------7d1f5a80420
Content-Disposition: form-data; name="email"

fayezmm@yahoo.com
-----------------------------7d1f5a80420
Content-Disposition: form-data; name="file"; filename="C:\folder_icon.gif"
Content-Type: image/gif

GIF89a2 2 ³ÿ ÿÿÿÌÌÿ™™ÿffÌUUUDDD33f"""                        ,    2 2 @
éÈI«½8ëÍ»¯H Ž" … ,‹|]HÎ49 7ì!Å Ô³[NGÔ Ž‡CqÉl:‹¯Sê'@žfB©<¯§v
†±ž
φC$
„+zN¯Ûün$u§/z-Vvc@*<,{bdd UX†ŽlCb=?•#f|jš4fqŒžŸ=>fo¦­®¯°±²³N
G¬´Ÿ<_z³2ˆT„Á…\R_-ƒ¥µÆ+ƒs”‡ÍŠÃMÑŽ]*gÖ›5ÝAm“áâ—Ökå/ßh Ýìuî[£­ò–npÊ…™"
ª(úø¨ió/ ®ƒ*¬/ ;
<!--"-->
-----------------------------7d1f5a80420
Content-Disposition: form-data; name="submit"

Submit
-----------------------------7d1f5a80420--

At this time when upload.asp started it cannot access the form data using Request.Form So it should use a third party component for help. The component will read the previous request, parse it and build a collection of items that can be accessed in a similar fashion to accessing Request.Form items.

How To Use the Component

Let us build upload.asp using our MyRequest.Form component

<%@ LANGUAGE="JScript%">
<%
    var form = Server.CreateObject("MyRequest.Form");
    form.Init();
    Response.Write("Name =" + form("name"));
    Response.Write("Email =" + form("email"));
    var file = form.Item("file").Item(1);
    Response.Write("FileName =" + file.FileName);
    Response.Write("FileExt  =" + file.FileExt);
    Response.Write("FilePath =" + file.FilePath);
    Response.Write("MimeType =" + file.ContentType);
    Response.Write("FileSize =" + file.TotalBytes);

    // ** To save into a file use Write method of the ADO Stream Object
    var fileStream = Server.CreateObject("ADODB.Stream");
    fileStream.Open();
    fileStream.Type = adTypeBinary;
    fileStream.Write(file.Value);
    fileStream.SaveToFile(Server.MapPath("Uploaded Files") + "\\" + file.FileName, adSaveCreateOverWrite);
    fileStream.Close();

    // ** To save into a database use AppendChunk method of the Field Object of ADO Recordset
    var cn = Server.CreateObject("ADODB.Connection");
    var rs = Server.CreateObject("ADODB.Recordset");
    cn.Open("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Server.MapPath("Database.mdb"));
    rs.Open("Users", cn, adOpenForwardOnly, adLockOptimistic, adCmdTable);
    rs.AddNew();

    rs.Fields("id") = 1000;
    rs.Fields("name") = form("name").Value;
    rs.Fields("email") = form("email").Value;
    rs.Fields("FileType") = file.ContentType;
    rs.Fields("file").AppendChunk(file.Value);

    rs.Update();
    rs.Close();
%>

Interfaces


Here is the IForm Interface

MethodDescription
Init(VARIANT varBinary) Initialize the form with posted data. varBinary is optional it is =Request.BinaryRead(Request.TotalBytes)
Item(VARIANT Index, IListItem** ppItem) (Default method) Returns the ListItem object with the specified key either as the item name or index.
Count(long* pVal) Number of listitem's objects.

Here is the IListItem Interface

MethodDescription
Value(VARIANT* pValue) (Default method) Item's value.
Item(long lIndex, IItem** ppItem) Returns the Item object with the specified index.
Count(long* pVal) Number of item's objects.
Name(BSTR* pName) Item's name.

Here is theIItem Interface

MethodDescription
Value(VARIANT* pValue) (Default method) Return the value of the item.
IsFile(BOOL *pVal) Return TRUE if the Item object is a file otherwise it returns FALSE.
FileName(BSTR *pVal) The name of the uploaded file. AVALIABLE ONLY if object is a file.
FilePath(BSTR *pVal) The path of the uploaded file. AVALIABLE ONLY if object is a file.
FileExt(BSTR *pVal) The extension of the uploaded file. AVALIABLE ONLY if object is a file.
ContentType(BSTR *pVal) The content-type (MIME TYPE) of the uploaded file. AVALIABLE ONLY if object is a file.
TotalBytes(long *pVal) Size in bytes of the uploaded file. AVALIABLE ONLY if object is a file.
GetChunk(long offset, long length, VARIANT* pChunk) Return a chunk of the file with the specified size and position. AVALIABLE ONLY if object is a file.

Further Help

Additional help is supplied with the demo project zip file which includes documentation !

Special thanks to Xicoloko who wrote http://www.codeproject.com/asp/uploader.asp which give me a push to also build my own component but this time (Complete).

