I am working on a product for Windows 8 that needs to perform some low-level tasks, display some UI, and communicate with an external server. I definitely need a Windows service to accomplish the low-level tasks. At the same time, I would like to use the cool features of Windows App Store apps, like push notifications, live tiles etc... for the UI. In this design, both my service and my app would communicate with my external server.
The flow would be something like: my Windows service sends some information to my server, which then sends a push notification to my App Store app.
I understand that deployment is not pretty in this scenario, but let's put that aside for now. My problem: How does the server know that the service and the app are on the same machine, and consequently linked together? i.e. When my Windows service sends information to the server, how does the server know where to send the push notification? I need is some sort of shared, unique, identifying information.
I have seen lots of discussion (usually frustrated in nature) about the lack of inter-process communication between App Store apps and desktop apps. In my case, I have two options:
Generate the exact same unique identifier in the service and in the app. This seems unlikely because apps don't seem to be able to access very much system-specific information. I'd love to be shown that I am wrong about this.
Generate a unique identifier in the server OR in the app and communicate it to the other component. Potential ways to do this:
Create the identifier in the app, save it to a file, and then access the file from the service.
Some sort of local socket solution (I've read this doesn't work, but have not tried)
Of course, option 2 seems likely to violate the Windows 8 app Certification Requirements, notably:
Windows Store apps must not communicate with local desktop
applications or services via local mechanisms, including via files and
registry keys.
Any advice would be most appreciated.
I'm not a lawyer, but if it says "via local mechanisms" then you could still possibly communicate via a cloud service as long as having both apps installed isn't necessary to have some features in the app or if you don't mean to publish the app in the store.
You could save some sort of a token in the documents folder or if your desktop app can run with appropriate permissions - it could access the local data folder of the Windows Store app to synchronize the token for use in communication with the web service.
Perhaps the user could just be asked to copy and paste a token between the two apps?
Related
I have a Teams application (Tab). I am an ISV provider, and provide a multi-tenant application that is installed by customers via Teams App Store in their organizations.
How do I save settings for my application organization-wide for the customers? For example, CustomerA has installed the app and then CustomerB. I want some storage that would be unique for CustomerA and CustomerB and the app, and located in customer's environment. The settings I want to save are not per-user, but per-organization (tenant).
Somewhat similar to "App Data" folder you have in Windows Desktop for example.
Does such a storage exist? Does API for this storage exist?
A tab app is a simply a web application that you render inside of Teams. As a result, what the app does, and where and how it does it, is totally up to you. This includes any data storage you choose to have behind the scenes. For example, your tab could be built in PHP and use MySQL, or built in ASP.Net and use SQL Azure or CosmosDB. It's totally up to you, but you need to implement it yourself, as an ISV.
The important piece to differentiate clients, however, is being aware of the TenantId for each user, so you can look up which client's settings you need from the database. The most simple way to do this is simply the tid property on the Teams tab context. You can read more about that here. Unfortunately, because it's just accessed via Javascript, it's not entirely secure - for a more secure mechanism, you should be creating an Azure Application, and generating jwt tokens that you can authenticate against in your backend. It's a much more complex topic, but hopefully this answer at least gives the background you need. For more info on the security aspects (validating the token etc.), please see this question: How to restrict access to Azure Function to only allow requests from a custom Microsoft Teams App?.
I want to send info between a desktop/laptop/tablet app and Windows Phone. One possibility is to send data to the SkyDrive account and have the other end pick it up from there. Is this feasible? What I have in mind is the "Windows 8" app running on the desktop, laptop, or tablet allowing the Windows Phone app[s] to send data to its account. Is this possible, such as by providing the Windows Phone app with the Skydrive login info, or...???
From all the other questions you've posted around this query, it sounds like you want to put a mechanism in place to communicate between a Windows 8 app and a windows phone app. I would recommend you look at building a service to handle the communication instead of trying to leverage mechanisms that weren't designed for what you want to achieve.
In direct answer to the this question, though, you can probably achieve it in this manner, but what happens if the user deletes the file you create?
So, SkyDrive is unique to a user, not a device. This means if your application is running on more than one device you can use SkyDrive as a shared, unified storage option. Not just for files but also for application settings. There's an SDK for every platform, not just MS.
