I wanna create a table somehow in wondows phone that holds data that never changes and the application querys that data. Pretty simple but not sure how to do it.
Example
a table with Name, Description
When you open the app all the theres an input box to enter a name then you press a button and the description displays.
Using isolated storage seems like you are writing all the data to a file everytime the a user opens the app. Is that how it works?
Using isolated storage seems like you are writing all the data to a file everytime the a user opens the app. Is that how it works?
No, IsolatedStorage is storage - you can think of it as "disk" - so everything in it is persisted between application runs.
When you first run your application, then you'll need to create your files there, but after that time, then the files will already be in place.
If you need to put a large amount of data into IsolatedStorage and then need to search that data later, then "lite" database solutions like http://sterling.codeplex.com/ or SqlLite might help
For test purposes simply hard code the values as a dictionary.
In the long term I suggest you store the information as a file in isolated storage.
Here is an article that describes how to load and save data to isolated storage
Related
I have developed an application which allows Users to select multiple "transactions"; each of this is directly related to a PDF file.
When a User multi-selects them, and "prints" them, these PDF files are merged into one longer file to provide ease of print.
Currently, "transaction" PDFs are generated on request, and so is PDF-merging.
I'm trying to scale this up relaying over Amazon infrastructure, some questions arised to me.
Should I implement a queue for the PDF generation per "transaction"? If so, how can I provide the user a seamless experience? We don't want them to "wait"
Can I use EC2 to generate these PDF files for me? If so, can I provide a "public" link for the user to download the file directly from Amazon, instead of using our resources.
Thanks a lot!
EDIT ---- More details
User inputs some information through a regular form
System generates a PDF per request, using the provided information for the document
The PDF generated by the system is kept under Amazon S3
We provide an API which allows you to "print" multiple pdfs at once, to do so, we merge the selected PDF files from S3, into one file for ease-of-print
When you multi-print documents, a new window is opened which is your merged file directly, user needs to wait around 20ish seconds for it to display.
We can to leverage the resources used to generate the PDFs onto Amazon infrastructure, but we need to keep the same flow, meaning, we should provide an instant public link to the User to download & print the files.
Based on your understanding, i think you just need your link to be created immediately right after user request for file. However, you want in parallel to create PDF merge. I have idea to do that based on my understanding, and may be it could work in your situations.
First start with some logic to create unique pdf file name, with random string representing name of file. And at same time in background generate PDF, but the name of PDF should be same as you created in first step. This will give user instant name of file with link to download. However, your file creation is still in progress.
Make sure, you use threads if using PHP or event loop if using Node.JS to run both steps at same time. This will avoid 404 error for file not found.
Transferring files from EC2 to S3 would also add latency delay. But if you want to preserve files for later or multiple use in future then S3 is good idea as it could simply serve PDF files for faster delivery. As we know S3 is used for static media storage. Otherwise simply compute everything and generate files on EC2
I'm contemplating on how to store images in my new site.
Should I save the images directly to the database
OR
should I upload them to my server, while storing the path in my database?
Also, should it be the second choice, how does one retrieve the path of a file he uploaded previously?
You should definitely go with the second option as you can take advantage of the user's browser caching these images after the initial request. It also means your database wont be hit constantly for large files which is always a bad thing.
In CodeIgniter there are various parameters you can use to get the name / full file path to store in the database.
See http://ellislab.com/codeigniter%20/user-guide/libraries/file_uploading.html
Also take a look at this great SO question Storing Images in DB - Yea or Nay?
I tried CI's own libraries , its good but not best, Image moo solved all my problems, uploading, resize, crop etc..
http://www.matmoo.com/digital-dribble/codeigniter/image_moo/
Currently I am working on a MVC web application that should have a creation dialog for some kind of entry.
It should be possible to enter some text information as well as upload documents, images, videos, etc.
The following problem arises:
Are there any general best practices for uploading the whole bunch of information at ONCE? The object should not be created in the database until the user really decides to submit the information.