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

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About the Author

Fayez Al-Mutairi

United States United States
No Biography provided

Comments and Discussions

 
QuestionThis doesn't work with Webkit based browsers PinmemberGPATI17-Jun-13 3:53 
Questionmultipart parsing without the upload/post part PinmemberLuka9-Jan-12 5:33 
Questionhow to register myrequest.dll on SQL Server 2005 or Vista Home Basic PinmemberMekoder20-Sep-07 1:52 
AnswerRe: how to register myrequest.dll on SQL Server 2005 or Vista Home Basic Pinmemberpawandhir24-Jun-09 6:50 
GeneralProblem compiling Pinmemberjerry Scannell6-Nov-06 15:38 
GeneralMyRequest.Form init error Pinmemberchoijung7120-Jul-06 23:42 
GeneralWrite file error PinmemberLienKim10-Feb-06 17:25 
GeneralRe: Write file error PinmemberVisible Soul30-Mar-06 1:42 
GeneralError "Server.Object" PinmemberShefa15-Jan-06 6:37 
GeneralRe: Error "Server.Object" PinmemberAdhan8-Feb-06 23:35 
GeneralSelect/Options - How does one handle them Pinmemberdougcranston5-Dec-05 6:41 
GeneralConvert JScript example to VBScript Pinmemberbbutler18-Aug-05 8:14 
GeneralRe: Convert JScript example to VBScript Pinmemberbbutler18-Aug-05 9:32 
GeneralRe: Convert JScript example to VBScript Pinmemberbbutler18-Aug-05 11:22 
GeneralRe: Convert JScript example to VBScript Pinmemberbbutler18-Aug-05 11:57 
GeneralError while creating object of MyRequest.DLL PinmemberTejal Metha16-Jun-05 0:35 
GeneralRe: Error while creating object of MyRequest.DLL Pinmemberpawandhir24-Jun-09 6:52 
QuestionHow to open file from database? Pinmemberknight_zhuge5-Aug-04 17:15 
General'adTypeBinary' is undefined PinmemberVexez14-Jun-04 18:12 
Generalerror : Det virker ikke en skid Pinmembermadspaaskesen25-Jan-04 8:18 
GeneralRe: error : Det virker ikke en skid Pinsusssketch18-Nov-04 5:22 
GeneralProblem solved PinmemberSketch24-Nov-04 9:17 
GeneralFile upload error PinmemberPopeye Doyle Murray14-Aug-03 8:47 
GeneralRe: File upload error PinmemberrepressedRadar15-Aug-07 6:09 
Generalwriting data to client; filenames.extensions are LOST PinmemberAdyRocker13-Jul-03 8:56 
GeneralError when show large files &gt; 65Kb PinmemberNicolay Ch29-Jun-03 0:46 
GeneralClear Text File PinsussJForck23-Oct-02 6:05 
GeneralRe: Clear Text File PinmemberPete Bassett23-Oct-02 6:32 
GeneralRe: Clear Text File PinmemberJForck23-Oct-02 12:55 
GeneralRe: Clear Text File PinmemberPete Bassett24-Oct-02 1:13 
GeneralRe: Clear Text File PinsussJForck24-Oct-02 8:10 
GeneralRe: Clear Text File PinmemberTony Truong3-Feb-03 0:49 
GeneralRe: Clear Text File PinmemberDaniel Turini23-Oct-02 6:39 
GeneralRe: Clear Text File PinsussJForck23-Oct-02 12:52 
GeneraladTypeBinary not defined Pinsussjdiana25-Sep-02 9:31 
GeneralRe: adTypeBinary not defined Pinsussersan ersoy1-Oct-04 7:27 
Questioncan i use chinese filename PinmemberAnonymous10-Apr-02 18:04 
GeneralUnable to create object of ADODB.Stream PinmemberStatbat22-Mar-02 1:31 
GeneralRe: Unable to create object of ADODB.Stream PinmemberAnonymous24-Mar-02 18:00 
Generalfiles stored in memory Pinmembersunisha19-Mar-02 11:35 
GeneralRe: files stored in memory PinmemberAl-Mutairi, Fayez6-Apr-02 22:40 
Generalpurpose of various functions in upload.inc PinmemberAnonymous18-Feb-02 9:32 
GeneralError While Uploading PinmemberDhaval_Parikh10-Jan-02 22:55 
GeneralRe: Error While Uploading Pinmembertranvan16-Jan-02 4:34 
GeneralASP KAMI Pinmemberkamranali10-Jan-02 18:39 
QuestionUse component in WINNT 4.0 and IIS 4.0 ? Pinmembertranvan31-Dec-01 6:42 
AnswerRe: Use component in WINNT 4.0 and IIS 4.0 ? PinmemberGabriel Paradelo8-Aug-03 12:20 
GeneralError with checkbox control Pinmembertranvan31-Dec-01 6:34 
QuestionOpera compatibility? PinmemberDave Hiseman7-Dec-01 2:08 
GeneralGetting Error when adding new fields Pinmemberdarend7-Nov-01 5:25 

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Article Copyright 2001 by Fayez Al-Mutairi
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