Problem

I'm trying to upload file using XMLHttpRequest and it seems to work only with small file (such as under 2MO of size). I tried many things so far and came to code shown at the end of the post. But, there is nothing to do; I keep getting the ::ERR_CONNECTION_RESET error. It is not a code issue as under 2MO files are getting unploaded correctly... What am I forgetting? I know this is probably a IIS or web.config issues but I can put my finger on it by googling this problem.

Error given by Chrome

POST WEBSITEANDSERVICEURL/Service/MyService.asmx/UploadFilesWithAJAX net::ERR_CONNECTION_RESET

• handleFileSelect
• x.event.dispatch
• v.handle

Javascript

<script type="text/javascript">
    $(function() {
        $('#<%= files.ClientID %>').change(handleFileSelect);
    });

    function handleFileSelect(e) {
        if (!e.target.files || !window.FileReader) return;

        var fd = new FormData();
        var file = document.getElementById("<%= files.ClientID %>");
        for (var i = 0; i < file.files.length; i++) {
            fd.append('_file', file.files[i]);
        }
        var xhr = new XMLHttpRequest();
        xhr.open('POST', '<%= ResolveURL("~/Services/MyService.asmx/UploadFilesWithAJAX") %>', true);
        xhr.onreadystatechange = function() {
            if (xhr.readyState == 4 && xhr.status == 200) {
                alert(xhr.responseText);
            }
        };
        xhr.upload.addEventListener("progress", updateProgress, false);
        xhr.send(fd);
    }

    function updateProgress(oEvent) {
        if (oEvent.lengthComputable) {
            var percentComplete = oEvent.loaded / oEvent.total;
            $("#progress").text(oEvent.loaded + " ON " + oEvent.total);
        }
    }
</script>

HTML Markup

<asp:FileUpload ID="files" runat="server" multiple="true" />
<br />
<table id="selectedFiles">
</table>
<span id="progress"></span>

MyService.asmx

<ScriptService()> _
<ToolboxItem(False)> _
<WebService(Namespace:="/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
Public Class AJAXServices : Inherits WebService
    <WebMethod(EnableSession:=True)> _
    <ScriptMethod(ResponseFormat:=ResponseFormat.Xml)> _
    Public Function UploadFilesWithAJAX()
        ' Some code which work fine, I'm sure of it.
    End Function
End Class

Web.config

<!-- [...] -->
<system.web>
    <httpRuntime maxRequestLength="2097151" executionTimeout="180" /><!-- MAXIMUM DURING TESTING -->
    <!-- [...] -->
</system.web>
<!-- [...] -->

Problem

I'm trying to upload file using XMLHttpRequest and it seems to work only with small file (such as under 2MO of size). I tried many things so far and came to code shown at the end of the post. But, there is nothing to do; I keep getting the ::ERR_CONNECTION_RESET error. It is not a code issue as under 2MO files are getting unploaded correctly... What am I forgetting? I know this is probably a IIS or web.config issues but I can put my finger on it by googling this problem.

Error given by Chrome

POST WEBSITEANDSERVICEURL/Service/MyService.asmx/UploadFilesWithAJAX net::ERR_CONNECTION_RESET

• handleFileSelect
• x.event.dispatch
• v.handle

Javascript

<script type="text/javascript">
    $(function() {
        $('#<%= files.ClientID %>').change(handleFileSelect);
    });

    function handleFileSelect(e) {
        if (!e.target.files || !window.FileReader) return;

        var fd = new FormData();
        var file = document.getElementById("<%= files.ClientID %>");
        for (var i = 0; i < file.files.length; i++) {
            fd.append('_file', file.files[i]);
        }
        var xhr = new XMLHttpRequest();
        xhr.open('POST', '<%= ResolveURL("~/Services/MyService.asmx/UploadFilesWithAJAX") %>', true);
        xhr.onreadystatechange = function() {
            if (xhr.readyState == 4 && xhr.status == 200) {
                alert(xhr.responseText);
            }
        };
        xhr.upload.addEventListener("progress", updateProgress, false);
        xhr.send(fd);
    }

    function updateProgress(oEvent) {
        if (oEvent.lengthComputable) {
            var percentComplete = oEvent.loaded / oEvent.total;
            $("#progress").text(oEvent.loaded + " ON " + oEvent.total);
        }
    }
</script>

HTML Markup

<asp:FileUpload ID="files" runat="server" multiple="true" />
<br />
<table id="selectedFiles">
</table>
<span id="progress"></span>

MyService.asmx

<ScriptService()> _
<ToolboxItem(False)> _
<WebService(Namespace:="http://tempuri/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
Public Class AJAXServices : Inherits WebService
    <WebMethod(EnableSession:=True)> _
    <ScriptMethod(ResponseFormat:=ResponseFormat.Xml)> _
    Public Function UploadFilesWithAJAX()
        ' Some code which work fine, I'm sure of it.
    End Function
End Class

Web.config

<!-- [...] -->
<system.web>
    <httpRuntime maxRequestLength="2097151" executionTimeout="180" /><!-- MAXIMUM DURING TESTING -->
    <!-- [...] -->
</system.web>
<!-- [...] -->

• javascript
• asp
• vb
• xmlhttprequest
• asmx

Share Improve this question Follow edited Jun 20, 2020 at 9:12 CommunityBot 111 silver badge asked Dec 11, 2014 at 17:00 Simon DugréSimon Dugré 19k1111 gold badges5959 silver badges7575 bronze badges

Add a ment  | 

2 Answers 2

Sorted by: Reset to default 3

Ok, I solved it...

Solution

If this happen to someone else, be sure to at least access to Context.Request.Files once in your WebService.

Because, during my tests, I was simply :

Public Function UploadFilesWithAJAX()
    Return "RETURN SOMETHING"
End Function

But it was not enough... If I only access to Context.Request.Files like :

 Public Function UploadFilesWithAJAX()
    Dim files = Context.Request.Files '<---- Simply adding this... make it works :|
    Return "RETURN SOMETHING"
End Function

It works. Hope it helps someone else.

By the way, if someone can explain me why it is working by doing this.

In your web config, you defined maxRequestLength="2097151" which is around 2mb, for this reason if you try to upload files more than 2mb it will fail eventually.

Example config below( it will allow up to 2gb )

<httpRuntime maxRequestLength="2048576000" executionTimeout="300" />