Remove old link preview system
Beaudan Brown
6 years ago
parent
a1921cfff3
commit
f538aeea50
@ -1,168 +0,0 @@
|
||||
/* global
|
||||
Signal,
|
||||
textsecure,
|
||||
StringView
|
||||
*/
|
||||
|
||||
/* eslint-disable no-bitwise */
|
||||
|
||||
// eslint-disable-next-line func-names
|
||||
(function() {
|
||||
'use strict';
|
||||
|
||||
window.Signal = window.Signal || {};
|
||||
window.Signal.LinkPreviews = window.Signal.LinkPreviews || {};
|
||||
|
||||
// A cache mapping url to fetched previews
|
||||
const previewCache = {};
|
||||
|
||||
async function makeChunkedRequest(url) {
|
||||
const PARALLELISM = 3;
|
||||
const size = await textsecure.messaging.getProxiedSize(url);
|
||||
const chunks = await Signal.LinkPreviews.getChunkPattern(size);
|
||||
|
||||
let results = [];
|
||||
const jobs = chunks.map(chunk => async () => {
|
||||
const { start, end } = chunk;
|
||||
|
||||
const result = await textsecure.messaging.makeProxiedRequest(url, {
|
||||
start,
|
||||
end,
|
||||
returnArrayBuffer: true,
|
||||
});
|
||||
|
||||
return {
|
||||
...chunk,
|
||||
...result,
|
||||
};
|
||||
});
|
||||
|
||||
while (jobs.length > 0) {
|
||||
const activeJobs = [];
|
||||
for (let i = 0, max = PARALLELISM; i < max; i += 1) {
|
||||
if (!jobs.length) {
|
||||
break;
|
||||
}
|
||||
|
||||
const job = jobs.shift();
|
||||
activeJobs.push(job());
|
||||
}
|
||||
|
||||
// eslint-disable-next-line no-await-in-loop
|
||||
results = results.concat(await Promise.all(activeJobs));
|
||||
}
|
||||
|
||||
if (!results.length) {
|
||||
throw new Error('No responses received');
|
||||
}
|
||||
|
||||
const { contentType } = results[0];
|
||||
const data = Signal.LinkPreviews.assembleChunks(results);
|
||||
|
||||
return {
|
||||
contentType,
|
||||
data,
|
||||
};
|
||||
}
|
||||
|
||||
async function sha256(string) {
|
||||
const arraybuffer = new TextEncoder('utf-8').encode(string);
|
||||
const digest = await window.crypto.subtle.digest('SHA-256', arraybuffer);
|
||||
return StringView.arrayBufferToHex(digest);
|
||||
}
|
||||
|
||||
// Wrapper function which utilizes cache
|
||||
async function getPreview(url, skipCache = false) {
|
||||
// If we have a request cached then use that
|
||||
if (!skipCache && url in previewCache) {
|
||||
return previewCache[url];
|
||||
}
|
||||
|
||||
// Start the request
|
||||
const promise = _getPreview(url).catch(e => {
|
||||
window.log.error(e);
|
||||
|
||||
// If we get an error then we can purge the cache
|
||||
if (url in previewCache) {
|
||||
delete previewCache[url];
|
||||
}
|
||||
|
||||
return null;
|
||||
});
|
||||
previewCache[url] = promise;
|
||||
|
||||
return promise;
|
||||
}
|
||||
|
||||
async function _getPreview(url) {
|
||||
let html;
|
||||
try {
|
||||
html = await textsecure.messaging.makeProxiedRequest(url);
|
||||
} catch (error) {
|
||||
if (error.code >= 300) {
|
||||
throw new Error(`Failed to fetch html: ${error}`);
|
||||
}
|
||||
}
|
||||
|
||||
const title = Signal.LinkPreviews.getTitleMetaTag(html);
|
||||
const imageUrl = Signal.LinkPreviews.getImageMetaTag(html);
|
||||
|
||||
let image;
|
||||
let objectUrl;
|
||||
try {
|
||||
if (imageUrl) {
|
||||
if (!Signal.LinkPreviews.isMediaLinkInWhitelist(imageUrl)) {
|
||||
const primaryDomain = Signal.LinkPreviews.getDomain(url);
|
||||
const imageDomain = Signal.LinkPreviews.getDomain(imageUrl);
|
||||
throw new Error(
|
||||
`imageUrl for domain ${primaryDomain} did not match media whitelist. Domain: ${imageDomain}`
|
||||
);
|
||||
}
|
||||
|
||||
const data = await makeChunkedRequest(imageUrl);
|
||||
|
||||
// Calculate dimensions
|
||||
const file = new Blob([data.data], {
|
||||
type: data.contentType,
|
||||
});
|
||||
objectUrl = URL.createObjectURL(file);
|
||||
|
||||
const dimensions = await Signal.Types.VisualAttachment.getImageDimensions(
|
||||
{
|
||||
objectUrl,
|
||||
logger: window.log,
|
||||
}
|
||||
);
|
||||
|
||||
image = {
|
||||
...data,
|
||||
...dimensions,
|
||||
contentType: file.type,
|
||||
};
|
||||
}
|
||||
} catch (error) {
|
||||
// We still want to show the preview if we failed to get an image
|
||||
window.log.error(
|
||||
'getPreview failed to get image for link preview:',
|
||||
error.message
|
||||
);
|
||||
} finally {
|
||||
if (objectUrl) {
|
||||
URL.revokeObjectURL(objectUrl);
|
||||
}
|
||||
}
|
||||
|
||||
const hash = await sha256(url);
|
||||
|
||||
return {
|
||||
title,
|
||||
url,
|
||||
image,
|
||||
hash,
|
||||
};
|
||||
}
|
||||
|
||||
window.Signal.LinkPreviews.helper = {
|
||||
getPreview,
|
||||
};
|
||||
})();
|
||||
Loading…
Reference in New Issue