Package Plumber Router

Details

Routers are the core request handler in plumber. A router is responsible for taking an incoming request, submitting it through the appropriate filters and eventually to a corresponding endpoint, if one is found.

See the Programmatic Usage article for additional details on the methods available on this object.

Super class

plumber::Hookable -> Plumber

Public fields

flags: For internal use only

Active bindings

endpoints: Plumber router endpoints read-only
filters: Plumber router filters read-only
mounts: Plumber router mounts read-only
environment: Plumber router environment read-only
routes: Plumber router routes read-only

Methods

Inherited methods

plumber::Hookable$registerHooks()

Method `new()`

Create a new Plumber router

Usage

Plumber$new(file = NULL, filters = defaultPlumberFilters, envir)

Arguments

file: path to file to plumb
filters: a list of Plumber filters
envir: an environment to be used as the enclosure for the routers execution

Returns

A new Plumber router

Method `run()`

Start a server using Plumber object.

Usage

Plumber$run(
  host = "127.0.0.1",
  port = get_option_or_env("plumber.port", NULL),
  swagger = deprecated(),
  debug = missing_arg(),
  swaggerCallback = missing_arg(),
  ...,
  docs = missing_arg(),
  quiet = FALSE
)

Arguments

host

a string that is a valid IPv4 or IPv6 address that is owned by this server, which the application will listen on. "0.0.0.0" represents all IPv4 addresses and "::/0" represents all IPv6 addresses.

port

a number or integer that indicates the server port that should be listened on. Note that on most Unix-like systems including Linux and Mac OS X, port numbers smaller than 1025 require root privileges.

This value does not need to be explicitly assigned. To explicitly set it, see options_plumber().

swagger

Deprecated. Please use docs instead. See $setDocs(docs) or $setApiSpec() for more customization.

debug

If TRUE, it will provide more insight into your API errors. Using this value will only last for the duration of the run. If a $setDebug() has not been called, debug will default to interactive() at $run() time. See $setDebug() for more details.

swaggerCallback

An optional single-argument function that is called back with the URL to an OpenAPI user interface when one becomes ready. If missing, defaults to information previously set with $setDocsCallback(). This value will only be used while running the router.

...

Should be empty.

docs

Visual documentation value to use while running the API. This value will only be used while running the router. If missing, defaults to information previously set with setDocs(). For more customization, see $setDocs() or pr_set_docs() for examples.

quiet

If TRUE, don't print routine startup messages.

Method `mount()`

Mount a Plumber router

Plumber routers can be “nested” by mounting one into another using the mount() method. This allows you to compartmentalize your API by paths which is a great technique for decomposing large APIs into smaller files.

Usage

Plumber$mount(path, router)

Arguments

path: a character string. Where to mount router.
router: a Plumber router. Router to be mounted.

Examples

\dontrun{
root <- pr()

users <- Plumber$new("users.R")
root$mount("/users", users)

products <- Plumber$new("products.R")
root$mount("/products", products)
}

Method `unmount()`

Unmount a Plumber router

Usage

Plumber$unmount(path)

Arguments

path: a character string. Where to unmount router.

Method `registerHook()`

Plumber routers support the notion of "hooks" that can be registered to execute some code at a particular point in the lifecycle of a request. Plumber routers currently support four hooks:

preroute(data, req, res)
postroute(data, req, res, value)
preserialize(data, req, res, value)
postserialize(data, req, res, value)

In all of the above you have access to a disposable environment in the data parameter that is created as a temporary data store for each request. Hooks can store temporary data in these hooks that can be reused by other hooks processing this same request.

One feature when defining hooks in Plumber routers is the ability to modify the returned value. The convention for such hooks is: any function that accepts a parameter named value is expected to return the new value. This could be an unmodified version of the value that was passed in, or it could be a mutated value. But in either case, if your hook accepts a parameter named value, whatever your hook returns will be used as the new value for the response.

You can add hooks using the registerHook method, or you can add multiple hooks at once using the registerHooks method which takes a name list in which the names are the names of the hooks, and the values are the handlers themselves.

