(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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#include <CkHttp.h>
#include <CkStringBuilder.h>
#include <CkJsonObject.h>
#include <CkBinData.h>
#include <CkDateTime.h>
#include <CkFileAccess.h>

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

    CkHttp 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.put_AuthToken("MICROSOFT_GRAPH_ACCESS_TOKEN");

    CkStringBuilder sbResponse;

    // 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
    const char *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.get_LastStatus() == 0)) {
        std::cout << http.lastErrorText() << "\r\n";
        return;
    }

    // The attachment data is contained within the JSON response.
    CkJsonObject json;
    json.LoadSb(sbResponse);
    json.put_EmitCompact(false);

    std::cout << "Status code = " << http.get_LastStatus() << "\r\n";
    if (http.get_LastStatus() != 200) {
        std::cout << json.emit() << "\r\n";
        std::cout << "Failed." << "\r\n";
    }

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

    CkStringBuilder sbSavePath;
    CkBinData attachData;
    CkDateTime lastMod;
    CkFileAccess fac;

    int i = 0;
    int numMessages = json.SizeOfArray("value");
    while (i < numMessages) {
        json.put_I(i);

        std::cout << "name: " << json.stringOf("value[i].name") << "\r\n";
        // See the note below about the contentId.
        std::cout << "contentId: " << json.stringOf("value[i].contentId") << "\r\n";
        std::cout << "contentType: " << json.stringOf("value[i].contentType") << "\r\n";
        int sizeInBytes = json.IntOf("value[i].size");
        std::cout << "size: " << sizeInBytes << "\r\n";

        // 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);

        std::cout << "----" << "\r\n";

        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>
    // 
    }