In summary
File.writeFile() creates a PNG file of 0 bytes when trying to write a Blob made from base64 data.
In my application, I am trying to create a file that consists of base64 data stored in the db. The rendered equivalent of the data is a small anti-aliased graph curve in black on a transparent background (never more that 300 x 320 pixels) that has previously been created and stored from a canvas element. I have independently verified that the stored base64 data is indeed correct by rendering it at one of various base64 encoders/decoders available online.
Output from "Ionic Info"
--------------------------------
Your system information:
Cordova CLI: 6.3.1
Gulp version: CLI version 3.9.1
Gulp local:
Ionic Framework Version: 2.0.0-rc.2
Ionic CLI Version: 2.1.1
Ionic App Lib Version: 2.1.1
Ionic App Scripts Version: 0.0.39
OS:
Node Version: v6.7.0
--------------------------------
The development platform is Windows 10, and I've been testing directly on a Samsung Galaxy S7 and S4 so far.
I know that the base64 data has to be converted into binary data (as a Blob) first, as File does not yet support writing base64 directly in to an image file. I found various techniques with which to do this, and the code which seems to suit my needs the most (and reflects a similar way I would have done it in java is illustrated below):
Main code from constructor:
this.platform.ready().then(() => {
this.graphDataService.getDataItem(this.job.id).then((data) =>{
console.log("getpic:");
let imgWithMeta = data.split(",")
// base64 data
let imgData = imgWithMeta[1].trim();
// content type
let imgType = imgWithMeta[0].trim().split(";")[0].split(":")[1];
console.log("imgData:",imgData);
console.log("imgMeta:",imgType);
console.log("aftergetpic:");
// this.fs is correctly set to cordova.file.externalDataDirectory
let folderpath = this.fs;
let filename = "dotd_test.png";
File.resolveLocalFilesystemUrl(this.fs).then( (dirEntry) => {
console.log("resolved dir with:", dirEntry);
this.savebase64AsImageFile(dirEntry.nativeURL,filename,imgData,imgType);
});
});
});
Helper to convert base64 to Blob:
// convert base64 to Blob
b64toBlob(b64Data, contentType, sliceSize) {
//console.log("data packet:",b64Data);
//console.log("content type:",contentType);
//console.log("slice size:",sliceSize);
let byteCharacters = atob(b64Data);
let byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
let slice = byteCharacters.slice(offset, offset + sliceSize);
let byteNumbers = new Array(slice.length);
for (let i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
let byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
console.log("size of bytearray before blobbing:", byteArrays.length);
console.log("blob content type:", contentType);
let blob = new Blob(byteArrays, {type: contentType});
// alternative way WITHOUT chunking the base64 data
// let blob = new Blob([atob(b64Data)], {type: contentType});
return blob;
}
save the image with File.writeFile()
// save the image with File.writeFile()
savebase64AsImageFile(folderpath,filename,content,contentType){
// Convert the base64 string in a Blob
let data:Blob = this.b64toBlob(content,contentType,512);
console.log("file location attempt is:",folderpath + filename);
File.writeFile(
folderpath,
filename,
data,
{replace: true}
).then(
_ => console.log("write complete")
).catch(
err => console.log("file create failed:",err);
);
}
I have tried dozens of different decoding techniques, but the effect is the same. However, if I hardcode simple text data into the writeFile() section, like so:
File.writeFile(
folderpath,
"test.txt",
"the quick brown fox jumps over the lazy dog",
{replace: true}
)
A text file IS created correctly in the expected location with the text string above in it.
However, I've noticed that whether the file is the 0 bytes PNG, or the working text file above, in both cases the ".then()" consequence clause of the File Promise never fires.
Additionally, I swapped the above method and used the Ionic 2 native Base64-To-Gallery library to create the images, which worked without a problem. However, having the images in the user's picture gallery or camera roll is not an option for me as I do not wish to risk a user's own pictures while marshalling / packing / transmitting / deleting the data-rendered images. The images should be created and managed as part of the app.
