I need to save the file that is on my hard drive.
File address: /home/mk/proj1/1.txt
Program address: /home/mk/proj2/
I try to save:
new dom.AnchorElement(href: '/home/mk/proj1/1.txt')
..setAttribute("download", '1.txt')
..click();
Displays information about saving, but writes: Failed! No file.
How to save a file?
There is not really a way to save a file in the browser (except perhaps limited support for temporary files)
You can search for JavaScript solutions. They will be quite similar for Dart in the browser.
For example JavaScript: Create and save file
If you want to store a file on the client machine, you can provide a download link.
See also How to force a Download File prompt instead of displaying it in-browser with HTML?
To provide a download link for data that is available in the browser clients code instead of a server file, you can use a data url.
See also https://stackoverflow.com/a/29691487/217408
Related
I'm trying to retrieve a picture from my file system after a good storage,(instead of putting it in the database I copy it to the disc and i put the path to the db)
I had store the picture to c:\images\ folder and supposing that the name the complete path is c:\images\mypic.jpg
when I try to retrieve it a set the img src attribute to <img src="c:\images\mypic.jps"> by using some java code
in the browser console I found this error Not allowed to load local resource: file:///C://images//mypic.jpg
Question: how to fix these path problem ? where Should I store the pictures ? and from where should I retrieve them ?
sending tag <img src="c:\images\mypic.jpg"> would cause user browser to access image from his filesystem.
if you have to store images in folder located in c:\images i would suggest to create an servlet like images.jsp, that as a parameter takes name of a file, then sets servlet response content to an image/jpg and then loads bytes of image from server location and put it to a response.
But what you use to create your application? is it pure servlet? Spring? JSF?
Here you can find some info about, how to do it.
In Chrome, you are supposed to be able to allow this capability with a runtime flag --allow-file-access-from-files
However, it looks like there is a problem with current versions of Chrome (37, 38) where this doesn't work unless you also pass the runtime flag --disable-web-security
That's an unacceptable solution, except perhaps as a short-term workaround, but it has been identified as an issue:
https://code.google.com/p/chromium/issues/detail?id=379206
You have Two alternatives :
First one is to create a ServletImageLoader that would take as a parameter an identifier of your image (the path of the image or a hash) that you will use inside the Servlet to handle your image, and it will print to the response stream the loaded image from the server.
Second one is to create a folder inside your application's ROOT folder and just save the relative path to your images.
Many browsers have changed their security policies to no longer allow reading data directly from file shares or even local resources. You need to either place the files somewhere that your tomcat instance can serve them up and put a "regular" http url in the html you generate. This can be accomplished by either providing a servlet which reads and provides the file putting the file into a directory where tomcat will serve it up as "static" content.
The concept of http location and disk location is different. What you need to do is:
for uploaded file summer.jpg
move that under a known (to the application) location to disk, e.g c:\images\summer.jpg
insert into db record representing the image with text summer.jpg
to display it use plain <img src="images/summer.jpg" />
you need something (e.g apache) that will serve c:\images\ under your application's /images. If you cannot do this then in step #2 you need to save somewhere under your web root, e.g c:\my-applications\demo-app\build\images
This error means you can not directly load data from file system because there are security issues behind this. The only solution that I know is create a web service to serve load files.
Here is a simple expressjs solution if you just want to run this app locally and security is not a concern:
On your server.js or app.js file, add the following:
app.use('/local-files', express.static('/'));
That will serve your ENTIRE root directory under /local-files. Needless to say this is a really bad idea if you're planning to deploy this app anywhere other than your local machine.
Now, you can simply do:
<img src="/local-files/images/mypic.jps"/>
note: I'm running macOS. If you're using Windows you may have to search and remove 'C:\' from the path string
Do not use ABSOLUTE PATH to refer to the name of the image for example: C:/xamp/www/Archivos/images/templatemo_image_02_opt_20160401-1244.jpg. You must use the reference to its location within webserver. For example using ../../Archivos/images/templatemo_image_02_opt_20160401-1244.jpg depending on where your process is running.
I want to invoke the file save as prompt while allowing the user to download a file in ExtJS from a URL.
