I need to be able to display ads on email forwarded through a server (preferably postfix) based on the demographic information of the recipient. Basically a message will arrive for someuser#fakedomain.com and be forwarded to realuser#theirdomain.com with a small advertisement at the bottom.
I would like to use postfix because it appears to be able to use mysql data for various tasks, which would be beneficial so that the system could be controlled by a web app that feeds the database.
I'd prefer to use OpenX for the ad server due to targetting channels (used to select ads based on demographic information), the ability to do text ads as well as email zones, and the ability to run it locally. Other ad servers that are better suited to this problem are acceptable, of course.
The core of the problem, as I see it, is being able to write something at the bottom of any given email message. Of course html messages make this even trickier, but I'd settle for having a solution that works for plain text and work up from there.
Commercial software is an option as well, but a few days of intermittent searching hasn't turned anything up.
Simply writing something to the bottom of the email message will fail miserably in a LOT of cases, particularly with HTML email encapsulated in a MIME multipart message (or anything else in a MIME multipart message) because anything after the last MIME section marker is explicitly supposed to be ignored by any MIME parser. If you want your app to work it needs to
determine if the target message is a MIME message other than TEXT/PLAIN
If it is not, append your text only ad at the end and you're done
if it is, determine if its multipart
if not, then you need to determine the content type of the whole message
If the content type is HTML then you can attempt to insert your ad HTML somewhere appropriate. This will be very hit or miss since you have no idea what the HTML layout will be like.
if the content type is anything OTHER than HTML (or maybe RTF), you're best off not touching the message.
If the message is multipart, determine the subtype
if its 'mixed', then you need to determine which part if any is the primary readable content, and then modify that portion as if it were the whole message based on the above rules
If its 'alternative' then you need to find ALL the readable portions and modify each of them in turn according to the above rules
Finally, and most importantly
Be prepared for the massive ill will you will receive from everyone who gets mail routed through your server.
Let me see... People sign up for your service, which I assume is free. They provide you their real email address and in return you provide them a different email address which they can use to e.g. subscribe to mailinglists and for other services. And maybe some spamfilter functionality? That sounds like a legit service to me, especially if you only provide the ads to the person who subscribed. I do wonder if you'd get many subscriptions, though, since many people can just as easy use a Google, Yahoo or Hotmail account for these purposes. So, what is the added value those subscribers will get?
Anyway, you would need to modify existing emails, which is a bit complex when they are HTML mails or if they're digitally signed. (Especially in the latter case, you would actually block the recipient from receiving those emails, since their email system would detect that the email has been tampered with. You might also be at risk of possible legal problems, although I don't think there's anything illegal as long as the recipient agrees with the terms of your service.
Related
I have a software that sends notifications, quotes and invoices to "clients of my clients" by email. Sometimes people don't answer it very fast, so someone needs to call by phone to confirm if they received and get the feedback. I would like to automate this, to know if them, at least, read the email. I know this is very difficult due to how email works, but some companies already try to do this in a satisfactory way, like:
mailgun.com
mailchimp.com
sendwithus.com (YCombinator funded).
In HTML mail messages we can create a resource that points to the server, like a image. But mail clients usually ask permission to the user to load the images. So, problem
here.
But for text mail messages? Is there any way to know the email was read? How companies these companies do?
PS: I don't know what tags is the best to classify my answer, I shall appreciate any edit.
There is no way to be 100% sure if a email was opened, because of its architecture. There are some techniques to do this, but it always depends of user actions and mail client configurations. But:
For HTML messages you can use images and/or the return receipts (RFC 3798).
For text based messages you can use only the return receipts (RFC 3798).
About opening tracking:
Opens are tracked by including a transparent .png file, which will
only work if there is an HTML component to the email (i.e., text only
emails will not track opens). You should note that many email service
providers disable images by default, so this data will only show up if
the recipient clicks on display images button in his/her email.
(Text extracted from mailgun.com user docs)
References:
MailGun.com documentation.
Previous discutions on this thread.
As arnt says, you're fighting the design and basic operation of e-mail. Whenever you send a mail, there is a boundary between a MTA you control (or at least have an account on) and a MTA that is responsible for your target user's mail. What you can know is whether the user's MTA accepted the mail for delivery. Whatever happens afterwards is outside of your control.
