graphile-build-pg/node8plus/pgPrepareAndRun.js

Build a GraphQL schema by reflection over a PostgreSQL schema. Easy to customize since it's built with plugins on graphile-build

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = pgPrepareAndRun;
var _crypto = require("crypto");
var _lru = _interopRequireDefault(require("@graphile/lru"));
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
const cacheSizeFromEnv = parseInt(process.env.POSTGRAPHILE_PREPARED_STATEMENT_CACHE_SIZE, 10);
const POSTGRAPHILE_PREPARED_STATEMENT_CACHE_SIZE = !!cacheSizeFromEnv || cacheSizeFromEnv === 0 ? cacheSizeFromEnv : 100;
let lastString;
let lastHash;
const hash = str => {
  if (str !== lastString) {
    lastString = str;
    lastHash = (0, _crypto.createHash)("sha1").update(str).digest("base64");
  }
  return lastHash;
};
function pgPrepareAndRun(pgClient, text,
// eslint-disable-next-line flowtype/no-weak-types
values) {
  const connection = pgClient.connection;
  if (!values || POSTGRAPHILE_PREPARED_STATEMENT_CACHE_SIZE < 2 || !connection || !connection.parsedStatements) {
    return pgClient.query(text, values);
  } else {
    const name = hash(text);
    if (!connection._graphilePreparedStatementCache) {
      connection._graphilePreparedStatementCache = new _lru.default({
        maxLength: POSTGRAPHILE_PREPARED_STATEMENT_CACHE_SIZE,
        dispose(key) {
          if (connection.parsedStatements[key]) {
            pgClient.query(`deallocate ${pgClient.escapeIdentifier(key)}`).then(() => {
              delete connection.parsedStatements[key];
            }).catch(e => {
              // eslint-disable-next-line no-console
              console.error("Error releasing prepared query", e);
            });
          }
        }
      });
    }
    if (!connection._graphilePreparedStatementCache.get(name)) {
      // We're relying on dispose to clear out the old ones.
      connection._graphilePreparedStatementCache.set(name, true);
    }
    return pgClient.query({
      name,
      text,
      values
    });
  }
}
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