mythz · September 27, 2015 10:58
diff --git a/FTweetStackAsp.fs b/FTweetStackAsp.fs
 (*  F# Twitter API ServiceStack ASP.NET Web Service on Windows/Mono/OSX

    Instructions:
      1) download https://github.com/ServiceStack/ServiceStack/downloads
      2) fsharpc -r:ServiceStack.Common.dll -r:ServiceStack.Interfaces.dll -r:ServiceStack.Text.dll -r:ServiceStack.dll --target:library FTweetStackAsp.fs
      3) mkdir bin && cp *.dll bin
      4) echo "<%@ Application Inherits=\"FTweetStack.Global\" %>" >> Global.asax
      5) copy Web.config mappings from https://www.servicestack.net/ServiceStack.Hello/
      6) xsp4
 *)

 namespace FTweetStack

    open System
    open ServiceStack.ServiceHost
    open ServiceStack.WebHost.Endpoints

    module FTweetStack =

        type System.Net.WebRequest with
            member x.GetResponseAsync() = Async.FromBeginEnd(x.BeginGetResponse, x.EndGetResponse)
                            
        let asyncHttp (url:string) =
            async {
                //printfn "downloading: %s" url
                let req = System.Net.WebRequest.Create(url)
                let! rsp = req.GetResponseAsync()
                use stream = rsp.GetResponseStream()
                use reader = new System.IO.StreamReader(stream)
                return reader.ReadToEnd() }

        let asyncJson url =
            async {
                try
                    return! asyncHttp url
                with 
                    | ex -> printfn "Error downloading: %s => %s" url ex.Message; return "[]" }

        let batchesOf size (s: seq<'v>) =
            seq {
                let en = s.GetEnumerator ()
                let more = ref true
                while !more do
                let group = [
                    let i = ref 0
                    while !i < size && en.MoveNext () do
                        yield en.Current
                        i := !i + 1 ]
                if List.isEmpty group then
                    more := false
                else
                    yield group }

        let joinWith delim seq =
            let sb = new System.Text.StringBuilder()
            seq |> Seq.iter (fun x -> sb.Append((if sb.Length > 0 then delim else "") + x.ToString()) |> ignore)
            sb.ToString()
        let join seq = joinWith "," seq

        let jsonTo<'a> json = ServiceStack.Text.JsonSerializer.DeserializeFromString<'a>(json)

        type UserStat = {
            mutable id: uint64;
            mutable screen_name: string;
            mutable name: string;
            mutable friends_count: int;
            mutable followers_count: int;
            mutable listed_count: int;
            mutable statuses_count: int }

        type TwitterIds = { mutable ids: uint64[]; }    
        
        let asyncUsers      screenNames = asyncJson("https://api.twitter.com/1/users/lookup.json?screen_name=" + (screenNames |> join)) 
        let asyncFollowerIds screenName = asyncJson("https://api.twitter.com/1/followers/ids.json?screen_name=" + screenName)
        let asyncFriendIds   screenName = asyncJson("https://api.twitter.com/1/friends/ids.json?screen_name=" + screenName)
        let asyncUserIds        userIds = asyncJson("https://api.twitter.com/1/users/lookup.json?user_id=" + (userIds |> join)) 
    
        let userCache = System.Collections.Concurrent.ConcurrentDictionary<uint64,UserStat>()

        let usersByIds userIds = 
            let cachedIds, missingIds = userIds |> List.partition userCache.ContainsKey
            missingIds |> batchesOf 100 
                |> Seq.map asyncUserIds
                |> Async.Parallel |> Async.RunSynchronously
                |> Seq.map jsonTo<UserStat[]>
                |> Seq.collect (fun xs -> xs |> Seq.map (fun x -> userCache.TryAdd(x.id, x) |> ignore; x)) |> Seq.toList  
                |> List.append (cachedIds |> List.map (fun x -> userCache.TryGetValue x |> snd))

        let followerIds   screenName = (asyncFollowerIds screenName |> Async.RunSynchronously |> jsonTo<TwitterIds>).ids |> Array.toList
        let friendIds     screenName = (asyncFriendIds screenName   |> Async.RunSynchronously |> jsonTo<TwitterIds>).ids |> Array.toList
        let followers     screenName = followerIds screenName |> usersByIds
        let friends       screenName = friendIds screenName   |> Seq.toList |> usersByIds
        let usersByNames screenNames = asyncUsers screenNames |> Async.RunSynchronously |> jsonTo<UserStat[]> |> Seq.toList

    open FTweetStack
    
    //Define Web Services
    type UserStats = { mutable ScreenNames: string; }
    type UserStatsService() =
        interface IService<UserStats> with
            member this.Execute (req:UserStats) = req.ScreenNames.Split(',') |> usersByNames :> Object
    
    type FollowerStats = { mutable ScreenName: string; }
    type FollowerStatsService() =
        interface IService<FollowerStats> with
            member this.Execute (req:FollowerStats) = followers req.ScreenName :> Object
    
    type FriendsStats = { mutable ScreenName: string; }
    type FriendsStatsService() =
        interface IService<FriendsStats> with
            member this.Execute (req:FriendsStats) = friends req.ScreenName :> Object


    //Define the Web Services AppHost
    type AppHost =
        inherit AppHostBase
        new() = { inherit AppHostBase("FTweetStack Services", typeof<UserStatsService>.Assembly ) }
        override this.Configure container =
            base.Routes
                .Add<UserStats>("/users/{ScreenNames}") 
                .Add<FollowerStats>("/followers/{ScreenName}") 
                .Add<FriendsStats>("/friends/{ScreenName}") 
                    |> ignore

    type Global =
        inherit System.Web.HttpApplication
        new() = { }
        member x.Application_Start() = 
            let appHost = new AppHost()
            appHost.Init()
	(* F# Twitter API ServiceStack ASP.NET Web Service on Windows/Mono/OSX

