87 lines
3.3 KiB
JavaScript
87 lines
3.3 KiB
JavaScript
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"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.responseInterceptor = void 0;
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const zlib = require("zlib");
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/**
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* Intercept responses from upstream.
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* Automatically decompress (deflate, gzip, brotli).
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* Give developer the opportunity to modify intercepted Buffer and http.ServerResponse
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*
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* NOTE: must set options.selfHandleResponse=true (prevent automatic call of res.end())
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*/
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function responseInterceptor(interceptor) {
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return async function proxyRes(proxyRes, req, res) {
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const originalProxyRes = proxyRes;
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let buffer = Buffer.from('', 'utf8');
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// decompress proxy response
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const _proxyRes = decompress(proxyRes, proxyRes.headers['content-encoding']);
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// concat data stream
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_proxyRes.on('data', (chunk) => (buffer = Buffer.concat([buffer, chunk])));
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_proxyRes.on('end', async () => {
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// copy original headers
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copyHeaders(proxyRes, res);
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// call interceptor with intercepted response (buffer)
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const interceptedBuffer = Buffer.from(await interceptor(buffer, originalProxyRes, req, res));
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// set correct content-length (with double byte character support)
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res.setHeader('content-length', Buffer.byteLength(interceptedBuffer, 'utf8'));
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res.write(interceptedBuffer);
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res.end();
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});
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_proxyRes.on('error', (error) => {
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res.end(`Error fetching proxied request: ${error.message}`);
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});
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};
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}
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exports.responseInterceptor = responseInterceptor;
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/**
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* Streaming decompression of proxy response
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* source: https://github.com/apache/superset/blob/9773aba522e957ed9423045ca153219638a85d2f/superset-frontend/webpack.proxy-config.js#L116
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*/
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function decompress(proxyRes, contentEncoding) {
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let _proxyRes = proxyRes;
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let decompress;
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switch (contentEncoding) {
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case 'gzip':
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decompress = zlib.createGunzip();
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break;
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case 'br':
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decompress = zlib.createBrotliDecompress();
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break;
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case 'deflate':
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decompress = zlib.createInflate();
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break;
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default:
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break;
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}
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if (decompress) {
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_proxyRes.pipe(decompress);
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_proxyRes = decompress;
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}
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return _proxyRes;
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}
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/**
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* Copy original headers
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* https://github.com/apache/superset/blob/9773aba522e957ed9423045ca153219638a85d2f/superset-frontend/webpack.proxy-config.js#L78
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*/
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function copyHeaders(originalResponse, response) {
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response.statusCode = originalResponse.statusCode;
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response.statusMessage = originalResponse.statusMessage;
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if (response.setHeader) {
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let keys = Object.keys(originalResponse.headers);
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// ignore chunked, brotli, gzip, deflate headers
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keys = keys.filter((key) => !['content-encoding', 'transfer-encoding'].includes(key));
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keys.forEach((key) => {
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let value = originalResponse.headers[key];
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if (key === 'set-cookie') {
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// remove cookie domain
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value = Array.isArray(value) ? value : [value];
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value = value.map((x) => x.replace(/Domain=[^;]+?/i, ''));
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}
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response.setHeader(key, value);
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});
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}
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else {
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response.headers = originalResponse.headers;
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}
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}
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