I thought about some solutions
Storing the uploads with the FileAPI in the browser
Immediate AJAX-Upload when selecting files. But where to "cache" the file on the server? The entry is not in the Database since I am creating the object.
Creation of a database entry when opening the form? But this would result in junk in the database
Any suggestions are much appreciated
Thank you
Kind regards
I think this approach will be good to follow.
Have Session cache which will keep the files-bytes in server memory.
When user comes on the upload page, clear it.
When user uploads the files, save file-bytes on server session cache.
When user really wants to upload files - say - submit files - kind of button, get the files from session cache and upload in the database.
Clears the session cache when its saved in database.
In case of large files, like videos, you would like to create a temporary folder(per user), save files inside that folder - instead of session cache, and clear/delete the folder after the files are saved in database.
I have a working Cocoa app that creates a database file and stores it locally. What I would like to do is store that file on a remove server so that different users of my app at different locations would be sharing the same file. My thought was to store the file on a website or ftp server, such as www.mydomain.com/mydatafile.
Forgetting about issues like two users attempting to access the file simultaneously for the moment, can someone point me to an example of how to property construct the URL to be used?
I'm thinking that it should be a fairly simple process with two parts, the first of which is a cocoa NSURL question, and the second which is really more of a w3 issue:
Create the URL to the file itself, and
Append the username and password require to login to the FTP site.
Any nudges in the right direction would be appreciated!
* edit *
I should mention that the file I would like to be shared by multiple users, is basically several custom objects stored as a file with NSKeyedArchiver...
I suggest you to intgrate your app with some cloud based document storage,sharing,editing service like Google docs/drive.
Until and unless you are going to provide very specific file formats native to your app and are doing something out of ordinary.
Using something like this would save you time, and user wont have to create yet another login-id.
I need a way for cache images and html files in PhoneGap from my site. I'm planning that users will see site without internet connection like it will be with it. But I see information only about sql data storing, but how can I store images (and use later).
To cache images check out this library -of which I'm the creator-:
imgcache.js
. It's designed for the very purpose of caching images using the local filesystem. If you check out the examples you will see that it can also detect when an image fails to be loaded (because you're offline or you have a very bad connection) and then replaces it automatically with the cached image. The user of the webapp doesn't even notice it's offline.
As for html pages.. if they're html static files, they could be stored locally in the web app (file:// in phonegap).
If they're dynamically generated pages, check the localStorage API if you have a small amount of data, otherwise the filesystem API.
For my web app I retrieve only json data from my server (and process/render it using Backbone+Underscore). The json payload is stored into the localStorage. If the application gets offline, it will fetch json data from the localStorage instead of the server (home-baked fork of Backbone.dualStorage)
You then get the full offline experience: pages+images.
Caching like you might need for simple offline operation is not exactly that easy.
Your first option is the cache manifest. It has some limitations (like the size of the cache) but might work for you since it was designed to do what you want.
Another options is that you can store content on the disk of the device using the file system APIs. This has some drawbacks like security and the fact that you have to load the file from a path / url that is different than you might normally load it from on the web. Check out the hydra plugin for an example of this.
One final option might be to store stuff in localStorage (which has the benefit of being private on all platforms) and then pull it out of there when needed ... that means base64'ing all your images tho so that is a pretty big departure from just standard caching.
Caching is very much possible on Android OS. but on Apple as stated above there are limitations with the size of the images and cache size etc.
If you are willing to integrate and allow the caching on iOS you can use "cache manifest" to do so. but keep the draw backs and limitations in mind.
Also
if you want to save the file to Documents folder under my App, Apple will reject your App. The reason is the system backup all data under Documents folder to iCould after iOS6, so Apple does not allow big data like images or JSON file which could sync from your server again to keep in this folder.
So there is another work around which is good So one can use LocalFileSystem.TEMPORARY instead. It does not save the data to Library/Cache, but it save data to temp folder of App, which does not been auto backup to iCloud and not auto deleted either.
Regards
Rajeev