Authentication Failed for get file using file service REST API Azure - azure

Question

I am trying to get a file using the shared key. I already get a list of files and directories by the shared key, but when I request to receive a specific file, I encounter this problem.
Code to generate shared key:
using System;
using System.Collections.Specialized;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Cryptography;
using System.Text;
using System.Web;
namespace StorageRestApiAuth
{
internal static class AzureStorageAuthenticationHelper
{
internal static AuthenticationHeaderValue GetAuthorizationHeader(
string storageAccountName, string storageAccountKey, DateTime now,
HttpRequestMessage httpRequestMessage, string ifMatch = "", string md5 = "")
{
// This is the raw representation of the message signature.
HttpMethod method = httpRequestMessage.Method;
String MessageSignature = String.Format("{0}\n\n\n{1}\n{5}\n\n\n\n{2}\n\n\n\n{3}{4}",
method.ToString(),
(method == HttpMethod.Get || method == HttpMethod.Head) ? String.Empty
: httpRequestMessage.Content.Headers.ContentLength.ToString(),
ifMatch,
GetCanonicalizedHeaders(httpRequestMessage),
GetCanonicalizedResource(httpRequestMessage.RequestUri, storageAccountName),
md5);
byte[] SignatureBytes = Encoding.UTF8.GetBytes(MessageSignature);
HMACSHA256 SHA256 = new HMACSHA256(Convert.FromBase64String(storageAccountKey));
string signature = Convert.ToBase64String(SHA256.ComputeHash(SignatureBytes));
returned.
AuthenticationHeaderValue authHV = new AuthenticationHeaderValue("SharedKey",
storageAccountName + ":" + Convert.ToBase64String(SHA256.ComputeHash(SignatureBytes)));
return authHV;
}
private static string GetCanonicalizedHeaders(HttpRequestMessage httpRequestMessage)
{
var headers = from kvp in httpRequestMessage.Headers
where kvp.Key.StartsWith("x-ms-", StringComparison.OrdinalIgnoreCase)
orderby kvp.Key
select new { Key = kvp.Key.ToLowerInvariant(), kvp.Value };
StringBuilder sb = new StringBuilder();
foreach (var kvp in headers)
{
StringBuilder headerBuilder = new StringBuilder(kvp.Key);
char separator = ':';
foreach (string headerValues in kvp.Value)
{
string trimmedValue = headerValues.TrimStart().Replace("\r\n", String.Empty);
headerBuilder.Append(separator).Append(trimmedValue);
separator = ',';
}
sb.Append(headerBuilder.ToString()).Append("\n");
}
return sb.ToString();
}
private static string GetCanonicalizedResource(Uri address, string storageAccountName)
{
StringBuilder sb = new StringBuilder("/").Append(storageAccountName).Append(address.AbsolutePath);
NameValueCollection values = HttpUtility.ParseQueryString(address.Query);
foreach (var item in values.AllKeys.OrderBy(k => k))
{
sb.Append('\n').Append(item).Append(':').Append(values[item]);
}
return sb.ToString().ToLower();
}
}
}
With this code I can get a list of directories and files, but I can’t get a specific file.
I'm use this url to request: https://myaccount.file.core.windows.net/myshare/mydirectorypath/myfile
Error sending request:
{
"Error": {
"Code": "AuthenticationFailed",
"Message": "Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.\nRequestId:4c9ca5be-301a-0045-29c9-f20135000000\nTime:2020-03-05T08:36:05.9908405Z",
"AuthenticationErrorDetail": "The MAC signature found in the HTTP request 'here is my key' is not the same as any computed signature. Server used following string to sign: 'GET\n\n\n\n\n\n\n\n\n\n\n\nx-ms-date:Thu, 05 Mar 2020 08:36:05 GMT\nx-ms-version:2017-04-17\n/my storage account/my share/myfile.JPG'."
}
}

Answer 1

I test in my site with your code and it works well. With your AzureStorageAuthenticationHelper and here it the following code that I get file content.
static void Main(string[] args)
{
GetFileContentAsyncREST("youraccount", "yourkey", CancellationToken.None).GetAwaiter().GetResult();
Console.WriteLine("Press any key to continue.");
Console.ReadLine();
}
private static async Task GetFileContentAsyncREST(string storageAccountName, string storageAccountKey, CancellationToken cancellationToken)
{
string uri = "https://xxxxx.file.core.windows.net/helloworld/directory/helloworld.txt";
Byte[] requestPayload = null;
using (var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, uri)
{
Content = (requestPayload == null) ? null : new ByteArrayContent(requestPayload) })
{
DateTime now = DateTime.UtcNow;
httpRequestMessage.Headers.Add("x-ms-date", now.ToString("R", CultureInfo.InvariantCulture));
httpRequestMessage.Headers.Add("x-ms-version", "2017-04-17");
httpRequestMessage.Headers.Authorization = AzureStorageAuthenticationHelper.GetAuthorizationHeader(
storageAccountName, storageAccountKey, now, httpRequestMessage);
using (HttpResponseMessage httpResponseMessage = await new HttpClient().SendAsync(httpRequestMessage, cancellationToken))
{
if (httpResponseMessage.StatusCode == HttpStatusCode.OK)
{
string content = await httpResponseMessage.Content.ReadAsStringAsync();
Console.Write(content);
}
}
}
}
}
For more details, you could refer to this storage rest api with auth sample.