User marcus-robinson seems to have experienced a similar issue outlined here, but it was across all file types, and not just binary types as seems to be the case here. Also, the issue seems to have been closed:
https://github.com/driftyco/ionic/issues/5638
Anybody experiencing something similar, or possibly spot some error I might have caused? I've tried dozens of alternatives but none seem to work.
I had similar behaviour saving media files which worked perfectly on iOS. Nonetheless, I had the issue of 0 bytes file creation on some Android devices in release build (dev build works perfectly). After very long search, I followed the following solution
I moved the polyfills.js script tag to the top of the index.html in the ionic project before the cordova.js tag. This re-ordering somehow the issue is resolved.
So the order should look like:
<script src="build/polyfills.js"></script>
<script type="text/javascript" src="cordova.js"></script>
Works on ionic 3 and ionic 4.
The credits go to 1
I got that working with most of your code:
this.file.writeFile(this.file.cacheDirectory, "currentCached.jpeg", this.b64toBlob(src, "image/jpg", 512) ,{replace: true})
The only difference i had was:
let byteCharacters = atob(b64Data.replace(/^data:image\/(png|jpeg|jpg);base64,/, ''));
instead of your
let byteCharacters = atob(b64Data);
Note: I did not use other trimming etc. like those techniques you used in your constructor class.
In the upgrade guide it states
Rails 4.0 removed the ActionController::Base.asset_path option. Use the assets pipeline feature.
I am currently in the process of upgrading from Rails 3.2 to Rails 4.1. In my app I use the select2-rails gem and in my js I add an image for the select menu options:
//mycode.js.erb
function format(image) {
var image_path = "<%= asset_path('" + image.id.toLowerCase() +"') %>"
return "<img class='flag' src='" + image_path + "' />";
}
The above worked in my Rails 3.2 app but I seemed to have broken it with my upgrade to 4.1 and now receive the following error:
Sprockets::FileNotFound - couldn't find file '" + image.id.toLowerCase() +"'
Is the asset_path helper still available in Rails 4.1? If yes, any ideas on where I may have gone wrong?
Update
The code above is in my .js.erb file which allows me to have Ruby code within my js file. This currently works well in my Rails 3.2 project. I am doing this as select2 allows us to format the display of our select menu items as per the below example:
//sample.js
function format(state) {
if (!state.id) return state.text; // optgroup
return "<img class='flag' src='images/flags/" + state.id.toLowerCase() + ".png'/>" + state.text;
}
My understanding was that it is correct usage to use the asset pipeline paths rather than manually adding something like 'assets/images/icons/small'
I have a tidbit model that has a carrierwave uploader. Im working on attaching an inline image in an email. If I do this:
#filename = #tidbit.image.instance_variable_get('#file').filename
attachments.inline[#filename] = #tidbit.image.read
I get an inline image in my email. However, it is the full size original version.
How would I inline attach a specific version (i.e.. :thumb) of the image?
If I do:
attachments.inline[#filename] = #tidbit.image(:thumb).read
I get an argument error 1 for 0.
Late reply, but it might help googlers and I had to do something similar. The following worked:
These are the versions present on my uploader class
version :thumb do
process :resize_to_fill => [122, 70]
end
version :medium do
process :resize_to_fill => [470, 470]
end
So to get the image in a certain version I just need to do, for example:
specific_version = uploader.image.medium.read
Where medium is the version I want.
In the original question's case you need to do:
attachments.inline[#filename] = #tidbit.image.thumb.read
I've got a problem with my font assets being served without digest in production.
As soon as I do rake assets:precompile I get:
5futurebit-webfont-c133dbefd9e1ca208741ed53c7396062.eot
I was trying to link it with font-face in scss with asset-url, asset-path, font-url and font-path but all of them end up outputting path:
/assets/5futurebit-webfont.eot
For now I'm copying assets from /app/assets/fonts straight to /public/assets/ but it doesn't feel like that's the way to do it.
