I display a file open box so the user can select a file on their computer:
<input type="file" id="upload_input"/>
but when I get the file the user chose in Javascript (see code below), which I believe is 'safe' since javascript executes on the client side -- all I get is the file, not the full path -- despite the fact that the full path and filename appear in the field next to the 'Browse' button that input type=file always gives you.
In other words the user selects a file located on his machine for example at c:/aFolder/thefile.rtf.
Then after choosing that file the full path appears in the field next to the 'Browse' button: c:/aFolder/thefile.rtf
Yet when I programmatically retrieve the value of that field, the entire path is stripped off and all I have is the filename:
filename = document.getElementById('upload_input').value;
alert("The selected file name is " + filename);
Why does the input type=file control even bother to show the user the full path if you can't get it programmatically?
It's all happening on the client side after all, it's not like this is a full path on the server.
One other question: I use the filename above and construct a fully qualified path to that file, only for the sake of getting my JWplayer code working. The full path I create for development here is temporary.
In otherwords, when I get the filename above, I do this:
vidFname = ("c:/xampp/htdocs/theWebsite/aFolder/" + filename);
alert("The full path is: " + vidFname);
and then I try to play the video in Jwplayer:
playlist = { file: vidFname };
theJwPlayer().load(playlist);
theJwPlayer().play(true);
but Jwplayer gives me "Permission denied or file not found."
Here is what I had to change to get this to work:
vidFname = ("http://localhost/theWebsite/aFolder/" + filename);
alert("The full path is: " + vidFname);
playlist = { file: vidFname };
theJwPlayer().load(playlist);
theJwPlayer().play(true);
By changing the path to my localhost the above code works -- the video loads and succesffully plays.
NOTE: I don't think this is a 'folder permissions' issue because I can play the exact same file in the same location with a different .FLV player (standalone) app on my computer. So it's not folder permissions in my c:/xampp that's making Jwplayer say 'permission denied or file not found.'
Why won't Jwplayer (or is it Javascript..?) not letting me use a fully-qualified pathname to the file when I call
jwplayer().load() ?
After all, I'm using 'theJwPlayer' in Javascript,' which is running on the client computer, and the file is on the client computer too, so it's not a security issue.
Or is there something I'm missing here? NOTE: I fully apologize if this question is ignorant but at my current level of web programming, which you may have passed LONG ago, this is puzzling, ESPECIALLY the jwplayer().load() not working with a fully qualified path name.
Browsers will not reveal actual file paths to JavaScript code. It's a security thing. You won't be able to get at local files without using the (new, only available in new browsers) HTML5 file handling APIs, and even those won't give you complete file pathnames.
Similarly, when the file input is submitted with a form, the server won't get the full path either.
I think it's not very likely that this media player tool you're working with is designed to work with local files (that is, files on the local file system where the browser is running).
Related
I am not an HTML/JavaScript developer. I am having to modify some legacy code written by someone who has left.
We have a Python app which acts as a local server with an HTML/JavaScript front end that can be viewed in a browser.
The Python creates a temporary cache file. I would like to give the user the option to save a copy of this temp file to a location of their choice or at least download it to the downloads directory (Windows & Linux)
I've tried adapting some of the ideas from here: https://www.delftstack.com/howto/javascript/javascript-download/
E.g.
const saveAnalysisBtn = document.getElementById("saveAnalysisBtn");
saveAnalysisBtn.addEventListener('click', saveAnalysis);
function saveAnalysis(evt) {
function download(filename) {
var element = document.createElement('a');
// hardcode temp file name just for POC
element.setAttribute('href','file://C:\\tmp\\my_temp_cache.db');
element.setAttribute('download', filename);
document.body.appendChild(element);
element.click();
//document.body.removeChild(element);
}
var filename = "output.txt";
console.log(`Call Download`);
download(filename);
}
In Firefox this gives a security error:
Security Error: Content at
http://127.0.0.1:5000/replay/fapi_15_6_udi.bin may not load or link to
file:///C:/tmp/my_temp_cache.db
Which isn't terribly surprising. (Edge & Chrome give similar errors)
Is there a way to do this? Can be in HTML or JavaScript or Python (though I would like user to see evidence of download taking place in the browser).
