Through the Interface

// Use lightweight F# syntax

#light

// Declare a specific namespace and module name

module MyNamespace.MyApplication

// Import managed assemblies

#I @"C:\Program Files\Autodesk\AutoCAD 2008"

#r "acdbmgd.dll"

#r "acmgd.dll"

open Autodesk.AutoCAD.Runtime

open Autodesk.AutoCAD.ApplicationServices

open Autodesk.AutoCAD.DatabaseServices

open Autodesk.AutoCAD.Geometry

open System.Xml

open System.Collections

open System.Collections.Generic

open System.IO

open System.Net

open Microsoft.FSharp.Control.CommonExtensions

// The RSS feeds we wish to get. The first two values are

// only used if our code is not able to parse the feed's XML

let feeds =

  [ ("Through the Interface",

    "http://blogs.autodesk.com/through-the-interface",

    "http://through-the-interface.typepad.com/through_the_interface/rss.xml");

    ("Don Syme's F# blog",

    "http://blogs.msdn.com/dsyme/",

    "http://blogs.msdn.com/dsyme/rss.xml");

    ("Shaan Hurley's Between the Lines",

    "http://autodesk.blogs.com/between_the_lines",

    "http://autodesk.blogs.com/between_the_lines/rss.xml");

    ("Scott Sheppard's It's Alive in the Lab",

    "http://blogs.autodesk.com/labs",

    "http://labs.blogs.com/its_alive_in_the_lab/rss.xml");

    ("Lynn Allen's Blog",

    "http://blogs.autodesk.com/lynn",

    "http://lynn.blogs.com/lynn_allens_blog/index.rdf");

    ("Heidi Hewett's AutoCAD Insider",

    "http://blogs.autodesk.com/autocadinsider",

    "http://heidihewett.blogs.com/my_weblog/index.rdf") ]

// Fetch the contents of a web page, synchronously

let httpSync (url:string) =

  let req = WebRequest.Create(url)

  use resp = req.GetResponse()

  use stream = resp.GetResponseStream()

  use reader = new StreamReader(stream)

  reader.ReadToEnd()

// Load an RSS feed's contents into an XML document object

// and use it to extract the titles and their links

// Hopefully these always match (this could be coded more

// defensively)

let titlesAndLinks (name, url, xml) =

  let xdoc = new XmlDocument()

  xdoc.LoadXml(xml)

  let titles =

    [ for n in xdoc.SelectNodes("//*[name()='title']")

        -> n.InnerText ]

  let links =

    [ for n in xdoc.SelectNodes("//*[name()='link']") ->

        let inn = n.InnerText

        if  inn.Length > 0 then

          inn

        else

          let href = n.Attributes.GetNamedItem("href").Value

          let rel = n.Attributes.GetNamedItem("rel").Value

          if href.Contains("feedburner") then

              ""

          else

            href ]

  let descs =

    [ for n in xdoc.SelectNodes

        ("//*[name()='description' or name()='content' or name()='subtitle']")

          -> n.InnerText ]

  // A local function to filter out duplicate entries in

  // a list, maintaining their current order.

  // Another way would be to use:

  //    Set.of_list lst |> Set.to_list

  // but that results in a sorted (probably reordered) list.

  let rec nub lst =

    match lst with

    | a::[] -> [a]

    | a::b ->

      if a = List.hd b then

        nub b

      else

        a::nub b

    | [] -> []

  // Filter the links to get (hopefully) the same number

  // and order as the titles and descriptions

  let real = List.filter (fun (x:string) -> x.Length > 0) 

  let lnks = real links |> nub

  // Return a link to the overall blog, if we don't have

  // the same numbers of titles, links and descriptions

  let lnum = List.length lnks

  let tnum = List.length titles

  let dnum = List.length descs

  if tnum = 0 || lnum = 0 || lnum <> tnum || dnum <> tnum then

    [(name,url,url)]

  else

    List.zip3 titles lnks descs

// For a particular (name,url) pair,

// create an AutoCAD HyperLink object

let hyperlink (name,url,desc) =

  let hl = new HyperLink()

  hl.Name <- url

  hl.Description <- desc

  (name, hl)

// Download an RSS feed and return AutoCAD HyperLinks for its posts

let hyperlinksSync (name, url, feed) =

  let xml = httpSync feed

  let tl = titlesAndLinks (name, url, xml)

  List.map hyperlink tl

// Now we declare our command

[<CommandMethod("rss")>]

let createHyperlinksFromRss() =

  // Let's get the usual helpful AutoCAD objects

  let doc =

    Application.DocumentManager.MdiActiveDocument

  let db = doc.Database

  // "use" has the same effect as "using" in C#

  use tr =

    db.TransactionManager.StartTransaction()

  // Get appropriately-typed BlockTable and BTRs

  let bt =

    tr.GetObject

      (db.BlockTableId,OpenMode.ForRead)

    :?> BlockTable

  let ms =

    tr.GetObject

      (bt.[BlockTableRecord.ModelSpace],

      OpenMode.ForWrite)

    :?> BlockTableRecord

  // Add text objects linking to the provided list of

  // HyperLinks, starting at the specified location

  // Note the valid use of tr and ms, as they are in scope

  let addTextObjects pt lst =

    // Use a for loop, as we care about the index to

    // position the various text items

    let len = List.length lst

    for index = 0 to len - 1 do

      let txt = new DBText()

      let (name:string,hl:HyperLink) = List.nth lst index

      txt.TextString <- name

      let offset =

        if index = 0 then

          0.0

        else

          1.0

      // This is where you can adjust:

      //  the initial outdent (x value)

      //  and the line spacing (y value)

      let vec =

        new Vector3d

          (1.0 * offset,

          -0.5 * (Int32.to_float index),

          0.0)

      let pt2 = pt + vec

      txt.Position <- pt2

      ms.AppendEntity(txt) |> ignore

      tr.AddNewlyCreatedDBObject(txt,true)

      txt.Hyperlinks.Add(hl) |> ignore

  // Here's where we use the varous functions

  // we've defined

  let links =

    List.map hyperlinksSync feeds

  // Add the resulting objects to the model-space 

  let len = List.length links

  for index = 0 to len - 1 do

    // This is where you can adjust:

    //  the column spacing (x value)

    //  the vertical offset from origin (y axis)

    let pt =

      new Point3d

        (15.0 * (Int32.to_float index),

        30.0,

        0.0)

    addTextObjects pt (List.nth links index)

  tr.Commit()