Usage

Plumber$registerHook(
  stage = c("preroute", "postroute", "preserialize", "postserialize", "exit"),
  handler
)

Arguments

stage: a character string. Point in the lifecycle of a request.
handler: a hook function.

Examples

\dontrun{
pr <- pr()
pr$registerHook("preroute", function(req){
  cat("Routing a request for", req$PATH_INFO, "...\n")
})
pr$registerHooks(list(
  preserialize=function(req, value){
    print("About to serialize this value:")
    print(value)

    # Must return the value since we took one in. Here we're not choosing
    # to mutate it, but we could.
    value
  },
  postserialize=function(res){
    print("We serialized the value as:")
    print(res$body)
  }
))

pr$handle("GET", "/", function(){ 123 })
}

Method `handle()`

Define endpoints

The “handler” functions that you define in these handle calls are identical to the code you would have defined in your plumber.R file if you were using annotations to define your API. The handle() method takes additional arguments that allow you to control nuanced behavior of the endpoint like which filter it might preempt or which serializer it should use.

See also: pr_handle(), pr_get(), pr_post(), pr_put(), pr_delete()

Usage

Plumber$handle(
  methods,
  path,
  handler,
  preempt,
  serializer,
  parsers,
  endpoint,
  ...
)

Arguments

methods: a character string. http method.
path: a character string. Api endpoints
handler: a handler function.
preempt: a preempt function.
serializer: a serializer function.
parsers: a named list of parsers.
endpoint: a PlumberEndpoint object.
...: additional arguments for PlumberEndpoint new method (namely lines, params, comments, responses and tags. Excludes envir).

Examples

\dontrun{
pr <- pr()
pr$handle("GET", "/", function(){
  "<html><h1>Programmatic Plumber!</h1></html>"
}, serializer=plumber::serializer_html())
}

Method `removeHandle()`

Remove endpoints

Usage

Plumber$removeHandle(methods, path, preempt = NULL)

Arguments

methods: a character string. http method.
path: a character string. Api endpoints
preempt: a preempt function.

Method `print()`

Print representation of plumber router.

Usage

Plumber$print(prefix = "", topLevel = TRUE, ...)

Arguments

prefix: a character string. Prefix to append to representation.
topLevel: a logical value. When method executed on top level router, set to TRUE.
...: additional arguments for recursive calls

Returns

A terminal friendly representation of a plumber router.

Method `serve()`

Serve a request

Usage

Plumber$serve(req, res)

Arguments

req: request object
res: response object

Method `route()`

Route a request

Usage

Plumber$route(req, res)

Arguments

req: request object
res: response object

Method `call()`

httpuv interface call function. (Required for httpuv)

Usage

Plumber$call(req)

Arguments

req: request object

Method `onHeaders()`

httpuv interface onHeaders function. (Required for httpuv)

Usage

Plumber$onHeaders(req)

Arguments

req: request object

Method `onWSOpen()`

httpuv interface onWSOpen function. (Required for httpuv)

Usage

Plumber$onWSOpen(ws)

Arguments

ws: WebSocket object

Method `setSerializer()`

Sets the default serializer of the router.

Usage

Plumber$setSerializer(serializer)

Arguments

serializer: a serializer function

Examples

\dontrun{
pr <- pr()
pr$setSerializer(serializer_unboxed_json())
}

Method `setParsers()`

Sets the default parsers of the router. Initialized to c("json", "form", "text", "octet", "multi")

Usage

Plumber$setParsers(parsers)

Arguments

parsers

Can be one of:

A NULL value
A character vector of parser names
A named list() whose keys are parser names names and values are arguments to be applied with do.call()
A TRUE value, which will default to combining all parsers. This is great for seeing what is possible, but not great for security purposes

If the parser name "all" is found in any character value or list name, all remaining parsers will be added. When using a list, parser information already defined will maintain their existing argument values. All remaining parsers will use their default arguments.

Example:

# provide a character string
parsers = "json"

# provide a named list with no arguments
parsers = list(json = list())

# provide a named list with arguments; include `rds`
parsers = list(json = list(simplifyVector = FALSE), rds = list())

# default plumber parsers
parsers = c("json", "form", "text", "octet", "multi")

Method `set404Handler()`

Sets the handler that gets called if an incoming request can’t be served by any filter, endpoint, or sub-router.

