Azure function not working properly after deployed [closed] - azure

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I have a barcode function which is working great in local environment. But random requests are not working correctly after deploying the barcode to azure.
I have downloaded the demo EAN13 barcodefont and tried with below code to print the barcode.
If I request multiple request in local environment it's working correctly. After deployed to Azure when we request multiple request at a time it's returning wrong barcode randomly. For example failure cases 3 out of 10 request.
c# BarCode Function
public string GenerateBarCodeFont(string barCodeTextP, out bool isError, int widthP = 0, int heightP = 0, string fontNameP = "", int fontP = 0)
{
isError = false;
aa:
try
{
fontArray = new byte[0];
dataLength = 0;
if (widthP == 0)
widthP = 1;
if (heightP == 0)
heightP = 1;
if (fontP == 0)
fontP = 16;
fontArray = VLCEANThirtenBarCode.Properties.Resources.UPCEAN_0;
dataLength = VLCEANThirtenBarCode.Properties.Resources.UPCEAN_0.Length;
barCodeText = EAN13(barCodeTextP);
IntPtr destination = Marshal.AllocCoTaskMem(dataLength);
Marshal.Copy(fontArray, 0, destination, dataLength);
uint pcFonts = 0;
AddFontMemResourceEx(destination, (uint)fontArray.Length, IntPtr.Zero, ref pcFonts);
PrivateFontCollection fonts = new PrivateFontCollection();
fonts.AddMemoryFont(destination, dataLength);
Marshal.FreeCoTaskMem(destination);
this.ff = fonts.Families[0];
int num3 = heightP * 2;
int num5 = Convert.ToInt32((double)(Convert.ToDouble(widthP) * 1.5));
int num6 = (heightP * 100) / 90;
Font font = new Font(this.ff, (float)fontP);
PointF point = new PointF(2f, 2f);
Bitmap bitmap = new Bitmap(widthP, heightP, PixelFormat.Format24bppRgb);
bitmap.SetResolution((float)num6, (float)num6);
Graphics graphics = Graphics.FromImage(bitmap);
graphics.FillRectangle(new SolidBrush(Color.White), 0, 0, widthP, heightP);
graphics.DrawString(barCodeText, font, new SolidBrush(Color.Black), point);
using (MemoryStream stream = new MemoryStream())
{
bitmap.Save(stream, ImageFormat.Png);
byte[] inArray = stream.ToArray();
Convert.ToBase64String(inArray);
barCodeText = Convert.ToBase64String(inArray, 0, inArray.Length);
}
bitmap.Dispose();
}
catch (Exception ex)
{
if (ex.Message == "A generic error occurred in GDI+.")
goto aa;
isError = true;
return ex.Message;
}
return barCodeText;
}
EAN13 BarCodefont logic
public string EAN13(string bcP)
{
string s = "", suppl = "", TempStrL = "";
int CountryFlagL = 0;
switch (bcP.Length)
{
case 12:
case 13:
s = bcP.Substring(0, 12) + CheckDigit(SYMB_EAN13, bcP.Substring(0, 12));
break;
case 14:
case 15:
s = bcP.Substring(0, 12) + CheckDigit(SYMB_EAN13, bcP.Substring(0, 12));
suppl = AddOn(bcP.Substring(bcP.Length - 2));
break;
case 17:
case 18:
s = bcP.Substring(0, 12) + CheckDigit(SYMB_EAN13, bcP.Substring(0, 12));
suppl = AddOn(bcP.Substring(bcP.Length - 5));
break;
}
TempStrL = GetChar(digitsOnly, s.Substring(0, 1));//
TempStrL = TempStrL + "{{{{{";
TempStrL = TempStrL + "|";
CountryFlagL = Convert.ToInt32(s.Substring(0, 1));//
for (int i = 1; i <= 6; i++)
{
if (GetParity(SYMB_EAN13, i - 1, CountryFlagL) == "A")//
TempStrL = TempStrL + GetChar(charsetA, s.Substring(i, 1));//
else
TempStrL = TempStrL + GetChar(charsetB, s.Substring(i, 1));//
