I want to write an iOS app that can act as a client and a server to other iPhones over the cellular data network (i.e., without a typical centralized server). The goal is to share series of about 200 short event messages, one at a time, from the iPhone server to multiple iPhone clients by some means of notification. Apple Push Notification service would be fine for such notifications, but there is no need to use it specifically.
I think sending push notifications from one iPhone to another is possible by connecting to gateway.push.apple.com from the serving iPhone as described in the Local and Push Notification Programming Guide, but I can't find anyone else discussing this approach (maybe it's too obvious?).
The reason for all this is an attempt to avoid the overhead of infrastructure. If this isn't feasible, alternatives which minimize or avoid additional hardware are welcome.
Requirements:
Communication must be [strictly] over cellular data network
Wi-Fi isn't available
Bluetooth doesn't have enough range
Unidirectional communication with an iPhone server multicasting to many iPhone clients
No jailbreaking
Ideally the serving phone's battery will be able to handle this without a recharge
Update 5/4/11 2:12 AM EST: Just to be clear, I don't have any particular requirement to use APNs; I thought it may have been feasible in this setup, but from the discussion below, it sounds like that's not the case. However, I'm still interested in any other system that could help me achieve the same end result with some type of message passing or similar form of communication.
Theoretically you should be able to write a iOS app that can connect to the APNS and send notifications to other devices running your applications. However, your main problem will be to actually acquire the 'tokens' of other devices. When you have a centralized server doing the job, its always online and thus, the clients can 'talk' to it via http and register them self (giving their tokens to the server in the process). Thus the server knows the client token and it can use them to send notifications to the clients via APNS.
However this is not possible in the scenario you are talking about. But this is not to say its impossible. May be you could use an email account X, to store all client tokens. Every client will send a email to this account with their token in it. So when a another 'client' want to send a notification to another client, it can find out the token by reffering to the inbox of the email account (you can cache this stuff and optimize it in a zillion ways of course).
But the point is some how a (third party(ex: email service provider)/your own) server that is online 24/7 will be involved in the process.
Let us know how you progress with this. It would be interesting to know.
Related
I have an idea for an iPhone app that will make billions of dollars for me, and help me take over the world. I am currently designing the architecture of the application. I had originally assumed that I would need to create and host a database that would allow users to upload their data and share it with other, targeted, users. But I thought it would be better if the users could send their data directly to each other without having it stored in a database. However, I haven't been able to find anything that would suggest this is possible.
Is it possible to send data between iPhones that are not in close proximity (bluetooth) and not on a LAN? For instance...User #1, who is in Tennessee, creates some information and hits "Send to others" and it sends that information directly to User #2, who is in Arizona, and User #3, who is in Maine. Could the text messaging functionality be hacked to do that?
(I realize that the phones belonging to Users #2 and #3 would have to be on, and running the app that would receive the data)
I am new to mobile development, and I am still getting used to the functionality of mobile devices so, I am certain this is a dumb question. But, it is worth asking because, if it can be done, this would dramatically change the architecture (and maintenance costs) of this application.
Thanks, in advance, for whatever advice/pointers you can give.
This is something handled by using the publish - subscribe pattern. You may want to look into a plug 'n play service such as pubnub. That will let you do just that. Phones that should be receiving each other's messages will have listeners set up on the same pubnub channel, and will receive a notification when any of the other phones publish to that channel. Something like pubnub has a pretty simple API/SDK that you can use to get a prototype up and running pretty quickly (and for free, at least at first).
User #1's app sends the message to your server. You server does an APNS push to the phones of users #2, and #3. They don't even need to be running the app.
No need to mark this correct or up-vote it, but I will take a high-paying job in the new world order.
Amazon has an application service called Simple Queue Service (Amazon SQS) which Allows you to create queue's with messages in them tat app's can subscribe to.
To quote their page:
Amazon Simple Queue Service (Amazon SQS) offers a reliable, highly
scalable, hosted queue for storing messages as they travel between
computers. By using Amazon SQS, developers can simply move data
between distributed components of their applications that perform
different tasks, without losing messages or requiring each component
to be always available. Amazon SQS makes it easy to build an automated
workflow, working in close conjunction with the Amazon Elastic Compute
Cloud (Amazon EC2) and the other AWS infrastructure web services.
