How can I display a Save As dialog in an Electron

问题:

I am writing a NodeJS Electron App to be distributed on all platforms. I have a download button that I would like to pop open a Save As dialog with the file being provided from the server. Does anybody know the best way to do this?

Here are the things I have tried that work when running the node app locally but fail after I have packaged the app with electron-packager:

• Setting window.location.href to the location of the file
• Setting the src of a hidden iframe to the location of the file

When running the packaged mac app, the "did-fail-load" event is fired and prevents the Save As dialog from showing. When looking at the network requests, I can see that the file is successfully retrieved from the server. I can't seem to figure out why the "did-fail-load" event is being fired.

回答1:

Take a look at this page on the electron docs https://github.com/atom/electron/blob/master/docs/api/dialog.md

There is a section about dialog.showSaveDialog

Then you can use the URL from the save dialog with a function similar to the one below to save it to that location.

session.on('will-download', function(event, item, webContents) {
  event.preventDefault();
  require('request')(item.getUrl(), function(data) {
    require('fs').writeFileSync('/somewhere', data);
  });
});

Found on this page https://github.com/atom/electron/blob/master/docs/api/session.md

回答2:

On the HTML button:

<button onclick='myUrlSaveAs("http://www.example.com/path/to/file.jpg")'>Save As</button>

In your javascript file:

// Include in the render side
var elerem = require('electron').remote;
var dialog = elerem.dialog;
var app = elerem.app;

var http = require('http');
var fs = require('fs');
var path = require('path');


function myUrlSaveAs(remoteUrl){
    // app.getPath("desktop")       // User's Desktop folder
    // app.getPath("documents")     // User's "My Documents" folder
    // app.getPath("downloads")     // User's Downloads folder

    var toLocalPath = path.resolve(app.getPath("desktop"), path.basename(remoteUrl) 

    var userChosenPath = dialog.showSaveDialog({ defaultPath: toLocalPath });

    if(userChosenPath){
        download (remoteUrl, userChosenPath, myUrlSaveAsComplete)
    }


}

function myUrlSaveAsComplete(err){
    alert("done");
}


function download (url, dest, cb) {
    var file = fs.createWriteStream(dest);
    var request = http.get(url, function(response) {
        response.pipe(file);
        file.on('finish', function() {
            file.close(cb); // close() is async, call cb after close completes.
        });
    }).on('error', function(err) { // Handle errors
        fs.unlink(dest); // Delete the file async. (But we don't check the result)
        if (cb) cb(err.message);
    });
};