Usage

Plumber$set404Handler(fun)

Arguments

fun: a handler function.

Examples

\dontrun{
pr <- pr()
pr$set404Handler(function(req, res) {cat(req$PATH_INFO)})
}

Method `setErrorHandler()`

Sets the error handler which gets invoked if any filter or endpoint generates an error.

Usage

Plumber$setErrorHandler(fun)

Arguments

fun: a handler function.

Examples

\dontrun{
pr <- pr()
pr$setErrorHandler(function(req, res, err) {
  message("Found error: ")
  str(err)
})
}

Method `setDocs()`

Set visual documentation to use for API

See also: pr_set_docs(), register_docs(), registered_docs()

Usage

Plumber$setDocs(docs = get_option_or_env("plumber.docs", TRUE), ...)

Arguments

docs: a character value or a logical value. See pr_set_docs() for examples. If using options_plumber(), the value must be set before initializing your Plumber router.
...: Arguments for the visual documentation. See each visual documentation package for further details.

Method `setDocsCallback()`

Set a callback to notify where the API's visual documentation is located.

When set, it will be called with a character string corresponding to the API docs url. This allows RStudio to locate visual documentation.

If using options_plumber(), the value must be set before initializing your Plumber router.

Usage

Plumber$setDocsCallback(
  callback = get_option_or_env("plumber.docs.callback", NULL)
)

Arguments

callback: a callback function for taking action on the docs url. (Also accepts NULL values to disable the callback.)

Method `setDebug()`

Set debug value to include error messages.

See also: $getDebug() and pr_set_debug()

Usage

Plumber$setDebug(debug = interactive())

Arguments

debug: TRUE provides more insight into your API errors.

Method `getDebug()`

Retrieve the debug value. If it has never been set, the result of interactive() will be used.

See also: $getDebug() and pr_set_debug()

Usage

Plumber$getDebug()

Method `filter()`

Add a filter to plumber router

Usage

Plumber$filter(name, expr, serializer)

Arguments

name: a character string. Name of filter
expr: an expr that resolve to a filter function or a filter function
serializer: a serializer function

Method `setApiSpec()`

Allows to modify router autogenerated OpenAPI Specification

Note, the returned value will be sent through serializer_unboxed_json() which will turn all length 1 vectors into atomic values. To force a vector to serialize to an array of size 1, be sure to call as.list() on your value. list() objects are always serialized to an array value.

Usage

Plumber$setApiSpec(api = NULL)

Arguments

api

This can be

an OpenAPI Specification formatted list object
a function that accepts the OpenAPI Specification autogenerated by plumber and returns a OpenAPI Specification formatted list object.
a path to an OpenAPI Specification

The value returned will not be validated for OAS compatibility.

Method `getApiSpec()`

Retrieve OpenAPI file

Usage

Plumber$getApiSpec()

Method `addEndpoint()`

addEndpoint has been deprecated in v0.4.0 and will be removed in a coming release. Please use handle() instead.

Usage

Plumber$addEndpoint(
  verbs,
  path,
  expr,
  serializer,
  processors,
  preempt = NULL,
  params = NULL,
  comments
)

Arguments

verbs: verbs
path: path
expr: expr
serializer: serializer
processors: processors
preempt: preempt
params: params
comments: comments

Method `addAssets()`

addAssets has been deprecated in v0.4.0 and will be removed in a coming release. Please use mount and PlumberStatic$new() instead.

Usage

Plumber$addAssets(dir, path = "/public", options = list())

Arguments

dir: dir
path: path
options: options

Method `addFilter()`

$addFilter() has been deprecated in v0.4.0 and will be removed in a coming release. Please use $filter() instead.

Usage

Plumber$addFilter(name, expr, serializer, processors)

Arguments

name: name
expr: expr
serializer: serializer
processors: processors

Method `addGlobalProcessor()`

$addGlobalProcessor() has been deprecated in v0.4.0 and will be removed in a coming release. Please use $registerHook(s) instead.

