Question

我正在处理的Google Chrome扩展程序的一部分，下面是现有的JavaScript，用于从屏幕截图中创建博客文件......

    getBlob = function(canvas) {
        // standard dataURI can be too big, let's blob instead
        // http://code.google.com/p/chromium/issues/detail?id=69227#c27

        var dataURI = canvas.toDataURL(),
            // convert base64 to raw binary data held in a string
            // doesn't handle URLEncoded DataURIs
            byteString = atob(dataURI.split(',')[1]),
            // separate out the mime component
            mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0],
            // write the bytes of the string to an ArrayBuffer
            ab = new ArrayBuffer(byteString.length),
            ia = new Uint8Array(ab),
            i;

        for (i = 0; i < byteString.length; i++) {
            ia[i] = byteString.charCodeAt(i);
        }

        return new Blob([ab], {type: mimeString});
    },

    saveBlob = function(blob, filename, callback, errback) {
        var onWriteEnd = function() {
            // Return the name of the file that now contains the blob.
            callback('filesystem:chrome-extension://' + chrome.runtime.id + '/temporary/' + filename);
        };

        window.webkitRequestFileSystem(TEMPORARY, 1024*1024, function(fs){
            fs.root.getFile(filename, {create:true}, function(fileEntry) {
                fileEntry.createWriter(function(fileWriter) {
                    fileWriter.onwriteend = onWriteEnd;
                    fileWriter.write(blob);
                }, errback);
            }, errback);
        }, errback);
    },

查看上面的saveBlob(blob, filename, callback, errback)。以这种方式创建的文件存在多长时间？浏览器关闭时它会消失吗？

Answer 1

该文件将一直存在，直到被用户直接删除或Clear browsing data用于settings;虽然不能保证持久性。

4.4.1.2 Constants

类型为TEMPORARY的
unsigned short用于存储时没有坚持不懈。

另见Temporary storage

在Chrome浏览器中创建Blob文件需要多长时间？

1 个答案: