Options for configuring a client.

A lens onto configuration of the connection manager provided by the http-client package.

In this example, we enable the use of OpenSSL for (hopefully) secure connections:

import OpenSSL.Session (context)
import Network.HTTP.Client.OpenSSL

let opts = defaults & manager .~ Left (opensslManagerSettings context)
withOpenSSL $
  getWith opts "https://httpbin.org/get"
 

In this example, we also set the response timeout to 10000 microseconds:

import OpenSSL.Session (context)
import Network.HTTP.Client.OpenSSL
import Network.HTTP.Client (defaultManagerSettings, managerResponseTimeout)

let opts = defaults & manager .~ Left (opensslManagerSettings context)
                    & manager .~ Left (defaultManagerSettings { managerResponseTimeout = Just 10000 } )

withOpenSSL $
  getWith opts "https://httpbin.org/get"
 

A lens onto all headers with the given name (there can legitimately be zero or more).

Example:

let opts = defaults & header "Accept" .~ ["*/*"]
getWith opts "http://httpbin.org/get"
 

A lens onto all query parameters with the given name (there can legitimately be zero or more).

In this example, we construct the query URL "http://httpbin.org/get?foo=bar&foo=quux".

let opts = defaults & param "foo" .~ ["bar", "quux"]
getWith opts "http://httpbin.org/get"
 

A lens onto the maximum number of redirects that will be followed before an exception is thrown.

In this example, a HttpException will be thrown with a TooManyRedirects constructor, because the maximum number of redirects allowed will be exceeded.

let opts = defaults & redirects .~ 3
getWith opts "http://httpbin.org/redirect/5"
 

A lens onto all headers (there can legitimately be zero or more).

In this example, we print all the headers sent by default with every request.

print (defaults ^. headers)
 

A lens onto all query parameters.

A traversal onto the cookie with the given name, if one exists.

N.B. This is an "illegal" Traversal': we can change the cookieName of the associated Cookie so that it differs from the name provided to this function.

A lens onto all cookies.

A lens to get the optional status check function

Supported authentication types.

Do not use HTTP authentication unless you are using TLS encryption. These authentication tokens can easily be captured and reused by an attacker if transmitted in the clear.

A lens onto request authentication.

Example (note the use of TLS):

let opts = defaults & auth ?~ basicAuth "user" "pass"
getWith opts "https://httpbin.org/basic-auth/user/pass"
 

Basic authentication. This consists of a plain username and password.

Example (note the use of TLS):

let opts = defaults & auth ?~ basicAuth "user" "pass"
getWith opts "https://httpbin.org/basic-auth/user/pass"
 

Note here the use of the ?~ setter to turn an Auth into a Maybe Auth, to make the type of the RHS compatible with the auth lens.

>>> let opts = defaults & auth ?~ basicAuth "user" "pass"
>>> r <- getWith opts "https://httpbin.org/basic-auth/user/pass"
>>> r ^? responseBody . key "authenticated"
Just (Bool True)

OAuth1 authentication. This consists of a consumer token, a consumer secret, a token and a token secret

An OAuth2 bearer token. This is treated by many services as the equivalent of a username and password.

Example (note the use of TLS):

let opts = defaults & auth ?~ oauth2Bearer "1234abcd"
getWith opts "https://public-api.wordpress.com/rest/v1/me/"
 

A not-quite-standard OAuth2 bearer token (that seems to be used only by GitHub). This will be treated by whatever services accept it as the equivalent of a username and password.

Example (note the use of TLS):

let opts = defaults & auth ?~ oauth2Token "abcd1234"
getWith opts "https://api.github.com/user"
 

AWS v4 request signature.

Example (note the use of TLS):

let opts = defaults & auth ?~ 'awsAuth AWSv4' "key" "secret"
getWith opts "https://dynamodb.us-west-2.amazonaws.com"
 

Define a HTTP proxy, consisting of a hostname and port number.

A lens onto proxy configuration.

Example:

let opts = defaults & proxy ?~ httpProxy "localhost" 8000
getWith opts "http://httpbin.org/get"
 

Note here the use of the ?~ setter to turn a Proxy into a Maybe Proxy, to make the type of the RHS compatible with the proxy lens.

Proxy configuration.

Example:

let opts = defaults & proxy ?~ httpProxy "localhost" 8000
getWith opts "http://httpbin.org/get"
 

Note here the use of the ?~ setter to turn a Proxy into a Maybe Proxy, to make the type of the RHS compatible with the proxy lens.

A product type for representing more complex payload types.

A key/value pair for an application/x-www-form-urlencoded POST request body.

A type that can be rendered as the value portion of a key/value pair for use in an application/x-www-form-urlencoded POST body. Intended for use with the FormParam type.

The instances for String, strict Text, and lazy Text are all encoded using UTF-8 before being URL-encoded.

The instance for Maybe gives an empty string on Nothing, and otherwise uses the contained type's instance.

A single part of a multipart message.

A lens onto the name of the input element associated with part of a multipart form upload.

A lens onto the filename associated with part of a multipart form upload.

A lens onto the content-type associated with part of a multipart form upload.

A lens onto the code that fetches the data associated with part of a multipart form upload.

