strata/lib/method-override.js

A modular, streaming HTTP server

var strata = require('./index');
var Request = require('./request');

/**
 * A middleware that substitutes `env.requestMethod` with a value from a request
 * parameter or HTTP header. This can be used to fake a PUT or DELETE request
 * from an HTTP client that only actually supports GET or POST, for example. The
 * default parameter name is "_method" and the default header name is
 * "X-Http-Method-Override".
 */
module.exports = function (app, paramName, headerName) {
  paramName = paramName || '_method';
  headerName = (headerName || 'X-Http-Method-Override').toLowerCase();

  function methodOverride(env, callback) {
    if (env.requestMethod === 'POST') {
      var req = new Request(env);

      req.params(function (err, params) {
        if (err && strata.handleError(err, env, callback)) {
          return;
        }

        var method = params[paramName] || env.headers[headerName];

        // Update the requestMethod.
        if (method) {
          env.strataOriginalMethod = env.requestMethod;
          env.requestMethod = method.toUpperCase();
        }

        app(env, function (status, headers, body) {
          // Revert for the sake of upstream apps.
          if (env.strataOriginalMethod) {
            env.requestMethod = env.strataOriginalMethod;
            delete env.strataOriginalMethod;
          }

          callback(status, headers, body);
        });
      });
    } else {
      app(env, callback);
    }
  }

  return methodOverride;
};