Question:
I’m using PowerShell to write messages to a message queue, which has a message size limit on it. Before writing a message to the queue, I need to know how many bytes a string is.
How can I figure out how many bytes the string is, so I can perform a size comparison, before writing to the queue?
Answer:
The answer to this depends on the text encoding you’re using.
You can use the static method GetByteCount() on a few different text encodings. Assuming you’re using UTF-8 text encoding, you can reference the UTF8 static property on the System.Text.Encoding class, to obtain a reference to the UTF8Encoding class.
Here’s an example, where we retrieve a System.Diagnostics.Process object, convert it to a JSON representation, and then determine how many bytes it uses, given a UTF8 encoding.
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$Process = Get-Process -Name System | ConvertTo-Json [System.Text.Encoding]::UTF8.GetByteCount($Process) |
Here’s the same example, but changing the text encoding to ASCII.
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[System.Text.Encoding]::ASCII.GetByteCount($Process) |
If your input string doesn’t contain any Unicode characters, you should get the same result for both ASCII and UTF-8 byte counts.
NOTE: The System.Text.Encoding base class declares a virtual method named GetByteCount(), however it’s up to the child classes (eg. UTF8Encoding) to actually implement this method.
https://msdn.microsoft.com/en-us/library/w3739zdy(v=vs.110).aspx