}
TempStrL = TempStrL + "{" + "|" + "{";
for (int i = 8; i <= 13; i++)
{
TempStrL = TempStrL + GetChar(charsetC, s.Substring(i - 1, 1));
}
TempStrL = TempStrL + "|";
if (suppl.Length > 0)
TempStrL = TempStrL + "}" + suppl;
return TempStrL;
}
protected string AddOn(string bcP)
{
string parL, ParSectionL = "", TempstrL;
int TotalL = 0, intbcL, MultiplierL, PositionL, CounterL = 0, SectLengthL;
switch (bcP.Length)
{
case 2:
parL = "AA" + "AB" + "BA" + "BB";
intbcL = Convert.ToInt32(bcP);
TotalL = intbcL % 4;
ParSectionL = parL.Substring(TotalL * 2, 2);
break;
case 5:
parL = "BBAAA" + "BABAA" + "BAABA" + "BAAAB" + "ABBAA" + "AABBA" + "AAABB" + "ABABA" + "ABAAB" + "AABAB";
for (int i = 1; i <= 5; i++)
{
MultiplierL = 3;
if (i % 2 == 0)
MultiplierL = 9;
intbcL = Convert.ToInt32(bcP.Substring(i - 1, 1));
TotalL = TotalL + MultiplierL * intbcL;
}
PositionL = (TotalL % 10) * 5;
ParSectionL = parL.Substring(PositionL, 5);
break;
}
TempstrL = "m";
SectLengthL = ParSectionL.Length;
for (int i = 1; i <= SectLengthL; i++)
{
if (ParSectionL.Substring(i - 1, 1) == "A")
TempstrL = TempstrL + GetChar(CharsetASupp, bcP.Substring(i - 1, 1));
else
TempstrL = TempstrL + GetChar(CharsetBSupp, bcP.Substring(i - 1, 1));
if (i < SectLengthL)
TempstrL = TempstrL + "n";
}
return TempstrL;
}
protected string CheckDigit(int SymbologyL, string c)
{
string s = "";
int NumDigitsL = 0, intc = 0, cd;
decimal TotalL = 0;
switch (SymbologyL)
{
case SYMB_UPCA:
NumDigitsL = 11;
break;
case SYMB_EAN13:
NumDigitsL = 12;
break;
case SYMB_EAN8:
NumDigitsL = 7;
break;
}
for (int i = 1; i <= NumDigitsL; i++)
{
if (((NumDigitsL + 1 - i) % 2) == 0)
{
string str = c.Substring(i - 1, 1);
intc = Convert.ToInt32(str);
TotalL = TotalL + 1 * intc;
}
else
{
string str = c.Substring(i - 1, 1);
intc = Convert.ToInt32(str);
TotalL = TotalL + 3 * intc;
}
}
cd = 10 - Convert.ToInt32(TotalL % 10);
if (cd == 10)
cd = 0;
return cd.ToString();
}
protected string GetChar(string c, string DigitP)
{
int intDigitL = Convert.ToInt32(DigitP);
return c.Substring(intDigitL, 1);
}
protected string GetParity(int SymbologyP, int PositionP, int CodeValP)
{
string parL = "", ParityL = "";
switch (SymbologyP)
{
case SYMB_EAN13:
parL = "AAAAAA" + "AABABB" + "AABBAB" + "AABBBA" + "ABAABB" + "ABBAAB" + "ABBBAA" + "ABABAB" + "ABABBA" + "ABBABA";
break;
case SYMB_UPCE:
parL = "BBBAAA" + "BBABAA" + "BBAABA" + "BBAAAB" + "BABBAA" + "BAABBA" + "BAAABB" + "BABABA" + "BABAAB" + "BAABAB";
break;
}
ParityL = parL.Substring(CodeValP * 6, 6);
return ParityL.Substring(PositionP, 1);
}
**Global Variables are below **
[DllImport("gdi32.dll")]
private static extern IntPtr AddFontMemResourceEx(IntPtr pbfont, uint cbfont, IntPtr pdv, [In] ref uint pcFonts);
FontFamily ff;
private string barCodeText = string.Empty;
byte[] fontArray;
int dataLength;
const int SYMB_UPCA = 1, SYMB_EAN13 = 3, SYMB_EAN8 = 4, SYMB_UPCE = 2;
string CharsetASupp = "+,./:;=?#K", CharsetBSupp = #"LMNOP[\]^_";
string charsetA = "ABCDEFGHIJ", charsetB = "QRSTUVWXYZ", charsetC = "0123456789", digitsOnly = "qrstuvwxyz";
The Correct one looks like below
The wrong one looks like below
I have created as vlcbarcode.dll file reference of above function and added the azure project same as refered url and written below function.