Here's what you need to consider.
The roaming API in Windows 8 puts information in a protected area of SkyDrive. As a result, the user cannot delete or screw up the files stored there. To that end, using SkyDrive as a shared location (like you are asking) doesn't have this benefit. The user can screw with your files or delete them - and wreck your app. There is no such thing as protecting your app files in SkyDrive (at this time).
Specifically, to your question:
The authorization model for SkyDrive requires a token that cannot be practically cached for any app. Also, you cannot cache credentials because you never get the credentials in the first place - you only get the resulting token. Listen, you would violate every possible best practice if you //asked// the user for their username and password and stored them. Please do not do this.
The final answer is this: an app on multiple devices can use SkyDrive as a shared storage solution for files and settings (like XML files) - but the developer needs to understand the risk and mitigate that (mitigation might be easy for your app). The user, on every device, would need to sign in and grant each application access to it folders. And, that's it.
I have a desktop application which uses flat files (some xml and small pictures) as data. I want this data to be available on other PCs which have the desktop application installed and usable by a smartphone client (WP7 at the moment) as well.
The user should have it very easy to synchronize this data. He should be able to use accounts he already possesses (Live-Login, Googlemail, Facebook,...).
I thought about using Azure Blob Storage to save the data in Azure, the Sync Framework to perform the actual synchronization and the Access Control Service to handle authentication.
I have not used any of this technologies before so any advice would be great but I'm searching foremost for errors or shortcomings in this strategy I don't see yet. Is this approach viable at all?
Windows Azure is basically a virtualized datacentre. It is elaborate and complicated and is pitched at corporations who don't want to own their server infrastructure or hardware.
If I understand correctly, what you want is a cloud fileserver, not a whole LAN. Windows SkyDrive fulfils this requirement nicely and offers 25GB of storage per member with no charge for membership.
About Hotmail and Windows Live People often confuse Hotmail and
Windows Live, because when you set up a Hotmail account it uses
Windows Live for authentication and therefore you end up with a
Windows Live account and all the associated facilities, including
SkyDrive. However, it is entirely possible to set up a Windows Live
account using any email address as the username.
If you do this, it is important to be aware that the Windows Live
password associated with a given email address is completely
independent of the password required by the mail server that hosts
mail for the account. This can cause a great deal of user confusion.
For Hotmail (or any other mail server that uses Windows Live for
authentication) they are guaranteed to be the same password.
There is no official Microsoft framework support for SkyDrive. There is an open source project called SkyDriveApiClient, but it only works with the full .NET framework. I tried porting it but the author was a bit of an architecture astronaut, and it is absolutely riddled with [Serializable] which is not available on WP7x.
The WP7 guys have said that the WP7 framework will probably include support for SkyDrive but not in Mango (WP7.1) and given that Microsoft's typical release cycle is 18 months and Mango has yet to hit the streets, I'd say it will be two years before you can count on intrinsic cloud file services for WP7.
Roll-your-own wouldn't be hard, WCF services are dead easy to use from WP7. But that's not really cloud since you have to provide and maintain the server infrastructure yourself. For this reason and given the MS timetable, I have put a great deal of effort into producing my own SkyDrive client for WP7. Core functionality is complete and I am now refactoring, improving robustness and adding performance enhancements like local cacheing of tokens (cookies, essentially). I don't intend to release it; I have a number of apps planned that depend on this functionality and it suits me fine that there is a substantial barrier to competition.
I didn't tell you that to tease you. My point is that I'm so sure SkyDrive is the right answer that I put a lot of work into making it happen.
Cloud file storage is a perfect fit for mobile devices.
Azure is not a good answer for the sort of phone apps individuals want because the data store isn't shared in a way that required indexing or supports high levels of concurrency
I can certainly think of corporate phone apps that would benefit from using SQL Server as storage
Azure can do file services but it represents an ongoing expense. Nobody's going to put up with that when Google and Microsoft both give away web based cloud storage.
I can personally attest that if you're determined, it is possible to use SkyDrive from WP7.
Cloud storage is the only way you're going to get programmatically accessible storage that's shared by your user's mobile device and his computer. One of the things I intend to do that depends on shared storage is write a Silverlight app that lets you prepare map routes with multiple waypoints on a desktop computer and a companion app that uses them on WP7.
