Package 'ambiorix'

Title: Web Framework Inspired by 'Express.js'
Description: A web framework inspired by 'express.js' to build any web service from multi-page websites to 'RESTful' application programming interfaces.
Authors: John Coene [aut, cre] , Opifex [fnd], Kennedy Mwavu [ctb]
Maintainer: John Coene <[email protected]>
License: GPL (>= 3)
Version: 2.1.1
Built: 2025-03-12 23:13:36 UTC
Source: https://github.com/ambiorix-web/ambiorix

Help Index

Ambiorix

Description

Web server.

Value

An object of class Ambiorix from which one can add routes, routers, and run the application.

Super class

ambiorix::Routing -> Ambiorix

Public fields

not_found

404 Response, must be a handler function that accepts the request and the response, by default uses response_404().

error

500 response when the route errors, must a handler function that accepts the request and the response, by default uses response_500().

on_stop

Callback function to run when the app stops, takes no argument.

Active bindings

port

Port to run the application.

host

Host to run the application.

limit

Max body size, defaults to 5 * 1024 * 1024.

Methods

Public methods

Inherited methods

Method new()

Usage
Ambiorix$new(
  host = getOption("ambiorix.host", "0.0.0.0"),
  port = getOption("ambiorix.port", NULL),
  log = getOption("ambiorix.logger", TRUE)
)
Arguments
host

A string defining the host.

port

Integer defining the port, defaults to ambiorix.port option: uses a random port if NULL.

log

Whether to generate a log of events.

Details

Define the webserver.

Method cache_templates()

Usage
Ambiorix$cache_templates()
Details

Cache templates in memory instead of reading them from disk.

Method listen()

Usage
Ambiorix$listen(port)
Arguments
port

Port number.

Details

Specifies the port to listen on.

Examples
app <- Ambiorix$new()

app$listen(3000L)

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start()

Method set_404()

Usage
Ambiorix$set_404(handler)
Arguments
handler

Function that accepts the request and returns an object describing an httpuv response, e.g.: response().

Details

Sets the 404 page.

Examples
app <- Ambiorix$new()

app$set_404(function(req, res){
 res$send("Nothing found here")
})

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start()

Method set_error()

Usage
Ambiorix$set_error(handler)
Arguments
handler

Function that accepts a request, response and an error object.

Details

Sets the error handler.

Examples
# my custom error handler:
error_handler <- function(req, res, error) {
  if (!is.null(error)) {
    error_msg <- conditionMessage(error)
    cli::cli_alert_danger("Error: {error_msg}")
  }
  response <- list(
    code = 500L,
    msg = "Uhhmmm... Looks like there's an error from our side :("
  )
  res$
    set_status(500L)$
    json(response)
}

# handler for GET at /whoami:
whoami <- function(req, res) {
  # simulate error (object 'Pikachu' is not defined)
  print(Pikachu)
}

app <- Ambiorix$
  new()$
  set_error(error_handler)$
  get("/whoami", whoami)

if (interactive()) {
  app$start(open = FALSE)
}

Method static()

Usage
Ambiorix$static(path, uri = "www")
Arguments
path

Local path to directory of assets.

uri

URL path where the directory will be available.

Details

Static directories

Method start()

Usage
Ambiorix$start(port = NULL, host = NULL, open = interactive())
Arguments
port

Integer defining the port, defaults to ambiorix.port option: uses a random port if NULL.

host

A string defining the host.

open

Whether to open the app the browser.

Details

Start Start the webserver.

Examples
app <- Ambiorix$new()

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start(port = 3000L)

Method serialiser()

Usage
Ambiorix$serialiser(handler)
Arguments
handler

Function to use to serialise. This function should accept two arguments: the object to serialise and ....

Details

Define Serialiser

Examples
app <- Ambiorix$new()

app$serialiser(function(data, ...){
 jsonlite::toJSON(x, ..., pretty = TRUE)
})

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start()

Method stop()

Usage
Ambiorix$stop()
Details

Stop Stop the webserver.

Method print()

Usage
Ambiorix$print()
Details

Print

Method clone()

The objects of this class are cloneable with this method.

Usage
Ambiorix$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Examples

app <- Ambiorix$new()

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

app$on_stop <- function(){
 cat("Bye!\n")
}

if(interactive())
 app$start()


## ------------------------------------------------
## Method `Ambiorix$listen`
## ------------------------------------------------

app <- Ambiorix$new()

app$listen(3000L)

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start()

## ------------------------------------------------
## Method `Ambiorix$set_404`
## ------------------------------------------------

app <- Ambiorix$new()

app$set_404(function(req, res){
 res$send("Nothing found here")
})

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start()

## ------------------------------------------------
## Method `Ambiorix$set_error`
## ------------------------------------------------

# my custom error handler:
error_handler <- function(req, res, error) {
  if (!is.null(error)) {
    error_msg <- conditionMessage(error)
    cli::cli_alert_danger("Error: {error_msg}")
  }
  response <- list(
    code = 500L,
    msg = "Uhhmmm... Looks like there's an error from our side :("
  )
  res$
    set_status(500L)$
    json(response)
}

# handler for GET at /whoami:
whoami <- function(req, res) {
  # simulate error (object 'Pikachu' is not defined)
  print(Pikachu)
}

app <- Ambiorix$
  new()$
  set_error(error_handler)$
  get("/whoami", whoami)

if (interactive()) {
  app$start(open = FALSE)
}

## ------------------------------------------------
## Method `Ambiorix$start`
## ------------------------------------------------

app <- Ambiorix$new()

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start(port = 3000L)

## ------------------------------------------------
## Method `Ambiorix$serialiser`
## ------------------------------------------------

app <- Ambiorix$new()

app$serialiser(function(data, ...){
 jsonlite::toJSON(x, ..., pretty = TRUE)
})

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start()

Define a Cookie Parser

Description

Identifies a function as a cookie parser (see example).

