I'm planning to develop a tool (running on the Windows PC) which allows comparing and merging calendar events between different calendars. My mobile device and my Lightning calendar should be supported.
The idea is to write an App for my mobile device connecting to the tool via TCP or UDP so the tool is able to modify the mobile device's calendar by sending commands to the App.
Unfortunately I'm not aware on how I can access the Thunderbird Lightning calendar with my tool.
Question 1: (Possibility 1)
Is it possible to access the Thunderbird (Lightning) calendar read/write from another application (e.g. by directly accessing the SQLite archive) in a safe way?
"In a safe way" means: No risk that the calendar format changes in the next Lightning release and writing events will destroy it!
Question 2: (Possibility 2)
Is there a possibility to access the Lightning calendar data from another Thunderbird plug-in?
(I was searching about this in Google for 2 hours and found nothing!)
Is it possible to create a "permanent" TCP connection from a Thunderbird plug-in (running some operations in the background)?
I would advise against option 1, but if you must then you can check the version table to see if the storage version has changed. This doesn't happen very often. As for accessing calendar data, you can reach the calendar manager and events as follows:
Components.utils.import("resource://calendar/modules/calUtils.jsm");
let calmgr = cal.getCalendarManager();
let calendars = calmgr.getCalendars({});
let mycal = calendars[0]; // pick one
The calendar in mycal will follow the calICalendar interface, which you can read about here. The most important methods are addItem, modifyItem, deleteItem, getItem and getItems.
As for creating a permanent connection from within Thunderbird, it is probably best to use web sockets, which you should be able to use from any DOM window. It might make sense to create your own e.g. with an iframe.
Related
I wonder to know which technique and tools I should use to have the ability to send real time notifications to users. Specifically if I build a messaging system.
I can see that modern social networks can send notifications about new messages almost immediately. Even when the user 'A' from one country writes a message to the user 'B' in another country you can see that the user 'A' writes a message and you immediately see it (even if those users live in different continents).
I tried to figure out how it is possible and find any information about this but without success.
The only thing I found out is the technique when we use a Redis or RabbitMQ server with several servers which acts like publishers and subscribers. Our API servers receive new messages then they push a new message in the queue then subscribers receives the messages and if they have an open WebSocket with the recipient they push this message in the WebSocket and a client receives the message.
But it really won't work if you have a distributed project and your clients are connected to the nearest servers in the nearest data center.
The question is: what technologies/techniques/anything we should use to be able to build notifications in a distributed project?
If you develop your distributed app/system using web technologies, you can consider building what is referred to as a Progressive Web App. With PWAs you can add push notifications in a relatively easy way. You could start with a PWA approach, and then decide later on if developing a native app as well (i.e. iOS or Android) would be necessary.
There are many resources to learn and guide you in developing progressive web apps. Check the references I mentioned above, and you can do this codelab as a starting point.
I am wondering if there is a way for a Firefox OS app to broadcast an event to all other apps and for the interested apps to hook on that event and trigger a corresponding action.
An example of use case I have in mind: the Camera app broadcasts the event "picture taken" and another app hooks on this event and take some action on the new picture that has been taken (for example, uploads it to a server).
There's not currently a web API in Firefox OS to broadcast events to all open and/or interested apps.
For your particular use-case of apps being notified when a new photo is taken by Camera, the best approach is probably to open DeviceStorage for "pictures" and listen to "change" events.
Documentation for this is at:
https://developer.mozilla.org/en-US/docs/Web/API/DeviceStorage
Alternatives exist but are more restricted functionally, and available in fewer releases and contexts:
The system can broadcast messages, but only certified apps can listen. https://developer.mozilla.org/en-US/docs/Web/API/Navigator.mozSetMessageHandler
The InterAppCommunication API allows web applications to message one or more other apps, but in a more tightly coupled way than a general broadcast. However this API is not yet standardized, and is only available to certified apps. https://bugzilla.mozilla.org/show_bug.cgi?id=876397
Access to system preferences is coming soon for non-certified apps, and maybe could be used to do this, but that's a hacky way of accomplishing messaging and data sharing. https://developer.mozilla.org/en-US/docs/Web/API/SettingsManager
Note: For every example here, your app would have to be running for it to work. There's no mechanism for waking an app up when a specific action or event occurs. Web Activities is the closest API for event-specific app loading. Timers API is for non-specific app loading.
From this article[1]:
App authors can build an app that will handle one or more activities. That means that the app will be callable by another app to perform some specific actions defined by the activity. For example, let's pretend we want to build a photo manager. It could be used by another application to pick a photo. As an activity handler our app will become part of the other application's workflow.
