Request Filter

A Filter is a function that receives the request and the response object from the gateway and must return a boolean value (or a Promise<boolean>) to inform if the given request should target the destination API or if it should be ignored.

Each filter must be defined on its own .js file.

Example:

/**
 * Where request and response are the original request and response objects created by [http](https://nodejs.org/api/http.html) module.
 */
module.exports = function (request, response) {
  return req.query.denyParam !== '1';
};

or, using Promises:

/**
 * Where request and response are the original request and response objects created by [http](https://nodejs.org/api/http.html) module.
 */
module.exports = function (request, response) {
  return new Promise((resolve, reject) => {
    setTimeout(function(){resolve(req.query.denyParam !== '1');}, 10);
  };
};

You can configure a request filter middleware through:

• Admin Rest API: POST /midleware/filters
• SDK: sdk.middleware.addFilter(name, fileName);
• CLI: treeGatewayConfig middleware filter -a <name> ./filename.js

Tree Gateway provide some filter middlewares for common tasks already included in its distribution. Check the list here.