Skip to content

Handle binary data in Base64 to string conversion (#14) #18

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
austoonz merged 1 commit into from
Jan 27, 2026
Merged

Handle binary data in Base64 to string conversion (#14) #18

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 12 additions & 4 deletions src/Convert/Public/ConvertFrom-Base64ToString.ps1
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -85,11 +85,19 @@ function ConvertFrom-Base64ToString {
$ptr = [ConvertCoreInterop]::base64_to_string($s, $Encoding)

if ($ptr -eq $nullPtr) {
$errorMsg = GetRustError -DefaultMessage "Base64 decoding failed for encoding '$Encoding'"
throw $errorMsg
$rustError = GetRustError -DefaultMessage ''
if ($rustError -match 'Invalid UTF-8|Invalid ASCII|Invalid UTF-16|Invalid UTF-32') {
# Binary data - fall back to Latin-1 which can represent any byte
$bytes = [System.Convert]::FromBase64String($s)
[System.Text.Encoding]::GetEncoding('ISO-8859-1').GetString($bytes)
} elseif ($rustError) {
throw $rustError
} else {
throw "Base64 decoding failed for encoding '$Encoding'"
}
} else {
ConvertPtrToString -Ptr $ptr
}

ConvertPtrToString -Ptr $ptr
} finally {
if ($ptr -ne $nullPtr) {
[ConvertCoreInterop]::free_string($ptr)
Expand Down
39 changes: 22 additions & 17 deletions src/Convert/Public/ConvertTo-String.ps1
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -133,33 +133,38 @@ function ConvertTo-String {
}

process {
$splat = @{}
switch ($PSCmdlet.ParameterSetName) {
'Base64String' {
$InputObject = $Base64EncodedString
$Function = 'ConvertFrom-Base64ToString'
$splat.Add('Encoding', $Encoding)
if ($Decompress) {
$splat.Add('Decompress', $true)
foreach ($b64 in $Base64EncodedString) {
try {
if ($Decompress) {
$b64 | ConvertFrom-Base64ToString -Encoding $Encoding -Decompress -ErrorAction Stop
} else {
try {
ConvertFrom-Base64ToString -String $b64 -Encoding $Encoding -ErrorAction Stop
} catch {
if ($_.Exception.Message -match 'does not represent valid .+ text') {
# Binary data - fall back to Latin-1 which can represent any byte
$bytes = [System.Convert]::FromBase64String($b64)
[System.Text.Encoding]::GetEncoding('ISO-8859-1').GetString($bytes)
} else {
throw
}
}
}
} catch {
Write-Error -ErrorRecord $_ -ErrorAction $userErrorActionPreference
}
}
break
}

'MemoryStream' {
$InputObject = $MemoryStream
$Function = 'ConvertFrom-MemoryStreamToString'
break
$MemoryStream | ConvertFrom-MemoryStreamToString -ErrorAction $userErrorActionPreference
}

'Stream' {
$InputObject = $Stream
$Function = 'ConvertFrom-MemoryStreamToString'
break
$Stream | ConvertFrom-MemoryStreamToString -ErrorAction $userErrorActionPreference
}
}

if ($InputObject) {
$InputObject | & $Function @splat -ErrorAction $userErrorActionPreference
}
}
}
20 changes: 20 additions & 0 deletions src/Tests/Unit/ConvertFrom-Base64ToString.Tests.ps1
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,26 @@ Describe -Name $function -Fixture {
$base64 = 'SGVsbG8'
{ ConvertFrom-Base64ToString -String $base64 -Encoding 'UTF8' -ErrorAction Stop } | Should -Throw
}

It -Name 'Converts binary data (non-UTF8) without error' -Test {
$binaryBytes = [byte[]](0xA1, 0x59, 0xC0, 0xA5, 0xE4, 0x94, 0xFF, 0x00, 0x80)
$base64 = [System.Convert]::ToBase64String($binaryBytes)

$result = ConvertFrom-Base64ToString -String $base64

$result | Should -Not -BeNullOrEmpty
$result | Should -BeOfType [string]
}

It -Name 'Round-trips binary data through Latin-1 fallback' -Test {
$binaryBytes = [byte[]](0xA1, 0x59, 0xC0, 0xA5, 0xE4, 0x94, 0xFF, 0x00, 0x80)
$base64 = [System.Convert]::ToBase64String($binaryBytes)

$resultString = ConvertFrom-Base64ToString -String $base64
$resultBytes = [System.Text.Encoding]::GetEncoding('ISO-8859-1').GetBytes($resultString)

$resultBytes | Should -Be $binaryBytes
}
}

Context -Name 'Error Handling' -Fixture {
Expand Down
21 changes: 21 additions & 0 deletions src/Tests/Unit/ConvertTo-String.Tests.ps1
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,27 @@ Describe -Name $function -Fixture {

$assertion | Should -BeExactly $String
}

It -Name 'Converts binary data (non-UTF8) without error' -Test {
# Binary data that is not valid UTF-8 (e.g., certificate/image data)
$binaryBytes = [byte[]](0xA1, 0x59, 0xC0, 0xA5, 0xE4, 0x94, 0xFF, 0x00, 0x80)
$base64 = [System.Convert]::ToBase64String($binaryBytes)

$assertion = ConvertTo-String -Base64EncodedString $base64

$assertion | Should -Not -BeNullOrEmpty
$assertion | Should -BeOfType [string]
}

It -Name 'Round-trips binary data through Latin-1 fallback' -Test {
$binaryBytes = [byte[]](0xA1, 0x59, 0xC0, 0xA5, 0xE4, 0x94, 0xFF, 0x00, 0x80)
$base64 = [System.Convert]::ToBase64String($binaryBytes)

$resultString = ConvertTo-String -Base64EncodedString $base64
$resultBytes = [System.Text.Encoding]::GetEncoding('ISO-8859-1').GetBytes($resultString)

$resultBytes | Should -Be $binaryBytes
}
}

Context -Name 'MemoryStream input' -Fixture {
Expand Down