README.md

In tjpalanca/webtools: Web Server Tools

webtools

Webtools is a set of utilities to build APIs, web applications, and other web services in R. It is primarily based on {fiery} as the main backend web framework.

Installation

This package is available from my R Universe.

install.packages("webtools", repos = "https://tjpalanca.r-universe.dev")

Features

• All the features provided by {fiery} and its associated packages {reqres} and {routr} through sthe main App object:

  • Create handler functions for events in the event cycle, such as for authentication, pre-, or post-processing.

  • Schedule asynchronous execution to increase concurrency especially with polling and long-running operations.

  • Setting global headers, application data, and client id conversion.

  • Logging with different events and message types.

  • Websocket message connection, receiving, and sending.

  • Attaching routes to the application via the {routr} package, with automatic attachment and detachment during application start and stop.

• along with some improvements:

  • Attach static files using {httpuv}’s staticPath which takes place on the I/O thread and does not block up the main R session, improving performance.

  • Configuration has a whole separate place from application data or metadata.

  • Plugin interface that is more flexible: (a) can be detached, (b) can contain methods in addition to adding handlers only.

  • Handler, router, and static path functions can have metadata attached to them so that they can be removed or inspected as a group.

  • Help on the various arguments and return types of the handlers through the $events active field.

  • Methods are prefixed for easier discovery and autocomplete, and methods return the object itself when appropriate, allowing for method chaining.

  • exports some instantiated objects for easier autocompletion when constructing handler functions.

• HTML Building and Rendering Utilities

  • html_render() is an optimized version that renders tags from {htmltools} into character vectors, for use in server side rendering applciations through HTMLPlugin.

  • html_template(), html_mustache(), and html_tags() help in building HTML pages natively or via text templates sprinkled with R inserts.

• Development Utilities

  • contains development utilities for auto reloading of applications (dev_app()) or static pages (dev_html()).

• Robustness

  • fully tested with 100% test coverage.

Getting Started

The starting point is the App object. This contains the base for the webserver. Afterwards, you can attach some plugins for specific functionality.

Application Plugins

We add subclasses of the main App class for different types of applications:

• AsyncPlugin - capabilities for asynchronous execution of tasks to ensure that the main app thread remains responsive and available even under high concurrency.

• TestPlugin - Provide a set of utilities to test requests going through the application logic, for profiling or testing.

• PerfPlugin - Provide a set of utilities for measuring the performance of Applications, from specific routes and handlers to the whole application.

• HTMLPlugin - an application that serves HTML generated via {htmltools}; pairs well with server side frameworks like Hotwire or htmx.

Related Work

• All of this is built on top of the excellent {fiery}, {reqres}, and {routr} by Thomas Lin Pedersen.

• {plumber} is a package for building Web APIs, supported by RStudio and built on top of {httpuv}.

• {ambiorix} is another web server implementation built on top of {httpuv}.

• {shiny} is the standard way to quickly build web applications in R.

tjpalanca/webtools documentation built on Dec. 23, 2021, 11 a.m.