Usage

as_cookie_parser(fn)

Arguments

fn

A function that accepts a single argument, req the Request and returns the parsed cookie string, generally a list. Note that the original cookie string is available on the Request at the HTTP_COOKIE field, get it with: req$HTTP_COOKIE

Examples

func <- function(req) {
 req$HTTP_COOKIE
}

parser <- as_cookie_parser(func)

app <- Ambiorix$new()
app$use(parser)

Define a Cookie Preprocessor

Description

Identifies a function as a cookie preprocessor.

Usage

as_cookie_preprocessor(fn)

Arguments

fn

A function that accepts the same arguments as the cookie method of the Response class (name, value, ...), and returns a modified value.

Examples

func <- function(name, value, ...) {
 sprintf("prefix.%s", value)
}

prep <- as_cookie_preprocessor(func)

app <- Ambiorix$new()
app$use(prep)

Path to pattern

Description

identify a function as a path to pattern function; a function that accepts a path and returns a matching pattern.

Usage

as_path_to_pattern(path)

Arguments

path

A function that accepts a character vector of length 1 and returns another character vector of length 1.

Create a Renderer

Description

Create a custom renderer.

Usage

as_renderer(fn)

Arguments

fn

A function that accepts two arguments, the full path to the file to render, and the data to render.

Content Headers

Description

Convenient functions for more readable content type headers.

Usage

content_html()

content_plain()

content_json()

content_csv()

content_tsv()

content_protobuf()

Examples

list(
 "Content-Type",
 content_json()
)

if(FALSE)
 req$header(
  "Content-Type",
  content_json()
 )

Dockerfile

Description

Create the dockerfile required to run the application. The dockerfile created will install packages from RStudio Public Package Manager which comes with pre-built binaries that much improve the speed of building of Dockerfiles.

Usage

create_dockerfile(port, host = "0.0.0.0")

Arguments

port, host

Port and host to serve the application.

Details

Reads the DESCRIPTION file of the project to produce the Dockerfile.

Examples

## Not run: create_dockerfile()

Cookie Parser

Description

Parses the cookie string.

Usage

default_cookie_parser(req)

Arguments

req

A Request.

Value

A list of key value pairs or cookie values.

Forward Method

Description

Makes it such that the web server skips this method and uses the next one in line instead.

Usage

forward()

Value

An object of class forward.

Examples

app <- Ambiorix$new()

app$get("/next", function(req, res){
 forward()
})

app$get("/next", function(req, res){
 res$send("Hello")
})

if(interactive())
 app$start()

Retrieve Websocket clients connected to the server.

Description

Retrieve Websocket clients connected to the server.

Usage

get_websocket_clients()

Import Files

Description

Import all R-files in a directory.

Usage

import(...)

Arguments

...

Directory from which to import .R or .r files.

Value

Invisibly returns NULL.

Examples

## Not run: import("views")

Is Renderer

Description

Check whether an object is a renderer.

Usage

is_renderer_obj(obj)

Arguments

obj

Object to check.

Value

Boolean

JSON Object

Description

Serialises an object to JSON in res$render.

Usage

jobj(obj)

Arguments

obj

Object to serialise.

Mock Request

Description

Mock a request, used for tests.

Usage

mockRequest(cookie = "", query = "", path = "/")

Arguments

cookie

Cookie string.
query

Query string.
path

Path string.

Examples

mockRequest()

Logger

Description

Returns a new logger using the log package.

Usage

new_log(prefix = ">", write = FALSE, file = "ambiorix.log", sep = "")

Arguments

prefix

String to prefix all log messages.
write

Whether to write the log to the file.
file

Name of the file to dump the logs to, only used if write is TRUE.
sep

Separator between prefix and other flags and messages.

Value

An R& of class log::Logger.

Examples

log <- new_log()
log$log("Hello world")

Parse application/x-www-form-urlencoded data

Description

This function parses application/x-www-form-urlencoded data, typically used in form submissions.

Usage

parse_form_urlencoded(req, ...)

Arguments

req

The request object.
...

Additional parameters passed to the parser function.

Details

Overriding Default Parser

By default, parse_form_urlencoded() uses webutils::parse_http(). You can override this globally by setting the AMBIORIX_FORM_URLENCODED_PARSER option: 

options(AMBIORIX_FORM_URLENCODED_PARSER = my_other_custom_parser)

Your custom parser function MUST accept the following parameters:

  1. body: Raw vector containing the form data.

  2. ...: Additional optional parameters.

Value

A list of parsed form fields, with each key representing a form field name and each value representing the form field's value.

See Also

parse_multipart(), parse_json()

Examples

if (interactive()) {
  library(ambiorix)
  library(htmltools)
  library(readxl)

  page_links <- function() {
    Map(
      f = function(href, label) {
        tags$a(href = href, label)
      },
      c("/", "/about", "/contact"),
      c("Home", "About", "Contact")
    )
  }

  forms <- function() {
    form1 <- tags$form(
      action = "/url-form-encoded",
      method = "POST",
      enctype = "application/x-www-form-urlencoded",
      tags$h4("form-url-encoded:"),
      tags$label(`for` = "first_name", "First Name"),
      tags$input(id = "first_name", name = "first_name", value = "John"),
      tags$label(`for` = "last_name", "Last Name"),
      tags$input(id = "last_name", name = "last_name", value = "Coene"),
      tags$button(type = "submit", "Submit")
    )