Maybe I'm not understanding, but it looks like we're talking about just copying a file from one local location to a user specified location. The file you want to copy is on the machine the user is using? Couldn't you just provide the location in the web page and then just go there in a file explorer, finder, or command line tool to copy it however you want? It would solve the security issue.
But if you're required to create a link, you could create a download process that zips the file up to make a file like "my_temp_cache_db.zip" (or whatever compression tool/extension works best for you), and then provide the link for that. Zip files work through browsers better than some other types of files, and the user just has to unzip it wherever it ended up.
If that's not ideal, you could create a download process that makes a copy of the file and just changes the extension to something like "txt". The user downloads that file and then has to rename it to have the right extension.
When uploading a file, before pressing the upload button, the folder/file path is visible in the website's upload form.
.
Is the website able to record that data?
Normally a website could possibly record any data typed into a web form - is this any different?
It doesn't appear to work. I created the following fiddle https://jsfiddle.net/5samkn5a/
Basically I took an input
<input type="file" id="input"/>
And set a listener to its value
$(function(){
$("#input").change(function(){
console.log($(this).val());
})
})
Then I tried it in the latest chrome/firefox/edge
They all give a fake path as value. The only thing that's real is the file name. May be that some browsers actually expose the full path, but not the ones I tested.
It makes sense that the browser is shielding this information since at least on windows when you are choosing a document it will most likely reside in your current user directory. So the path will contain your local user name and that's not something you want to give to a random website, right?
I am using angular and ASP.NET Web API to allow users to download files that are generated on the server.
HTML Markup for download link:
<img src="/content/images/table_excel.png">
<a ng-click="exportToExcel(report.Id)">Excel Model</a>
<a id="report_{{report.Id}}" target="_self"></a>
The last anchor tag is there to serve as a place holder for an automatic click event. The visible anchor calls the exportToExcel method to initiate the call to the server and begin creating the file.
$scope.exportToExcel = function(reportId) {
reportService.excelExport(reportId, function (result) {
var url = "/files/report_" + reportId + "/" + result.data.Model.fileName;
var dLink = document.getElementById("report_" + reportId);
dLink.href = url;
dLink.setAttribute('download', result.data.Model.fileName);
dLink.click();
});
}
The Web API code creates an Excel file. The file, on the server is about 279k, but when it is downloaded on the client it is only 7k. My first thought was that the automatic click might be happening before the file is completely written. So, I added a 10 second $timeout around the click event as a test. It failed with the same result.
This seems to only be happening on our remote QA server. On my local development server I always get the entire file back. I am at a loss as to why this might be happening. We have similar functionality where files are constructed from a database blob and saved to the local disk for download. The same method is employed for the client side download and that seems to work fine. I am wondering if anyone else has run into a similar issue.
Update
After the comment by SilentTremmor we think it actually may be IIS or some sort of Sever issue. Originally, we didn't think it could be, but after some digging it may be. It seems the instance of the client code is only allowing 7k of data to be downloaded. It doesn't matter what we try to download the result is always the same.
It turns out the API application was writing the file to a different instance of our application. The client code had no idea and was trying to download a file that did not exist. So, when the download link was creating the file it was empty, thus the small file size.
I have a file structure on a web page, and look for a solution for the following scenario:
The chosen file should be downloaded in browser cache and opened (if it's an excel document, open with excel, etc.).
Now when the user changes the file, it should be detected and the file should be uploaded again.
Is this even possible with JavaScript?
If yes, where do I store the file (temporary internet folder?) and how do I detect the changes?
The only way for this to work you would need to have the user select the downloaded file, and then check for modification.
HTML
<label for="excelFile">Select the excel file: </label><input type="file" id="excelFile" />
JS
//Change event to detect when the user has selected a file
document.querySelector("#excelFile").addEventListener("change",function(e){
//get the selected file
var file = this.files[0];
//get the last modified date
var lastModified = file.lastModified;
//check lastModified against stored lastModified
//this assumes you store the last mod in localStorage
if(localStorage['excelLastMod'] < lastModified){
//It has modified update last mod
localStorage['excelLastMod'] = lastModified;
//do upload
}
});
If you know your user is using Chrome you can use Chrome's FileSystem api
The way you describe it: No, that is not possible in JavaScript.
