Error during serialization or deserialization using in asp.net webapi POST

Question

I was trying to POST base64 string of 2 image (4MB + in Size) in a object. Here is the Model Sample :

public class DemoModel
{
    public string No{ get; set; }
    public string OneBase64 { get; set; }
    public string TwoBase64 { get; set; }
}

Here is how I am trying to capture POST-ed data in webapi controller.

  [HttpPost]
  public string PostSimpleData([FromBody] DemoModel data)
    { 
       // do something 
    }

but when I post the json it shows serialization / deserialization error.

Then I added few lines in webconfig to increase response size & json size.

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

and

<security>
  <requestFiltering>
    <requestLimits maxAllowedContentLength="2147483647" />
  </requestFiltering>
</security>

and

<httpRuntime targetFramework="4.5" maxRequestLength="2147483647" />

Still no result. If I post anything except Base64 data It automatically serialize and bind with object in controllers method.

here is the JSON I am trying to POST.

{
   "NO" : "01",
   "OneBase64" : "Some base 64 Data",
   "TwoBase64" : "Some base 64 Data"
}

any kind of help is appreciated.

I believe that the setting in your web.config applies to WebMethod, but not Web API or MVC. You tagged this as both MVC and Web API - which are you using? You'll need to find a way to adjust the max size for the serializer that your framework is using. — mason, Oct 02 '20 at 16:51
I am using Web Api 2. can you suggest how should i adjust the max size for serializer ? I used "" also. — Khaled Md Tuhidul Hossain, Oct 02 '20 at 17:01
Does [this](https://stackoverflow.com/a/18262484/1139830) solve your issue? — mason, Oct 02 '20 at 17:58
As an alternative, you can [swap the serializer used by Web API](https://weblog.west-wind.com/posts/2012/mar/09/using-an-alternate-json-serializer-in-aspnet-web-api). — mason, Oct 02 '20 at 18:01
@mason I already tried this. I added this line but nop. no luck. — Khaled Md Tuhidul Hossain, Oct 02 '20 at 18:02
Then I recommend you try swapping out the serializer used by Web API, as I couldn't find any other solution for adjusting that size on the serializer used in Web API by default. — mason, Oct 02 '20 at 18:06
@KhaledMdTuhidulHossain have you tried to use exact "50000000" value for configurations? — svyat1s, Oct 02 '20 at 18:47

score 1 · Accepted Answer · answered Oct 03 '20 at 07:43

I changed my method from this

[HttpPost]
public string PostSimpleData([FromBody] DemoModel data)
{ 
   // do something 
}

to this

 [HttpPost]
 public string PostSimpleData()
 {
        Stream req = Request.InputStream;
        req.Seek(0, System.IO.SeekOrigin.Begin);
        string json = new StreamReader(req).ReadToEnd();
        DemoModel model = JsonConvert.DeserializeObject<DemoModel>(json);

   //Now i Can Do whatever I want with this data
 }

and it worked like a charm. Thanks to this post here ASP.Net WEB API Failing POST Large JSON data from Mobile

score -1 · Answer 2 · answered Oct 02 '20 at 17:38

-1

You need to configure not your web api but your sender serializer instance directly by applying serializer.MaxJsonLength = Int32.MaxValue; from where are you sending that json object

answered Oct 02 '20 at 17:38

svyat1s

868
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21

I am sending data from android & web (vue js ) application. in android I made a json using GSON . Gson gson = new Gson(); String json = gson.toJson(data); after this I post the data like this. String response = mReq.sendPost(fullUrl, json, "application/json"); can u suggest where should I make the change ????? – Khaled Md Tuhidul Hossain Oct 02 '20 at 17:53
1

No, this answer does not apply at all. The error is happening on the server when trying to convert the JSON into a .NET object, so changing the settings for the serializer on the client would have no affect. – mason Oct 02 '20 at 17:55

Error during serialization or deserialization using in asp.net webapi POST

2 Answers2