    form2 <- tags$form(
      action = "/multipart-form-data",
      method = "POST",
      enctype = "multipart/form-data",
      tags$h4("multipart/form-data:"),
      tags$label(`for` = "email", "Email"),
      tags$input(id = "email", name = "email", value = "[email protected]"),
      tags$label(`for` = "framework", "Framework"),
      tags$input(id = "framework", name = "framework", value = "ambiorix"),
      tags$label(`for` = "file", "Upload CSV file"),
      tags$input(type = "file", id = "file", name = "file", accept = ".csv"),
      tags$label(`for` = "file2", "Upload xlsx file"),
      tags$input(type = "file", id = "file2", name = "file2", accept = ".xlsx"),
      tags$button(type = "submit", "Submit")
    )

    tagList(form1, form2)
  }

  home_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("hello, world!"),
      forms()
    )

    res$send(html)
  }

  home_post <- function(req, res) {
    body <- parse_json(req)
    cat(strrep(x = "-", times = 10), "\n")
    cat("Parsed JSON:\n")
    print(body)
    cat(strrep(x = "-", times = 10), "\n")

    response <- list(
      code = 200L,
      msg = "hello, world"
    )
    res$json(response)
  }

  url_form_encoded_post <- function(req, res) {
    body <- parse_form_urlencoded(req)
    cat(strrep(x = "-", times = 8), "\n")
    cat("Parsed application/x-www-form-urlencoded:\n")
    print(body)
    cat(strrep(x = "-", times = 8), "\n")

    list_items <- lapply(
      X = names(body),
      FUN = function(nm) {
        tags$li(
          nm,
          ":",
          body[[nm]]
        )
      }
    )
    input_vals <- tags$ul(list_items)

    html <- tagList(
      page_links(),
      tags$h3("Request processed"),
      input_vals
    )

    res$send(html)
  }

  multipart_form_data_post <- function(req, res) {
    body <- parse_multipart(req)

    list_items <- lapply(
      X = names(body),
      FUN = function(nm) {
        field <- body[[nm]]

        # if 'field' is a file, parse it & print on console:
        is_file <- "filename" %in% names(field)
        is_csv <- is_file && identical(field[["content_type"]], "text/csv")
        is_xlsx <- is_file &&
          identical(
            field[["content_type"]],
            "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
          )

        if (is_file) {
          file_path <- tempfile()
          writeBin(object = field$value, con = file_path)
          on.exit(unlink(x = file_path))
        }

        if (is_csv) {
          print(read.csv(file = file_path))
        }

        if (is_xlsx) {
          print(readxl::read_xlsx(path = file_path))
        }

        tags$li(
          nm,
          ":",
          if (is_file) "printed on console" else field
        )
      }
    )
    input_vals <- tags$ul(list_items)

    html <- tagList(
      page_links(),
      tags$h3("Request processed"),
      input_vals
    )

    res$send(html)
  }

  about_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("About Us")
    )
    res$send(html)
  }

  contact_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("Get In Touch!")
    )
    res$send(html)
  }

  app <- Ambiorix$new(port = 5000L)

  app$
    get("/", home_get)$
    post("/", home_post)$
    get("/about", about_get)$
    get("/contact", contact_get)$
    post("/url-form-encoded", url_form_encoded_post)$
    post("/multipart-form-data", multipart_form_data_post)

  app$start()
}

Parse application/json data

Description

This function parses JSON data from the request body.

Usage

parse_json(req, ...)

Arguments

req

The request object.
...

Additional parameters passed to the parser function.

Details

Overriding Default Parser

By default, parse_json() uses yyjsonr::read_json_raw() for JSON parsing. You can override this globally by setting the AMBIORIX_JSON_PARSER option: 

my_json_parser <- function(body, ...) {
  txt <- rawToChar(body)
  jsonlite::fromJSON(txt, ...)
}
options(AMBIORIX_JSON_PARSER = my_json_parser)

Your custom parser MUST accept the following parameters:

  1. body: Raw vector containing the JSON data.

  2. ...: Additional optional parameters.

Value

An R object (e.g., list or data frame) parsed from the JSON data.

See Also

parse_multipart(), parse_form_urlencoded()

Examples

if (interactive()) {
  library(ambiorix)
  library(htmltools)
  library(readxl)

  page_links <- function() {
    Map(
      f = function(href, label) {
        tags$a(href = href, label)
      },
      c("/", "/about", "/contact"),
      c("Home", "About", "Contact")
    )
  }

  forms <- function() {
    form1 <- tags$form(
      action = "/url-form-encoded",
      method = "POST",
      enctype = "application/x-www-form-urlencoded",
      tags$h4("form-url-encoded:"),
      tags$label(`for` = "first_name", "First Name"),
      tags$input(id = "first_name", name = "first_name", value = "John"),
      tags$label(`for` = "last_name", "Last Name"),
      tags$input(id = "last_name", name = "last_name", value = "Coene"),
      tags$button(type = "submit", "Submit")
    )

    form2 <- tags$form(
      action = "/multipart-form-data",
      method = "POST",
      enctype = "multipart/form-data",
      tags$h4("multipart/form-data:"),
      tags$label(`for` = "email", "Email"),
      tags$input(id = "email", name = "email", value = "[email protected]"),
      tags$label(`for` = "framework", "Framework"),
      tags$input(id = "framework", name = "framework", value = "ambiorix"),
      tags$label(`for` = "file", "Upload CSV file"),
      tags$input(type = "file", id = "file", name = "file", accept = ".csv"),
      tags$label(`for` = "file2", "Upload xlsx file"),
      tags$input(type = "file", id = "file2", name = "file2", accept = ".xlsx"),
      tags$button(type = "submit", "Submit")
    )

