Good afternoon,
I would like to control a mailbox (it is an internal mailbox, different than gmail, outlook etc..), and I am using POP3 or IMAP to do it.
Everything it is okay, but right now I am using a scheduler to check the e-mail every X minutes. Is there any option like an event or something (or a library/protocol), to launch a function every time an e-mail it is received/created in one folder of the mailbox?
Thanks in advance
This is known as forwarding to a program, or forwarding to a pipe. It was common practice 20-40 years ago. People seem to have forgotten nowadays, but still ask about it.
Your program will receive the email on stdin. If you want to process the email, you can parse your input and do... whatever. If you want to control the inbox, you can forward to both the inbox and the pipe (the aliases/.forward syntax allows that), discard the input from stdin, and and manipulate the inbox. Your program will be started at the right time to do the manipulation you want.
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I'm working on an app that lets users submit orders, and also make custom orders where they upload an image. I then want to receive all this information by email. Initially, I was using JavaMail API with Gmail, but I heard that it can cause a blocking of the account due to "Suspicious Activity". Apparently a way around this is to use the Amazon SES SMTP server, but with that I cannot seem to find any documentation whatsoever on sending emails with attachments for Android (there is one but it's for general Java and it does not work on Android).
There must be a better way to to do this, I'm just not sure where to start looking. This is my first dev project (I'm in my 2nd year of computer science), so I'm pretty green with this stuff. If someone could point me in the right direction I would be so grateful. I'm open to learning new things, I'm just not even sure about what I need to learn in the first place for this.
your email will be blocked if you are sending emails in huge amount like hundreds of email in a second if you are not sending email in such amount so don't worry about getting blocked and if you are sending in email in such amount then you can take external email service theirs a lot of marketing via email services i hope this might help
I currently am developing a semi-simple chat app. I want the user to be able to communicate with one other person in a private chat. Just plain text will be sent. Currently my system calls php scripts from a webpage, passes in parameters and then parses the data returned. I have it so that the client sends the message, which calls a send message script on my webserver, the script then makes a message file on the webserver and then returns a success or failure back to the client. Then for the client to view this message, it would have to call a script that checks the server for a message file with a message for him. If it finds one, it sends the message back, if not, it sends a response about not having messages.
This technique works perfectly besides the fact that the client either would have to manually refresh to check to see if he had messages, or a background thread would have to refresh every few seconds. That would be fine, however that would use data if the user was on a mobile network. Not to mention the kind of resources a background loop would pull if it was refreshing at a speed that would be convenient.
So, I decided on a second idea, this would be a server programmed in Java, which would communicate over sockets. The user would send the message as a packet over the socket and the server would check to see who it was meant to go to. If the person is online, it passes the message along to that user. However this method requires a constant connection between the client and the server and that is unreliable because what if the user is in the car and data cuts out. Or some other situation where the connection gets severed. Then it would throw errors and have to reconnect.
Anyhow, my question is which technique is better. Or are they both terrible? If so, what is the correct way of doing this? Thanks in advance.
AngularJs and Ajax will be the perfect solution for you , try to learn
for actually real time messaging Use AngularJs
If the amount of data is very less ..say 20-25 messages per day...you can REST APIs on your server to transfer actual text messages and Google Cloud messaging for pushing notifications..Recently I followed this approach to develop private chat for one of my friend.
First of all, this is a kinda broad question, and I believe it belongs partially on Serverfault also, so bear with me. I tried googling and searching here, but only found parts of this question but not the whole idea of it. Here goes:
My problem is:
Im writing a web application, and my server is Java. I want to add a feature where my users can do BY EMAIL some of the possible interactions they can already do on the interface. For this part I believe to setup a mail server (any server recommendations?), and from my Java app (Tomcat) connect to the mail server and read the emails via POP3 or something (any API recommendations?).
The tricky part is that I dont want to use a single email address for that purpose. I want, for example, that if my user Joe want to CREATE an object in my application, then he would send an email to joe#create.mydomain.com, if he would like to DELETE an object, he would send to joe#delete.mydomain.com. The possible actions are previously known and limited, of course (since I would have to mess with the DNS for that purpose). This is just an example, most likely I would have to "tokenize" the left part of the email address (before the #), or else any user would be able to create and delete other user´s objects (since email is semi-anonymous).
And the extra-tricky part is that I already have an email server running on mydomain.com, for the corporate emails. How to make that all emails from the actions words ("subdomains"?) go to my "application email server" and those without action words go to my "corporate email server"?
I guess thats it!
Thanks all
Since you're already using Java, it sounds like Apache James might be a good fit for you.
