1
0
mirror of https://github.com/imgproxy/imgproxy.git synced 2024-12-09 09:56:01 +02:00
imgproxy/examples/signature.cs
2017-09-29 11:06:07 +10:00

61 lines
2.2 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
namespace ImgProxy.Examples
{
class Program
{
static void Main(string[] args)
{
const string Key = "943b421c9eb07c830af81030552c86009268de4e532ba2ee2eab8247c6da0881";
const string Salt = "520f986b998545b4785e0defbc4f3c1203f22de2374a3d53cb7a7fe9fea309c5";
const string Url = "http://img.example.com/pretty/image.jpg";
const string Resize = "fill";
const int Width = 300;
const int Height = 300;
const string Gravity = "no";
const int Enlarge = 1;
const string Extension = "png";
var url = GenerateUrl(Key, Salt, Url, Resize, Width, Height, Gravity, Enlarge, Extension);
Console.WriteLine(url);
}
static string GenerateUrl(string key, string salt, string url, string resize, int width, int height, string gravity, int enlarge, string extension)
{
var keybin = StringToByteArray(key);
var saltBin = StringToByteArray(salt);
var encodedUrl = string.Join("/", WholeChunks(Convert.ToBase64String(Encoding.UTF8.GetBytes(url)).TrimEnd('='), 16));
var path = $"/{resize}/{width}/{height}/{gravity}/{enlarge}/{encodedUrl}.{extension}";
using (var hmac = new HMACSHA256(keybin))
{
var hash = hmac.ComputeHash(saltBin.Concat(Encoding.UTF8.GetBytes(path)).ToArray());
return $"/{Convert.ToBase64String(hash).TrimEnd('=')}{path}";
}
}
static byte[] StringToByteArray(string hex)
{
return Enumerable.Range(0, hex.Length)
.Where(x => x % 2 == 0)
.Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
.ToArray();
}
static IEnumerable<string> WholeChunks(string str, int maxChunkSize)
{
for (int i = 0; i < str.Length; i += maxChunkSize)
yield return str.Substring(i, Math.Min(maxChunkSize, str.Length - i));
}
}
}