    tagList(form1, form2)
  }

  home_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("hello, world!"),
      forms()
    )

    res$send(html)
  }

  home_post <- function(req, res) {
    body <- parse_json(req)
    cat(strrep(x = "-", times = 10), "\n")
    cat("Parsed JSON:\n")
    print(body)
    cat(strrep(x = "-", times = 10), "\n")

    response <- list(
      code = 200L,
      msg = "hello, world"
    )
    res$json(response)
  }

  url_form_encoded_post <- function(req, res) {
    body <- parse_form_urlencoded(req)
    cat(strrep(x = "-", times = 8), "\n")
    cat("Parsed application/x-www-form-urlencoded:\n")
    print(body)
    cat(strrep(x = "-", times = 8), "\n")

    list_items <- lapply(
      X = names(body),
      FUN = function(nm) {
        tags$li(
          nm,
          ":",
          body[[nm]]
        )
      }
    )
    input_vals <- tags$ul(list_items)

    html <- tagList(
      page_links(),
      tags$h3("Request processed"),
      input_vals
    )

    res$send(html)
  }

  multipart_form_data_post <- function(req, res) {
    body <- parse_multipart(req)

    list_items <- lapply(
      X = names(body),
      FUN = function(nm) {
        field <- body[[nm]]

        # if 'field' is a file, parse it & print on console:
        is_file <- "filename" %in% names(field)
        is_csv <- is_file && identical(field[["content_type"]], "text/csv")
        is_xlsx <- is_file &&
          identical(
            field[["content_type"]],
            "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
          )

        if (is_file) {
          file_path <- tempfile()
          writeBin(object = field$value, con = file_path)
          on.exit(unlink(x = file_path))
        }

        if (is_csv) {
          print(read.csv(file = file_path))
        }

        if (is_xlsx) {
          print(readxl::read_xlsx(path = file_path))
        }

        tags$li(
          nm,
          ":",
          if (is_file) "printed on console" else field
        )
      }
    )
    input_vals <- tags$ul(list_items)

    html <- tagList(
      page_links(),
      tags$h3("Request processed"),
      input_vals
    )

    res$send(html)
  }

  about_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("About Us")
    )
    res$send(html)
  }

  contact_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("Get In Touch!")
    )
    res$send(html)
  }

  app <- Ambiorix$new(port = 5000L)

  app$
    get("/", home_get)$
    post("/", home_post)$
    get("/about", about_get)$
    get("/contact", contact_get)$
    post("/url-form-encoded", url_form_encoded_post)$
    post("/multipart-form-data", multipart_form_data_post)

  app$start()
}

Parse multipart form data

Description

Parses multipart form data, including file uploads, and returns the parsed fields as a list.

Usage

parse_multipart(req, ...)

Arguments

req

The request object.
...

Additional parameters passed to the parser function.

Details

If a field is a file upload it is returned as a named list with:

  • value: Raw vector representing the file contents. You must process this further (eg. convert to data.frame). See the examples section.

  • content_disposition: Typically "form-data", indicating how the content is meant to be handled.

  • content_type: MIME type of the uploaded file (e.g., "image/png" or "application/pdf").

  • name: Name of the form input field.

  • filename: Original name of the uploaded file.

If no body data, an empty list is returned.

Overriding Default Parser

By default, parse_multipart() uses webutils::parse_http() internally. You can override this globally by setting the AMBIORIX_MULTIPART_FORM_DATA_PARSER option: 

options(AMBIORIX_MULTIPART_FORM_DATA_PARSER = my_custom_parser)

Your custom parser function must accept the following parameters:

  1. body: Raw vector containing the form data.

  2. content_type: The 'Content-Type' header of the request as defined by the client.

  3. ...: Additional optional parameters.

See Also

parse_form_urlencoded(), parse_json()

Examples

if (interactive()) {
  library(ambiorix)
  library(htmltools)
  library(readxl)

  page_links <- function() {
    Map(
      f = function(href, label) {
        tags$a(href = href, label)
      },
      c("/", "/about", "/contact"),
      c("Home", "About", "Contact")
    )
  }

  forms <- function() {
    form1 <- tags$form(
      action = "/url-form-encoded",
      method = "POST",
      enctype = "application/x-www-form-urlencoded",
      tags$h4("form-url-encoded:"),
      tags$label(`for` = "first_name", "First Name"),
      tags$input(id = "first_name", name = "first_name", value = "John"),
      tags$label(`for` = "last_name", "Last Name"),
      tags$input(id = "last_name", name = "last_name", value = "Coene"),
      tags$button(type = "submit", "Submit")
    )

    form2 <- tags$form(
      action = "/multipart-form-data",
      method = "POST",
      enctype = "multipart/form-data",
      tags$h4("multipart/form-data:"),
      tags$label(`for` = "email", "Email"),
      tags$input(id = "email", name = "email", value = "[email protected]"),
      tags$label(`for` = "framework", "Framework"),
      tags$input(id = "framework", name = "framework", value = "ambiorix"),
      tags$label(`for` = "file", "Upload CSV file"),
      tags$input(type = "file", id = "file", name = "file", accept = ".csv"),
      tags$label(`for` = "file2", "Upload xlsx file"),
      tags$input(type = "file", id = "file2", name = "file2", accept = ".xlsx"),
      tags$button(type = "submit", "Submit")
    )

    tagList(form1, form2)
  }

  home_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("hello, world!"),
      forms()
    )

    res$send(html)
  }

  home_post <- function(req, res) {
    body <- parse_json(req)
    cat(strrep(x = "-", times = 10), "\n")
    cat("Parsed JSON:\n")
    print(body)
    cat(strrep(x = "-", times = 10), "\n")

