Base64Encode an image string works in Windows but not in Mac

[mmustala]

I tried to use the Base64Encoding function for a string containing image file bytes.

file = FreeFile()
Open ThisWorkbook.Path & dirSeparator & "temp_receipt.jpg" For Binary As #file
    imageString = Input(LOF(1), #file)
Close #file
encoded = Base64Encode(imageString)

This works in Windows but not in Mac.

In Mac the base64 encoding is done with these lines in the WebHelpers

web_Command = "printf " & PrepareTextForShell(Text) & " | openssl base64"
Base64Encode = ExecuteInShell(web_Command).Output

I'm not sure if the reason for the failure is in the PrepareTextForShell method or in the way how the data is given to the command line.

Luckily the #If Mac and ExecuteInShell works also outside of the VBA-Web files and I was able to add my own encoding logic for the Mac.

#If Mac Then
    Dim web_Command As String
    web_Command = "cat /path/to/image | openssl base64"
    encoded = ExecuteInShell(web_Command).Output
#Else
    file = FreeFile()
    Open image_path For Binary As #file
        imageString = Input(LOF(1), #file)
    Close #file
    encoded = Base64Encode(imageString)
#End If

I'm not sure if a fix for this issue should be made by modifying the existing Base64Encode method so that it can accept strings containing file contents or should it be fixed by adding a new method Base64EncodeFile.

[timhall]

@mmustala Thanks for bringing this up and I'm glad you found a fix. I hadn't tried Base64 encoding files, so this is interesting. I was worried that there could be encoding issues passing strings to and from the shell, I'll add a few test cases to try and identify the issue.

[kzimny]

Thank you for sharing your great library on GitHub. I love it!
I have exactly the same issue as mmustala. Please fix the bug as soon as possible.

[RichardWein]

Hi. I'm currently working on an API integration (for Salesforce) that uploads base64-encoded binary files.

I've been reading the file into a Byte array, which means I can't use VBA-Web's Base64Encode function, as that takes a String parameter. So I'm using the web_AnsiBytesToBase64 function instead. (Unfortunately that function is Private in WebHelpers, so I had to make my own copy of it.)

That works fine on a PC, but then I started worrying about Mac-compatibility, as I will probably have to support Macs later. And that brought me to this discussion. It looks like mmustala's solution could be the answer (thanks!), but I'm a bit worried about storing binary data in a String variable. It seems to work, but is this a recognized feature? Is it safe? (Alternatively, can the "web_fread" function be made to return a Byte array instead of a String?)