In my app I upload a file to the server using HTML5 File API, however I am encountering a situation where a file is not accessible because it is being used by another process. This actually creates two different error conditions in firefox and in chrome. Is there a way to detect if a file is inaccessible using html5?
Have you looked the sample in this link which shows how you can read a file and in case of error you can write proper error handler:
http://www.azoft.com/spotlight/2011/02/02/filesystem-apifile-api.html
About your second questions "if there's an API call to just check if it is readable without actually having to read it locally", I verified that there is no such API to just get the file handle state and verify it. I think it could be because (but i may be wrong):
the web application runs on any box with limited privilege and getting file handle could require SYSTEM level access
The file handle access could be different for different OS (Linux or Windows)
Related
I've read up about this error but the proposed solutions don't seem to work for .doc/.docx files.
I am building a web app which involves displaying pdf/doc files. The files are stored in a google storage bucket, and I am using Firebase's getDownloadURL() method to get a link which I can use as the source in an <iframe>. This works fine for PDF files directly. However, given that this direct display is not possible for doc/docx files, I tried displaying them through Google Docs Viewer by taking the generated URL and appending as follows:
https://docs.google.com/gview?url=https://firebasestorage.googleapis.com/v0/b/project-name.appspot.com/o/filename?alt=media&token=a-b-c-1-2-3
This yields a Refused to display <URL> in a frame because it set X-Frame-Options to same origin error. I have also tried adding an &embedded=true to the URL as has been suggested in other similar queries, but that yields another error: Unchecked runtime.lastError: Could not establish connection. Receiving end does not exist.
I thought this could be an issue with parsing the URL due to the "&", so I changed it to "%26", but the "sameorigin" error persists.
I'm not sure how to tackle this, and any guidance on how to resolve this issue (or alternative ways of solving the problem) would be greatly appreciated.
Google docs creates its own storage objects, and will only serve those objects. It won't display other objects that happen to be in doc/docx format from other repositories.
It sounds like you need a way to render objects you uploaded (using Firebase) to GCS. I don't have experience doing that specific thing but I suggest you try to find some software that does it. For example from a quick web search I found Render docx file in a browser.
I'm getting an error when I try to create a directory (i.e. snapshots) in my wp8 app but I don't understand why it works fine when in my emulator and when I transfer my app directly from my laptop onto my phone but when it's coming from the wp8 store, it generates the following error:
System.UnauthorizedAccessException: Access to the path 'Snapshots\' is denied.
I don't know if this is ok to do but everywhere I deal with files, I don't bother specifying a path but just a folder as I assume that it will go into the "app path\". Is this not the case?
2 Questions arising from the problem:
Why does it work with local app and not app downloaded from the store? Are access rights different?
If I'm not allowed to create files directly into the app's folder (no path provided, just a filename i.e. data.xml) or sub-folder (sub-folder only + filename provided i.e. Snapshots\test.jpg), where should I store my data (xml, jpg, etc...)
Thanks.
I found out the hard way that you should not try to write data directly in the root folder of a wp8 app as it is an "install folder". I found this interesting article/pdf from Microsoft Files and Storage in Windows Phone 8. Check out page 7, where it clearly explains the difference between installation and local folder.
The question originally originate trying to figure out why my live tile would not update and there were numerous reasons, so while unrelated to this question, I'll include them anyway as it may help someone in the future.
Folder creation problem: See above. Still can't explain why it works when app is transferred from pc to phone but when coming from the app store, it doesn't. Point is that I was going about it the wrong way and you should not be storing files in the root folder, even in a sub-folder as it can't be created in this location. You should use isolated storage or data storage.
Files still failed to update the live tiles when storing them in StorageFolder (LocalFolder). I then found these 2 articles which clearly state that images used by the Live Tiles should be stored in Isolated Storage but in a specific location i.e. Shared\ShellContent
WP8 Tip: Creating Live Tiles with Dynamic Images
Capturing image from camera and updating live tile
The minute I applied what was suggested i.e. use the specific path and use isolated storage, it sorted all my problems i.e. creating folder, creating file, etc...
