This is very similar to Where should cross-platform apps keep their data?, but expanding on it a bit.
There is some good advice on where the parent directory for data should be, but not so much on what a given app's directory should be.
For example, let's say we have a cross-platform application, written by My Corp, within My Brand, called My App. Assume there are other products in My Brand which presumably want their own data, and other brands in My Corp as well. Where should its data and/or configuration go on Windows? On Unix? Mac OS9? Mac OSX? Other?
e.g., on Windows, would the data go in "...\Application Data\My Corp\My Brand\My App", while on Mac OS X the data would go into ~/Library/Application Support/My Corp/My Brand/My App" and on Unix it would go into "~/.mycorp/mybrand/myapp"? (I would imagine other platforms would use the mangling of unix, even if the base directory may be different.)
If there is no real convention, does this seem reasonable? Any suggestions for Mac OS9?
Just to start the reflection:
You have to make a clear difference between:
application state data
settings
data (can be common for several applications)
The latter may eventually be in a database, or could be managed by one or several applications, or encapsulated by a communication bus in order to avoid all the other applications to dialog between themselves to access those data.
The data representing the state of an application can go in 'Application Data' as mentioned in the question "where cross-platform apps keep their data ?".
But the settings... It depends if you application need to be launched with several "configurations":
one for each platform: in case you must manage them in the development stage, and package that file in the release stage, in order to store it in 'Application Data'
many for one platform, like with different Heap sizes, or different settings representing different operations to be executed by your same app. And that leads to an explosion of setting files (also stored in various sub-directory of 'Application Data')
That is where the idea of abstracting those data into a Setting Provider is a good idea.
Actually, we have so many different configurations for our settings we store them into a database on a separate production machine. That way all the apps can access them, but more importantly, we can access and change them in real time, without having to stop / restart the applications for each modification, or without having to go to each deployment platform.
Related
First of all, I don't mean version control such as git.
I do use git locally but, I'm trying to determine the best way to do back-ups of source code (as well as other app assets) in case of hardware failure or such.
I was thinking I could set up a script to tar my project folders, and encrypt them with gpg. I would then save the encrypted tar to external hard drives and to 1 or more off-site locations using a service such as amazon drive or dropbox.
Currently, I'm a sole developer so my thinking was that this method should be okay. But I wanted to get some input to make sure I'm doing this the best/most reliable way possible.
If there is a better approach to this that may be more applicable to small teams, then please let me know, as I'm more than happy to do the extra work implementing the approach.
There are much of ways of doing that.
But, if you always work local and you need a simple way of doing that, you may take a look at run scripts if some specific usb device is plugged in.
Meaning that a simple backup script with tar would run if you plug in your specific backup hdd.
Take a look at udev rules in linux.
udev is a generic device manager running as a daemon on a Linux system and listening (via a netlink socket) to uevents the kernel sends out if a new device is initialized or a device is removed from the system. The udev package comes with an extensive set of rules that match against exported values of the event and properties of the discovered device. A matching rule will possibly name and create a device node and run configured programs to set up and configure the device.
Take a look at these posts:
https://unix.stackexchange.com/questions/65891/how-to-execute-a-shellscript-when-i-plug-in-a-usb-device
&
https://askubuntu.com/questions/401390/running-a-script-on-connecting-usb-device
If you plan to go further, to extend the team or even to keep your code for a while in other words, if you want to be professional, I would go with a scalable and reliable tool designed for this: use a real backup and restore tool and don't use scripts. A lot of people, small (and even not so small) companies are doing it and they end up in trouble: maintenance, scalabolity, update, and so on.
There are plenty of backup & restore tools for different purposes and/or platforms, prices and so on. https://en.wikipedia.org/wiki/List_of_backup_software would be a good start :)
Cheers
Werlan
I am developing a Win8 Store app which allows users to download different types of files from an online learning platform and store them locally. I am also considering the function to help users organize these downloaded files by placing them in different folders (based on course name and etc.).
I was using Documents Library previously. But for every type of file that the user could download, I need to add a file type association, which does not make a lot of sense since my app would be able to open such files. So which local storage should my app use?
Many thanks in advance.
Kaizhi
The access to storage by Windows Store apps is quite restrictive, especially the DocumentsLibrary.
As you have noticed, you need to declare a file type association for every file type you want to read from or write to the DocumentsLibrary. This means your app need to handle file activations for these types in a meaningful way, which your app probably should not do.
But even if you jump through this hoop, there is another one that is not documented on the MSDN page of the DocumentsLibrary, but "hidden" in a lengthy page about app capability declarations: According to the current rules, you are not allowed to use the DocumentsLibrary for anything but offline access to SkyDrive! Bummer...
So what's left?
You can use SkyDrive or another cloud storage to put files in a well known place (which might or might not be somewhere on the hard disk). This is probably both overkill and undesirable in your case.
Or you save the files in the local app storage, provide your own in-app file browser and open the files with their default app. Seems viable to me.
Or, maybe, you can do something with share contracts or other contracts. I don't know much about these yet, but I doubt that they are helpful in your situation.
And that's it...
(Based on my current experience. No guaranty for correctness or completeness)
I am in the process of building a completely fresh version of an application that has been in existence for a good many years. I can look back with horror now at some of the things I had done, but the whole point of life is to learn as we go along. The nice thing now is that I have a clean slate from which to work, and it's because of that that I thought that I would seek some advice from you all.
