I've been having this design-pattern problem for weeks. Where do I put the logic for sending emails? Behaviors can be accessed through the asp.net mvc web interface or through a wcf endpoint hosted inside the asp.net app.
Here are the features of the app:
Email notifications.
Template rendering - This means I have to know the url structure (actions, base address, etc).
Currently, I am storing base url and paths inside the web.config file and having this email service inside the service layer.
One particular feature is sending confirmation emails to the user and sending the generated confirm url to them. (no idea how to generate this url from the service layer)
Emails should never ever ever ever be served from the web layer. You never want a user to wait while an email is sending.
The best thing to do is create a persistent email queue ( sql is fine ) which another job accesses to send the email. This gives you the ability to re-send failed emails and run them completely outside your web request thread.
What jfar say is true; that said, you could use Postal to generate your emails and then store those emails in a database, again, as jfar suggests.
From the postal website:
Postal lets you create emails using
regular MVC views.
That means you'll have an Email folder under your Views folder; those views are actually your email templates and have full access to all Html and URL helpers any other view has which will probably make it easy for you to generate a confirm URL or whatever it is that you may need.
Postal includes and IEmailService interface with a concrete EmailService implementation. This service allows you to directly send an email message or, even better, generate a regular MailMessage object. You could then just store the ready-to-go email in a table on your db and send it later on with a background job.
You can also run an SMTP server on your web server machine, and simply have your business logic layer send mails to that SMTP server.
As long as the SMTP server is up and running, there will be no performance hit on your web application, and the SMTP server itself queues incoming requests and handles them in the background.
Related
My intranet web application (written in C#/ASP.Net MVC) sends email notifications in certain situations. I would like to intercept replies to such emails and perform actions based on the content of such replies.
I have no preference for scripting language - it could be Powershell, Python, VBA, anything - as long as I can parse the subject and body of the email, I can then alter the database of my web application through this script and pick up changes with an automated task, but I really have no clue where to start. I would be really grateful if someone could point me in the right direction.
QUESTION
How can I intercept emails sent to the Outlook server and perform action based on the content of such emails?
It sounds like you need an inbound email parsing service. I've worked with the one from SendGrid and it will catch any replies to a specific email address, and then post the email contents to an action on a controller in your MVC app. This will give you access to the full email contents and you can process it as needed.
See Setting up Inbound Parse
I'm in the process of planning the development of a mail-server to hand the sending of email across our multiple websites. Below is a description of what we are planning to implement and I'd like your opinion/suggestions.
We use ASP.NET MVC and have many web-sites hosted on Azure. We currently send mail internally within each of the web applications using SMTPServer.Send(). Obviously this is not the ideal way to send emails when you have a decently busy set of websites because the send mail call is blocking and cannot guarantee mails are sent. With this I'm worried out getting an influx of mail requests when we launch our next website (we think it'll get a decent amount of traffic and lots of emails will be sent).
My plan of action : to build a centralised mail-server that runs in the background (we use azure and this will be simply another web-application). When each one of our web applications wants to send a mail, instead of doing this internally, it'll call a web method on the mail-server called sendMail() this function will accept certain parameters and insert the mail parameters, content etc. into a database. The mail server will then poll the database at fixed time intervals, select a set of unsent emails and attempt to send them using the same SMTPServer.Send() function. If an email fails for some reason we won't flag it as sent and in the next poll interval the email will be selected again and another send attempt will be made. (we will cap the number of send attempts to say 20).
This will allow each of the websites to run smoothly without having loads of blocking send mail calls internally and the mail server will handle all the sending sequentially and in a controlled environment as a separate standalone web-application.
Thanks in advance!
Looks like a good design, Don't know the entire scenario which let to you building something like an email server. The problem has been solved well by using a service that already exist like Office 365.
Your design is good, My suggestions would be the following,
You can use Azure WebJobs to build the polling agent. You can make the web job run as a scheduled web job that does the polling and sending the mail and it can be written very clean as a simple console app.
You can use Azure API App to build the SendMail() call and you can use the Azure AD Auth on the API to authenticate the caller of the API using the Authentication and Authorization feature to easily secure your email server. You can also enable CORS easily as well to make sure you receive requests from other websites and process it.
Some issues I foresee for you,
Volume and Scaling : You can only process so much email between each polling. If you cannot then you will need to create another polling agent which will making things complicated as they need to know they are picking different sets of emails to send. If you volume is going to be low you should be fine.
Challenge : Why can't the websites send the mail them selves ? And then record it on the database for tracking. All you have to do build module or a component that they use on their web page to create and send the mail. Polymer 1.0 works well for this scenario.
Hope this helps to get you started.
With my rails application, I'm supposed to provide following features:
There a limited number of users interacting with my system (in order of 10 to 20)
Like any normal mail client users should be able to have an inbox page showing received message, response to individual email and etc....
The mail client part cannot be an external application, they want everything packaged into a single application!