[1] https://developer.mozilla.org/en-US/docs/Web/API/Web_Activities
I am trying to create a shared calendar as a web app. When someone adds an event on the calendar i want everyone who shared that calendar to see that event too. When someone create an event, I made an ajax that sends the data to a database. Is there a way to send the event from server to other clients that are online on the page and share the same calendar? I did it now by constantly 'refreshing' the info from database.
If anyone has a clue how this can be made, please tell me.
Wanting a web server to "push" information back to the browser is a time old issue. The traditional way to handle this is to have any active clients (i.e. the people still logged into your app with a page open) continuously "poll" the server at a regular interval to see if there's any new information for it. In your case, you can have some JS on the page make an AJAX call every 10 seconds to see if they have any new calendar events they should be aware of. This does increase the overall traffic to your web server so pick your polling time appropriately - otherwise you'll cripple your web server because it will spend all of its time handling these "is there anything new?" requests when most of the time there won't be.
If you want to be a little more cutting edge, you can look at HTML5 websockets. A google search for "html5 websockets tutorial" should give you plenty of resources. They're a bit trickier to use and require that you are running a web server that supports them (you probably are). For browsers that support it, you can maintain a more long term open connection where you can then push data from the web server back to the browser like you want to and your JS will capture "onmessage" events with the updated info. Pointing you at google isn't trying to flake out of a more complete answer, but there's already a number of excellent tutorials out there so look for HTML websockets and you should be able to pull off what you're looking to do.
I working on a project were mobile users can receive alerts based on diferent factors, the server side will be implemented using the MVC framework.
My question is regarding the client side; what would be the most efficient way to send the alerts to the clients? is there any way to broadcast the alerts to each device or do I have to set up some system where each device pulls the data from the server on an interval of mins/seconds? I am afraid pulling the data every X secs/mins would create an unnesesary overhead on the mobile devices.
One way would be using SMS but SMS gateway services are expensive and not on my budget right now.
I haven't personally tried it, but this service might work for you:
http://www.airgramapp.com/api
It is free for limited use. Downside is it appears to be a separate install on the mobile device. This might means less control of the content of the message or its look. Upside is it looks quick and easy if you just need a proof of concept at this point.
I'm trying to write the most basic application for windows phone 7 and want to be able to send files (specifically XML in case that changes anything) to my app. Currently I have a WCF service setup so I can send push notifications through it. The problem is that there is a limit on the amount of raw data I can send via a push notification.
My solution to this is to send the initial push notification (either tile or raw) to alert my application that I want to send a file to it and then make the app somehow communicate with a server (everything is on my personal computer btw - I'm just trying to figure out how things work) - from which the app will recieve/download the files.
What is the easiest way to accomplish this? Note that I'm not concerned with security or anything like that.
Clarification - the question is essentialy: how do I transfer files from/to a server to/from the phone? Assume everything else was handled - the app is up and running and the user has given or will give permissions to every possible thing he may give his permission to.
Unfortunately, the total size of a push notification (including HTTP headers) is 1kb. This means that it can't be used to send large amounts of data.
Instead of sending the whole file, send a notification (raw or toast—as appropriate) which should be treated by the application as a trigger to go and retrieve the new file/data/whatever from the server. It may also be worth checking for new messages when your app starts. However, if when you start the app it will notify the server that it is ready to receive raw notifications and such messages will be sent indicating new content is available, it may be unnecessary to add this extra check.
To transfer files to/from the phone you will need to use either HttpWebRequest or WebClient as this is the only way to use HTTP on the device and HTTP is the only protocol currently available to transfer data.
While WebClient may appear to be easier to use than HttpWebRequest it is less flexible and will automatically perform it's callback on the UI thread and if you're downloading files in the background you almost certainly don't want this.
There is no way to transfer files to/from a conencted PC and have them exclusively available to your app.
First of all: you won't be able to do this approach automatically - the user will have to open your app to do that because WP7 SDK doesn't allow your app to run on background/start automatically once a push notification is received.
The only way to communicate with your server, at this point in time, is web services. If I were you, I would check for new information available once the app is started, if there is new info, I would call one or more web services which would return me all the information that I need.
If you want, you can use a timer to check for information periodically.
As I said, it will only work while your app is running (check the app lifecycle if you don't know it yet), WP7 doesn't allow apps to run in background, that is a serious limitation IMHO.
Good Luck,
Oscar
Maybe a little bit off topic but when I was thinking about file sharing in my WP7 app, I found two approaches:
Integrate an app with Dropbox
Use advanced explorer for WP7
You can use the WebClient class and the DownloadStringAsync method in order to download data from a web service .
A good example of this is Scott Guthrie's Twitter app from MIX10 .
George