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2 years ago
"use strict";
const MIMEType = require("whatwg-mimetype");
const { parseURL, serializeURL } = require("whatwg-url");
const {
stripLeadingAndTrailingASCIIWhitespace,
stringPercentDecode,
isomorphicDecode,
forgivingBase64Decode
} = require("./utils.js");
module.exports = stringInput => {
const urlRecord = parseURL(stringInput);
if (urlRecord === null) {
return null;
}
return module.exports.fromURLRecord(urlRecord);
};
module.exports.fromURLRecord = urlRecord => {
if (urlRecord.scheme !== "data") {
return null;
}
const input = serializeURL(urlRecord, true).substring("data:".length);
let position = 0;
let mimeType = "";
while (position < input.length && input[position] !== ",") {
mimeType += input[position];
++position;
}
mimeType = stripLeadingAndTrailingASCIIWhitespace(mimeType);
if (position === input.length) {
return null;
}
++position;
const encodedBody = input.substring(position);
let body = stringPercentDecode(encodedBody);
// Can't use /i regexp flag because it isn't restricted to ASCII.
const mimeTypeBase64MatchResult = /(.*); *[Bb][Aa][Ss][Ee]64$/.exec(mimeType);
if (mimeTypeBase64MatchResult) {
const stringBody = isomorphicDecode(body);
body = forgivingBase64Decode(stringBody);
if (body === null) {
return null;
}
mimeType = mimeTypeBase64MatchResult[1];
}
if (mimeType.startsWith(";")) {
mimeType = "text/plain" + mimeType;
}
let mimeTypeRecord;
try {
mimeTypeRecord = new MIMEType(mimeType);
} catch (e) {
mimeTypeRecord = new MIMEType("text/plain;charset=US-ASCII");
}
return {
mimeType: mimeTypeRecord,
body
};
};