Sending attachments with Mailgun using Powershell - powershell

Question

I cannot find any answer on Google or either Mailgun support on how to send attachments using Powershell. Sending mails without attachments works fine with Mailgun and Powershell. This is my code.
$apikey = "key-1342323f7d35352fa4dda3af3ca10e"
$idpass = "api:$($apikey)"
$basicauth = [System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes($idpass))
$headers = #{
Authorization = "Basic $basicauth";
}
$url = "https://api.mailgun.net/v3/sandboxac77741768d442323b96495501ac24b.mailgun.org/messages"
$mailbody = #{
from = "Mailgun Sandbox <postmaster#sandboxac77741768d442323b96495501ac24b.mailgun.org>";
to = "myadress#email.com";
subject = "Testing mail";
text = "Email body here";
attachment = "D:\temp\logfile.txt"
}
Invoke-RestMethod -Uri $url -Method Post -Headers $headers -Body $mailbody -ContentType "multipart/form-data"
This results in:
Invoke-RestMethod : The remote server returned an error: (400) Bad Request

Answer 1

Special thanks to https://stackoverflow.com/users/213135/alex from whom I stole code.
function ConvertTo-MimeMultiPartBody {
param([Parameter(Mandatory=$true)][string]$Boundary, [Parameter(Mandatory=$true)][hashtable]$Data)
$body = "";
$Data.GetEnumerator() |% {
$name = $_.Key
$value = $_.Value
$body += "--$Boundary`r`n"
$body += "Content-Disposition: form-data; name=`"$name`""
if ($value -is [byte[]]) {
$fileName = $Data['FileName']
if(!$fileName) { $fileName = $name }
$body += "; filename=`"$fileName`"`r`n"
$body += 'Content-Type: application/octet-stream'
$value = [System.Text.Encoding]::GetEncoding("ISO-8859-1").GetString($value)
}
$body += "`r`n`r`n" + $value + "`r`n"
}
return $body + "--$boundary--"
}
$emaildomain = "example.com"
$apikey = "key-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
$url = "https://api.mailgun.net/v2/$($emaildomain)/messages"
$headers = #{
Authorization = "Basic " + ([System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes("api:$($apikey)")))
}
$email_parms = #{
from = "me#example.com";
to = "you#example.com";
subject = "My Test Email";
text = 'Your email does not support HTML.';
html = "Hello World!";
filename = "example.pdf"
attachment = ([IO.File]::ReadAllBytes("c:\example.pdf"));
}
$boundary = [guid]::NewGuid().ToString()
$body = ConvertTo-MimeMultiPartBody $boundary $email_parms
Invoke-RestMethod -Uri $url -Method Post -Headers $headers -Body $body -ContentType "multipart/form-data; boundary=$boundary"