Please note that while it states that you should store the file in \Shared\ShellContent, it also highlights that it can be stored in any sub-folders within that folder, so in my case, I've got \Shared\ShellContent\\Snapshots and it work as expected.
Again, if time permits I'll investigate the StorageFolder some more as I'd like to get it to work as it is the recommended method to use with WP8/WP8.1 by Microsoft and Isolated Storage appears to be recommended for WP7.
I hope it will save you some time if you encounter similar problems.
Well, using HTML5 file handlining api we can read files with the collaboration of inpty type file. What about ready files with pat like
/images/myimage.png
etc??
Any kind of help is appreciated
Yes, if it is chrome! Play with the filesytem you will be able to do that.
The simple answer is; no. When your HTML/CSS/images/JavaScript is downloaded to the client's end you are breaking loose of the server.
Simplistic Flowchart
User requests URL in Browser (for example; www.mydomain.com/index.html)
Server reads and fetches the required file (www.mydomain.com/index.html)
index.html and it's linked resources will be downloaded to the user's browser
The user's Browser will render the HTML page
The user's Browser will only fetch the files that came with the request (images/someimages.png and stuff like scripts/jquery.js)
Explanation
The problem you are facing here is that when HTML is being rendered locally it has no link with the server anymore, thus requesting what /images/ contains file-wise is not logically comparable as it resides on the server.
Work-around
What you can do, but this will neglect the reason of the question, is to make a server-side script in JSP/PHP/ASP/etc. This script will then traverse through the directory you want. In PHP you can do this by using opendir() (http://php.net/opendir).
With a XHR/AJAX call you could request the PHP page to return the directory listing. Easiest way to do this is by using jQuery's $.post() function in combination with JSON.
Caution!
You need to keep in mind that if you use the work-around you will store a link to be visible for everyone to see what's in your online directory you request (for example http://www.mydomain.com/my_image_dirlist.php would then return a stringified list of everything (or less based on certain rules in the server-side script) inside http://www.mydomain.com/images/.
Notes
http://www.html5rocks.com/en/tutorials/file/filesystem/ (seems to work only in Chrome, but would still not be exactly what you want)
If you don't need all files from a folder, but only those files that have been downloaded to your browser's cache in the URL request; you could try to search online for accessing browser cache (downloaded files) of the currently loaded page. Or make something like a DOM-walker and CSS reader (regex?) to see where all file-relations are.
I've got a slightly unusual scenario. A web app running on a local network can perform various operations on any file on the network it can access. At present the user copies/pastes the UNC path to the file into a text input and clicks submit.
The server retrieves the file, performs some operations and returns the results to the user.
I'd like to allow the user to browse for the file using the webpage - but I don't want to upload the file, just get the full path to it. Is this possible?
I'm aware there will be a couple of scenarios which are doomed to failure - eg browsing to a local path not a UNC share but I can cover this with some validation. There will also be scenarios when the server can access a path the user can't (this is intentional) so browsing wouldn't work here.
All users will be techies who should get the point. Of course, if there were a way to limit the browse dialog to a UNC path, that would be even better but I suspect it's impossible.
Note, we already limit support to the latest versions of the main browsers and since this is just a utility feature, limited support is acceptable.
Sorry, that can't be done. It's a security feature.
Is there a way to check file size on the client (without the use of ActievX which also errors out), before it is passed back to the server? in asp
In ASP? No, by definition. Active Server Pages can't do anything before they get a request from the client.
There is a draft File API that will allow you to perform this sort of check using client side JavaScript. The Mozilla Developer Network has a guide on getting information about selected files. Once you have a reference to the file, you can just access its .size property.
Note that since the specification is a draft, it is rather new and subject to change. This one is very new and thus has [very limited browser support](http://caniuse.com/#search=file api).
You might also be able to achieve what you want using a Java applet or Flash (the latter of which would be better supported).