是否对Ajax中的POST数据大小有任何限制？

Question

I'm trying to send an array of data from my page to the MVC Action using jQuery Ajax. Here is my jQuery code:

$('#btnSave').click(
  function () {
    result = [];
    $('#tblMatters tbody tr.mattersRow').each(function () {
      if (!($(this).hasClass('warning'))) {
        var item = {};
        if ($(this).find('td.qbmatter > div.dropdown').length > 0) {
          item.QBDescription = $(this).find('td.qbmatter > div.dropdown > a').text();
        } else {
          item.QBDescription = $(this).find('td.qbmatter').text();
        }
        var id = $(this).find("td:first > a").text();
        item.Narrative = $("#collapse" + id).find("div.scrollCell").text();
        item.WorkDate = $(this).find('td.workDate').text();
        item.Hours = $(this).find('td.hours').text();
        item.Person = $(this).find('td.person').text();
        if ($(this).find('td.rate > div.dropdown').length > 0) {
          item.Rate = $(this).find('td.rate > div.dropdown > a').text();
        } else {
          item.Rate = $(this).find('td.rate').text();
        }
        item.Amount = $(this).find('td.amount').text();
        result.push(item);
      }
    });
    var originalRecords = $("#tblSummary tr.summaryTotalRow td.summaryOriginalRecords").text();
    var originalHours = $("#tblSummary tr.summaryTotalRow td.summaryOriginalHours").text();
    var excludedHours = $("#tblSummary tr.summaryTotalRow td.summaryExcludedHours").text();
    var totalHours = $("#tblSummary tr.summaryTotalRow td.summaryTotalHours").text();
    $.ajax({
      url: "/Home/SaveQBMatter",
      type: "POST",
      data: JSON.stringify({ 'Matters': result, 'originalRecords': originalRecords, 'originalHours': originalHours, 'excludedHours': excludedHours, 'totalHours': totalHours }),
      dataType: "json",
      traditional: true,
      contentType: "application/json; charset=utf-8",
      success: function (data) {
        if (data.status == "Success") {
          alert("Success!");
          var url = '@Url.Action("Index", "Home")';
          window.location.href = url;
        } else {
          alert("Error On the DB Level!");
        }
      },
      error: function () {
        alert("An error has occured!!!");
      }
    });
});

Let me explain a little bit. I have an HTML table that was built dynamically and I need to store this data into a database. In jQuery I have a loop going through the table and I store data of every row in the result array. Then I pass this data using Ajax into MVC Action.

And here is where my problem starts... I've realized that sometimes it goes as it should be, but sometimes I'm getting an error from Ajax alert("An error has occured!!!"); Now I've understood that this error occurs when my result array is getting big. For example: If it contains 100-150 items > everything is good, but when there are more than ~150 > Error.

Is there any POST limit in Ajax? How can I set it up for any sizes? I really need this functionality! Any help please!

My ActionResult Code:

public ActionResult SaveQBMatter(QBMatter[] Matters, string originalRecords, string originalHours, string excludedHours, string totalHours) {
  DBAccess dba = new DBAccess();
  int QBMatterID = 0;
  int exportedFileID = 0;
  foreach (QBMatter qb in Matters) {
    dba.InsertQBMatter(qb.QBDescription, qb.Narrative, qb.WorkDate, qb.Person, qb.Hours, qb.Rate, qb.Amount, ref QBMatterID);
  }
  ExcelTranslator translator = new ExcelTranslator();
  translator.CreateExcelFile("", Matters, originalRecords, originalHours, excludedHours, totalHours);
  return Json(new { status = "Success", message = "Passed" });
}

UPDATE: Found a solution

JSON has a maximum length! I need to increase this value. In web.config add the following:

<appSettings>
  <add key="aspnet:MaxJsonDeserializerMembers" value="150000" />
</appSettings>

Answer 1

JSON has a maximum length! I need to increase this value. In web.config add the following:

<appSettings>
  <add key="aspnet:MaxJsonDeserializerMembers" value="150000" />
</appSettings>

Answer 2

Is it any POST Limit in Ajax?

No, the HTTP specification doesn't impose a specific size limit for posts. However it depends on the Web Server which you are using or the programming technology used to process the form submission.

In ASP.NET MVC you can try this:

<system.webServer>
<security>
    <requestFiltering>
        <requestLimits maxAllowedContentLength="1000000" />
    </requestFiltering>
</security>

Answer 3

The HTTP spec doesn't defining a limitation of POST data size.

But using ASP.NET MVC, there could be a POST data limitation, try to increase it in your Web.Config file:

<system.webServer>
<security>
    <requestFiltering>
        <requestLimits maxAllowedContentLength="1000000" />
    </requestFiltering>
</security>

From MSDN :

Specifies the maximum length of content in a request, in bytes. The default value is 30000000.

Answer 4

IF there is a client-side limit then it would be browser specific but the HTTP spec does not define a limitation of POST data size.

Keep in mind that a POST is merely bytes across the network so the more fields you are posting then the longer it can take to upload that data.

A 1MB POST is going to make the user feel like the form is broken and unresponsive if using a traditional form submit.

If there are a lot of fields to serialize() then AJAX could hang up the browser while it collects all of the data. I think browsers do have a memory limit for JavaScript overall so if you hit that limit then the AJAX process will fail.

// wanna have some fun?
var html = '<div></div>';

for(var i = 0; i < 1000000; i++){
    html += html;
}

Your best bet is to increase the maximum allowable POST size on the server-side to avoid issues.

Most commonly issues arise when people make an upload script which simply seems to hang while the user is confused why their 3MB pictures are going slow on a 125KB/s upload link.

Answer 5

This solved my problem:

<system.web.extensions>
    <scripting>
        <webServices>
            <jsonSerialization maxJsonLength="2147483647" />
        </webServices>
    </scripting>
</system.web.extensions>

Answer 6

The limit is set through a server 'max_post_size' or similar naming. Typical default server settings are 2-8 MB in one post.

On the client side, only GET has a maximum limit, generally considered 1500 bytes (minus 30-150 from request headers) and the reason is the MTU in the more lowlevel network hardware