Consider an example of a snail mail. When the package enters the recipient's box, you won't know whether they put the whole unopened envelope to a trash bin, or whether they opened is and read the contents very carefully. You can approximate that goal by using crude measures (like embedding a webcam-and-a-computer which will activate upon envelope opening and send you the snapshot of the face of the opener via a cell phone), but doing so is unreliable, unethical, and probably illegal in plenty of countries.
The "return receipts" or embedded image links are similar -- because the whole e-mail is already in the hands of the user's SW, they can do anything with it. A good MUA will probably ask before sending out dumb return receipts, and it also won't load remote images in HTML mail (because it's easy to create an http://trackme.example.org/mail/for/user/12345/message/666/image.png and have a database which says "hey, this URL belongs to Mr. Pichler, and is used in the first message we sent him). The most you can do is to ask nicely, and return receipts (RFC 3798) are a machine-readable way of doing just that.
Although Apple doesn't allow apps to send text messages without explicit user permission (unlike Android, which just requires you to ask for permissions like this when installing the app), I was wondering if anyone had any ideas for other ways to get around this issue. Specifically:
Is it possible to allow the user to pre-approve a specific text message, and delay sending it until the desired time?
Can an external client be used? Ex., ping a server to do the work of sending the text message for the user? This seems like it will get ugly quickly though (since provider info is required), and would require the user to have internet access, not just cell signal. However, perhaps the application can require an initialization text.
The goal here is to send a specific text message for the user when they are unable to do so themselves, so naturally, having them pre-approve the message would be impossible.
You can't send text messages directly from the device.
But I think there is no problem sending them from a webserver, however your app needs to have an internet connection to do this and I am not aware of a service, which allows you to send text messages for free, so you need to pay to provide this service to your users (I can't say if it is ok for Apple to charge your users for such a service). Another drawback of this solution is, that the sender of the text message wouldn't probably be the users number.
I'm using the Subscriptions module of Drupal to send out subscribed emails on a regular basis and I've noticed that the links embedded in the email will break if the link is too long, but only for some users. The email client that user is using is Entourage. The crazy thing is that I use Entourage, also, but I don't have that problem with the links in my subscription emails that are sent to me. Here's what's happening:
http:samplelinkhere?var=blahblah
blahblah
The top line of the link will be underlined and part of the link, but the bottom part will not be underlined (even though it should be) and so, the link is broken. Does anyone know how to fix this issue?
AFAIK, there is not much you can do about this. As long as the links do not contain line breaks in the original mails sent by your server, it is up to the receivers mail client to add line breaks for readability, usually based on some user preference settings (Which could explain the difference to your own Entourage client).
Also, some clients try to detect links and avoid breaking them, others don't, and some even have plugins for this.
A possible workaround would be sending HTML mails instead, but that opens a huge different can of worms concerning mail client compatibility, so I do not recommend it.
A number of applications have the handy feature of allowing users to respond to notification emails from the application. The responses are slurped back into the application.
For example, if you were building a customer support system the email would likely contain some token to link the response back to the correct service ticket.
What are some guidelines, hints and tips for implementing this type of system? What are some potential pitfalls to be aware of? Hopefully those who have implemented systems like this can share their wisdom.
Some guidelines and considerations:
The address question: The best thing to do is to use the "+" extension part of an email (myaddr**+custom**#gmail.com) address. This makes it easier to route, but most of all, easier to keep track of the address routing to your system. Other techniques might use a token in the subject
Spam: Do spam processing outside the app, and have the app filter based on a header.
Queuing failed messages: Don't, for the most part. The standard email behavior is to try for up to 3 days to deliver a message. For an application email server, all this does is create giant spool files of mail you'll most likely never process. Only queue messages if the failure reasons are out of your control (e.g., server is down).
Invalid message handling: There are a multiple of ways a message can be invalid. Some are limitations of the library (it can't parse the address, even though its an RFC valid one). Others are because of broken clients (e.g., omitting quotes around certain headers). Other's might be too large, or use an unknown encoding, be missing critical headers, have multiple values where there should only be one, violate some semantic specific to your application, etc, etc, etc. Basically, where ever the Java mail API could throw an exception is an error handling case you must determine how to appropriately handle.
Error responses: Not every error deserves a response. Some are generated because of spam, and you should avoid sending messages back to those addresses. Others are from automated systems (yourself, a vacation responder, another application mail system, etc), and if you reply, it'll send you another message, repeating the cycle.
