(.NET Core C#) 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

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

Chilkat.Http http = 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";

Chilkat.StringBuilder sbResponse = 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
string messageId = "AQMkADAwATM0MDAAMS1iNTcwLWI2NTEtMDACLTAwCgBGAAADsVyfxjDU406Ic4X7ill8xAcA5_vF7TKKdE6bGCRqXyl2PQAAAL8huv8AAADn68XtMop0TpsYJGpfKXY9AAAAwSju2QAAAA==";
http.SetUrlVar("message_id",messageId);

// Send the request to download the attachments.  However, this will also download the embedded images. (Who knew???)
bool success = http.QuickGetSb("https://graph.microsoft.com/v1.0/users/{$userPrincipalName}/messages/{$message_id}/attachments",sbResponse);
if ((success != true) && (http.LastStatus == 0)) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

// The attachment data is contained within the JSON response.
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.LoadSb(sbResponse);
json.EmitCompact = false;

Debug.WriteLine("Status code = " + Convert.ToString(http.LastStatus));
if (http.LastStatus != 200) {
    Debug.WriteLine(json.Emit());
    Debug.WriteLine("Failed.");
}

// 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"
//     }
//   ]
// }

Chilkat.StringBuilder sbSavePath = new Chilkat.StringBuilder();
Chilkat.BinData attachData = new Chilkat.BinData();
Chilkat.CkDateTime lastMod = new Chilkat.CkDateTime();
Chilkat.FileAccess fac = new Chilkat.FileAccess();

int i = 0;
int numMessages = 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"));
    int sizeInBytes = json.IntOf("value[i].size");
    Debug.WriteLine("size: " + Convert.ToString(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;
}

// 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>
//