Below is the azure function
[FunctionName("GetBarCodes")]
public static async Task<HttpResponseMessage> Run([HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "GetBarCodes/")]HttpRequestMessage req, TraceWriter log)
{
log.Info("C# HTTP trigger function processed a request.");
// Get request body
VLCBarCodes[] barCodeList = await req.Content.ReadAsAsync<VLCBarCodes[]>();
List<QueryStringClass> resultList = new List<QueryStringClass>();
string errorText = "";
string result = "";
bool isError = false;
foreach (var list in barCodeList)
{
errorText = "";
result = "";
if (string.IsNullOrWhiteSpace(list.BarCodeFontType))
errorText = " Bar code Type can not be empty or null";
if (string.IsNullOrWhiteSpace(list.BarCodeValue))
errorText += " Bar code text can not be empty or null";
if (string.IsNullOrWhiteSpace(list.BarCodeFontHeight))
errorText += " Bar code height can not be empty or null";
if (string.IsNullOrWhiteSpace(list.BarCodeFontWidth))
errorText += " Bar code width can not be empty or null";
if (string.IsNullOrWhiteSpace(list.BarCodeFontSize))
errorText += " Bar code font can not be empty or null";
if (list.BarCodeImageUID == 0)
errorText += " Bar Code Image Id can not be empty or null";
if (string.IsNullOrWhiteSpace(list.BarCodeEntryNo))
errorText += " Bar Code entry no can not be empty or null";
if (!string.IsNullOrWhiteSpace(list.BarCodeFontType) && !string.IsNullOrWhiteSpace(list.BarCodeValue) && !string.IsNullOrWhiteSpace(list.BarCodeFontHeight)
&& !string.IsNullOrWhiteSpace(list.BarCodeFontWidth) && list.BarCodeImageUID != 0 && string.IsNullOrWhiteSpace(errorText))
{
switch (list.BarCodeFontType)
{
case "EAN-13":
GenerateEANTBarCode generateEANTBarCode = new GenerateEANTBarCode();
result = generateEANTBarCode.GenerateBarCodeFont(list.BarCodeValue, out isError, Convert.ToInt32(list.BarCodeFontWidth), Convert.ToInt32(list.BarCodeFontHeight), "EAN-13", Convert.ToInt32(list.BarCodeFontSize));
break;
default:
isError = true;
result = "Please specify the bar code font type";
break;
}
if (isError)
resultList.Add(new QueryStringClass { BarCodeEntryNo = list.BarCodeEntryNo, BarCodeImageUID = list.BarCodeImageUID, Type = list.BarCodeFontType, Value = "", ErrorText = result });
else
resultList.Add(new QueryStringClass { BarCodeEntryNo = list.BarCodeEntryNo, BarCodeImageUID = list.BarCodeImageUID, Type = list.BarCodeFontType, Value = result, ErrorText = "" });
}
else
resultList.Add(new QueryStringClass { BarCodeEntryNo = list.BarCodeEntryNo, BarCodeImageUID = list.BarCodeImageUID, Type = list.BarCodeFontType, Value = result, ErrorText = errorText });
}
return req.CreateResponse(HttpStatusCode.OK, resultList);
}
QueryStringClass can get the results from vlcbarcode.dll function and return to the end user.
public class QueryStringClass
{
public int BarCodeImageUID { get; set; }
//public Guid Guid { get; set; }
public string BarCodeEntryNo { get; set; }
public string Type { get; set; }
public string Value { get; set; }
public string ErrorText { get; set; }
}
VLCBarCodes class is refere to original calss fields to validate the request and send the values to .dll file function.
public class VLCBarCodes
{
public int BarCodeImageUID { get; set; }
public string BarCodeValue { get; set; }
public string BarCodeFontWidth { get; set; }
public string BarCodeFontHeight { get; set; }
public string BarCodeFontType { get; set; }
public string BarCodeFontSize { get; set; }
public string BarCodeEntryNo { get; set; }
}
Please suggest if I went anything wrong.

Answer 1

In Azure App service most of the GDI32 system calls are blocked.
All Azure Web Apps (as well as Mobile App/Services, WebJobs and Functions) run in a secure environment called a sandbox.
The sandbox generally aims to restrict access to shared components of Windows. Unfortunately, many core components of Windows have been designed as shared components: the registry, cryptography, and graphics subsystems, among others. This section outlines the limitations placed on usage of these often essential, yet shared components.
For the sake of radical attack surface area reduction, the sandbox prevents almost all of the Win32k.sys APIs from being called, which practically means that most of User32/GDI32 system calls are blocked. For most applications this is not an issue since most Azure Web Apps do not require access to Windows UI functionality (they are web applications after all).
Reference doc: https://github.com/projectkudu/kudu/wiki/Azure-Web-App-sandbox
You can host this Azure function in an Azure Virtual machine if you are willing to use same code else you can try some alternative approach to generate the BAR code as explained in this blog.