HTTP filters

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HTTP filters

HTTP filters enable pipelined processing of http requests.

Filters

Filters enable you to step into the request pipeline, and execute code at at both request and response of the execution pipeline, possibly intercepting the request directly. Similar to an HTTP Controller, standalone filters are triggered based on an export.

As such, to make a filter, it must be export a filter function:

Minimal filter timing the subsequent request
exports.filter = function (req, next) {
    var before = new Date().getTime();
    var response = next(req);  // next(req) hands over the request to the engine pipeline and returns the response
    var after = new Date().getTime();
    log.info((after - before) + 'ms');
    return response;
};
Filter manipulating the request
exports.filter = function (req, next) {
  req.requestLogging = true; // Manipulate request
  log.info("Request:" + JSON.stringify(req, null, 2));
  var response = next(req); // Continue request pipeline
  response.responseLogging = true; // Manipulate response
  log.info("Response:" + JSON.stringify(response, null, 2));
  return response;
};
Filter intercepting the request
exports.filter = function (req, next) {

    if (req.headers['X-Auth-Token'] !== 'letMeIn') {
        // intercept request pipeline
        return {
            status: 403
        }
    }

    req.headers['Authenticated'] = true;
    return next(req);
};

Filters may currently be wired into the execution pipeline in the following ways:

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