	Instructions:
	1) download https://github.com/ServiceStack/ServiceStack/downloads
	2) fsharpc -r:ServiceStack.Common.dll -r:ServiceStack.Interfaces.dll -r:ServiceStack.Text.dll -r:ServiceStack.dll --target:library FTweetStackAsp.fs
	3) mkdir bin && cp *.dll bin
	4) echo "<%@ Application Inherits=\"FTweetStack.Global\" %>" >> Global.asax
	5) copy Web.config mappings from https://www.servicestack.net/ServiceStack.Hello/
	6) xsp4
	*)

	namespace FTweetStack

	open System
	open ServiceStack.ServiceHost
	open ServiceStack.WebHost.Endpoints

	module FTweetStack =

	type System.Net.WebRequest with
	member x.GetResponseAsync() = Async.FromBeginEnd(x.BeginGetResponse, x.EndGetResponse)

	let asyncHttp (url:string) =
	async {
	//printfn "downloading: %s" url
	let req = System.Net.WebRequest.Create(url)
	let! rsp = req.GetResponseAsync()
	use stream = rsp.GetResponseStream()
	use reader = new System.IO.StreamReader(stream)
	return reader.ReadToEnd() }

	let asyncJson url =
	async {
	try
	return! asyncHttp url
	with
	\| ex -> printfn "Error downloading: %s => %s" url ex.Message; return "[]" }

	let batchesOf size (s: seq<'v>) =
	seq {
	let en = s.GetEnumerator ()
	let more = ref true
	while !more do
	let group = [
	let i = ref 0
	while !i < size && en.MoveNext () do
	yield en.Current
	i := !i + 1 ]
	if List.isEmpty group then
	more := false
	else
	yield group }

	let joinWith delim seq =
	let sb = new System.Text.StringBuilder()
	seq \|> Seq.iter (fun x -> sb.Append((if sb.Length > 0 then delim else "") + x.ToString()) \|> ignore)
	sb.ToString()
	let join seq = joinWith "," seq

	let jsonTo<'a> json = ServiceStack.Text.JsonSerializer.DeserializeFromString<'a>(json)

	type UserStat = {
	mutable id: uint64;
	mutable screen_name: string;
	mutable name: string;
	mutable friends_count: int;
	mutable followers_count: int;
	mutable listed_count: int;
	mutable statuses_count: int }

	type TwitterIds = { mutable ids: uint64[]; }

	let asyncUsers screenNames = asyncJson("https://api.twitter.com/1/users/lookup.json?screen_name=" + (screenNames \|> join))
	let asyncFollowerIds screenName = asyncJson("https://api.twitter.com/1/followers/ids.json?screen_name=" + screenName)
	let asyncFriendIds screenName = asyncJson("https://api.twitter.com/1/friends/ids.json?screen_name=" + screenName)
	let asyncUserIds userIds = asyncJson("https://api.twitter.com/1/users/lookup.json?user_id=" + (userIds \|> join))

	let userCache = System.Collections.Concurrent.ConcurrentDictionary<uint64,UserStat>()

	let usersByIds userIds =
	let cachedIds, missingIds = userIds \|> List.partition userCache.ContainsKey
	missingIds \|> batchesOf 100
	\|> Seq.map asyncUserIds
	\|> Async.Parallel \|> Async.RunSynchronously
	\|> Seq.map jsonTo<UserStat[]>
	\|> Seq.collect (fun xs -> xs \|> Seq.map (fun x -> userCache.TryAdd(x.id, x) \|> ignore; x)) \|> Seq.toList
	\|> List.append (cachedIds \|> List.map (fun x -> userCache.TryGetValue x \|> snd))

	let followerIds screenName = (asyncFollowerIds screenName \|> Async.RunSynchronously \|> jsonTo<TwitterIds>).ids \|> Array.toList
	let friendIds screenName = (asyncFriendIds screenName \|> Async.RunSynchronously \|> jsonTo<TwitterIds>).ids \|> Array.toList
	let followers screenName = followerIds screenName \|> usersByIds
	let friends screenName = friendIds screenName \|> Seq.toList \|> usersByIds
	let usersByNames screenNames = asyncUsers screenNames \|> Async.RunSynchronously \|> jsonTo<UserStat[]> \|> Seq.toList

	open FTweetStack

	//Define Web Services
	type UserStats = { mutable ScreenNames: string; }
	type UserStatsService() =
	interface IService<UserStats> with
	member this.Execute (req:UserStats) = req.ScreenNames.Split(',') \|> usersByNames :> Object

	type FollowerStats = { mutable ScreenName: string; }
	type FollowerStatsService() =
	interface IService<FollowerStats> with
	member this.Execute (req:FollowerStats) = followers req.ScreenName :> Object

	type FriendsStats = { mutable ScreenName: string; }
	type FriendsStatsService() =
	interface IService<FriendsStats> with
	member this.Execute (req:FriendsStats) = friends req.ScreenName :> Object


	//Define the Web Services AppHost
	type AppHost =
	inherit AppHostBase
	new() = { inherit AppHostBase("FTweetStack Services", typeof<UserStatsService>.Assembly ) }
	override this.Configure container =
	base.Routes
	.Add<UserStats>("/users/{ScreenNames}")
	.Add<FollowerStats>("/followers/{ScreenName}")
	.Add<FriendsStats>("/friends/{ScreenName}")
	\|> ignore

	type Global =
	inherit System.Web.HttpApplication
	new() = { }
	member x.Application_Start() =
	let appHost = new AppHost()
	appHost.Init()