User settings are great for those things that each individual user would naturally want to and ought to be able to change, a theme or visual style for example. Application settings should quite obviously apply to the entire application irrespective of whoever uses it.
Somewhere in the middle though are a set of settings that I would like to give the system administrator the opportunity to change (default work periods, appointment time slots, the currency the company wants to use as its main trading one etc etc). These can't be user settings because individual users should not be able to change them, nor should they be application settings because I as the developer have no idea what the end user (or to be more exact the senior end user) would want to set them to.
Many years ago I might have considered writing such settings to the registry, or an ini file. I could perhaps (as this is an application that is tightly integrated with its own custom database) create a one off settings table, and read in the relevant settings at program startup. I could perhaps opt for a separate 'universal settings' xml configuration file stored in the all users directory. Clearly a number of options.
What I would like to try and establish though is the most efficient way to approach this. What is the best trade off between file read and write operations as against reading everything into a set of public constants at application start-up? These are not going to be settings that will only be referred to occasionally so efficiency is going to be key.
Just so that there is no ambiguity as to what the application will be. Traditional winforms, using vs 2012 as the development ide and vb.net as the code base based on .net4.5 and ef 5.0. Backend data to be stored in either sql express or full sql server. Target operating system for end users will be windows 7 or above (so due respect for the uac will be required).
I'd welcome any suggestions that you might have.
I have read several articles about creating a Sharepoint Developer VM. They all say to "sysprep" them. Why (exactly) must the sysprep be done? What kind of problems (and why) will we run into if we don't sysprep them?
(I suppose what I am asking is, what would be the difference in doing "sysprep" and just bringing up the VM, changing its Name/IP, reboot then install SP?)
I've had success in the past with just copying Hyper-V vhd's as a method of cloning VM's - however, I now use sysprep when cloning any of my machines as it's been mentioned as a best practice in many places. And, it does some nice things like allowing you to cleaning up a bunch of stuff that I don't want to duplicate and letting me choose a new name for the machine on boot. From MS Sysprep Technical Reference:
Sysprep prepares a computer for disk
imaging or delivery to a customer by
configuring the computer to create a
new computer security identifier (SID)
when the computer is restarted. In
addition, Sysprep cleans up user- and
computer-specific settings and data
that must not be copied to a
destination computer.
And you may want to read Russinovich's post on The Machine SID Duplication Myth (and Why Sysprep Matters) for more good explanation of how SIDs work and the very last paragraph has another reason for going this route:
Note that Sysprep resets other
machine-specific state that, if
duplicated, can cause problems for
certain applications like Windows
Server Update Services (WSUS), so
Microsoft’s support policy will still
require cloned systems to be made
unique with Sysprep.
Good luck!
I have a particular file I want to monitor for file read attempts by all applications on OSX. I'd like to be able to interrupt the requests so I could decide which applications have permission to read the file and which don't (by querying the user, or checking a cache of user responses). Is this possible with the OSX API? If not, is it even possible to get a list of which applications or processes do read a file?
I'm not saying there's no way to do this, but what #Jonathan is talking about isn't it.
That API is for tracking the creation, change, and destruction of files. Notably this tool is used by things like Spotlight to watch activity on the filesystem for new, interesting files.
But, wisely, reading isn't one of the events it tracks.
And even if reading WAS tracked, it is still the wrong mechanism, as it's a notification system after the fact, not in line with the call itself.
I seriously doubt what you want is possible the way you describe it.
With Access Control Lists, you can limit access at the user level (Fred can read the file, but Bob can not). This is a setting on the file itself. But there's no mechanism to allow Bobs App1 to read a file, while Bobs App2 can not, since there's really no formal mechanism of "application identity" beyond the command to executed, or whatever the program "says" its name is (both of which can be spoofed if motivated enough).
However, feel free to crawl the Darwin sources -- no doubt the answer is buried in there somewhere near the open(2) call.
EDIT, regarding comment.
What are you trying to do? What's the overall context?
Another thing that you may want to try is to use FUSE.
FUSE is a utility that let's you have "user space filesystems". People use FUSE for many purposes, like reading NTFS volumes, or mounting remote system via SSH.
They have a simple example, that gives you a skeleton that you can fill in for your purposes.
For most of the use cases, you'll simple defer to the system. However, for OPEN you will add your logic. Then you could point your FUSE utility at a directory, and "mount it". Then all of the files below that directory can use your new behavior.
I'm still not sure how you will identify Apps by name, but if it's not a real "security" issue, just for local control, I imaging you can come up with something. Activity Monitor has apps names, so they must be available, and FUSE will be running within the process space (I think), rather than through some external mechanism.
All that said, I think FUSE is your best bet, but it's probably not appropriate if you want to do this to "any file" with no preparation by the user (like not installing FUSE). If you wanted to do "any file", your FUSE system would need to be mounted at root, and then you'll simply have a full "clone" of the filesystem, with those files from the normal root "unprotected", while those from your new FUSE root will be protected. So, if someone wanted to NOT use your FUSE system, the real file is readily available to them through the actual file location.
If not, is it even possible to get a list of which applications or processes do read a file?
The command-line tool fs_util allows you to monitor filesystem activity, including reading.
The writings of Amit Singh should come in very handy. He explored the API that provides FileSystem events a few years ago, and provided a sample tool that allows you to intercept FS events. It's open source!
If i remember his conclusion properly, their isn't an official API, but you can use apple's tools to achieve what you want.