How to upload files into Azure Blob Storage with Postman?

Question

I am trying to upload base64 string as image file to Azure Blob Storage. Using https://docs.microsoft.com/en-us/rest/api/storageservices/put-blob documentation tried to create blob.

Request Syntax:  
PUT https://myaccount.blob.core.windows.net/mycontainer/myblockblob HTTP/1.1  
  
Request Headers:  
x-ms-version: 2015-02-21  
x-ms-date: <date>  
Content-Type: text/plain; charset=UTF-8  
x-ms-blob-content-disposition: attachment; filename="fname.ext"  
x-ms-blob-type: BlockBlob  
x-ms-meta-m1: v1  
x-ms-meta-m2: v2  
Authorization: SharedKey myaccount:YhuFJjN4fAR8/AmBrqBz7MG2uFinQ4rkh4dscbj598g=  
Content-Length: 11  
  
Request Body:  
hello world 

I am getting response as below,

<?xml 
version="1.0" encoding="utf-8"?>
<Error>
    <Code>AuthenticationFailed</Code>
    <Message>Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
RequestId:a5d32623-f01e-0040-4275-c1880d000000
Time:2020-11-23T08:45:49.6994297Z</Message>
    <AuthenticationErrorDetail>The MAC signature found in the HTTP request 'YhuFJjN4fAR8/AmBrqBz7MG2uFinQ4rkh4dscbj598g=' is not the same as any computed signature. Server used following string to sign: 'PUT


11

text/plain; charset=UTF-8

x-ms-blob-content-disposition:attachment; filename="demo.txt"
x-ms-blob-type:BlockBlob
x-ms-date:Mon, 23 Nov 2020 13:08:11 GMT
x-ms-encryption-key:YhuFJjN4fAR8/AmBrqBz7MG2uFinQ4rkh4dscbj598g=
x-ms-meta-m1:v1
x-ms-meta-m2:v2
x-ms-version:2015-02-21
/<myaccount>/<mycontainer>/<myblob>'.</AuthenticationErrorDetail>
</Error>

How to resolve this issue?

Answer 1

A simple way to upload a blob is to use the sas token.

Nav to azure portal -> your storage account -> Shared access signature, then select the following options in the screenshot -> then click the Generate SAS and connection string button. The screenshot is as below:

Then copy the SAS token, and append it to the url. Then the new url looks like this: https://myaccount.blob.core.windows.net/mycontainer/myblockblob?sv=2019-12-12&ss=b&srt=coxxxxx

Next, in the postman, paste the new url. And in the Headers, you can remove Authorization field.

The test result is as below:

Answer 2

@sathishKumar

If you look closely in this article Authorize with Shared Key

The syntax is as below :

Authorization="[SharedKey|SharedKeyLite] <AccountName>:<Signature>"  

It is the signature that is passed along and not the Account key.

Signature is a Hash-based Message Authentication Code (HMAC) constructed from the request and computed by using the SHA256 algorithm, and then encoded by using Base64 encoding.

There are detailed steps how to construct the same mentioned on the above document.

Also, came across the post which talks about a PowerShell script which creates an Signature string through the Powershell that could be useful for you.

Sample Powershell Script

C# Implementation :

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);

    // Now turn it into a byte array.
    byte[] SignatureBytes = Encoding.UTF8.GetBytes(MessageSignature);

    // Create the HMACSHA256 version of the storage key.
    HMACSHA256 SHA256 = new HMACSHA256(Convert.FromBase64String(storageAccountKey));

    // Compute the hash of the SignatureBytes and convert it to a base64 string.
    string signature = Convert.ToBase64String(SHA256.ComputeHash(SignatureBytes));

    // This is the actual header that will be added to the list of request headers.
    AuthenticationHeaderValue authHV = new AuthenticationHeaderValue("SharedKey",
        storageAccountName + ":" + signature);
    return authHV;
}