In my Visual Studio 2013 Solution, I added a folder "mAppData" with some static Content for the app.
One of the files is a Textfile ("imprint.txt").
On a phone page, I Display the content of this file. This works fine.
Is there a way to replace this file on runtime? I want to download new Content from web and replace this file with the downloaded content.
rather than downloading and replacing the "imprint.txt" you could simply download the imprint as text (from your imprint.txt - stored online) and display it:
var client = new System.Net.WebClient();
client.DownloadStringCompleted += (sender, args) => MessageBox.Show("downloaded imporint: " + args.Result);
client.DownloadStringAsync(new Uri("http://yourSite.ch/imprint.txt"));
My sample simply shows a MessageBox with the downloaded text. However, you can update a text control or similar.
If you want the content to be available even if you are temporary offline, you can store the file in the filestorage.
Consider adding multiple files for different languages in your build and load the file depending on the localization of your phone.
However - replacing a existing file for your Solution is not allowed on runtime. Consider this as a safety feature. If the Codebase of your app could change during runtime, your code would be injectable by an attacker.
You can't alter the package content at runtime, it is read-only.
The place where you can store data locally is the Isolated Storage. What you should do is create a file in the Isolated Storage at first launch that stores the original content of your file ("imprint.txt") and then you'll be able to change it any time you want.
Here is a tutorial that explains how to read and write text in the Isolated Storage: All about WP7 Isolated Storage - Read and Save Text files
Related
I am building a simple editor-type application in react-redux, and I want to mimic the operation of downloading and uploading json files for saving and loading data - entirely client side. The server side does not need the data. Local storage may be too small, and it would be nice to provide the user the data in a portable file they could upload on a new machine. Is this even possible, and if so how?
Using a blob file.
You can set the content of a new file which is temp and local, then trigger a click event to download the file.
duplicate answer here and here
File input allows user to access a local file from browser. Is it possible to load a local file given by file input, modify it and save it back to same local file? I know that HTML5 allows creating writeable filesystem, but basically it seems to be abstract directory.
For security reasons, I don't think the browser can overwrite the local file. Using the File-System API you could only copy the contents of the local file to the sandboxed File-System API directory(found under various obfuscated file names). All manipulation/saving would be done in AppData.
Perhaps displaying the modified image on the screen, right click, save-as to the given file location would also be suitable? (other than that I think you have to upload the image to a server and download it back again)
I am facing problem in HTML 5. I need to statically load data into web page from local saved files. Up to now, I have been only able to load data via < input type="file" id="fileinput" / > but I want to load data from static location, which never changes. How to do that? And is there any way how to determine, whether some local file was changed from previous version?
Thanks
no, this isn't possible if by 'local', you mean a file at /home/waypoint/somefile.txt. You can make a 'link' with the filesystem api (if you selected it in an input field, for instance), which is valid to do computations with it (to read it, write to it, display it in img,etc). But it is deleted/unvalid, as soon as the window closes. If you could just magically "read" any local file via javascript which resides on the file system, who would stop google to read out your /etc/passwd file?
if your local computer is also your server and therefor your server-side code has access to the local file /home/waypoint/somefile.txt, your app can get it via ajax. Checking if the file exists, would be done the same way.
I would like to allow my users to upload HTML content to my AppEngine web app. However if I am using the Blobstore to upload all the files (HTML files, css files, images etc.) this causes a problem as all the links to other files (pages, resources) will not work.
I see two possibilities, but both of them are not very pretty and I would like to avoid using them:
Go over all the links in the html files and change them to the relevant blob key.
Save a mapping between a file and a blob key, catch all the redirections and serve the blobs (could cause problems with same name files).
How can I solve this elegantly without having to go over and change my user's files?
Because app engine is running your content on multiple servers, you are not able to write to the filesystem. What you could do is ask them to upload a zip file containing their html, css, js, images,... The zipfile module from python is available in appengine, so you can unzip these files, and store them individually. This way, you know the directory structure of the zip. This allows you to create a mapping of relative paths to the content in the blobstore. I don't have enough experience with zipfile to write a full example here, I hope someone more experienced can edit my answer, or create a new one with an example.
Saving a mapping is the best option here. You'll need to identify a group of files in some way, since multiple users may upload a file with the same name, then associate unique pathnames with each file in that group. You can use key names to make it a simple datastore get to find the blob associated with a given path. No redirects are required - just use the standard Blobstore serving approach of setting the blobstore header to have App Engine serve the blob to the user.
Another option is to upload a zip, as Frederik suggests. There's no need to unpack and store the files individually, though - you can serve them directly out of the zip in blobstore, as this demo app does.
I have a few HTML files that I'd like to include via tags in my webapp.
Within some of the files, I have pseudo-dynamic code - specially formatted bits of text that, at runtime, I'd like to be resolved to their respective bits of data in a MySQL table.
For instance, the HTML file might include a line that says:
Welcome, [username].
I want this resolved to (via a logged-in user's data):
Welcome, user#domain.com.
This would be simple to do in a JSP file, but requirements dictate that the files will be created by people who know basic HTML, but not JSP. Simple text-tags like this should be easy enough for me to explain to them, however.
I have the code set up to do resolutions like that for strings, but can anyone think of a way to do it across files? I don't actually need to modify the file on disk - just load the content, modify it, and output it w/in the containing JSP file.
I've been playing around with trying to load the files into strings via the apache readFileToString, but I can't figure out how to load files from a specific folder within the webapp's content directory without hardcoding it in and having to worry about it breaking if I deploy to a different system in the future.
but I can't figure out how to load files from a specific folder within the webapp's content directory without hardcoding it in and having to worry about it breaking if I deploy to a different system in the future.
If those files are located in the webcontent, use ServletContext#getRealPath() to convert a relative web path to an absolute disk file system path. This works if the WAR is exploded in the appserver (most does it by default, only Weblogic doesn't do that by default, but this is configureable IIRC). Inside servlets you can obtain the ServletContext by the inherited getServletContext() method.
String relativeWebappURL = "/html/file.html";
String absoluteFilePath = getServletContext().getRealPath(relativeWebappURL);
File file = new File(absoluteFilePath);
// ...
Alternatively, you can put it in the classpath of the webapplication and make use of ClassLoader#getResource():
String relativeClasspathURL = "/html/file.html";
URL absoluteClasspathURL = Thread.currentThread().getContextClassLoader().getResource(relativeClasspathURL);
File file = new File(absoluteClasspathURL.toURI());
// ...
As to the complete picture, I question if you have ever considered an existing templating framework like Freemarker or Velocity to ease all the job?