Client-specific hacks: like above, each client has little differences that'll complicate your code. Keep this in mind anytime you traverse the structure of a message.
Senders, replies, and loops: Depending on your situation, you might receive mail from some of the following sources:
Real people, maybe from external sources
Mailing lists
Yourself, or one of your own recipient addresses
Other mail servers (bounces, failures, etc)
Entity in another system (my-ldap-group#company.com, system-monitor#localhost)
An automated system
An alias to one of the above
An alias to an alias
Now, your first instinct is probably "Only accept mail from correct sources!", but that'll cause you lots of headaches down the line because people will send the damnedest things to an application mail server. I find its better to accept everything and explicitly deny the exceptions.
Debugging: Save a copy of the headers of any message you receive. This will help out tremendously anytime you have a problem.
--Edit--
I bought the book, Building Scalable Web Sites, mentioned by rossfabricant. It -does- have a good email section. A couple of important points it has are about handling email from wireless carriers and authentication of emails.
You can set the address that the email is sent from, what will be put into the To: address if someone just presses 'Reply-to'. Make that unique, and you'll be able to tell where it came from, and to where it must be directed back to.
When it comes to putting a name beside it though '"something here" ' - put something inviting to have them just reply to the mail. I've seen one major web-app, with Email capturing that has 'do not reply', which turns people off from actually sending anything to it though.
Building Scalable Web sites has a nice section on handling email. It's written by a Flickr developer.
(source: lsl.com.au)
EDIT: I misunderstood your question.
You could configure your email server to catch-all, and generate a unique reply-to address. E.g. CST-2343434#example.com.
A polling process on the server could read the inbox and parse out the relevant part from the received email, CS-2343434 could mean Customer Support ticket ID no. 2343434.
I implemented something like this using JavaMail API.
Just a thought.
The best way to achieve this will be to write a window service that acts like a mail client [pop3 or imap]. This windows service should execute a timed action triggered by a timer, which connects to the mail server and polls the server for any unread message(s) available in the email inbox. The email ID to check for is the email ID on which the users will give their input on/to. If the windows service client finds that there exists any new mail(s) then it should download and filter the email body and push further for processing based on the user input in the email. You can host the input processing in the same windows service but it is not advisable to do so. The windows service can put the inputs in a special application directory or database from where your main appication can read the user inputs received in email and process them as needed.
You will be required to develop a high performance TCP/IP client for doing so. I advise you not to use the default .Net library due to performance issues, instead use one of the best availabel open source TCP/IP implementations for .Net like XF.Server from kodart. we have used this in our applications and achieved remarkably grear results.
Hope this helps..
Bose has a pretty great system where they embed a Queue and Ticket ID into the email itself.
My company has the traditional Case # on the subject line, but when CREATING a case, require a specific character string "New Case" "Tech Support Issue" on the subject line to get through the spam filters.
If the email doesn't match the create or update semantics, the autoresponder sends an email back to the recipient demonstrating how to properly send an email, or directs them to our forums or web support site.
It helps eliminate the spam issue, and yet is still accessible to a wide technical audience that is still heavily email dependent.
Spam is going to be a bit of a concern. However since you are initiating the conversation you can use the presence of your unique identifier (I prefer to use the subject line - "Trouble ticket: Unable to log into web...[artf123456]") to filter out spam. Be sure to check the filter on occasion since some folks mangle the subject when replying.
Email is a cesspool of bad standards and broken clients. You need to be prepared to accept almost anything as input. You will need to be very forgiving about what kinds of input are tolerated. Anything easy for you to program will likely be difficult for your users to use correctly. Consider the old mailing list programs that require you to issue commands in the subject line. Only hardcore nerds can use those effectively. And some of those trouble-ticket CRM things you mentioned have bizarre requirements, such as forcing the user to reply between two specific text markers in the text. That sort of thing is confusing to people.
You'll need to deal with email clients that send you formatted text instead of plain text. Some email clients still don't handle HTML properly (cough GMail) so your replies will also need to be designed appropriately. There are various ways in which photos might be "uploaded" via email as well, especially when mobile phones are involved. You will need to implement various hacks and heuristics to deal with these situations.
It's also entirely possible that you will get email that is valid but unusable by the email parsing library you are using. Whether or not this is important enough to roll your own will be a judgement call.
