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module Giraffe.Htmx
open Microsoft.AspNetCore.Http
open Microsoft.Extensions.Primitives
open System
/// Determine if the given header is present
let private hdr (headers : IHeaderDictionary) hdr =
match headers.[hdr] with it when it = StringValues.Empty -> None | it -> Some it.[0]
/// Extensions to the header dictionary
type IHeaderDictionary with
/// Indicates that the request is via an element using `hx-boost`
member this.HxBoosted with get () = hdr this "HX-Boosted" |> Option.map bool.Parse
/// The current URL of the browser _(note that this does not update until after settle)_
member this.HxCurrentUrl with get () = hdr this "HX-Current-URL" |> Option.map Uri
/// `true` if the request is for history restoration after a miss in the local history cache
member this.HxHistoryRestoreRequest with get () = hdr this "HX-History-Restore-Request" |> Option.map bool.Parse
/// The user response to an `hx-prompt`
member this.HxPrompt with get () = hdr this "HX-Prompt"
/// `true` if the request came from HTMX
member this.HxRequest with get () = hdr this "HX-Request" |> Option.map bool.Parse
/// The `id` of the target element if it exists
member this.HxTarget with get () = hdr this "HX-Target"
/// The `id` of the triggered element if it exists
member this.HxTrigger with get () = hdr this "HX-Trigger"
/// The `name` of the triggered element if it exists
member this.HxTriggerName with get () = hdr this "HX-Trigger-Name"
/// Extensions for the request object
type HttpRequest with
/// Whether this request was initiated from htmx
member this.IsHtmx with get () = this.Headers.HxRequest |> Option.defaultValue false
/// Whether this request is an htmx history-miss refresh request
member this.IsHtmxRefresh with get () =
this.IsHtmx && (this.Headers.HxHistoryRestoreRequest |> Option.defaultValue false)
/// HTTP handlers for setting output headers
[<AutoOpen>]
module Handlers =
/// Convert a boolean to lowercase `true` or `false`
let private toLowerBool (trueOrFalse : bool) =
(string trueOrFalse).ToLowerInvariant ()
/// Serialize a list of key/value pairs to JSON (very rudimentary)
let private toJson (evts : (string * string) list) =
evts
|> List.map (fun evt -> sprintf "\"%s\": \"%s\"" (fst evt) ((snd evt).Replace ("\"", "\\\"")))
|> String.concat ", "
|> sprintf "{ %s }"
// Pushes a new url into the history stack
let withHxPush : string -> HttpHandler =
setHttpHeader "HX-Push"
// Explicitly do not push a new URL into the history stack
let withHxNoPush : HttpHandler =
toLowerBool false |> withHxPush
/// Can be used to do a client-side redirect to a new location
let withHxRedirect : string -> HttpHandler =
setHttpHeader "HX-Redirect"
/// If set to `true` the client side will do a a full refresh of the page
let withHxRefresh : bool -> HttpHandler =
toLowerBool >> setHttpHeader "HX-Refresh"
/// Allows you to override the `hx-target` attribute
let withHxRetarget : string -> HttpHandler =
setHttpHeader "HX-Retarget"
/// Allows you to trigger a single client side event
let withHxTrigger : string -> HttpHandler =
setHttpHeader "HX-Trigger"
/// Allows you to trigger multiple client side events
let withHxTriggerMany evts : HttpHandler =
toJson evts |> setHttpHeader "HX-Trigger"
/// Allows you to trigger a single client side event after changes have settled
let withHxTriggerAfterSettle : string -> HttpHandler =
setHttpHeader "HX-Trigger-After-Settle"
/// Allows you to trigger multiple client side events after changes have settled
let withHxTriggerManyAfterSettle evts : HttpHandler =
toJson evts |> setHttpHeader "HX-Trigger-After-Settle"
/// Allows you to trigger a single client side event after DOM swapping occurs
let withHxTriggerAfterSwap : string -> HttpHandler =
setHttpHeader "HX-Trigger-After-Swap"
/// Allows you to trigger multiple client side events after DOM swapping occurs
let withHxTriggerManyAfterSwap evts : HttpHandler =
toJson evts |> setHttpHeader "HX-Trigger-After-Swap"