Basically the idea is to allow the user to change the file name and select his desired location before saving the file on their machine.
Is there any way I could do this?
I do not want to use:
A server side code to send the headers.
Nor do I want to use the Flash-based Downloadify library to do this.
Also, <a> tag's "download" attribute does download the file, but it does not prompt the dialog box if the browser settings are not set right.
Is there any way apart from the above where we could handle the file download in our application?
No, it cannot be done with javascript alone due to the security restrictions of the contemporary browsers. You can read files but I have no knowledge of a way to save files directly from the javascript alone.
If your "I do not want tos" are not that strict, here you can find an example of file downloading. The essence is to send "Content-Disposition: attachment" header.
If you work with Google Docs your first file format is .gdoc / .gsheet / .gwhatever
What I want to understand is, how this file format works. When you open a .gdoc you basically open the browser and go to a specific URL. So is a .gdoc just a .html-file with a changed file extension?
I would like to build something similiar: A rich-text-editor which saves the content in my own file format, that you can download and if you open the file, the browser opens and links to a specific URL.
BTW: I opened a .gsheet in a text editor and found this source code:
{"url": "https://docs.google.com/a/test.com/spreadsheet/ccc?key=01234567898765432123456789&usp=docslist_api", "resource_id": "spreadsheet:0A12345B678HJK9TZPL9078767"}
*Changed the URL a bit ;)
.gdoc and .gsheet files don't contain html, but JSON. These extensions are usually linked to the Google Drive application, which just reads the file and opens the URL with your standard browser.
If you're going to implement something like this yourself, you can go the same route: let the user install a program that handles your own files and start e.g. the browser.
Another way is to just use standard shortcuts; or use can use html files (maybe with another file extension if you link this extension to the standard browser) which just redirects to your target url.
in response to your comments:
to create a simple shortcut, you'll have to generate a file with the following content:
[InternetShortcut]
URL=your.url.com
and save it as YourFileName.YourExtension.url. Note that the "real" file-extension is .url. When saved to disk, windows explorer will usually hide the .url part (regardless of the Hide known file types setting). When the user starts this file, it will just open your.url.com. Chrome provides an API to create and save files client-side, but I don't know about other browsers. Probably you'll have to use a third-party library for creating the files (if you want to do this client-side).
Note this is a Windows-only solution. I don't know how you would handle this on Mac OS.
I want to export the data in a celltable to a CSV file. I understand this must be done in the server side. I'm a bit lost on how to create a file, write the lines and then make the client download it.
One it's served, it could be downloaded automatically or by a "Download" button, is the same.
If you just want to generate file and serve it directly you can create a servlet and hit the servlet url in a Window, You may want to take the same datasource and use it at the server side to convert it into a csv. Please follow along the steps as described in (Download a generated pdf from client) and for downloading that from GWT Window follow (How to download a file via a button click i GWT?),
I am writing a program in C that acts like a proxy server in a Linux system: Client asks it for a web page,
it sends an HTTP GET Request to a distant server, and it gets the servers response (web page), which is saved in an .html file.
Here goes my problem: Most web sites got some references to images, so when i try to view the .html file proxy created, the images don't appear.
I have searched a lot, but found nothing..Is there a way to write some code to GET images too?
Thank you in advance
You're going to have to write code that parses the HTML file you get back and looks for image references (img tags), then queries the server for those image files. This is what web browsers are doing under the hood.
You have an additional problem though which is that the image references in the HTML file are to the original server. I'm assuming that since they don't load for you the server that returned the original HTML isn't available. In that case after you get each image file you will need to give it a name on the local filesystem and then alter the reference in the HTML (programmatically) to point to your new local image name.
So for example:
<img src='http://example.com/image1.png'>
would become
<img src='localImage1.png'>
If you're querying arbitrary websites then you'll also find that there are various other files you'll need to do the same with like CSS files and JavaScript files. In general its hard to mirror arbitrary web pages accurately - browsers have complex object models they use to interpret web pages because they have to deal with things like CSS and Javascript and you may need to be able to 'run' all that dynamic code to even be sure what files to download from the server (e.g. JavaScript including other JavaScript etc).