It allows you to create Matchers and Mailets which pick out and process emails based on your defined criteria (which could be address based sender/receiver matching, subject lines, etc). The process could insert records into a database, invoke a web service, anything you want to write in Java.
I have a constantly-running Java program that needs to send an email whenever it encounters a problem. However it is possible that the mail server it uses could be down at the time it tries to send the email.
What is the best way to ensure that the email will be delivered when the mail server comes back up?
Queue up the requests. Have a separate thread which merely waits for something to enter the queue, then tries to email it. If it fails, it waits a few hours and tries again. Once it sends a message, it goes back to the queue to get the next message.
Put the email object into a stack or list when it fails to send, when the email server comes back up, pop each email out until it is empty.
You may want to save the email in a file, perhaps an xml file, so that should the application crash you won't lose this information.
This file is loaded when the application starts, and it keeps everything in memory, so that while there are pending emails then it keeps checking every 5 minutes or so, then, as it sends each email it will resave the xml file, so that should it crash after sending 3 emails out of 10 it won't resend those three when it starts up.
But, how you handle that is really going to depend on the specification for how to handle error conditions.
If you go from "forward everything to this SMTP server which is always there" to a situation where you need to handle all kinds of conditions normally handled by a full SMTP-server like retry later, retransmit if connection closed, use MX-hosts in their stated order and similar, you may want to consider simply having a SMTP-server inside your client (but one that does not accept incoming connections) since this moves all the dirty logic away from your applications.
I believe that the James email server - http://james.apache.org/ - is easily embeddable, but I have not actually tried.
The suggestion of using James is a good one but I've had some issues in the past of James being a bit flaky and needing to be restarted.
You could use something like Quartz to have a scheduler check for messages that need to be sent. If the message can't be sent (eg. smtp server isn't available), then that message is rescheduled to be sent at a later time. You could either have a task per message or have a persistent task that checks for messages and available mail server then sends the messages. The persistent task would give you email batching.
If you are in a Unix/Linux world, then consider the alternative of sending your alerts using syslog, and dealing with the generation of emails on that side. For example, nsyslogd has a module called ommail for generating emails natively.
IIRC, there are adapters for log4j and the like that can bridge between the Java and syslog worlds with a minimum of (zero ?) coding.
Apache James - http://james.apache.org/ will let you run your own mailserver as a proxy, not only that but is written in 100% java, so you can figure out what its doing,
and as an extra bonus James uses databases to queue the mail, so you can even inject mail directly into the queues by inserting into a database, then leave whole business of sending the mail up to James.
I have written a nice program in Java that connects to a gmail account and download atachments sent to it. Once an attachment has been downloaded, it is marked as read and is not downloaded ever again. This program will have to run in multiple instances with each program downloading unique attachments so that a single attachment is never downloaded twice. The problem is that at the moment if the attachment is of a decent size, one program is still downloading it, when another instance connects and also starts to download the attachment before it has been marked as read.
I have tried checking and setting various flags and checking whether the folder is open, nothing seems to work. Any solutions?
Update: Thank you for the quick answers, sadly IMAP is not an option due to other reasons.
Consider using IMAP instead - it is designed for client-server interaction.
From RFC1939 (Post Office Protocol - Version 3):
POP3 is not intended to provide
extensive manipulation operations of
mail on the server; normally, mail is
downloaded and then deleted. A more advanced (and complex) protocol, IMAP4, is discussed in RFC1730.
I don't think POP3 is made for multiple simultaneous access.
Ask yourself this: do i really need multiple processes accessing the same mailbox?
If you do, you'll have to find a way to have these processes communicate to each other.
Use a common database or server process to coordinate actions.
IMAP does have more options, but i'm not sure if you can "lock" a single mail to mark it as being processed.
As the others have mentioned, POP3 isn't really intended for this kind of scenario.
If you absolutely have to use POP3, I'd suggest downloading all the e-mail to an intermediate server which sorts the messages and makes them available for each of the other clients.
It sounds like you're just trying to distribute the processing of the e-mails. If that's the case, you can just have each client connect to your intermediate server to retrieve the next available message.
I'm not sure what your constraints are, but you may even want to consider receiving the attachments some other way besides e-mail. If people are uploading files, you could set up a web form that automatically sends each file to the next available instance of your application for processing.
If you need to stay with a POP3 connection, you could keep a local database of previously downloaded message ids. Then new instances could check against that before downloading again. The best solution is just to use IMAP, though, as IMAP is able to set the read/unread flags before downloading.
You could mark the mail as read before starting the download, and then start downloading it.