Source code
Revision control
Copy as Markdown
Other Tools
<!doctype html>
<meta charset="utf-8">
<title>Fetch and create Blob</title>
<script>
async function responseToBlob(response) {
let blob;
try {
blob = await response.blob();
} catch (e) {
return { error: `blob error: ${e.name}` };
}
return { url: URL.createObjectURL(blob) };
}
async function responseToData(response) {
const mimeType = response.headers.get("content-type");
let text;
try {
text = await response.text();
} catch(e) {
return { error: `text error: ${e.name}` };
}
return { url: `data:${mimeType},${encodeURIComponent(text)}` };
}
async function responseToFilesystem(response) {
if (!window.webkitRequestFileSystem) {
return { error: "unimplemented" };
}
let blob;
try {
blob = await response.blob();
} catch (e) {
return { error: `blob error: ${e.name}` };
}
const fs = await new Promise(resolve => {
window.webkitRequestFileSystem(window.TEMPORARY, 1024*1024, resolve);
});
const file = await new Promise(resolve => {
fs.root.getFile('fetch-and-create-url', { create: true }, resolve);
});
const writer = await new Promise(resolve => file.createWriter(resolve));
try {
await new Promise((resolve, reject) => {
writer.onwriteend = resolve;
writer.onerror = reject;
writer.write(blob);
});
} catch (e) {
return { error: `file write error: ${e.name}` };
}
return { url: file.toURL() };
}
async function responseToScheme(response, scheme) {
switch (scheme) {
case "blob":
return responseToBlob(response);
case "data":
return responseToData(response);
case "filesystem":
return responseToFilesystem(response);
default:
return { error: `unknown scheme: ${scheme}` };
}
}
async function fetchToScheme(url, scheme) {
let response;
try {
response = await fetch(url);
} catch (e) {
return { error: `fetch error: ${e.name}` };
}
return responseToScheme(response, scheme);
}
const params = new URL(window.location).searchParams;
fetchToScheme(params.get("url"), params.get("scheme"))
.then((message) => { parent.postMessage(message, "*"); });
</script>