Make a Part whose content is a strict ByteString.

The Part does not have a file name or content type associated with it.

Make a Part whose content is a lazy ByteString.

The Part does not have a file name or content type associated with it.

Make a Part whose content is a strict Text, encoded as UTF-8.

The Part does not have a file name or content type associated with it.

Make a Part whose content is a String, encoded as UTF-8.

The Part does not have a file name or content type associated with it.

Make a Part from a file.

The entire file will reside in memory at once. If you want constant memory usage, use partFileSource.

The FilePath supplied will be used as the file name of the Part. If you do not want to reveal this name to the server, you must remove it prior to uploading.

The Part does not have a content type associated with it.

Stream a Part from a file.

The FilePath supplied will be used as the file name of the Part. If you do not want to reveal this name to the server, you must remove it prior to uploading.

The Part does not have a content type associated with it.

A simple representation of the HTTP response.

Since 0.1.0

A lens onto the body of a response.

r <- get "http://httpbin.org/get"
print (r ^. responseBody)
 

A lens onto all matching named headers in an HTTP response.

To access exactly one header (the result will be the empty string if there is no match), use the (^.) operator.

r <- get "http://httpbin.org/get"
print (r ^. responseHeader "Content-Type")
 

To access at most one header (the result will be Nothing if there is no match), use the (^?) operator.

r <- get "http://httpbin.org/get"
print (r ^? responseHeader "Content-Transfer-Encoding")
 

To access all (zero or more) matching headers, use the (^..) operator.

r <- get "http://httpbin.org/get"
print (r ^.. responseHeader "Set-Cookie")
 

A fold over Link headers, matching on both parameter name and value.

For example, here is a Link header returned by the GitHub search API.

Link:
  <https://api.github.com/search/code?q=addClass+user%3Amozilla&page=2>; rel="next",
  <https://api.github.com/search/code?q=addClass+user%3Amozilla&page=34>; rel="last"

And here is an example of how we can retrieve the URL for the next link programatically.

r <- get "https://api.github.com/search/code?q=addClass+user:mozilla"
print (r ^? responseLink "rel" "next" . linkURL)
 

A fold over any cookies that match the given name.

r <- get "http://www.nytimes.com/"
print (r ^? responseCookie "RMID")
 

A lens onto all headers in an HTTP response.

A lens onto all cookies set in the response.

A lens onto the status of an HTTP response.

HTTP Status.

Only the statusCode is used for comparisons.

Please use mkStatus to create status codes from code and message, or the Enum instance or the status code constants (like ok200). There might be additional record members in the future.

Note that the Show instance is only for debugging.

A lens onto the numeric identifier of an HTTP status.

A lens onto the textual description of an HTTP status.

An element of a Link header.

A lens onto the URL portion of a Link element.

A lens onto the parameters of a Link element.

The error type used by asJSON and asValue if a failure occurs when parsing a response body as JSON.

Convert the body of an HTTP response from JSON to a suitable Haskell type.

In this example, we use asJSON in the IO monad, where it will throw a JSONError exception if conversion to the desired type fails.

 {-# LANGUAGE DeriveGeneric #-}
import GHC.Generics (Generic)

 {- This Haskell type corresponds to the structure of a
   response body from httpbin.org. -}

data GetBody = GetBody {
    headers :: Map Text Text
  , args :: Map Text Text
  , origin :: Text
  , url :: Text
  } deriving (Show, Generic)

 -- Get GHC to derive a FromJSON instance for us.
instance FromJSON GetBody

 {- The fact that we want a GetBody below will be inferred by our
   use of the "headers" accessor function. -}

foo = do
  r <- asJSON =<< get "http://httpbin.org/get"
  print (headers (r ^. responseBody))
 

If we use asJSON in the Either monad, it will return Left with a JSONError payload if conversion fails, and Right with a Response whose responseBody is the converted value on success.

Convert the body of an HTTP response from JSON to a Value.

In this example, we use asValue in the IO monad, where it will throw a JSONError exception if the conversion to Value fails.

foo = do
  r <- asValue =<< get "http://httpbin.org/get"
  print (r ^? responseBody . key "headers" . key "User-Agent")
 

A lens onto the name of a cookie.

A lens onto the value of a cookie.

A lens onto the expiry time of a cookie.

A lens onto the domain of a cookie.

A lens onto the path of a cookie.

Turn an attoparsec Parser into a Fold.

Both headers and bodies can contain complicated data that we may need to parse.

Example: when responding to an OPTIONS request, a server may return the list of verbs it supports in any order, up to and including changing the order on every request (which httpbin.org /actually does/!). To deal with this possibility, we parse the list, then sort it.

>>> import Data.Attoparsec.ByteString.Char8 as A
>>> import Data.List (sort)
>>> 
>>> let comma = skipSpace >> "," >> skipSpace
>>> let verbs = A.takeWhile isAlpha_ascii `sepBy` comma
>>> 
>>> r <- options "http://httpbin.org/get"
>>> r ^. responseHeader "Allow" . atto verbs . to sort
["GET","HEAD","OPTIONS"]

The same as atto, but ensures that the parser consumes the entire input.

Equivalent to:

atto_ myParser = atto (myParser <* endOfInput)