Studio JSON Request

📡 A tiny Node HTTP(S) request wrapper for JSON APIs.

• Transparent JSON request / response handling
• Timeout support
• Status code validation and default validation for 2xx responses
• Follows redirects, but only once
• Unified error handling with status codes
• Consistent logging with Studio Log

Usage

const request = require('@studio/json-request');

request({
  method: 'POST',
  hostname: 'some-host',
  path: '/some-path',
  timeout: 5000
}, { some: 'payload' }, (err, data, res) => {
  // ...
});

API

• request(options[, data], callback): Creates a new HTTPS request, passing the options to Node http.request, except for these properties:
  • protocol: The protocol to use. Must be either "http:" or "https:". Defaults to "https:".
  • timeout: The number of milliseconds after which the request should time out, causing en E_TIMEOUT error.
  • expect: The expected status code(s). This can be a number or an array of numbers.
  • stream: If true, the callback is invoked with (null, res) once the header was retrieved to allow to stream the response.
  • log: A parent logger to use for the "Request" logger.

Behavior

• If the timeout option is specified, a timer is installed which will abort the request and invoke the callback with an error.
• If the expect option is specified, it validates the response HTTP status code. If it's a number the status code has to equal that number. If an array is given, any number in the array is accepted. If the option is not given, the request will fail for non 2xx status codes.
• If the stream option is specified, the response is returned immediately after the status code was checked. No further response processing is done by this library. It is the callers responsibility to consume the response.
• If data is given, it is stringified and passed as the request body and the request is sent. The Content-Type header is set to application/json, unless this header was already provided. The Content-Length is set to the request body length.
• If data is set to null, the request is sent without a body.
• If data is omitted, the request object is returned and it's the callers responsibility to invoke req.end() to complete the request.

Callback

The callback is invoked with (err, data, response).

• err: An error object or null. The error will have a code property with these possible string values:
  • E_TIMEOUT: The request timed out.
  • E_EXPECT: The response status code does not match the expectation. The statusCode property on the error object is set to the response status code.
  • E_JSON: Could not parse the response body as JSON. In this case data is the raw body.
  • E_ERROR: If an error event was thrown.
• data: The parsed response data, or if it could not be parsed the raw body.
• response: The response object.

Logging

Every request produces a log entry when the response was processed with this data:

• request:
  • protocol: The protocol used
  • method: The request method used
  • host: The host name
  • path: The path
  • headers: The request headers, if any
  • port: The port, if specified
  • body: The request body, if given
• response:
  • statusCode: The response status code
  • headers: The response headers
  • body: The response body, if available
• ms_head: The time it took to receive the response header
• ms_body: The time it took to receive the response body

If stream was set, the log entry is produced once the response header was received without the response and ms_body properties, and another log entry is produced when the response body was received with ms_body.

To remove confidential information from the logs, you can use Studio Log X. For example, you can X-out all Authorization headers from the logs like this:

const logger = require('@studio/log');
const Console = require('@studio/log-format/console');
const logX = require('@studio/log-x');

// Install filter on namespace "Request":
logger
  .pipe(logX('request.headers.Authorization'))
  .pipe(new Console());

Related modules

• 🎮 Studio CLI this module was initially developed for the JavaScript Studio command line tool.
• 👻 Studio Log is used for logging.
• ❎ Studio Log X can be use to X-out confidential information from the logs.
• 📦 Studio Changes is used to create the changelog for this module.

License

MIT

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