Remove coercion of Console GET requests to POST

[cjcenizal]

To-do

Verify all of these on master, then create tests for them:

• See if this affects [Console] Autocomplete support for read only users #36635

• Streaming large responses (should be handled by lib)

• Limited user permissions
  
  

• Error response (e.g. ES is down) HEAD /?pretty=true

• HEAD request HEAD twitter/_doc/0

• Test on https and ensure agent has intended effect. What about rejectUnauthorized? Did it ever actually work? ([console] support HEAD requests #10611)

• DELETE with body works (https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-scroll.html)

• cat format is preserved

• Send body with GET

• Fixes original problem of returning an error when a GET is inappropriately sent with a body

• Ensure proxyConfig and proxyFilters still work (https://www.elastic.co/guide/en/kibana/5.0/configuring-console.html)

In master, we should remove support for proxyConfig and proxyFilters (#11670, #9823).

Alternative solution

This alternative uses the http Node library which is more low-level but removes the need for the request dependency.

import http from 'http';

/* ... */

    handler: async (req, h) => {
      const { payload, query } = req;
      const { path, method } = query;
      const uri = resolveUri(baseUrl, path);
      const { timeout, rejectUnauthorized, agent, headers } = getConfigForReq(req, uri);

      return await new Promise((resolve) => {
        const {
          protocol,
          hostname,
          port,
          pathname,
          search,
        } = new URL(uri);

        const requestHeaders = {
          ...headers,
          ...getProxyHeaders(req),
        };

        const esRequest = http.request({
          protocol,
          host: hostname,
          port,
          path: `${pathname}${search}`,
          method,
          timeout,
          headers: requestHeaders,
        }, (esResponse) => {
          const {
            statusCode,
            statusMessage,
            headers: { warning },
          } = esResponse;

          const data = [];

          esResponse.setEncoding('utf8');

          esResponse.on('data', (chunk) => {
            data.push(chunk);
          });

          esResponse.on('end', () => {
            const responseBody = data.join();
            let result;

            if (method.toUpperCase() !== 'HEAD') {
              result = h
                .response(responseBody)
                .code(statusCode)
                .header('warning', warning);
            } else {
              result = h
                .response(`${statusCode} - ${statusMessage}`)
                .code(statusCode)
                .type('text/plain')
                .header('warning', warning);
            }

            resolve(result);
          });
        });

        esRequest.on('error', (e) => {
          reject(e);
        });

        // Write data to request body
        if (payload) {
          esRequest.write(JSON.stringify(payload));
        }

        esRequest.end();
      });
    },

[elasticmachine]

Pinging @elastic/es-ui

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request

[cjcenizal]

Closing in favor of #46200