ambiorix (version 2.2.0)

parse_form_urlencoded: 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, ...)

Value

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

Named list

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.

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 = "[e-mail]"),
      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)
    # print(body)

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

  url_form_encoded_post <- function(req, res) {
    body <- parse_form_urlencoded(req)
    # print(body)

    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()
}