Working with MySQL Blob
There two mode for working with MySQL BLOB, first mode is string mode. You can use BLOB only for storing long-long string value. In this case you can working with the same way.
However in other case you need to working with BLOB exactly as byte, for example if you store in db image or password.
This is more interesting way, look to this code (this code is part of this project BackendAPI (Net Core 5) project template with Custom Attribute, Service and Controller Example, MySQL database with masked password in config, SwaggerUI, EF Core and extension to EF Core).
1: Imports System.IO
2: Imports System.Text
3: Imports BackendAPI.Helper
4: Imports BackendAPI.Model
5: Imports BackendAPI.Services
6: Imports Microsoft.AspNetCore.Mvc
7: Imports Newtonsoft.Json.Linq
8:
9: Namespace WebApi.Controllers
10:
11: <ApiController>
12: <Route("[controller]/[action]")>
13: Public Class AesController
14: Inherits ControllerBase
15:
16: Private ReadOnly Aes As AesCryptor
17: Private ReadOnly _DB As ApplicationDbContext
18: Private ReadOnly _UserService As IUserService
19:
20: Public Sub New(ByVal UserService As IUserService, Cryptor As IAesCryptor, DbContext As ApplicationDbContext)
21: Aes = Cryptor
22: _DB = DbContext
23: _UserService = UserService
24: End Sub
25:
26: <HttpGet>
27: Public Function NetCrypt(Text As String, KeyString As String) As String
28: Return Aes.EncryptString(Text, KeyString)
29: End Function
30:
31: <HttpGet>
32: Public Function NetDeCrypt(CipherText As String, KeyString As String) As String
33: Return Aes.DecryptString(CipherText, KeyString)
34: End Function
35:
36: 'Authorize because vulnerable to SQL injection
37: <Jwt.Authorize>
38: <HttpGet>
39: Public Function SqlCrypt(Text As String, KeyString As String) As JsonResult
40: Dim CurUsers = _UserService.GetCurrentUser(Request.Headers("JwtUserName")(0))
41: If CurUsers.IsAdmin Then
42: Dim Buf1 As Byte() = New Byte() {}
43: ReDim Buf1(100)
44: _DB.RawSqlQuery(Of Byte())($"select aes_encrypt('{Text}','{KeyString}') as aes_encrypt", Function(X)
45: CType(X("aes_encrypt"), Byte()).CopyTo(Buf1, 0)
46: ReDim Preserve Buf1(CType(X("aes_encrypt"), Byte()).Length - 1)
47: Return Nothing
48: End Function)
49: Dim Sb1 As New StringBuilder
50: For Each One As Byte In Buf1.ToArray
51: Sb1.Append(One.ToString("X2"))
52: Next
53: Dim Ret1 As New With {.ToBase64String = Convert.ToBase64String(Buf1), .Hex = Sb1.ToString, .Utf8String = UTF8Encoding.UTF8.GetString(Buf1)}
54: Return New JsonResult(Ret1)
55: Else
56: Return New JsonResult(Unauthorized())
57: End If
58:
59: End Function
60:
61: <Jwt.Authorize>
62: <HttpGet>
63: Public Function SqlDeCrypt(HexCipherText As String, KeyString As String) As JsonResult
64: Dim CurUsers = _UserService.GetCurrentUser(Request.Headers("JwtUserName")(0))
65: If CurUsers.IsAdmin Then
66: Dim Buf1 As Byte() = New Byte() {}
67: ReDim Buf1(100)
68: _DB.RawSqlQuery(Of Byte())($"select aes_decrypt(X'{HexCipherText}','{KeyString}') as aes_decrypt", Function(X)
69: CType(X("aes_decrypt"), Byte()).CopyTo(Buf1, 0)
70: ReDim Preserve Buf1(CType(X("aes_decrypt"), Byte()).Length - 1)
71: Return Nothing
72: End Function)
73: Dim Sb1 As New StringBuilder
74: For Each One As Byte In Buf1.ToArray
75: Sb1.Append(One.ToString("X2"))
76: Next
77: Dim Ret1 As New With {.ToBase64String = Convert.ToBase64String(Buf1), .Hex = Sb1.ToString, .Utf8String = UTF8Encoding.UTF8.GetString(Buf1)}
78: Return New JsonResult(Ret1)
79: Else
80: Return New JsonResult(Unauthorized())
81: End If
82: End Function
83: End Class
84: End Namespace
And look, please, to related topic.
- Робота з байтами у VB.NET - ChrW, BitConverter.ToInt32, Convert.ToInt32, Byte.Parse, ToString("X2") / AllowHexSpecifier, GetBytes/GetString, New Byte(N) {}, UInt32 = &H33
- Linux shell parser (Renci.SshNet.SshClient, MySqlConnector.NET, RSA encription, Console password, XDocument/XPath, Tuple, Regex, Buffer.BlockCopy, Stream, Base64String, UTF8.GetBytes, ToString("X2"))
- Хранение графики в SQL-сервере
- Cекционирование графики при SQL-хранении.
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