It sounds like you want an FTP client.
When the user changes the file, it should be detected and the file should be uploaded again.
That is not possible due to JS having almost no access to the file system.
The only way you can access a file at all is by requesting the user to select one, see:
How to open a local disk file with Javascript?
So the most you could do would be:
File is downloaded.
Based on browser & settings, file may be opened automatically, or not.
User is presented with a file selection dialog that they can use when they are done editing.
Compare selected file to file on server and upload if changed.
After downloading a file, you have no control over it.
For applications that have a protocol registered (such a steam://, for example), you might be able to request the URL being opened in a program, but that would require an if per file type/program.
Detecting file changes is not at all possible (because you have no access to the file), and uploading again requires the user to select the file manually, using a file dialog.
Thanks for your help and ideas. I saw a software (https://www.group-office.com/) which includes this function so there has to be way to do it.
New Idea, using chrome filesystem api (#Siguza already said it):
Create file from servers database on users local filesystem with filesystem api
open file locally (should work with filesystem:http://www.example.com/persistent/info.txt, or?)
poll last changes of file every x seconds
if change detected, upload file back to servers database
I saw some problems with excel locking the files Check if file has changed using HTML5 File API
but except of that this should work, shouldn't it?
I'm working on an HTML/javascript app intended to be run locally.
When dealing with img tags, it is possible to set the src attribute to a file name with a relative path and thereby quickly and easily load an image from the app's directory. I would like to use a similar method to retrieve a text file from the app's directory.
I have used TideSDK, but it is less lightweight. And I am aware of HTTP requests, but if I remember correctly only Firefox has taken kindly to my use of this for local file access (although accessing local images with src does not appear to be an issue). I am also aware of the FileReader object; however, my interface requires that I load a file based on the file name and not based on a file-browser selection as with <input type="file">.
Is there some way of accomplishing this type of file access, or am I stuck with the methods mentioned above?
The browser will not permit you to access files like that but you can make javascript files instead of text files like this:
text1.js:
document.write('This is the text I want to show in here.'); //this is the content of the javascript file
Now call it anywhere you like:
<script type="text/javascript" src="text1.js"></script>
There are too many security issues (restrictions) within browsers making many local web-apps impossible to implement so my solution to a similar problem was to move out of browsers and into node-webkit which combines Chromium + Node.js + your scripts, into an executable with full disk I/O.
http://nwjs.io/
[edit] I'm sorry I thought you wanted to do this with TideSDK, I'll let my answer in case you want to give another try to TideSDK [/edit]
I'm not sure if it's what you're looking for but I will try to explain my case.
I've an application which allow the user to save the state of his progress. To do this, I allow him to select a folder, enter a filename and write this file. When the user open the app, he can open the saved file, and get back his progress. So I assume this enhancement is similar of what you are looking for.
In my case, I use the native File Select to allow the user to select a specific save (I'm using CoffeeScript) :
Ti.UI.currentWindow.openFileChooserDialog(_fileSelected, {
title: 'Select a file'
path: Ti.Filesystem.getDocumentsDirectory().nativePath()
multiple: false
})
(related doc http://tidesdk.multipart.net/docs/user-dev/generated/#!/api/Ti.UI.UserWindow-method-openFileChooserDialog)
When this step is done I will open the selected file :
if !filePath?
fileToLoad = Ti.Filesystem.getFile(scope.fileSelected.nativePath())
else
fileToLoad = Ti.Filesystem.getFile(filePath)
data = Ti.JSON.parse(fileToLoad.read())
(related doc http://tidesdk.multipart.net/docs/user-dev/generated/#!/api/Ti.Filesystem)
Please note that those snippets are copy/paste from my project and they will not work without the rest of my code but I think it's enough to illustrate you how I manage to open a file, and read his content.
In this case I'm using Ti.JSON.parse because there is only javascript object in these files but in your case you can just get the content. The openFileChooserDialog isn't mandatory, if you already know the file name, or if you get it from another way you can use Ti.Filesystem in your own way.