FAQ: Upload Problems

Q: I am trying to configure Image Uploader, but some parameters have no effect. What is wrong?

Probably, there are some errors in your Image Uploader embedding script. For example, addParam method has a wrong call syntax or the specified parameter does not exist.

To debug such errors Image Uploader embedding scripts library exposes the IUCommon.debugLevel parameter. If it is set to 2 you will get warnings in most cases when syntax errors occur. See the Library Overview topic for the detailed information about debug levels.

Q: I am trying to upload files with Image Uploader, but receive an error message: "Some server-side error occurred". What is wrong?

This message means that the server page, which you upload files to (specified with the Action property), cannot be run properly. It may be:

• Some syntax error.
• Insufficient permissions to save uploaded files.
• Invalid connection string to a database
• ...and some other errors in the upload processing page.

To get more detailed information about this error, you can do the following:

• Set the ShowDebugWindow property to true. It will have Image Uploader to open a window containing the HTML code returned from the server. Typically, a web server writes the error message into it.
• Use the Java console to see a server response.

See the Debugging Server Scripts topic for more information on how to debug server errors.

Q: I am uploading files in PHP and Image Uploader says that upload completes, but selected files are not in the destination folder. Where can I find them?

First of all check a path and permissions of the folder you save files to. If it is correct and the problem still persists, probably, you have an error in your upload script (specified with the Action property). The point is that PHP applications may not return other than 200 HTTP codes but send the result page in the response. So, to debug your script, enable display_errors parameter in php.ini and set the showNonemptyResponse of your ImageUploaderWriter instance to alert. This way you will see an alert containing the response from your upload script whenever it is received.

See the Debugging Server Scripts topic for more information about showNonemptyResponse property.

Q: I am trying to upload files with Image Uploader, but receive an error message: "The server or proxy not found". What is wrong?

This message states that the server with the name, specified in the Action parameter cannot be found. The reasons are:

• The Action property is specified incorrectly or contains misprints.
• The specified server is down.
• The specified server is accessible via proxy, but the proxy settings are not set in a browser.
• If the previous reason is eliminated, and you still encounter this problem in Image Uploader Java try to configure Java to use proxy settings from the default browser. To do it, open Java Control Panel, click Network Settings..., and then click Use browser settings in the Network Settings window.

Q: I am trying to upload files with Image Uploader, but receive an error message: "Upload failed (the connection was interrupted)". What is wrong?

This error means that the server closed the connection unexpectedly. Typically, it happens when the server has some server-side limitations for maximum POST request length. Main indicator of this situation is that the problem occurs when the total upload size exceeds some value.

Another possible problem is that script execution timeout expires.

Both timeout and maximum POST request length are configured in the server settings. Find more information on how to resolve this problem for the following server environment:

• ASP.NET
• ASP
• ColdFusion
• PHP
• JSP
• Perl
• Python
• Ruby

Q: I cannot upload files larger than N megabytes. How to solve this problem?

Typically, this problem occurs when server-side limitations for maximum POST request length are configured. See the previous question of this FAQ for more information on how to get this problem fixed.

Q: I am trying to upload files with Image Uploader, but received an error message: "The server attempted to redirect, but server redirects are not supported". What is wrong?

The main reason of this problem is that Image Uploader does not support redirection from the upload script. So, if your server-side script attempts to redirect to some page the upload will be stopped and you will get this error message. This may occur in the following cases:

1. You lose session or authorization cookies in Image Uploader Java

This case is related to Image Uploader Java only and implies that Java version loses HTTP-only cookies during upload. In detail, it can be explained as follows. When Java version of Image Uploader prepares a POST request before uploading it to the server, it extracts all the cookies which are downloaded along with the page that hosts the applet. To get the cookies, Image Uploader uses the same object model as you do in JavaScript (as if you use document.cookie). However, this model does not allow retrieving HTTP-only cookies. As the result, these cookies will not be attached to the POST request as well as sent to the server.

Thus, when you use HTTP-only cookies to keep authentication tickets your server-side upload script will not be able to recognize the user who initiated the upload. Probably, your script will try to redirect the user to a login page, but such action is not supported by Image Uploader. So, the upload process will fail.

To avoid this problem you can explicitly attach HTTP-only cookies to the upload request using the AddCookie() method as it is described in the Preserving Sessions and Authentication Tickets Passed in Cookies topic. Another way is to use Image Uploader ASP.NET control or Image Uploader PHP library to embed Image Uploader into your web application. This way you do not need to care about keeping your cookies saved because the ASP.NET control as well as PHP library performs this action itself.

2. You redirect users to some page after upload completion

If you want to redirect the user after upload do not use server redirection for it. Among the server redirection methods are Response.Redirect in ASP.NET, header("Location: ...") in PHP, and others. However, this problem can be solved through Image Uploader facilities. See the Handling Upload Completion topic which describes all available solutions.

3. You use custom error pages

In the case when your server is configured to use custom error pages it will automatically redirect your upload script to the corresponding page if some error occurs. However, as it was said above, Image Uploader does not support such redirection.

To eliminate this problem you should disable custom error pages and debug your upload script using Debugging Server Scripts guidelines.

Q: Upload fails on slow connections. How to resolve this problem?

Try to increase the value of the TimeOut.

Q: Where can I find information on how to configure automatic upload recovery feature?

See the Configuring Automatic Upload Recovery topic.

Q: Where can I find information on how to send additional data with files?

See the Uploading Additional Data with Files topic.

Q: I use the additional HTML form as described in this topic, but no additional fields are uploaded. Why?

First of all, make sure that the form name is the same as the AdditionalFormName property. Also, check for misprints of field names in your server-side code.

If you are using Java version, take a look into Java console. Image Uploader writes all fields it recognizes into the console. If you see your fields there, you should try to debug your server page.

If you are sure that the server code is correct, try to reproduce the same problem with simplified HTML code. In other words, do the following:

1. Create empty HTML page.
2. Insert a form with the same fields as you try to send.
3. Insert Image Uploader-related code. Try to put only parameters, without event handlers and dynamic properties modification.
4. Upload files with additional form to the same Action page.

If additional data is uploaded from the simplified page successfully, it means that the problem occurs because of malformed HTML code in your original page. So you should re-format it to make it valid. Alternatively, you can use AddField() method instead of HTML form.

Q: I want to upgrade from Image Uploader 5.x but I found that FallbackMode is not supported any more. How should I configure such functionality in a newer version?

Since version 6.0 Image Uploader does not support UploadThumbnailXFallbackMode group of properties and introduces the UploadThumbnailXCompressionMode group (UploadThumbnail1CompressionMode, UploadThumbnail2CompressionMode, UploadThumbnail3CompressionMode, and UploadThumbnailCompressionMode) instead. New properties completely replace UploadThumbnailXFallbackMode functionality and provide additional features like ZIP compression. Find the detailed information on how to use UploadThumbnailXCompressionMode properties in the Handling Files Compression topic.

If you need to implement the UploadThumbnailXFallbackMode finctionality via the UploadThumbnailXCompressionMode properties use the code sample below:

// Send the source file if the first thumbnail cannot be created
// Similarly to UploadThumbnail1FallbackMode = "SourceFile"
iu.addParam("UploadThumbnail1CompressionMode", "*.*=Jpeg,SourceFile");

// Send an icon if the second thumbnail cannot be created
// Similarly to UploadThumbnail2FallbackMode = "Icon"
iu.addParam("UploadThumbnail2CompressionMode", "*.*=Jpeg,Icon");