[MonoDevelop] Convert.ToBase64String yields different result than on windows...

[IBBoard]

You might be better off reporting that to the Mono mailing list, 
possibly even the Mono ASP.Net mailing list 
(http://www.mono-project.com/Mailing_Lists). This list is meant for 
MonoDevelop, the IDE, rather than the Mono framework itself.

Regards,

IBBoard


On 04/06/11 20:55, Quandary wrote:
> Hmm, strange...
>
> It turns out that when you have
>
> ----------------------------------------------------
> <%@ Page Language="C#" %>
>
>      <script runat="server">
>
> public void WriteImage()
> {
>      // Write image to output stream
>      // Response.End()
> }
>
> </script><% WriteImage(); %>
>
> ----------------------------------------------------
>
> You may not have a whitespace/tab/newline between</script>  and<%
> WriteImage %>  ...
> Apart from that, although base64 encoding returns a different string on
> Windows and Linux,
> the string created on Windows can be decoded and returns a valid image
> on Linux too, although the base64 string is different for the same image...
> Very strange.
> I have not yet tested whether the string created on Linux will work on
> Windows, but I suppose so.
>
>
> On 06/04/2011 08:19 PM, Quandary wrote:
>> Hi,
>>
>> Question on the below code (with mono 2.10.2):
>> I'm converting an image to base64 string, and use this string to embed
>> it on a webpage, there I write the image back in the ResponseStream.
>>
>> For that I use the below code, using
>> Convert.ToBase64String on the image byte array.
>>
>> It seems it results in a different base64 string on Linux than on Windows.
>> With PHP, it doesn't.
>>
>> To reproduce:
>> Encode an image (i used gif format) on Windows to base64.
>> Then put the resulting base64 string into a string on an asp.net
>> website, and base64 decode that string there, writing the image to the
>> output stream.
>> It works fine on Windows.
>> It works fine on Linux.
>> But if you base64 encode the image on windows, and put the result string
>> from windows into the decoding website on Linux, then you will get an
>> invalid image..
>>
>> If you copy the base64 string generated on Windows to Linux into a PHP
>> site, and base64 decode it there, it results in a perfectly fine image.
>>
>> I think this is a bug...
>> And if it is, this should be put into a unit test.
>> Because once base64 values are in a database, you can't just correct the
>> encoding/decoding algorithms, because in the database there will still
>> be values encoded by the old faulty algorithm (I do this in a reporting
>> service solution, to get the logo image for each customer into the
>> header)...
>>
>>
>> Here the code:
>> Note that you need to put a constant as value into variable str to cause
>> the error.
>>
>> ------------------ Code running on Linux
>> string strBase64Content = "base 64 converted image string here";
>> byte[] bt64 = System.Convert.FromBase64String(strBase64Content);
>>      //string strMIME = GetImageMime(ref bt64);
>>
>>
>>      Response.ContentType = "image/gif"; //strMIME;
>>      Response.OutputStream.Write(bt64, 0, strBase64Content.Length);
>>      Response.End();
>> --------------------------------------------
>>
>>
>>
>>
>>          void _Default_Load(object sender, EventArgs e)
>>          {
>>              string strPath = Server.MapPath("~/file.gif");
>>              System.Drawing.Image imgThisImage =
>> System.Drawing.Image.FromFile(strPath);
>>
>>              string str = ImageToBase64(imgThisImage,
>> System.Drawing.Imaging.ImageFormat.Gif);
>>
>>
>>              Base64ToImage(str);
>>              Response.Write(str);
>>              // load event
>>          }
>>
>>
>>          public string ImageToBase64(System.Drawing.Image image,
>>                System.Drawing.Imaging.ImageFormat format)
>>          {
>>                using (System.IO.MemoryStream ms = new
>> System.IO.MemoryStream())
>>                {
>>                  // Convert Image to byte[]
>>                  image.Save(ms, format);
>>                  byte[] imageBytes = ms.ToArray();
>>
>>                  // Convert byte[] to Base64 String
>>                  string base64String = Convert.ToBase64String(imageBytes);
>>                  return base64String;
>>                }
>>          }
>>
>>
>>          public System.Drawing.Image Base64ToImage(string base64String)
>>          {
>>                // Convert Base64 String to byte[]
>>                byte[] imageBytes = Convert.FromBase64String(base64String);
>>                System.IO.MemoryStream ms = new
>> System.IO.MemoryStream(imageBytes, 0, imageBytes.Length);
>>
>>              // Convert byte[] to Image
>>                ms.Write(imageBytes, 0, imageBytes.Length);
>>                System.Drawing.Image image =
>> System.Drawing.Image.FromStream(ms, true);
>>                return image;
>>          }
>>
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