cod-dicomweb-server
Version:
A wadors server proxy that get data from a Cloud Optimized Dicom format.
34 lines (33 loc) • 1.43 kB
JavaScript
import { CustomError } from '../../classes/customClasses';
import { readFile, writeFile, createPartialFileName } from '../../fileAccessSystemUtils';
const filePartial = {
async partial(args, callBack) {
const { url, offsets, headers, directoryHandle } = args;
if (offsets?.startByte && offsets?.endByte) {
headers['Range'] = `bytes=${offsets.startByte}-${offsets.endByte - 1}`;
}
const storageName = createPartialFileName(url, offsets);
if (directoryHandle) {
const file = (await readFile(directoryHandle, storageName, { offsets, isJson: false }));
if (file?.byteLength) {
const fileBuffer = new Uint8Array(file);
callBack({ url, fileArraybuffer: fileBuffer, offsets });
return fileBuffer;
}
}
return await fetch(url, { headers })
.then((response) => response.arrayBuffer())
.then((data) => {
const fileBuffer = new Uint8Array(data);
callBack({ url, fileArraybuffer: fileBuffer, offsets });
if (directoryHandle) {
writeFile(directoryHandle, storageName, data);
}
return fileBuffer;
})
.catch((error) => {
throw new CustomError('filePartial.ts: Error when fetching file: ' + error?.message);
});
}
};
export default filePartial;