Amazon SQS works by exposing Amazon’s web-scale messaging
infrastructure as a web service. Any computer on the Internet can add
or read messages without any installed software or special firewall
configurations. Components of applications using Amazon SQS can run
independently, and do not need to be on the same network, developed
with the same technologies, or running at the same time.
They have an iOS API to integrate it into your app, and it is free for up to 100,000 messages per month and then $0.01 per 10,000 messages after that.
More info here:
http://aws.amazon.com/sqs/
Is it possible to send data between iPhones that are not in close
proximity (bluetooth) and not on a LAN?
The two devices obviously need some kind of connectivity.
For instance...User #1, who is in Tennessee, creates some information
and hits "Send to others" and it sends that information directly to
User #2, who is in Arizona, and User #3, who is in Maine. Could the
text messaging functionality be hacked to do that?
The problems here are:
helping each device discover the correct address for the others, and...
ensuring that the devices can reach each other.
Mobile devices are constantly moving around on the network and changing their IP addresses as they go. As you're driving to work, your device may have Internet access through it's 3G connection, except for those times when you're driving through a tunnel and don't have any connectivity at all. Once you enter your building, a wifi connection becomes available, so the device switches to that. But your company's network has a firewall that blocks incoming connections, and it's impossible to know in advance which IP address you'll get from the DHCP server at any given time anyway. The same is true for the folks in Arizona and Maine and wherever else.
A server, on the other hand, is usually located at an address that's both easy to discover (thanks to the Domain Name System), easy to reach, and almost always available. For those reasons, it's common to have mobile devices communicate with each other by going through an intermediate server.
It is very usual that an iPhone send data to internet server.
But what if a server wants to connect to an iphone?
I have wondered long about it.
For example, like many web-based apps like Facebook, what is the mechanism/algorithm behind, so that when, for example, any updates on your wall can be noticed to you in a real-time manner?
Hope some can understand my query.
Have a look at this Wikpedia article about Push Technology.
Push technology, or server push, describes a style of Internet-based communication where the request for a given transaction is initiated by the publisher or central server. It is contrasted with pull technology, where the request for the transmission of information is initiated by the receiver or client.
Your iPhone could intermittently 'poll' the server, looking for any data it needs to be sent. Say every 5 seconds, or after some trigger - it would call the server and ask for new data.
You could use push technology: i.e. have a continuous http connection open to your server that allows data to be sent both ways. LightStreamer is a product that does this that i've used before. This is the most elegant and efficient solution for streaming data.
You could use iOS push notifications. The server can trigger a push message and target it at a specific device and send your iPhone something...
Push notifications are the way to go with iOS. I have used push notifications through the cloud-based Cocoafish backend server. This is a great solution as you can 'subscribe' mobile devices to a push notifications channel - for example, a channel for friends requests or a channel for chat etc. Its real easy to set up with all the correct certification. There's good set up instructions in the documentation on their site too.
I need to send remote APNS notifications from my server application to my iPhone applications. I want to know the frequency with which I can send remote APNS notifications in the following scenarios:
From my server application to the iPhone application on the same device.
From my server application to the iPhone applications on different devices.
I know that Apple has set some limit on this, but I do not know the limit.
Thanks
As per my information Apple has not specified any specific limit but following text in programming guide of service.
Apple Push Notification service continually monitors providers for irregular behavior, looking for sudden spikes of activity, rapid connect-disconnect cycles, and similar activity. Apple seeks to notify providers when it detects this behavior, and if the behavior continues, it may put the provider’s certificate on a revocation list and refuse further connections. Any continued irregular or problematic behavior may result in the termination of a provider's access to APNs.
Following paragraph is given here
If you find any further details then post here......
I understand that some applications need to check against a server periodically, but why don't servers let a mobile device know when it's time to update.
For example, let's say you receive an e-mail in gmail. As it stands now, there can be a delay between receiving the e-mail and your device notifying you. I assume this has to do with waiting until the device has checked the gmail server, at which point it sees the new e-mail and notifies the user. It makes more sense to me that when the gmail server receives an e-mail, it should ping (or however the creator wants to implement it) all registered devices to let them know that it's time to update. This way notifications would be synchronized and mobile device could save battery by not having to periodically check a server.
What you are describing is called a "server push". Some mobile applications does use server push. And Google actually have a technology in place to make this easier to implement, named "Cloud to device messaging" (C2DM). It works by having the servers sending a tiny little message, via googles C2DM servers, to the application running on the device, informing it its time for a update. And the device then retrieves the actual update from the original server (not from C2DM).
Its good stuff. It allows the service listening for C2DM manages to wake up the phone and everything. The downside is, the user of the application needs a google account. For android users, this isnt really a downside though.
Except they do, in some cases. In the "Mail, Contacts, Calendars" section of Settings on my iPod, there's a submenu labeled "Fetch New Data", which contains an option to have the mail server or whatever "Push" the data to the iPod. The Fetch aspect, which you can set the schedule for, is for when Push is off or you're syncing with applications that don't support push.
That is how Android does it. It pushes notifications to the device and that api is open to third party developers as well so they can push notifications to their users.
That thing is it is difficult to know the address of a mobile device at any particular time, the I.P address is dynamic, on a server the address is much more stable, so the device knows it will always find Google at google.com but Google has no real way of knowing where to find the device, it wouldn't know where to ping in the first place.
This is where push comes in, there are different implementations but i think they work by having the device maintain a connection to the server, and reestablishing it if its lost.
See http://en.wikipedia.org/wiki/Push_technology
This of course is much harder to implement and maintain then a simple client pull.
I want to send some Text plus a image from one iphone application to other iphone app but restriction is I should not use a web server in between communication,Is there any way to fulfill it ?
Details: There are two independent devices and could be far enough say out of network. My requirement one app adds some text with a image and sends it to another iphone which can be at any long distance , and the app installed in another iphone will read that info and image into itself.
Actually there is a solution that meets your needs — and that fits to bbums answer:
Create a HTTP-Server on the iPhone, using cocoahttpserver. than you will ask some webservice like whatismyip.com for your public ip. with this your iPhone can be connected worldwide.
But very likely ur wifi-network is not forwarding your port to the iPhone. Ash.
And even if: Now it gets difficult. How to publish your ip from one phone to the other? hmmm... — I got it: I will exchange the information in a centralized space! In the web!
... wait — that would be a Webserver.
You see: Without any kind of server in the Web the users would need to exchange ip manually and have full admin power and knowledge about the local network.
So IMHO bbums answer is the only way to go.
PS: I am working with http server running on iPhones. In local network that works great, especially with bonjour. And you can use them over distance network — but only with reconfiguration of your router — something you shouldn't force your user to do
There is far from enough information to provide a specific answer.
two apps on two different devices?
are the two devices on the same network?
are the two devices both on WiFi?
do you need the user to receive a notification or something if the app isn't running?
If on same device, you can define a custom URL handler in the destination app and then openURL: in the source app to pass the data over. Encode your image and text into the URL, but be careful of size limitations.
If on different devices, there are many possible solutions, but answering the above questions will be critical to actually knowing what solution is appropriate.
Given your comment -- two apps, different devices, arbitrary networks -- then you are going to have to have some kind of server in between. Note that the recently added Game Center does have the ability to rendezvous two users, but it has a very particular user experience that may not be appropriate to your needs.
I would suggest that you investigate using push notifications to notify the receiving user of the availability of content. As for moving the content between, no direct connection is possible and you will have to have some kind of store-and-forward server in between. And, yes, a web server is going to be the easiest possible solution simply because HTTP is ubiquitous these days.
If there's no network of any kind available, but both parties have amateur radio licenses, then hooking the two devices up to HF packet radios might work.
THIS is super EASY.
I would code up some software that can turn data into modem signal, like the good old dial up modem. The device would actually make those annoying buzzing sounds.
You get the phone number for your friends nearest landline and call him.
He places his iPhone near the phones receiver in listen mode and you connect to his phone using your audible modem.
Bingo, via the power of sounds you have sent data which is decoded on his device and all for the very cheap price of a phone call, there are pretty cheap these days especially if you use Skype.
Easy Way (relatively speaking)
A way two apps on different networks can communicate without setting up a web server of some sort is as follows.
Use an existing third party storage system like DropBox.
Each app would need the login and password for your DropBox. Then both apps can read and write files that the other app can see.
An existing app that does this is a shopping list app called ShopShop.
The app on my phone and my wife's phone both link to the same DropBox account and the app keeps the shopping list synced up when one of us adds something to the list.