I've been looking at a similar issue and am currently using the non-stupid-digest-assets gem: https://github.com/alexspeller/non-stupid-digest-assets
For more info on how you can use it, see here.
Correct use of non-stupid-digest-assets gem
Now that being said, the link provided by Chris (specifically, https://stackoverflow.com/a/17367264/291640) seems like it may accomplish the same as the gem without the gem itself. I know I need to look into it further.
Make sure you have the exact filename WITH extention name of the font in your font-url declaration like:
Correct:
#font-face{
font-family: 'Sawasdee';
src: font-url('Sawasdee.ttf') format('truetype');
}
Wrong:
#font-face{
font-family: 'Sewasdee';
src: font-url('Sewasdee') format('truetype');
}
My font folder:
fonts
|_ Sewasdee.ttf
|_ Otherfont.ttf
Here is our solution, that is based partially on what Sprocets does. It is working with Rails4. It automatically generates a nondigest version for all assets, that were listed in config.assets.precompile, after precompilation was done.
# lib/tasks/assets_nondigest.rake
require 'fileutils'
namespace "assets:precompile" do
desc "Create nondigest versions of defined assets"
task :nondigest => :environment do
sprocket_task = Sprockets::Rails::Task.new ::Rails.application
assets = ::Rails.application.config.assets.precompile
paths = sprocket_task.index.each_logical_path(assets).to_a +
assets.select { |asset| Pathname.new(asset).absolute? if asset.is_a?(String)}
paths.each do |path|
if asset = sprocket_task.index.find_asset(path)
copy_target = File.join(sprocket_task.output, asset.digest_path)
target = File.join(sprocket_task.output, asset.logical_path)
sprocket_task.logger.info "Writing #{target}"
asset.write_to target
asset.write_to "#{target}.gz" if asset.is_a?(Sprockets::BundledAsset)
end
end
end
end
Rake::Task['assets:precompile'].enhance do
Rake::Task['assets:precompile:nondigest'].invoke
end
Let me start by saying I have absolutely no idea what I should be doing because the documentation and available information on Assetic is either limited or Symfony oriented.
Here is my folder structure.
Assetic
+ assets
+ css
+ example.css
+ docs
+ src
+ tests
+ vendor
+ index.php
+ styles.php
Now, I have the following test code. Basically I cloned a clean copy of Assetic and ran composer install. Then I create an index.php file which simply links to my styles.php file with HTMLs <link> tag.
Here is my styles.php
<?php
require 'vendor/autoload.php';
$assetPath = __DIR__.'/assets/css/example.css';
$assetBasePath = __DIR__.'/assets/css';
$asset = new Assetic\Asset\FileAsset($assetPath, array(), $assetBasePath, 'example.css');
header('Content-Type: text/css');
$asset->setTargetPath(__DIR__);
echo $asset->dump(new Assetic\Filter\CssRewriteFilter);
Here is my example.css stylesheet.
body {
background-image: url('../img/background.png');
}
When I load up the styles.php in my browser I get the following output.
url('../img/background.png');
That's the same as the actual CSS. If I use the CSS URI Rewriter from Mr. Clay I get the expected output.
url('/Assetic/assets/img/background.png');
So what am I doing wrong with Assetic? I have no idea what paths I should be passing in and to where.
Thanks.
Just a pretty hard time with it, but finally (after reading the doc. of webassets, python library on which assetic is based) I won over the lack of documentation.
Here you go
<?php
require 'vendor/autoload.php';
$assetPath = __DIR__.'/assets/css/example.css';
$asset = new Assetic\Asset\FileAsset($assetPath, array(new Assetic\Filter\CssRewriteFilter), dirname($assetPath), '/assets/css');
// I assume the 'assets' directory is at the root of your website
header('Content-Type: text/css');
$asset->setTargetPath('/path/to/dumped/asset');
// As above, it's the path to the generated asset from your http root
echo $asset->dump();
I'm not sure to be very clear, so ask if you didn't understand something.