    response <- list(
      code = 200L,
      msg = "hello, world"
    )
    res$json(response)
  }

  url_form_encoded_post <- function(req, res) {
    body <- parse_form_urlencoded(req)
    cat(strrep(x = "-", times = 8), "\n")
    cat("Parsed application/x-www-form-urlencoded:\n")
    print(body)
    cat(strrep(x = "-", times = 8), "\n")

    list_items <- lapply(
      X = names(body),
      FUN = function(nm) {
        tags$li(
          nm,
          ":",
          body[[nm]]
        )
      }
    )
    input_vals <- tags$ul(list_items)

    html <- tagList(
      page_links(),
      tags$h3("Request processed"),
      input_vals
    )

    res$send(html)
  }

  multipart_form_data_post <- function(req, res) {
    body <- parse_multipart(req)

    list_items <- lapply(
      X = names(body),
      FUN = function(nm) {
        field <- body[[nm]]

        # if 'field' is a file, parse it & print on console:
        is_file <- "filename" %in% names(field)
        is_csv <- is_file && identical(field[["content_type"]], "text/csv")
        is_xlsx <- is_file &&
          identical(
            field[["content_type"]],
            "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
          )

        if (is_file) {
          file_path <- tempfile()
          writeBin(object = field$value, con = file_path)
          on.exit(unlink(x = file_path))
        }

        if (is_csv) {
          print(read.csv(file = file_path))
        }

        if (is_xlsx) {
          print(readxl::read_xlsx(path = file_path))
        }

        tags$li(
          nm,
          ":",
          if (is_file) "printed on console" else field
        )
      }
    )
    input_vals <- tags$ul(list_items)

    html <- tagList(
      page_links(),
      tags$h3("Request processed"),
      input_vals
    )

    res$send(html)
  }

  about_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("About Us")
    )
    res$send(html)
  }

  contact_get <- function(req, res) {
    html <- tagList(
      page_links(),
      tags$h3("Get In Touch!")
    )
    res$send(html)
  }

  app <- Ambiorix$new(port = 5000L)

  app$
    get("/", home_get)$
    post("/", home_post)$
    get("/about", about_get)$
    get("/contact", contact_get)$
    post("/url-form-encoded", url_form_encoded_post)$
    post("/multipart-form-data", multipart_form_data_post)

  app$start()
}

Pre Hook Response

Description

Pre Hook Response

Usage

pre_hook(content, data)

Arguments

content

File content, a character vector.
data

A list of data passed to glue::glue_data.

Request

Description

A request.

Public fields

HEADERS

Headers from the request.

HTTP_ACCEPT

Content types to accept.

HTTP_ACCEPT_ENCODING

Encoding of the request.

HTTP_ACCEPT_LANGUAGE

Language of the request.

HTTP_CACHE_CONTROL

Directorives for the cache (case-insensitive).

HTTP_CONNECTION

Controls whether the network connection stays open after the current transaction finishes.

HTTP_COOKIE

Cookie data.

HTTP_HOST

Host making the request.

HTTP_SEC_FETCH_DEST

Indicates the request's destination. That is the initiator of the original fetch request, which is where (and how) the fetched data will be used.

HTTP_SEC_FETCH_MODE

Indicates mode of the request.

HTTP_SEC_FETCH_SITE

Indicates the relationship between a request initiator's origin and the origin of the requested resource.

HTTP_SEC_FETCH_USER

Only sent for requests initiated by user activation, and its value will always be ?1.

HTTP_UPGRADE_INSECURE_REQUESTS

Signals that server supports upgrade.

HTTP_USER_AGENT

User agent.

SERVER_NAME

Name of the server.

httpuv.version

Version of httpuv.

PATH_INFO

Path of the request.

QUERY_STRING

Query string of the request.

REMOTE_ADDR

Remote address.

REMOTE_PORT

Remote port.

REQUEST_METHOD

Method of the request, e.g.: GET.

rook.errors

Errors from rook.

rook.input

Rook inputs.

rook.url_scheme

Rook url scheme.

rook.version

Rook version.

SCRIPT_NAME

The initial portion of the request URL's "path" that corresponds to the application object, so that the application knows its virtual "location". #' @field SERVER_NAME Server name.

SERVER_PORT

Server port

CONTENT_LENGTH

Size of the message body.

CONTENT_TYPE

Type of content of the request.

HTTP_REFERER

Contains an absolute or partial address of the page that makes the request.

body

Request, an environment.

query

Parsed QUERY_STRING, list.

params

A list of parameters.

cookie

Parsed HTTP_COOKIE.

Methods

Public methods

Method new()

Usage
Request$new(req)
Arguments
req

Original request (environment).

Details

Constructor

Method print()

Usage
Request$print()
Details

Print

Method get_header()

Usage
Request$get_header(name)
Arguments
name

Name of the header

Details

Get Header

Method parse_multipart()

Usage
Request$parse_multipart()
Details

Parse Multipart encoded data

Method parse_json()

Usage
Request$parse_json(...)
Arguments
...

Arguments passed to parse_json().

Details

Parse JSON encoded data

Method clone()

The objects of this class are cloneable with this method.

Usage
Request$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Response

Description

Response class to generate responses sent from the server.

Active bindings

status

Status of the response, defaults to 200L.

headers

Named list of headers.

Methods

Public methods

Method set_status()

Usage
Response$set_status(status)
Arguments
status

An integer defining the status.

Details

Set the status of the response.

Method send()

Usage
Response$send(body, headers = NULL, status = NULL)
Arguments
body

Body of the response.

headers

HTTP headers to set.

status

Status of the response, if NULL uses self$status.

Details

Send a plain HTML response.

