I am developing a tab pane app in Excel which needs to read the current document. In Word, the Office JavaScript API has the method Office.context.document.getFileAsync(), but this is not available in Excel.
I can get the URL of the document with Office.context.document.getFileProperties(), and then I thought I could read the file with this.
I tried using the HTML5 FileReader() object, but this only works for files selected from the file input control. I tried manipulating a hidden file input control so it automatically uses the current document, but JavaScript understandably prevents you from doing this for security reasons. I could ask the user to browse to the document they are currently using but that would be a poor user experience.
So I tried using ActiveXObject('Scripting.FileSystemObject') but ActiveX is not allowed in tab pane apps at all, whatever the current security setting are in IE.
What other options do I have?
According to the API road map, Office.context.document.getFileAsync() is not available in Excel at this moment.
I don't think it's feasible by using getFilePropertiesAsync(). It only returns the URL. Usually browser forbids developer touching any content in the file system. Therefore, it's hard to access the local file system in JavaScript code.
Besides, the file may not be in local file system. For example, it could be hosted in Onedrive or SharePoint. getFilePropertiesAsync() should return its real URL in Onedrive/SharePoint, instead of local file system.
I guess Microsoft will support getFileAsync() in the future.
Related
I'm developing a HTML5/.net POC in which I have a local HTML5 webapp shown inside a .net (C#) WebBrowser control.
The page is developed in asp.net MVC, downloaded as a single .htm file (using Chrome's SingleFile extension) and saved in a DB (or stored in a filesystem, doesn't matter), loaded and shown inside a .net webbrowser control.
[almost] Everything works: the page is rendered correctly, i can invoke js functions from C#, etc.
But now I have to show some pdf inline inside the page. The pdf is not served from a remote server (there's no server at all), but will be loaded from the filesystem (e.g. a temp file). The idea I have is to make a js function like showPdf(path, pageNum) in the html5 app and call it from .net.
The problem is that it looks there's no way (at least I couldn't find it) to load local pdf, both using Mozilla's pdf.js or html tags, I get "Not allowed to load local resource" in Chrome console/"Access denied" alert in IE.
Is there some kind of component I can try/option I can set to allow the browser to load local pdfs?
The WebBrowser component uses IE to render the page, so maybe some kind of IE option/key registry I can change (the machines that will eventually use this webapp are known, we can configure them as we want)?.
You could try a traditional anchor element (<a href="file:...">) and then enable the File Protocol Navigation feature control for your app. (And, though it may seem obvious, it's probably worth confirming that IE feature controls do not to enable functionality in other browsers.)
I don't know that this would work, but it seems like a possible solution given the question.
Note that accessing file objects may permission to access local file system objects may be disabled by other policies or security measures. More info/research may be needed.
Hope this helps...
-- Lance
I forgot to write here how I solved it:
well, it was a webapp shown inside a WinForm WebBrowser control, so I used this article to call a C# method from JS. The C# method used the default OS pdf reader to show the pdf inside the form.
I have developed a script for myself to read and process local text and csv files on my computer using recent Chrome or Firefox browsers with the filereader api. The script will work on the computer, even though it is not connected to the internet or a local webserver.
The reasoning behind this is to have a standalone text file interrogator, which will work on almost any computer, requiring only a browser to execute and display reasonably formatted output. similar to an awk type application.
I use the filereader api and it works well.
I do not properly understand the workings of the browser, so my question may be very stupid.
Is it possible that my script can somehow pass the filename to the script filereader api, without having to choose a file from input type=file field.
eg I have a file called addresses.csv and it resides in the same directory as my html/js file with the filereader api code.
I want to simulate the choosing of a file, without accessing my local directory and without using a webserver, but a dropdown box of predefined filenames would be even better.
No, for security reasons its not possible, because otherwise people could open arbitrary files on the computers of their visitors which is definitely not intended.
