I think that most of us know that you can use the SNDDST command to send an email with a single attachment. But what do you do if you need to send multiple attachments? Or send to multiple persons? Well, you have a few options. First, you can take the easy way out and just send multiple emails with a single attachment (no shame in that...I did it for years). Or you can take the bull by the horns and use the QTMMSENDMAIL API to send multiple attachments to multiple people in a single email. Although getting started using QTMMSENDMAIL will require some work up front, the returns are well worth the effort. But there are several items to be addressed (no pun intended) before using the API.
First, you need to create a MIME-formatted email file and place it in the IFS. In my opinion, this is the most difficult part of using the QTMMSENDMAIL API. IBM apparently figures that if you are using the API, then you must be able to recite RFC822 from memory, because IBM has no documentation regarding building a MIME email file. For those of you who are unfamiliar with RFC822, it is the document that defines the "standard for the format of ARPA Internet text messages." Feel free to wade through it at your leisure. It is not an easy read, but it does have some good information. Personally, I would not bother with it unless you are planning to build your own version of Outlook or Eudora. I found an excellent "how-to" article that was much more helpful. In addition, I have included a sample of a valid MIME-formatted email below. If you are only going to be sending text messages and text files (flat text or comma delimited), you can just use the sample I have included as a guide. If you are planning to email programs or *SAVF types of files, you will probably need to get detailed information from the sources mentioned above.
Once you understand how to create your MIME email file, you can move on to the next hurdle. To send email using QTMMSENDMAIL, you need to call it with the correct parameters. However, in this instance, that is not as simple as it sounds. To start with, the IBM documentation is not clear on how to format the parameters. To make matters worse, those of us who are predominantly RPG programmers are used to working with fixed field lengths and tend to be thrown off by variable field lengths and pointers.
If you are familiar with C and/or C++ and the use of structures, you can probably skip the next few paragraphs. For the rest of you, I will walk you through the process so you get a thorough understanding of how to build the structure(s) needed for the QTMMSENDMAIL API.
The QTMMSENDMAIL API has seven required parameters:
- File Name is the IFS path and file name of the MIME email file. Maximum file name length is 255.
- File Name Length is the length of the file name. Max is 255.
- Originator Address is the email address of the sender. Maximum originator address length is 256.
- Length of Originator is the length of the originator address. Max is 256.
- Recipient Structure is the data structure (ADDTO100) of all recipients. Maximum length for any single recipient address is 256.
- Total Number of Recipients should be obvious. It's the total number of persons the email is being sent to, including carbon copies (CC) and blind carbon copies (BCC).
- Error Code is the standard API error structure. See the IBM documentation for details.
The tricky part is that the file name, originator address, recipient structure, and error code are passed as pointers, and the recipient structure occurs once for each recipient. Passing pointers is simply a matter of using the %ADDR BIF to get the address of each of the fields. The multiple occurrences of the recipient structure (ADDTO100) need to be placed end to end into a large field or data structure. In the sample program, I use a function to prepare each occurrence and then append it to the large RecipTbl field. This process of appending each occurrence could be further shortcut by using a pointer and moving the data directly into the RecipTbl field (alas, I have a deadline, so I'm not going back to change it now).
There are a few things to watch for when using QTMMSENDMAIL. Foremost among these is that if your MIME email file is incorrect in some way, the API will complete successfully (i.e., QUSEC shows no error), but the email(s) never show up at the destination. This was an irritating problem when I was learning to create the MIME emails correctly. As a side note, the originator and recipients listed in the MIME file do not necessarily have to match the ones you send as parms to the QTMMSENDMAIL API. However, this causes some unexpected results (as I found out) and is not recommended.
Also, the conversion between EBCDIC and ASCII can be a problem. If everything you are sending is binary data (e.g., programs, *SAVF files, etc.), you will not have this problem. However, if you are sending data from a file as an attachment, you will need to convert the data to ASCII.
Lastly, I have not included any error checking on the API call in the sample program. You may want to add some (just in case).
Jeff Olen is a member of the AS/400 development team at Gauss Interprise, a content management software company located in Irvine, California. He can be reached by email at firstname.lastname@example.org.