(VB.NET UWP/WinRT) Outlook --Download MIME Embedded Images in an HTML Email

Demonstrates how to download the MIME embedded images for a particular HTML email message.

The code for downloading the embedded HTML images is the same as for downloading attachments. When an HTML email has embedded images (and no real attachments), the JSON returned when listing the message will indicate "hasAttachments": false. However, you can still use the URL for getting attachments to get the embedded images.

Note: This example requires Chilkat v9.5.0.67 or greater.

This example applies to: Exchange Online | Office 365 | Hotmail.com | Live.com | MSN.com | Outlook.com | Passport.com

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

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

Dim http As New Chilkat.Http

' Use your previously obtained access token here:
' See the following examples for getting an access token:
'    Get Microsoft Graph OAuth2 Access Token (Azure AD v2.0 Endpoint).
'    Get Microsoft Graph OAuth2 Access Token (Azure AD Endpoint).
'    Refresh Access Token (Azure AD v2.0 Endpoint).
'    Refresh Access Token (Azure AD Endpoint).

http.AuthToken = "MICROSOFT_GRAPH_ACCESS_TOKEN"

Dim sbResponse As New Chilkat.StringBuilder

' Sends:  GET /users/{user_id | userPrincipalName}/messages/{message_id}/attachments
' Note: It is also possible to use the literal string "me" for the current logged-on user.
' For example: GET /me/messages/{message_id}/attachments

http.ClearUrlVars()
http.SetUrlVar("userPrincipalName","chilkatsoft@outlook.com")

' Assume we already have a message ID from previously listing the messages in a folder
Dim messageId As String = "AQMkADAwATM0MDAAMS1iNTcwLWI2NTEtMDACLTAwCgBGAAADsVyfxjDU406Ic4X7ill8xAcA5_vF7TKKdE6bGCRqXyl2PQAAAL8huv8AAADn68XtMop0TpsYJGpfKXY9AAAAwSju2QAAAA=="
http.SetUrlVar("message_id",messageId)

' Send the request to download the attachments.  However, this will also download the embedded images. (Who knew???)
Dim success As Boolean = Await http.QuickGetSbAsync("https://graph.microsoft.com/v1.0/users/{$userPrincipalName}/messages/{$message_id}/attachments",sbResponse)
If ((success <> True) And (http.LastStatus = 0)) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


' The attachment data is contained within the JSON response.
Dim json As New Chilkat.JsonObject
json.LoadSb(sbResponse)
json.EmitCompact = False

Debug.WriteLine("Status code = " & http.LastStatus)
If (http.LastStatus <> 200) Then
    Debug.WriteLine(json.Emit())
    Debug.WriteLine("Failed.")
End If


' This is a sample JSON response.  The code for parsing and extracting/saving the MIME images
' is shown below.

' {
'   "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#users('chilkatsoft%40outlook.com')/messages('AQMkADAwATM0MDAAMS1iNTcwLWI2NTEtMDACLTAwCgBGAAADsVyfxjDU406Ic4X7ill8xAcA5_vF7TKKdE6bGCRqXyl2PQAAAL8huv8AAADn68XtMop0TpsYJGpfKXY9AAAAwSju2QAAAA%3D%3D')/attachments",
'   "value": [
'     {
'       "@odata.type": "#microsoft.graph.fileAttachment",
'       "id": "AQMkADAwATM0MDAAMS1iNTcwLWI2NTEtMDACLTAwCgBGAAADsVyfxjDU406Ic4X7ill8xAcA5_vF7TKKdE6bGCRqXyl2PQAAAL8huv8AAADn68XtMop0TpsYJGpfKXY9AAAAwSju2QAAAAESABAAgZG0LQdbKEy5FudPGeyRCg==",
'       "lastModifiedDateTime": "2017-05-10T00:22:45Z",
'       "name": "starfish.jpg",
'       "contentType": "image/jpeg",
'       "size": 6497,
'       "isInline": true,
'       "contentId": "part1.A9EACD6E.4E93E87E@chilkatsoft.com",
'       "contentLocation": null,
'       "contentBytes": "/9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGh ... +vo//2Q=="
'     },
'     {
'       "@odata.type": "#microsoft.graph.fileAttachment",
'       "id": "AQMkADAwATM0MDAAMS1iNTcwLWI2NTEtMDACLTAwCgBGAAADsVyfxjDU406Ic4X7ill8xAcA5_vF7TKKdE6bGCRqXyl2PQAAAL8huv8AAADn68XtMop0TpsYJGpfKXY9AAAAwSju2QAAAAESABAABRgWReFlhEmqGvKeoT0E6g==",
'       "lastModifiedDateTime": "2017-05-10T00:22:45Z",
'       "name": "hedgehogs.jpg",
'       "contentType": "image/jpeg",
'       "size": 48845,
'       "isInline": true,
'       "contentId": "part2.05D9E5DC.BA8874F4@chilkatsoft.com",
'       "contentLocation": null,
'       "contentBytes": "/9j/4AAQSkZJRg ... 9YEa//AMr/AP/Z"
'     }
'   ]
' }


Dim sbSavePath As New Chilkat.StringBuilder
Dim attachData As New Chilkat.BinData
Dim lastMod As New Chilkat.CkDateTime
Dim fac As New Chilkat.FileAccess

Dim i As Integer = 0
Dim numMessages As Integer = json.SizeOfArray("value")
While i < numMessages
    json.I = i

    Debug.WriteLine("name: " & json.StringOf("value[i].name"))
    ' See the note below about the contentId.
    Debug.WriteLine("contentId: " & json.StringOf("value[i].contentId"))
    Debug.WriteLine("contentType: " & json.StringOf("value[i].contentType"))
    Dim sizeInBytes As Integer = json.IntOf("value[i].size")
    Debug.WriteLine("size: " & sizeInBytes)

    ' Extract the data and save to a file.
    sbSavePath.SetString("qa_output/")
    sbSavePath.Append(json.StringOf("value[i].name"))

    attachData.Clear()
    attachData.AppendEncoded(json.StringOf("value[i].contentBytes"),"base64")
    attachData.WriteFile(sbSavePath.GetAsString())

    ' Get the last-modified date/time and set the output file's last-mod date/time..
    lastMod.SetFromTimestamp(json.StringOf("value[i].lastModifiedDateTime"))
    fac.SetLastModified(sbSavePath.GetAsString(),lastMod)

    Debug.WriteLine("----")

    i = i + 1
End While

' The output of the above loop is:

' 	name: starfish.jpg
' 	contentId: part1.A9EACD6E.4E93E87E@chilkatsoft.com
' 	contentType: image/jpeg
' 	size: 6497
' 	----
' 	name: hedgehogs.jpg
' 	contentId: part2.05D9E5DC.BA8874F4@chilkatsoft.com
' 	contentType: image/jpeg
' 	size: 48845
' 	----


' ----------------------------
' NOTE: About the Content-ID
' ----------------------------

' Each image's contentId will correspond to a "cid" in the HTML body of the email.
' For example, in this case, the HTML email contained this:

' 	<html>
' 	<head>
' 	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
' 	<meta content="text/html; charset=utf-8">
' 	</head>
' 	<body bgcolor="#FFFFFF">
' 	<font face="Calibri">This is a test email with images.<br>
' 	<br>
' 	<img alt="" src="cid:part1.A9EACD6E.4E93E87E@chilkatsoft.com" height="120" width="120"><br>
' 	<img alt="" src="cid:part2.05D9E5DC.BA8874F4@chilkatsoft.com" height="427" width="600"><br>
' 	</font>
' 	</body>
' 	</html>
'