How to read and extract zip entries from java.sql.Blob type zip file without having FileInputStream or filepath as a string java

This is a more generic solution than just zip files (also Java’s native ZIP support does not handle all ZIP formats [1]). Use the loadjava utility to load commons-compress and it’s dependency xz: loadjava -user USERNAME/PASSWORD@SID xz.jar commons-compress-1.10.jar (Update as needed for newer versions) Then you can create a Java source inside the database: CREATE … Read more

How to save Chart JS charts as image without black background using blobs and filesaver?

If you want a customized background color then, you’d have to draw a background with your preferred color, and you can do so, like this … var backgroundColor=”white”; Chart.plugins.register({ beforeDraw: function(c) { var ctx = c.chart.ctx; ctx.fillStyle = backgroundColor; ctx.fillRect(0, 0, c.chart.width, c.chart.height); } }); DEMO // draw background var backgroundColor=”white”; Chart.plugins.register({ beforeDraw: function(c) { … Read more

Javascript make audio blob

Suppose you have base64 encoded version of audio like this data=”data:audio/ogg;base64,T2dnUwACAAAAAAAAAADSeWyXAU9nZ1MAAAAAAAAAAAAA0nl”; 1.First remove the base64 headers (preamble) and decode it to pure binary form, the form it lies in as in your iPad. You can use convertDataURIToBinary an excellent snippet by borismus on github for that var binary= convertDataURIToBinary(data); 2.Now create a Blob from the … Read more

HTML5 File API downloading file from server and saving it in sandbox

I’m going to show you how to download files with the XMLHttpRequest Level 2 and save them with the FileSystem API or with the FileSaver interface. ##Downloading Files## To download a file you will use the XMLHttpRequest Level 2 (aka XHR2), which supports cross-origin requests, uploading progress events, and uploading/downloading of binary data. In the … Read more

Appending Blob data

Blobs are “immutable” so you can’t change one after making it. Constructing a new Blob that appends the data to an existing blob (as you wrote in your initial question) is a good solution. If you don’t need to use the Blob each time you append a part, you can just track an array of … Read more