Finally, others have mentioned using specific email addresses to uniquely identify a "conversation". This is probably the easiest way to do this, as the content of the mail will often not survive a round trip to a client. Be prepared, however, to get mail to old IDs from old customers who, instead of opening a new ticket somehow, reply to an old ticket. Your application will probably need some way to push emails with an old ID into a new case, either manually or automatically. For a CRM system it's very likely that a user would reply to an old email even if you already sent him a new email with a new ID in it. As for whether you should use some.email.address+some.id#yourdomain.com or just some.id#yourdomain.com, I'd go with the latter because the plus-sign confuses some email clients. Make your IDs guids or something and have some way to validate them (such as a CRC or something) and you'll get less junk. Humans should never have to type in the GUIDs, just reply to them. The downside is spam filtering: a user's computer might view such email addresses as spam, and there wouldn't be an easy way to whitelist the addresses.
Which reminds me: sending email these days is full of pitfalls. There are many anti-spam technologies which make it extremely hard for you to send email to your customers. You will need to research all of these and you need to be careful, and do some testing, to ensure that you can reach the major email providers. A website like Campaign Monitor
can help you if you are sending email.
Our clients sometimes don't get the emails that we send out. It's a BIG loss. How do I assure that they receive the emails so that if it's not received in the other end, the program can resend it or do something about it.
None of the suggestions above will work 100% of the time. Many email clients will (rightly so) refuse to load foreign images, negating the usefulness of "web bugs". They will also refuse (or be unable to) return Outlook-style "receipts". And many mail servers either deliberately (to curb spam) or mistakenly (due to misconfiguration) won't return bounce messages. Or possibly an over-aggressive spam filter ate your message, so it arrived but was never seen by the end user. Plus there is the little matter of mail taking hours or days to reach the end user or bounce, and how do you correlate these late notifications or bounces with the mail you sent 4 days ago?
So basically, you can catch some but not all, no matter what you do. I'd say that any design that relies on being able to know with certainty whether the end user got your mail is fatally flawed.
One thing that you can do is set up a bounceback address that receives any mail that is undeliverable. Use the bounceback address as the From address -- you may want a different one for Reply-To so that replies get directed properly.
Check the bounceback mailbox daily and contact customers to get updated email addresses for the ones that fail. You may be able to automate a couple of retries to failed addresses before resorting to the manual contact in case the failure is only intermittent.
This would take some code outside your application that scans the mailbox and keeps some state information about the number of contacts, etc. and attempts the resend.
Depending on how you generate the mails, you might be able to make this process easier: generate a unique bounce address for every single email you send out. You could use bounces+1234#example.com, for example.
Many SMTP servers will allow you to use the part after the + as a parameter to an external script, etc.
The problem is that many (broken) SMTP servers don't return enough info with a bounce to identify the original message -- sometimes, when there are forwardings involved, you don't even get back the original addressee...
With the above trick you can reliably correlate outgoing messages with incoming bounces.
There is no standard way to know whether the email reached the destination. Many email clients support different types of receipts though. You can use any of those if you want.
There are some ways to know when the user actually read the email.
There are many techniques like adding an image to your email that is to be fetched from your web server. When the user reads the email, the request for the image comes to your server and you can capture the event.
The problem is that there is no way to know that the mail did not reach the destination.
I worked on a bulk email system in a previous life. Deliverability was one of our major issues. The most common cause of undelivered emails is a spam filter.
Here are the steps we took to ensure the highest delivery rates:
We used Return Path to test emails for that spam-like smell.
If you send a lot of emails, you need to make sure your SMTP server is not blacklisted.
Remind your users to add your FROM address to their "safe senders" list.
Use a system that collects bouncebacks and use them to scrub your mailing list. This will also help keep you off the blacklists.
If the emails are critical, consider sending them return-receipt-requested. This will not really guarantee anything, but it might give you some metrics on actual deliverability.
There's not really a good way to determine if the email actually arrives in their inbox, you can only confirm that you sent it. Attach a receipt that lets you know when they open it perhaps?
Microsoft Outlook provides similar functionality, however it is based on the email client. I'm not sure if other clients, like Thunderbird, support this.
However, there is nothing in the protocols that specify receipts.
One option that may work: send a link to a generate web page and monitor that page for hits. This provides its own issues however: confidentiality, etc.