I am considering PouchDB & CouchDb as an alternative to Amazon Cognito Sync for a hybrid mobile app that will need data synced between devices and users. I have pouchdb working in a small sample app that syncs with a local couchdb.
I need to be able to intercept the communications back and forth between the pouchdb and couchdb in Java in order to do things in response to these sync events. Sort of like Amazon Cognito Sync's sync triggers. Also, I keep thinking much like Spring's AOP around.
Since the couchdb has a rest interface, I thought I could point the pouchdb to my application server which has a controller listening for any request with the db name as the base. When a request, from pouchdb comes in the Java Rest Controller can optionally do something, then forward the request to the real rest endpoint of the couchdb and get a response, then optionally do something again, then return the response to the pouchdb.
Does this seem like a feasible solution? I am currently working on trying to get this concept working. Has anyone else done anything like this? Any major pitfalls to this approach? Currently, I'm using Java 8 with Spring Boot & Jersey.
I think the architecture goes like this:
Data is empty everywhere.
Data changes, the device where the data changed pushes via a REST APIs.
Your server "master", send notification GCM or APN to devices.
In your notification listener, you check the type of notification and you sync the data.
If a new device connects to your "list of devices to sync" you send a push notification to sync the data.
Keep a list of connected devices.
The same ideas goes for every device/web browser. You have a local cache that you push to the "master" if it changes locally.
You will have many cases to deal with, and I don't think there are open source projects that offers the same patter as Cognito Sync.
Also think about scalability, devices don't have to pull your "master", the master sends notification to trigger devices to download the data.
You have to deal with diffs, regular checks, and so on ...
Good luck
Related
I am working in banking sector and we have different portals for managing employee information, performance etc. I want to send push notification in mobile app from our asp.net web service when a new event (e.g. a Line Manager has to approve any pending request) occurs. How can I send notification to mobile app from our servers(where the web service has been deployed)? We don't have rights to place employee data on cloud servers or cloud databases.
Hopefully this is your request:
We don't have rights to place employee data on cloud servers or cloud
databases.
And not this:
Send Push Notification In Xamarin Forms Without Firebase
As they are entirely different. If you want to send data to Android devices you need to use Firebase for that just like you need to use Apple's servers for iOS devices. However you don't need to have any database or store data on them.
You can use PushSharp nuget if you want to minimize 3rd party server usage or some other similar solution.
Just for the record using Firebase (or other services like Azure) to send push notifications doesn't require you to place employee data on cloud servers either. Firebase and other solutions contain range of services that can be used independently and it seems that you consider them as all or nothing solution.
Is it possible to leverage transaction on the client, when using azure app service offline sync?
It seems to me that you can pretty much only insert into the SQLite store a record at a time, but ideally i'd like to be able to commit multiple records in a transaction.
I'm using Xamarin with Android right now,but will be also supporting iOS.
Thanks
Matt
Unfortunately, on Windows, Xamarin, and Android you can only commit one record at a time on the local MobileServicesSQLiteStore. This is because changes need to be made one at a time using methods like SyncTable.UpdateAsync, which is how you mark a change as being tracked to send to the server.
On native iOS, the Mobile Services offline sync feature uses Core Data, which does support a form of transaction (https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/CoreData/Articles/cdMemory.html). If you use these APIs, you still need to make calls to the Mobile Services SDK methods to track each individual change in the internal tracking tables.
Why do you need transactions on the client side? There might be a different way to achieve your goal.
I am new to SignalR. I am hoping to integrate SignalR to send notification in dashboard (i.e. latest applications created by staff) so that new applications will be shown without refreshing the dashboard. Applications should be fetched from a database (sql server) and notified to the dashboard. Is there any sample that I can look in to and take some idea how to start on this? Any help is highly appreciated.
Regards
Samitha
Sounds cut and dry. You want to create a Hub which your dashboard clients can connect to to receive updates. Then either the Hub itself could have a monitoring routine (e.g. background thread that is watching some stream of events from some external resource) that is pushing out updates to the connected clients.
Alternatively you could go with a better separation and just have the Hub be "dumb" and move the monitoring/notification off into another background process which just connects to the Hub like any other client and just pushes its notifications to the other clients through the Hub.
I would highly recommend just reading the Wiki and taking a look at some of the samples that come with the SignalR solution.
I am working as part of a team using Android and WP7 to create apps that communicate with a server. So ideally we want a consistent approach to receiving the data from the server.
I currently am using HTTPWebRequest to form a SOAP message and send it to a Java-based web service to receive messages (Adding as a ServiceReference didn't work no matter what I tried) At the moment it's a simple case of receiving the full list of things and just recreate the list each time via DespatchTimer to do periodic calls. But of course periodic pollin is likely to be ratehr battery intensive so not the best apporach for my needs.
I now need to change the code so that changes are pushed rather than polled. The team is looking at XMPP to do this as Android libraries are readily available to do this but I am having trouble finding open source libraries to do this.
Microsoft Push seems available but this appears to require a Microsoft based server side environment to push unless I have misinterpreted this? Or even if push notifications are a sensible way to do this.
So what I would like to know is the approach to handling pushed messages in this scenario which i hope someone out there has had experience in
Thanks
Microsoft Push Notification System [MPNS] does not require a MSFT-based server backend. It simply relays the Push Notifications through carrier or other data channels to subscribing phones. You should be able to make HTTP POST requests to MPNS at the Windows Phone subscriber Channel URI & MPNS would deliver the Push Notifications for you. Your server side can be anything, as long as you able to make the HTTP requests.
A good starting point can be found here.
Hope this helps!
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