Normally These emails should be stored for future use
In order to send a receive email, we do not need to setup a mail server. They will provide the server and we will fetch the message with POP3 or something else. Same goes for sending emails.
The application itself often needs to look into these message as well, so it should be able to access corresponding email objects.
Separate part of these applications can be handled with individual gems such as Mailman, ActionMailer, and etc...
But what would be your suggestions to get this done?
I suggestion customizing an open source solution according to your needs. This is a gem/project that you should look at https://github.com/mailboxer/mailboxer It has all the features that you mentioned and its straightforward in its customizations.
For my client's custom-built CRM, I want users (technicians) to be notified of changes to marked cases via email.
This warrants a simple subscription mapping table between users and cases and automated emails to be sent every time a change is made to a case from within the logging method.
How do I send 10-100 emails to subscribed users without bogging down my logging method? My SMTP server is on a peer on my LAN, so sends should be quick, but ideally this should be handled by an external queuing process.
I can have a cron job send any outstanding emails every 10 minutes, but for this specific client cases are quite time-sensitive and instant notification (as instant as email can be) would be great.
How can I send bulk notification emails from within ASP.NET MVC without bogging down my logging method?
Back in 2007 I was asked to look into a case where Web Server would suddenly freeze and start sending 503 errors and come back after a few minutes. Cutting a long story short it turned out at the end that it was sending email which was blocking the server (in addition to some bad code).
Basically Microsoft's SMTP server is implemented as a single-thread service - last I checked. This will mean that all your valuable ASP.NET threads serving requests will have to queue to a single thread monolithic application to send a not so urgent email. You need to decouple your web site from sending emails - that is what everyone does and there is a good reason for it.
Write your emails to a queue and have a process reading and sending emails.
Sending emails from an ASP.NET application is not a good idea as it might monopolize valuable server resources. A better solution would be to setup a Windows Service to perform this task or even write a Console application which could be scheduled to run with Windows Scheduler. Quartz.NET is a good solution you might take a look at allowing you to schedule jobs.
If you want those email sending to be triggered from within a particular controller action you could also have a separate WCF service which could be invoked asynchronously.
How would i go about to receive mails in a Ruby on Rails application without going through a mail server like PostFix or to fetch them by pop3 etc.
What i was to do is to catch all mails sent to #mydomain.com and just do something with them in my application. I don't need to store the mails or anything like that.
Is this posible?
I just implemented this for my SAAS to autoprocess mailer-bounce notification messages.
Call me, call you?
You call me
You can set up a local mail server. It would then respond to an incoming email, and start up a rails executable to process the email. This method is NOT recommended since starting up rails is a big task (takes multiple secs and lots of memory). You don't want a Rails bad boy started up just because you received an email. You'd be writing your own DDOS attack. (Attacking yourself.)
I call you
Instead, poll for email on your own schedule by using a single job to process all currently waiting emails. You need to set up a background job handler since stock rails is focused on responding to web requests. I use delayed_job, but there are other alternatives including kicking off a cron job every so in often.
Another benefit is that you don't need to manage a mail server. Leave that headache to someone else. Then use the Ruby library net::imap to read the incoming mail and process it.
If your process doesn't recognize the email format, then forward the msg to a human for processing.
And be sure that if the process sends mail in addition to reading/processing it, that the process uses a different email address as its From address. Otherwise, odds are good that sometime along the way, you'll end up in an email loop and many gigabytes of messages going back and forth. For example, your process receives a message, responds to it, but in the meantime the sender (a human) has switched on vacation response. And your robot then responds to the vacation response..... oops....
Writing your own mail server
Re:
How would i go about to receive mails in a Ruby on Rails application without going through a mail server like PostFix or to fetch them by pop3 etc.
What i was to do is to catch all mails sent to #mydomain.com and just do something with them in my application. I don't need to store the mails or anything like that.
Direct answer: Yes, you could do this by writing an smtp server and setting up dns so your machine will be the mail destination for the domain. Your smtp server would process the messages on the fly, they would not be stored on your system at any point.
Is this a good idea? No, not at all. While appearances may be to the contrary, email is a store and forward system. Trying to avoid storing the messages before your app processes them is not smart. It would be a very very poor "optimization." However, using an access protocol (POP3 or IMAP) is a good way to avoid the costs of installing, configuring and managing a mail server.
You can do this if you write your own mail server, or if your mail server supports hooks to run external programs upon receipt of mail (e.g. procmail).
If you don't have procmail available (or, if on something like Exchange Server, don't feel like writing custom rules or extensions), you're simply better off using a pop3 library to fetch mail.
Obviously, writing a mail server is more difficult than any of the alternatives.
If you're mostly worried about checking potentially hundreds of email accounts, that's solvable by configuring your email server properly. If you're on a hosted provider, ask your server administrator about creating a "catch-all" account that routes all mail to unknown addresses to a single account.
If you're aiming to avoid having to poll a server, consider the IMAP IDLE command. I've successfully written a Ruby client that opens a connection to an IMAP server, and gets told by the server when new mail arrives.