The Windows Live team has released what they call support for WP7. They supply a sample project showing you how to instantiate a browser object and load their login pages and manipulate them to log in and use their javascript API to manipulate SkyDrive.
This has one big advantage: browser cookies and cached credentials. The disadvantages are obvious; technical shortcomings notwithstanding the Windows Live team seems to think the only thing people want to do with a phone is tag their photos and fiddle with social media.
I have finished my own libraries. They do not support most of the social media twaddle. I have treated SkyDrive as no more or less than a cloud file system, providing
Authenticate(username, password)
CreateFolder(folderpath[, blocking=false])
Delete(fileOrFolderPath[, blocking=false])
SaveString(filepath, value[, blocking=false])
LoadString(filepath)
I could handle binaries but Convert.ToBase64 makes this unnecessary and strings are convenient for XML. CreateFolder, Delete and SaveString are optionally blocking. LoadString is always blocking because it's a function that returns the loaded string. CreateFolder is recursive so you can create an entire path in one call (eg /folder1/folder2/folder3). Calling CreateFolder on a pre-existing path has no effect, and SaveString uses CreateFolder to ensure the path is valid, making it unnecessary to create a filepath in advance. Authenticate loads the file system (except file content) into memory eliminating server chatter. This is asynchronous and a FileSystemReady event announces when the file system is completely loaded. The model is maintained as you add and remove files and folders.
This was a lot of work and no one reponded to my attempt to make it an open source project so I'm not inclined to give the fruits of my labour away, but provided your plans don't compete with mine I could be persuaded to come to an arrangement.
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
I want to be able to synchronize several text files on a user's PC in real time from my web application. Basically I want a few data files on the local PC to mirror the state of a user's data in my web application so if the web application or the user's internet connection is lost he can use those data files to get some critical info (possibly using html/javascript code stored in with those files that would run in offline mode on those data files.)
I know that google gears has a lot of interesting tools for working with offline state, but I'd prefer an even simpler application in html/javascript that wouldn't be as reliant on google gears. I'd rather use google gears to just create those files and slowly keep them in synch with the web application's version of data throughout the day.
Update on answers:
PersistJS is a good suggestion I will look into, but I was hoping people would direct me towards really good Google Gears tutorials resources.
You can save data on the browser using PersistJS, which uses the best client-side persistent storage mechanism it can find, supporting:
Flash
Google Gears
HTML 5 storage specs
browser-specific extensions
cookies
When your app reconnects, you can resync. Creating and reading text files is something the browser will generally block your web site from doing.
Risking of stating the obvious; if you want to store user state locally, isn't cookies the standard way?
maybe more then one cookie will be needed, but that sounds like the simplest of ways.
You're going to need to make an ActiveX control and a FireFox plugin to get these permissions. Short of that I agree with orip try using PersistJS
You can ask the user to download a subversion client that is predefined to interface with your subversion server only. Then write your web application to interface with the subversion service from your side only.
There is a good deal of security harm associated with granting access to a user's file system so you will want to lock down all possible points of exploitation. You will want to ensure that the user cannot access the subversion server except through the client that you ask them to install. You will want to ensure the connection between the application server and the subversion server is extremely secure so that the transmission path cannot be compromised and that malicious logic that may be loaded onto the application server cannot access the subversion server. I would say to encrypt the transmission path between those two servers and put the subversion server behind the firewall separating your network DMZ. I would also suggest use a challenge/response mechanism between the application server and the subversion server to prevent malicious code from appearing to be legitimate decisions made on the application server. Also, ensure that data only flows form the application server to the subversion server in a unidirectional fashion only, because if there is malicious logic planted on your application server then any data that comes from the subversion server is compromised without even accessing that server.
you could use the File System Object FSO through javascript, however it is dependant on Microsoft as it is an ActiveX control, it would also require permissions in the browser, or perhaps a HTA (HTML Application).
http://www.webreference.com/js/column71/
Its a real security issue so most avenues are closed down inhrentley.
Inherently the web model was designed not to authorize upstream from server to client. Now things are changing slowly maybe could you do this with Websocket ?