Method sendf()

Usage
Response$sendf(body, ..., headers = NULL, status = NULL)
Arguments
body

Body of the response.

...

Passed to ... of sprintf.

headers

HTTP headers to set.

status

Status of the response, if NULL uses self$status.

Details

Send a plain HTML response, pre-processed with sprintf.

Method text()

Usage
Response$text(body, headers = NULL, status = NULL)
Arguments
body

Body of the response.

headers

HTTP headers to set.

status

Status of the response, if NULL uses self$status.

Details

Send a plain text response.

Method send_file()

Usage
Response$send_file(file, headers = NULL, status = NULL)
Arguments
file

File to send.

headers

HTTP headers to set.

status

Status of the response.

Details

Send a file.

Method redirect()

Usage
Response$redirect(path, status = NULL)
Arguments
path

Path or URL to redirect to.

status

Status of the response, if NULL uses self$status.

Details

Redirect to a path or URL.

Method render()

Usage
Response$render(file, data = list(), headers = NULL, status = NULL)
Arguments
file

Template file.

data

List to fill ⁠[% tags %]⁠.

headers

HTTP headers to set.

status

Status of the response, if NULL uses self$status.

Details

Render a template file.

Method json()

Usage
Response$json(body, headers = NULL, status = NULL, ...)
Arguments
body

Body of the response.

headers

HTTP headers to set.

status

Status of the response, if NULL uses self$status.

...

Additional named arguments passed to the serialiser.

Details

Render an object as JSON.

Method csv()

Usage
Response$csv(data, name = "data", status = NULL, ...)
Arguments
data

Data to convert to CSV.

name

Name of the file.

status

Status of the response, if NULL uses self$status.

...

Additional arguments passed to readr::format_csv().

Details

Sends a comma separated value file

Method tsv()

Usage
Response$tsv(data, name = "data", status = NULL, ...)
Arguments
data

Data to convert to CSV.

name

Name of the file.

status

Status of the response, if NULL uses self$status.

...

Additional arguments passed to readr::format_tsv().

Details

Sends a tab separated value file

Method htmlwidget()

Usage
Response$htmlwidget(widget, status = NULL, ...)
Arguments
widget

The widget to use.

status

Status of the response, if NULL uses self$status.

...

Additional arguments passed to htmlwidgets::saveWidget().

Details

Sends an htmlwidget.

Method md()

Usage
Response$md(file, data = list(), headers = NULL, status = NULL)
Arguments
file

Template file.

data

List to fill ⁠[% tags %]⁠.

headers

HTTP headers to set.

status

Status of the response, if NULL uses self$status.

Details

Render a markdown file.

Method png()

Usage
Response$png(file)
Arguments
file

Path to local file.

Details

Send a png file

Method jpeg()

Usage
Response$jpeg(file)
Arguments
file

Path to local file.

Details

Send a jpeg file

Method image()

Usage
Response$image(file)
Arguments
file

Path to local file.

Details

Send an image Similar to png and jpeg methods but guesses correct method based on file extension.

Method ggplot2()

Usage
Response$ggplot2(plot, ..., type = c("png", "jpeg"))
Arguments
plot

Ggplot2 plot object.

...

Passed to ggplot2::ggsave()

type

Type of image to save.

Details

Ggplot2

Method print()

Usage
Response$print()
Details

Print

Method set()

Usage
Response$set(name, value)
Arguments
name

String. Name of the variable.

value

Value of the variable.

Details

Set Data

Returns

Invisible returns self.

Method get()

Usage
Response$get(name)
Arguments
name

String. Name of the variable to get.

Details

Get data

Method header()

Usage
Response$header(name, value)
Arguments
name

String. Name of the header.

value

Value of the header.

Details

Add headers to the response.

Returns

Invisibly returns self.

Method header_content_json()

Usage
Response$header_content_json()
Details

Set Content Type to JSON

Returns

Invisibly returns self.

Method header_content_html()

Usage
Response$header_content_html()
Details

Set Content Type to HTML

Returns

Invisibly returns self.

Method header_content_plain()

Usage
Response$header_content_plain()
Details

Set Content Type to Plain Text

Returns

Invisibly returns self.

Method header_content_csv()

Usage
Response$header_content_csv()
Details

Set Content Type to CSV

Returns

Invisibly returns self.

Method header_content_tsv()

Usage
Response$header_content_tsv()
Details

Set Content Type to TSV

Returns

Invisibly returns self.

Method get_headers()

Usage
Response$get_headers()
Details

Get headers Returns the list of headers currently set.

Method get_header()

Usage
Response$get_header(name)
Arguments
name

Name of the header to return.

Details

Get a header Returns a single header currently, NULL if not set.

Method set_headers()

Usage
Response$set_headers(headers)
Arguments
headers

A named list of headers to set.

Details

Set headers

Method set_header()

Usage
Response$set_header(name, value)
Arguments
name

Name of the header.

value

Value to set.

Details

Set a Header

Returns

Invisible returns self.

Method pre_render_hook()

Usage
Response$pre_render_hook(hook)
Arguments
hook

A function that accepts at least 4 arguments:

  • self: The Request class instance.

  • content: File content a vector of character string, content of the template.

  • data: list passed from render method.

  • ext: File extension of the template file.

This function is used to add pre-render hooks to the render method. The function should return an object of class responsePreHook as obtained by pre_hook(). This is meant to be used by middlewares to, if necessary, pre-process rendered data.

Include ... in your hook to ensure it will handle potential updates to hooks in the future.

Details

Add a pre render hook. Runs before the render and send_file method.

Returns

Invisible returns self.

Method post_render_hook()

Usage
Response$post_render_hook(hook)
Arguments
hook

A function to run after the rendering of HTML. It should accept at least 3 arguments:

  • self: The Request class instance.

