Create a properly encoded URL with a query string. The first argument is the portion of the URL before the query string, which is assumed to be properly encoded already. The second argument is a list of all the key/value pairs needed for the query string. Both the keys and values will be appropriately encoded, so they can contain spaces, ampersands, etc.

url "http://example.com/users" [ ("name", "john doe"), ("age", "30") ] --> "http://example.com/users?name=john+doe&age=30"

Encode a string to be placed in any part of a URI. Same behavior as JavaScript's encodeURIComponent function.

uriEncode "hat" --> "hat"


uriEncode "to be" --> "to%20be"


uriEncode "99%" --> "99%25"

Decode a URI string. Same behavior as JavaScript's decodeURIComponent function.

-- ASCII
uriDecode "hat" --> "hat"


uriDecode "to%20be" --> "to be"


uriDecode "99%25" --> "99%"




-- UTF-8
uriDecode "%24" --> "$"


uriDecode "%C2%A2" --> "¢"


uriDecode "%E2%82%AC" --> "€"




-- Failing
uriDecode "%" --> "%"  -- not followed by two hex digits


uriDecode "%XY" --> "%XY"  -- not followed by two HEX digits


uriDecode "%C2" --> "%C2"  -- half of the "¢" encoding "%C2%A2"

In later verions of Elm, the signature of the equivalent functions is String -> Maybe String to account for the fact that the input may be invalidly encoded. We can't do exactly that here, so if the input is invalid, we return it unchanged.

Send a GET request to the given URL. You will get the entire response as a string.

hats : Task Error String
hats =
    getString "http://example.com/hat-categories.markdown"

Send a GET request to the given URL. You also specify how to decode the response.

hats : Task Error (List String)
hats =
    get (list string) "http://example.com/hat-categories.json"

Send a POST request to the given URL, carrying the given body. You also specify how to decode the response with a JSON decoder.

hats : Task Error (List String) hats = post (list string) "http://example.com/hat-categories.json" empty

The kinds of errors you typically want in practice. When you get a response but its status is not in the 200 range, it will trigger a BadResponse. When you try to decode JSON but something goes wrong, you will get an UnexpectedPayload.

A new BadUrl constructor has been added which was not in Elm 0.17.

An opaque type representing the body of your HTTP message. With GET requests this is empty, but in other cases it may be a string or blob.

An empty request body, no value will be sent along.

Provide a string as the body of the request.

Notice that the first argument is a MIME type so we know to add Content-Type: application/json to our request headers. Make sure your MIME type matches your data. Some servers are strict about this!

Im Elm 0.17, the first parameter was missing, and it seems that Elm did not send a Content-type header at all. In later versions of Elm, there is no way of avoiding sending a Content-type header, so we have to supply the content type here. Thus, you will need to modify your code to specify the desired content type.

Create multi-part request bodies, allowing you to send many chunks of data all in one request. All chunks of data must be given a name.

Currently, you can only construct stringData, but we will support blobData and fileData once we have proper APIs for those types of data in Elm.

Represents data that can be put in a multi-part body. Right now it only supports strings, but we will support blobs and files when we get an API for them in Elm.

A named chunk of string data.

import Json.Encode as JS


body =
    multipart
        [ stringData "user" (JS.encode user)
        , stringData "payload" (JS.encode payload)
        ]

Send a request exactly how you want it. The Settings argument lets you configure things like timeouts and progress monitoring. The Request argument defines all the information that will actually be sent along to a server.

crossOriginGet : String -> String -> Task RawError Response
crossOriginGet origin url =
    send defaultSettings
        { verb = "GET"
        , headers = [ ( "Origin", origin ) ]
        , url = url
        , body = empty
        }

Fully specify the request you want to send. For example, if you want to send a request between domains (CORS request) you will need to specify some headers manually.

corsPost : Request
corsPost =
    { verb = "POST"
    , headers =
        [ ( "Origin", "http://elm-lang.org" )
        , ( "Access-Control-Request-Method", "POST" )
        , ( "Access-Control-Request-Headers", "X-Custom-Header" )
        ]
    , url = "http://example.com/hats"
    , body = empty
    }

In later versions of Elm, this becomes an opaque type.

Configure your request if you need specific behavior.

• timeout lets you specify how long you are willing to wait for a response before giving up. By default it is 0 which means “never give up!”

It is not feasible to re-implement the onStart or onProgress fields with the same signatures as in Elm 0.17. For this reason, those fields have been omitted ... to track progress, you will need to use the Elm 0.19 APIs.

It is also not possible in Elm 0.19 to re-implement what Elm 0.17 did with the desiredResponseType field. Therefore, it has also been omitted.

The default settings used by get and post.

{ timeout = 0
, onStart = Nothing
, onProgress = Nothing
, desiredResponseType = Nothing
, withCredentials = False
}

All the details of the response. There are many weird facts about responses which include:

• The status may be 0 in the case that you load something from file://
• You cannot handle redirects yourself, they will all be followed automatically. If you want to know if you have gone through one or more redirect, the url field will let you know who sent you the response, so you will know if it does not match the URL you requested.
• You are allowed to have duplicate headers, and their values will be combined into a single comma-separated string.

We have left these underlying facts about XMLHttpRequest as is because one goal of this library is to give a low-level enough API that others can build whatever helpful behavior they want on top of it.

The information given in the response. Currently there is no way to handle Blob types since we do not have an Elm API for that yet. This type will expand as more values become available in Elm itself.

Turn a Response into an Elm value that is easier to deal with. Helpful if you are making customized HTTP requests with send, as is the case with get and post.

Given a Response this function will:

• Check that the status code is in the 200 range.
• Make sure the response Value is a string.
• Convert the string to Elm with the given Decoder.

Assuming all these steps succeed, you will get an Elm value as the result!

The things that count as errors at the lowest level. Technically, getting a response back with status 404 is a “successful” response in that you actually got all the information you asked for.

The fromJson function and Error type provide higher-level errors, but the point of RawError is to allow you to define higher-level errors however you want.

We needed to add a new constructor RawBadUrl to cover an error state added in Elm 0.18.