Answer 2

a slight addition to have multiple attachments, pushed it in a module:
mailgun.psm1
<#
.SYNOPSIS
Interface to the Mailgun API Module
.DESCRIPTION
Sends an e-mail through the Mailgun API see https://documentation.mailgun.com/en/latest/user_manual.html#sending-via-api
Define your maildomain and API key in MailGun.psd1 and place inside the module folder
.EXAMPLE
$from = "from#stackoverflow.com"
$to = "to1#stackoverflow.com", "another#stackoverflow.com"
$bcc = "bcc1#stackoveflow.com", "bcc2#stackoverflow.com"
$subject = "a mail with a subject"
$html = "this <b>test with attachments</b> text<br/> And another interesting line <hr />"
$attachments = #{
"ExampleAttachment1.png" = 'c:\temp\whatapps.png'
"AnotherExample.txt" = 'c:\temp\Msinfo.txt'
}
Send-MailgunEmail -from $from -to -bcc $bcc $to -subject $subject -htmlText $html -attachments $attachments
#>
$ModuleData = Import-PowerShellDataFile "$PSScriptRoot\MailGun.psd1"
function ConvertTo-MimeMultiPartBody {
<#
.SYNOPSIS
Convert email content with multiple attachments to correct format
with help from https://stackoverflow.com/questions/45463391/sending-attachments-with-mailgun-using-powershell
#>
param(
[Parameter(Mandatory = $true)]
[string]
$Boundary,
[Parameter(Mandatory = $true)]
[hashtable]
$Data
)
$lb = "`r`n"
$body = ""
$Data.GetEnumerator() | ForEach-Object {
$body += "--{0}{1}Content-Disposition: form-data; name=`"" -f $Boundary, $lb
if ($_.Value -is [byte[]]) {
$body += "attachment`"; filename=`"{0}`"{1}Content-Type: application/octet-stream{2}{3}{4}" -f
$_.Key, $lb, $lb, $lb, [System.Text.Encoding]::GetEncoding("ISO-8859-1").GetString($_.Value)
}
else {
$body += "{0}`"{1}{2}{3}" -f $_.Key, $lb, $lb, $_.Value
}
$body += $lb
}
return "{0}{1}--{2}--" -f $lb, $body, $boundary
}
function Send-MailgunEmail() {
<#
.SYNOPSIS
Sends an email through mailguns API
#>
param(
# The From e-mail address
[Parameter(Mandatory = $True)]
[string] $from,
# The To e-mail address (comma divided string)
[Parameter(Mandatory = $True)]
[array] $to,
# The bcc e-mail adresses
[Parameter(Mandatory = $False)]
[array] $bcc,
# the subject
[Parameter(Mandatory = $False)]
[string] $subject = 'Mail without subject',
# the text in the Text part
[Parameter(Mandatory = $False)]
[string] $text = 'Mail does not support Non Html readers',
# the text in the HTML part
[Parameter(Mandatory = $False)]
[string] $htmlText = '<html>no body content</html>',
# Either pass as parameter or set in MailGun.psd1
[Parameter(Mandatory = $False)]
[string] $emaildomain = $ModuleData.PrivateData.mailgun_emaildomain,
# the api key as found in the mailgun profile either pass or set in MailGun.psd1
[Parameter(Mandatory = $False)]
[string] $apikey = $ModuleData.PrivateData.mailgun_apikey,
# a list of attachments
[Parameter(Mandatory = $False)]
[hashtable] $attachments
)
$data = #{
from = $from
to = $to -join ','
subject = $subject
text = $text
html = "<html>$htmlText</html>"
}
if ($bcc) { $data.Add('bcc', [string]($bcc -join ',')) }
foreach ($attachment in $attachments.GetEnumerator()) {
$attachmentbytes = [IO.File]::ReadAllBytes($attachment.Value)
$data.Add($attachment.Name, $attachmentbytes)
}
$url = "https://api.mailgun.net/v3/$($emaildomain)/messages"
$headers = #{Authorization = "Basic " + [System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes("api:$($apikey)"))}
$boundary = [guid]::NewGuid().ToString()
$contenttype = "multipart/form-data; boundary=$boundary"
$body = ConvertTo-MimeMultiPartBody -Boundary $boundary -Data $data
return Invoke-RestMethod -Method Post -Uri $url -Headers $headers -Body $body -ContentType $contenttype
}
Export-ModuleMember -Function Send-MailgunEmail
mailgun.psd1
#{
RootModule = 'MailGun.psd1'
ModuleVersion = '1.0.0.0'
GUID = 'e0383493-22b2-4838-8095-67c865ae46de'
Author = 'edelwater'
PrivateData = #{
mailgun_emaildomain = 'EXAMPLE.COM'
mailgun_apikey = 'key-123fdsdafgd9gf043dfgd03sdd'
}
}
testmailgunmodule.ps1
Import-Module "$PSScriptRoot\.\Modules\MailGun.psm1" -Force
$from = "from#stackoverflow.com"
$to = "to1#stackoverflow.com", "another#stackoverflow.com"
$bcc = "bcc1#stackoveflow.com", "bcc2#stackoverflow.com"
$subject = "a mail with a subject"
$html = "this <b>test with attachments</b> text<br/> And another interesting line <hr />"
$attachments = #{
"ExampleAttachment1.png" = 'c:\temp\whatapps.png'
"AnotherExample.txt" = 'c:\temp\Msinfo.txt'
}
Send-MailgunEmail -from $from -to $to -subject $subject -htmlText $html -attachments $attachments