Nezaldi

From the Nahuatl 'Path' or 'Trail'. Nezaldi is an HTTP Proxy Server created to help developers that need to serve several sources under the same domain.

Nezaldi works as a simplistic replacement for Nginx or other HTTP routers. It is not intended to be used in production environments. If you need a router in production, you should be using Nginx. But if you need to have a router in your local environment and you don't want or can't install Nginx locally Nezaldi will be a great option.

The most common use case and the one that inspired me to create this tool is when you are developing a serverless single page application (SPA) which may be served by a local development server as Webpack and that also needs access to an API in another server, it may be local or remote, or probably more than one of this APIs. In these cases, you want all resources to be served as if they were under the same domain or server. This is what Nezaldi will do.

Usage

Install it with NPM:

npm install nezaldi

or Yarn

yarn add nezaldi --dev

Create a file in your project root named nezaldi.json and write your route configuration there:

{
  "debug": false,
  "rules": [
    {
      "path": "^/$",
      "resetPath": true,
      "target": "http://localhost:4000/index.html"
    },
    {
      "path": "^/bundles/",
      "target": "http://mywebpackserver/bundles/"
    },
    {
      "path": "^/redirect/",
      "redirect": "http://myotherserver/home/"
    },
    {
      "path": "^/(books|pets)/",
      "target": "http://$1-server/"
    },
    {
      "path": "^/html/",
      "accept": "text/html",
      "target": "http://myhtmlserver/"
    },
    {
      "path": "^/users/",
      "target": "http://myserverneedsaheader/",
      "addHeaders": [
        {
          "name": "X-MyHeader",
          "value": "Hello Header"
        }
      ]
    }
  ]
}

Start the server from a package.json script:

{
    "scripts": {
      "start": "npm nezaldi"
    }
}

Available Options

• --conf Configuration file to use, by default it will use nezaldi.json
• -p <port> Sets the port for running Nezaldi. Default 3000. It can be specified in the configuration file.

Global Configuration Settings

• debug [Boolean] It will print information on the console on every request, including path, match and headers

Rule Configuration Settings

• path [String] The string should be a valid regex argument. It will be used to match rules with requests. Rules are executed in order. If you have rules that are more specific than others, it is better to place the more specific ones before the general ones

• target [String] This is the URL of the server that will be used when the rule matches

• redirect [String] URL to be used as a redirect response. redirect should not be used in combination with target setting in the same rule.

• resetPath [Boolean] Will force Nezaldi to not add any fragments to the target URL. By default, Nezaldi will remove the path fragment from the url adding the rest of it to the target url. For example, on the request http://localhost:4000/a/b/c lets suppose the match rule has path ^/a and target http://server/some/more/stuff/, the default behavior will be to proxy the call to http://server/some/more/stuff/b/c if you set resetPath to true, then the call will be to http://server/some/more/stuff/

• accept [String] Sometimes you want that a rule only applies when the accept type is a specific one, like text/html. Use this property to limit the matches to only those containing the given accept type

• addHeaders [Key Value Map Array] In the case you need to add some headers to your calls that are not present in the original request, you can do so by adding them here.

• removeHeaders [Key Value Map Array] In the case you need to remove some headers from the original request, you can do so by adding them here.

Troubleshooting

• Error ECONNREFUSED when trying to connect to a local server running in localhost. Some servers when running in localhost will not use the IPv4 address 127.0.0.1 which will be the one tried by NodeJS when the schema of the server is localhost. Before doing any change, verify that a curl call works using localhost, if it does, it is probable that your server is not using the IPv4 address but the IPv6 one. As a workaround you can change your target from something like http://localhost:5555/a/b/c to http://[::1]:5555/a/b/c.

Dependencies

Nezaldi is intended to be superlight. It only depends on Node itself as a library. In development mode it depends on Jasmine for testing and Elm for generating the dashboard static resources.