Usage

Plumber$addGlobalProcessor(proc)

Arguments

proc: proc

Method `openAPIFile()`

Deprecated. Retrieve OpenAPI file

Usage

Plumber$openAPIFile()

Method `swaggerFile()`

Deprecated. Retrieve OpenAPI file

Usage

Plumber$swaggerFile()

Method `clone()`

The objects of this class are cloneable with this method.

Usage

Plumber$clone(deep = FALSE)

Arguments

deep: Whether to make a deep clone.

Examples


## ------------------------------------------------
## Method `Plumber$mount`
## ------------------------------------------------

if (FALSE) {
root <- pr()

users <- Plumber$new("users.R")
root$mount("/users", users)

products <- Plumber$new("products.R")
root$mount("/products", products)
}

## ------------------------------------------------
## Method `Plumber$registerHook`
## ------------------------------------------------

if (FALSE) {
pr <- pr()
pr$registerHook("preroute", function(req){
  cat("Routing a request for", req$PATH_INFO, "...\n")
})
pr$registerHooks(list(
  preserialize=function(req, value){
    print("About to serialize this value:")
    print(value)

    # Must return the value since we took one in. Here we're not choosing
    # to mutate it, but we could.
    value
  },
  postserialize=function(res){
    print("We serialized the value as:")
    print(res$body)
  }
))

pr$handle("GET", "/", function(){ 123 })
}

## ------------------------------------------------
## Method `Plumber$handle`
## ------------------------------------------------

if (FALSE) {
pr <- pr()
pr$handle("GET", "/", function(){
  "<html><h1>Programmatic Plumber!</h1></html>"
}, serializer=plumber::serializer_html())
}

## ------------------------------------------------
## Method `Plumber$setSerializer`
## ------------------------------------------------

if (FALSE) {
pr <- pr()
pr$setSerializer(serializer_unboxed_json())
}

## ------------------------------------------------
## Method `Plumber$set404Handler`
## ------------------------------------------------

if (FALSE) {
pr <- pr()
pr$set404Handler(function(req, res) {cat(req$PATH_INFO)})
}

## ------------------------------------------------
## Method `Plumber$setErrorHandler`
## ------------------------------------------------

if (FALSE) {
pr <- pr()
pr$setErrorHandler(function(req, res, err) {
  message("Found error: ")
  str(err)
})
}

Package Plumber Router

Details

See also

Super class

Public fields

Active bindings

Methods

Public methods

Method new()

Usage

Arguments

Returns

Method run()

Usage

Arguments

Method mount()

Usage

Arguments

Examples

Method unmount()

Usage

Arguments

Method registerHook()

Usage

Arguments

Examples

Method handle()

Usage

Arguments

Examples

Method removeHandle()

Usage

Arguments

Method print()

Usage

Arguments

Returns

Method serve()

Usage

Arguments

Method route()

Usage

Arguments

Method call()

Usage

Arguments

Method onHeaders()

Usage

Arguments

Method onWSOpen()

Usage

Arguments

Method setSerializer()

Usage

Arguments

Examples

Method setParsers()

Usage

Arguments

Method set404Handler()

Usage

Arguments

Examples

Method setErrorHandler()

Usage

Arguments

Examples

Method setDocs()

Usage

Arguments

Method setDocsCallback()

Usage

Arguments

Method setDebug()

Usage

Arguments

Method getDebug()

Usage

Method filter()

Usage

Method `new()`

Method `run()`

Method `mount()`

Method `unmount()`

Method `registerHook()`

Method `handle()`

Method `removeHandle()`

Method `print()`

Method `serve()`

Method `route()`

Method `call()`

Method `onHeaders()`

Method `onWSOpen()`

Method `setSerializer()`

Method `setParsers()`

Method `set404Handler()`

Method `setErrorHandler()`

Method `setDocs()`

Method `setDocsCallback()`

Method `setDebug()`

Method `getDebug()`

Method `filter()`

Method `setApiSpec()`

Method `getApiSpec()`

Method `addEndpoint()`

Method `addAssets()`

Method `addFilter()`

Method `addGlobalProcessor()`

Method `openAPIFile()`

Method `swaggerFile()`

Method `clone()`