  • content: File content a vector of character string, content of the template.

  • ext: File extension of the template file.

Include ... in your hook to ensure it will handle potential updates to hooks in the future.

Details

Post render hook.

Returns

Invisible returns self.

Method cookie()

Usage
Response$cookie(
  name,
  value,
  expires = getOption("ambiorix.cookie.expire"),
  max_age = getOption("ambiorix.cookie.maxage"),
  domain = getOption("ambiorix.cookie.domain"),
  path = getOption("ambiorix.cookie.path", "/"),
  secure = getOption("ambiorix.cookie.secure", TRUE),
  http_only = getOption("ambiorix.cookie.httponly", TRUE),
  same_site = getOption("ambiorix.cookie.savesite")
)
Arguments
name

String. Name of the cookie.

value

value of the cookie.

expires

Expiry, if an integer assumes it's the number of seconds from now. Otherwise accepts an object of class POSIXct or Date. If a character string then it is set as-is and not pre-processed. If unspecified, the cookie becomes a session cookie. A session finishes when the client shuts down, after which the session cookie is removed.

max_age

Indicates the number of seconds until the cookie expires. A zero or negative number will expire the cookie immediately. If both expires and max_age are set, the latter has precedence.

domain

Defines the host to which the cookie will be sent. If omitted, this attribute defaults to the host of the current document URL, not including subdomains.

path

Indicates the path that must exist in the requested URL for the browser to send the Cookie header.

secure

Indicates that the cookie is sent to the server only when a request is made with the https: scheme (except on localhost), and therefore, is more resistant to man-in-the-middle attacks.

http_only

Forbids JavaScript from accessing the cookie, for example, through the document.cookie property.

same_site

Controls whether or not a cookie is sent with cross-origin requests, providing some protection against cross-site request forgery attacks (CSRF). Accepts Strict, Lax, or None.

Details

Set a cookie Overwrites existing cookie of the same name.

Returns

Invisibly returns self.

Method clear_cookie()

Usage
Response$clear_cookie(name)
Arguments
name

Name of the cookie to clear.

Details

Clear a cookie Clears the value of a cookie.

Returns

Invisibly returns self.

Method clone()

The objects of this class are cloneable with this method.

Usage
Response$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Plain Responses

Description

Plain HTTP Responses.

Usage

response(body, headers = list(), status = 200L)

response_404(
  body = "404: Not found",
  headers = list(`Content-Type` = content_html()),
  status = 404L
)

response_500(
  body = "500: Server Error",
  headers = list(`Content-Type` = content_html()),
  status = 500L
)

Arguments

body

Body of response.
headers

HTTP headers.
status

Response status

Examples

app <- Ambiorix$new()

# html
app$get("/", function(req, res){
 res$send("hello!")
})

# text
app$get("/text", function(req, res){
 res$text("hello!")
})

if(interactive())
 app$start()

R Object

Description

Treats a data element rendered in a response (res$render) as a data object and ultimately uses dput().

Usage

robj(obj)

Arguments

obj

R object to treat.

Details

For instance in a template, ⁠x <- [% var %]⁠ will not work with res$render(data=list(var = "hello")) because this will be replace like x <- hello (missing quote): breaking the template. Using robj one would obtain x <- "hello".

Router

Description

Web server.

Super class

ambiorix::Routing -> Router

Public fields

error

500 response when the route errors, must a handler function that accepts the request and the response, by default uses response_500().

Methods

Public methods

Inherited methods

Method new()

Usage
Router$new(path)
Arguments
path

The base path of the router.

Details

Define the base route.

Method print()

Usage
Router$print()
Details

Print

Method clone()

The objects of this class are cloneable with this method.

Usage
Router$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Examples

# log
logger <- new_log()
# router
# create router
router <- Router$new("/users")

router$get("/", function(req, res){
 res$send("List of users")
})

router$get("/:id", function(req, res){
 logger$log("Return user id:", req$params$id)
 res$send(req$params$id)
})

router$get("/:id/profile", function(req, res){
 msg <- sprintf("This is the profile of user #%s", req$params$id)
 res$send(msg)
})

# core app
app <- Ambiorix$new()

app$get("/", function(req, res){
 res$send("Home!")
})

# mount the router
app$use(router)

if(interactive())
 app$start()

Core Routing Class

Description

Core routing class. Do not use directly, see Ambiorix, and Router.

Public fields

error

Error handler.

Active bindings

basepath

Basepath, read-only.

websocket

Websocket handler.

Methods

Public methods

Method new()

Usage
Routing$new(path = "")
Arguments
path

Prefix path.

Details

Initialise

Method get()

Usage
Routing$get(path, handler, error = NULL)
Arguments
path

Route to listen to, : defines a parameter.

handler

Function that accepts the request and returns an object describing an httpuv response, e.g.: response().

error

Handler function to run on error.

Details

GET Method

Add routes to listen to.

Examples
app <- Ambiorix$new()

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start()

Method put()

Usage
Routing$put(path, handler, error = NULL)
Arguments
path

Route to listen to, : defines a parameter.

handler

Function that accepts the request and returns an object describing an httpuv response, e.g.: response().

error

Handler function to run on error.

Details

PUT Method

Add routes to listen to.

Method patch()

Usage
Routing$patch(path, handler, error = NULL)
Arguments
path

Route to listen to, : defines a parameter.

handler

Function that accepts the request and returns an object describing an httpuv response, e.g.: response().

error

Handler function to run on error.

Details

PATCH Method

Add routes to listen to.