This specification also assumes that the primary user interaction is with the element of HTML forms [HTML], and that all files that are being read by FileReader objects have first been selected by the user.
See http://www.w3.org/TR/FileAPI/#security-discussion
No you cannot. Javascript cannot read your local filesystem without the use of a file input or drag and drop files (html5) as it would be vulnerable to malicious use.
There was a start of a filesystem api which Chrome has included. But you cannot read/write to just any place you want on the filesystem, you can only do so to a sandboxed area on the filesystem. Wither or not they will continue to have this in future versions of Chrome though I do not know.
It also appears the W3C itself has discontinued the file system api
Is it possible to create something like Google Chrome's Workspaces, but with HTML5, Javascript or some other web based language?
I'm currently working on a web based ide, and I'm interested in implementing something similar to how Google Chrome handles local file editing. Basically asking the user for permission for accessing files in a particular directory that they select.
I've managed to open files that the user selects and show its content, but after editing there's no way to save it back to the same file, short of downloading it every time they save.
Is this possible with current technologies? or would I have to use something like Java?
The Achilles heel of your plan comes from a misunderstanding of the File System API. The most common misunderstanding about the File System API is that it might somehow give scripts direct read/write access to the client's local file system (e.g., C://whatever). As has been widely documented, including in the tag Wiki for HTML5-FileSystem here on Stackoverflow, "the File System API cannot directly access the local file system." The API provide access to a "virtual" file system, not the user's local file system. You cannot, therefore, use the File System API to "ask the user for permission for accessing files in a particular directory that they select," as you're seeking to do for your browser-based IDE project.
I am writing a very simple Elearning application for my virtual class. I wander if there may be a way using Javascript that works on the background to read the content of a file located on the user's computer and send its content to my server. Any one knows an open source code of Javascript doing this ?
I think that this can be done using XMLHttpRequest, i.e. AJAX, but I could not graps my way through. Any help
You can't gain access to a local file in browser because you are in sandbox, but there are some File API for Html 5 that you can programmatically select them and access their data just have a look at the following link
File API
Web applications should have the ability to manipulate as wide as possible a range of user input, including files that a user may wish to upload to a remote server or manipulate inside a rich web application. This specification defines the basic representations for files, lists of files, errors raised by access to files, and programmatic ways to read files. Additionally, this specification also defines an interface that represents "raw data" which can be asynchronously processed on the main thread of conforming user agents. The interfaces and API defined in this specification can be used with other interfaces and APIs exposed to the web platform.
Unfortunately there is no way to give JavaScript any access to the user's local files.
There is a very serious security issue with that.
There is however API for that on IE browsers (Which give nice big warning when you attempt to access the files)
I recommend to ask from the user to upload his own file (using <input type="file" />) and upload it to the server.
HTML5 specifications specify an API to access the local filesystem. It is supported in the latest versions of Chrome. See here for details http://net.tutsplus.com/tutorials/html-css-techniques/toying-with-the-html5-filesystem-api/.
If the environment is controlled (i.e in a classroom or intranet) you can build your application using this API.
how can you retrieve the data from a document with javascript that isn't the page you are on if you have the url of the new document.
what i am trying to do is create a page that has a text field for providing a local file name and a button that retrieves the words from the document provided.
thanks.
HTML5 has a File API that lets you read local files. It's supported in at least Firefox (3.6 and later, I think) and Chrome. I don't know if any other browsers support it yet or not. If you need to support other browsers, you'll have to fall back to something like Flash, but I don't have any experience with that.
Unfortunately, by default Chrome doesn't allow local files to access other local files (each file is considered to be from its own domain). You can explicitly allow it by adding the --allow-file-access-from-files flag when you launch Chrome.
Here's a good introduction to the File API with several examples: http://www.html5rocks.com/en/tutorials/file/dndfiles/.
Browser security does not allow direct access to the local filesystem. If it could, web pages would be able to steal any file of your machine.
HTML5 local storage does allow local access, but on a different principle.