Tcl
Mailgun Send Email using MIME

Send an email using MIME. This allows for the Chilkat email object to be used to construct the email. Then it can be sent using Mailgun.
Chilkat Tcl Downloads

Download Chilkat for Tcl
Tcl

load ./chilkat.dll

set success 0

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# We're going to create an email that contains an .zip attachment,
# and also both plain-text and HTML alternative bodies.
# The HTML body will include an image.

set email [new_CkEmail]

# Adding attachments, HTML/plain-text bodies, etc can be done
# in any order:

# Add an attachment
set contentType [CkEmail_addFileAttachment $email "qa_data/hamlet.zip"]
if {[CkEmail_get_LastMethodSuccess $email] == 0} then {
    puts [CkEmail_lastErrorText $email]
    delete_CkEmail $email
    exit
}

# Add some headers:
CkEmail_put_Subject $email "This is a complex email"
# Please change this email address before testing.
set success [CkEmail_AddTo $email "Joe Example" "joe@example.com"]
CkEmail_put_From $email "Your Name <mailgun@YOUR_DOMAIN_NAME>"

# Add a plain-text body:
CkEmail_AddPlainTextAlternativeBody $email "This is the plain-text body"

# Add an image that will be embedded in the HTML body.
set success [CkEmail_AddRelatedFile2 $email "qa_data/jpg/starfish.jpg" "starfish.jpg"]
if {$success == 0} then {
    puts [CkEmail_lastErrorText $email]
    delete_CkEmail $email
    exit
}

# Add an HTML body:

set html "<html><body><b>This is the HTML body</b><br><img src=\"starfish.jpg\"></body></html>"

CkEmail_AddHtmlAlternativeBody $email $html

# ------------------------------------------------------------------------
# Send the above email using Mailgun

set http [new_CkHttp]

# Implements the following CURL command:

CkHttp_put_Login $http "api"
CkHttp_put_Password $http "sending_api_key"#  Replace with your actual sending API key.

set req [new_CkHttpRequest]

CkHttpRequest_put_HttpVerb $req "POST"
CkHttpRequest_put_Path $req "/v3/YOUR_DOMAIN_NAME/messages.mime"
CkHttpRequest_put_ContentType $req "multipart/form-data"

CkHttpRequest_AddParam $req "from" "Your Name <mailgun@YOUR_DOMAIN_NAME>"
CkHttpRequest_AddParam $req "to" "Joe Example <joe@example.com>"
CkHttpRequest_AddStringForUpload2 $req "message" "message.eml" [CkEmail_getMime $email] "utf-8" "application/octet-stream"

set resp [new_CkHttpResponse]

set success [CkHttp_HttpSReq $http "api.mailgun.net" 443 1 $req $resp]
if {$success == 0} then {
    puts [CkHttp_lastErrorText $http]
    delete_CkEmail $email
    delete_CkHttp $http
    delete_CkHttpRequest $req
    delete_CkHttpResponse $resp
    exit
}

set sbResponseBody [new_CkStringBuilder]

CkHttpResponse_GetBodySb $resp $sbResponseBody
set jResp [new_CkJsonObject]

CkJsonObject_LoadSb $jResp $sbResponseBody
CkJsonObject_put_EmitCompact $jResp 0

puts "Response Body:"
puts [CkJsonObject_emit $jResp]

set respStatusCode [CkHttpResponse_get_StatusCode $resp]
puts "Response Status Code = $respStatusCode"
if {$respStatusCode >= 400} then {
    puts "Response Header:"
    puts [CkHttpResponse_header $resp]
    puts "Failed."
    delete_CkEmail $email
    delete_CkHttp $http
    delete_CkHttpRequest $req
    delete_CkHttpResponse $resp
    delete_CkStringBuilder $sbResponseBody
    delete_CkJsonObject $jResp
    exit
}

# Sample JSON response:
# (Sample code for parsing the JSON response is shown below)

# {
#   "id": "<20210429234809.1.2D550E1C94D3D98F@sandbox0e542e4c577f4bbb98c8bf6b6bca727b.mailgun.org>",
#   "message": "Queued. Thank you."
# }

# Sample code for parsing the JSON response...
# Use the following online tool to generate parsing code from sample JSON:
# Generate Parsing Code from JSON

set id [CkJsonObject_stringOf $jResp "id"]
set message [CkJsonObject_stringOf $jResp "message"]

delete_CkEmail $email
delete_CkHttp $http
delete_CkHttpRequest $req
delete_CkHttpResponse $resp
delete_CkStringBuilder $sbResponseBody
delete_CkJsonObject $jResp