Method delete()

Usage
Routing$delete(path, handler, error = NULL)
Arguments
path

Route to listen to, : defines a parameter.

handler

Function that accepts the request and returns an object describing an httpuv response, e.g.: response().

error

Handler function to run on error.

Details

DELETE Method

Add routes to listen to.

Method post()

Usage
Routing$post(path, handler, error = NULL)
Arguments
path

Route to listen to.

handler

Function that accepts the request and returns an object describing an httpuv response, e.g.: response().

error

Handler function to run on error.

Details

POST Method

Add routes to listen to.

Method options()

Usage
Routing$options(path, handler, error = NULL)
Arguments
path

Route to listen to.

handler

Function that accepts the request and returns an object describing an httpuv response, e.g.: response().

error

Handler function to run on error.

Details

OPTIONS Method

Add routes to listen to.

Method all()

Usage
Routing$all(path, handler, error = NULL)
Arguments
path

Route to listen to.

handler

Function that accepts the request and returns an object describing an httpuv response, e.g.: response().

error

Handler function to run on error.

Details

All Methods

Add routes to listen to for all methods GET, POST, PUT, DELETE, and PATCH.

Method receive()

Usage
Routing$receive(name, handler)
Arguments
name

Name of message.

handler

Function to run when message is received.

Details

Receive Websocket Message

Examples
app <- Ambiorix$new()

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

app$receive("hello", function(msg, ws){
 print(msg) # print msg received
 
 # send a message back
 ws$send("hello", "Hello back! (sent from R)")
})

if(interactive())
 app$start()

Method print()

Usage
Routing$print()
Details

Print

Method engine()

Usage
Routing$engine(engine)
Arguments
engine

Engine function.

Details

Engine to use for rendering templates.

Method use()

Usage
Routing$use(use)
Arguments
use

Either a router as returned by Router, a function to use as middleware, or a list of functions. If a function is passed, it must accept two arguments (the request, and the response): this function will be executed every time the server receives a request. Middleware may but does not have to return a response, unlike other methods such as get Note that multiple routers and middlewares can be used.

Details

Use a router or middleware

Method get_routes()

Usage
Routing$get_routes(routes = list(), parent = "")
Arguments
routes

Existing list of routes.

parent

Parent path.

Details

Get the routes

Method get_receivers()

Usage
Routing$get_receivers(receivers = list())
Arguments
receivers

Existing list of receivers

Details

Get the websocket receivers

Method get_middleware()

Usage
Routing$get_middleware(middlewares = list(), parent = "")
Arguments
middlewares

Existing list of middleswares

parent

Parent path

Details

Get the middleware

Method prepare()

Usage
Routing$prepare()
Details

Prepare routes and decomposes paths

Method clone()

The objects of this class are cloneable with this method.

Usage
Routing$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Examples

## ------------------------------------------------
## Method `Routing$get`
## ------------------------------------------------

app <- Ambiorix$new()

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

if(interactive())
 app$start()

## ------------------------------------------------
## Method `Routing$receive`
## ------------------------------------------------

app <- Ambiorix$new()

app$get("/", function(req, res){
 res$send("Using {ambiorix}!")
})

app$receive("hello", function(msg, ws){
 print(msg) # print msg received
 
 # send a message back
 ws$send("hello", "Hello back! (sent from R)")
})

if(interactive())
 app$start()

Serialise an Object to JSON

Description

Serialise an Object to JSON

Usage

serialise(data, ...)

Arguments

data

Data to serialise.
...

Passed to serialiser.

Details

Ambiorix uses yyjsonr::write_json_str() by default for serialization.

Custom Serialiser

To override the default, set the AMBIORIX_SERIALISER option to a function that accepts:

  • data: Object to serialise.

  • ...: Additional arguments passed to the function.

For example: 

my_serialiser <- function(data, ...) {
 jsonlite::toJSON(x = data, ...)
}

options(AMBIORIX_SERIALISER = my_serialiser)

Examples

if (interactive()) {
  # a list:
  response <- list(code = 200L, msg = "hello, world!")

  serialise(response)
  #> {"code":200,"msg":"hello, world"}

  serialise(response, auto_unbox = FALSE)
  #> {"code":[200],"msg":["hello, world"]}

  # data.frame:
  serialise(cars)
}

Customise logs

Description

Customise the internal logs used by Ambiorix.

Usage

set_log_info(log)

set_log_success(log)

set_log_error(log)

Arguments

log

An object of class Logger, see log::Logger.

Set Parameters

Description

Set the query's parameters.

Usage

set_params(path, route = NULL)

Arguments

path

Correspond's the the requests' PATH_INFO
route

See Route

Value

Parameter list

Stop

Description

Stop all servers.

Usage

stop_all()

Token

Description

Create a token

Usage

token_create(n = 16L)

Arguments

n

Number of bytes.

HTML Template

Description

Use htmltools::htmlTemplate() as renderer. Passe to use method.

Usage

use_html_template()

Websocket

Description

Handle websocket messages.

Methods

Public methods

Method new()

Usage
Websocket$new(ws)
Arguments
ws
Details

Constructor

Method send()

Usage
Websocket$send(name, message)
Arguments
name

Name, identifier, of the message.

message

Content of the message, anything that can be serialised to JSON.

Details

Send a message

Method print()

Usage
Websocket$print()
Details

Print

Method clone()

The objects of this class are cloneable with this method.

Usage
Websocket$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Websocket Client

Description

Handle ambiorix websocket client.

Usage

copy_websocket_client(path)

get_websocket_client_path()

Arguments

path

Path to copy the file to.

Functions

  • copy_websocket_client Copies the websocket client file, useful when ambiorix was not setup with the ambiorix generator.

  • get_websocket_client Retrieves the full path to the local websocket client.