Huddled Masses » HttpWebRequest http://huddledmasses.org You can do more than breathe for free... Tue, 31 Aug 2010 04:13:52 +0000 en hourly 1 http://wordpress.org/?v=3.0.1 Get-Web (Another round of wget for PowerShell) http://huddledmasses.org/get-web-another-round-of-wget-for-powershell/ http://huddledmasses.org/get-web-another-round-of-wget-for-powershell/#comments Fri, 02 May 2008 02:08:08 +0000 Joel 'Jaykul' Bennett http://HuddledMasses.org/?p=520 Well, after multiple attempts at a wget PowerShell script (the last one works very well for downloading web pages, files, as long as you don’t need to send post parameters or anything like that) ... I found myself writing a script last week that included a custom HTTP POST function as well as using some prior functionality I wrote (ConvertFrom-Html) to convert HTML files to XML documents — which PowerShell can deal with nicely.

So I’ve taken my Huddled.Html code and worked it in together with a few extra bits … and I’m releasing it under the new name “PoshHttp” (which has the sole benefit of being short, in the case when you need to type the full command names, like: PoshHttp\Get-Web.

In lieu of providing proper documentation for this, there’s a script below which shows off some of the features of the Get-Web cmdlet … but first, you’re going to want to download PoshHttp and I can give you a basic overview.

Get-Web

Downloads a file from the web URI, optionally passing POST or GET parameters which it accepts as a Hashtable. If the resulting file is an xml or html file, it converts it to XML and outputs it as an XmlDocument object. If they are not, it saves them to file, and outputs the FileInfo object.

  • Plain will prevent the conversion to xml
  • Save will force saving to file (either xml or binaries)
  • Path lets you specify the file name/path (normally, it selects a path based on what you’re downloading).
  • Force will prevent it from asking if you want to overwrite files

ConvertFrom-Html

Converts HTML to XML. I’ll eventually tweak this so it supports passing it a file path and even saving the xml in-place on the original file … but for now you can use it on a stream of text, like this: (Get-Content file.html | ConvertFrom-Html).save( "file.xml" ). Note that it outputs an xmldocument object … you can get the xml as text to the console using Get_OuterXml().

ConvertTo-Hashtable

Converts a url-style query string or NameValueCollection into a Hashtable. It’s mainly to make it easier to use the Get-Web in cases where you’re getting the URL or POST data from elsewhere.

Here’s a script with a few example uses of Get-Web:


## Find the url of the image (download an html file as an xmldocument)
$ImgURL = (Get-Web http://dilbert.com/fast/).html.body.div.img.src

if($Host.Name -eq "PoshConsole") {
      #In PoshConsole, show it inline
      $ImgUrl | Out-WPF -source "<Image Height='174' Source='{Binding Path=AbsoluteUri}' xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' />"
} else {
   ## Use Get-Web to download an image (it's saved to file by default), and open it in my default viewer
   ## When Get-Web saves a file, it outputs the [FileInfo] which can be invoked with &
   &(Get-Web "http://dilbert.com$ImgURL" -force)
}

###################################################################################################
## Determine the language of a snippet of text (5 words minimum for best results)
function Resolve-Language([string]$text) {
   ## This time, we're using Get-Web with POST parameters ...
   return (Get-Web "http://www.xrce.xerox.com/cgi-bin/mltt/LanguageGuesser" -Post (@{Text=$text})
          ).SelectSingleNode("//font")."#text".Trim()
}

###################################################################################################
## Translate text to English ... This is obviously reworkable as a general translation tool
## But I don't have much use for that, since I only speak Spanish, English, and code ...
function Get-English([string]$text,[string]$FromLanguage) {
   if(!$FromLanguage) {
      $FromLanguage = Resolve-Language $text
   }
   $post = @{text=$text}
   switch($FromLanguage) {
      "Arabic"       { $post["langpair"] = "ar|en" }
      "Chinese"      { $post["langpair"] = "zh|en" }
      "Dutch"        { $post["langpair"] = "nl|en" }
      "French"       { $post["langpair"] = "fr|en" }
      "German"       { $post["langpair"] = "de|en" }
      "Greek"        { $post["langpair"] = "el|en" }
      "Italian"      { $post["langpair"] = "it|en" }
      "Japanese"     { $post["langpair"] = "ja|en" }
      "Korean"       { $post["langpair"] = "ko|en" }
      "Portuguese"   { $post["langpair"] = "pt|en" }
      "Russian"      { $post["langpair"] = "ru|en" }
      "Spanish"      { $post["langpair"] = "es|en" }
      default { return "Sorry, but I can't translate $FromLanguage" }
   }
   
   ## Using Get-Web with POST parameters ... nothing remarkable, but it's just nice with the previous function ...
   return (Get-Web "http://www.google.com/translate_t" -Post $post
          ).SelectSingleNode("//div[@id='result_box']")."#text".Trim()
}


####################################
## Figure out the real url behind those shortened forms
function Resolve-URL([string[]]$urls) {
   [regex]$snip  = "(?:https?://)?(?:snurl|snipr|snipurl)\.com/([^?/ ]*)\b"
   [regex]$tiny  = "(?:https?://)?TinyURL.com/([^?/ ]*)\b"
   [regex]$isgd  = "(?:https?://)?is.gd/([^?/ ]*)\b"
   [regex]$twurl = "(?:https?://)?twurl.nl/([^?/ ]*)\b"

   switch -regex ($urls) {
      $snip {
         ## Notice that {{ Get-Web ... -plain }} returns plain text, not an xml doc
         write-output $snip.Replace( $_, (Get-Web "http://snipurl.com/resolveurl?id=$($snip.match( $_ ).groups[1].value)" -plain))
      }
      $tiny {
         ## GET parameters this time ...
         $doc = Get-Web "http://tinyurl.com/preview.php" -Get @{num=$tiny.match( $_ ).groups[1].value}
         write-output $tiny.Replace( $_, "$($doc.SelectSingleNode(""//a[@id='redirecturl']"").href)" )
      }
      $isgd {
         $doc = Get-Web "http://is.gd/$($isgd.match( $_ ).groups[1].value)-"
         write-output $isgd.Replace( $_, "$($doc.SelectSingleNode(""//div[@id='main']/p/a"").href)")
      }
      $twurl {
         $doc = Get-Web "http://tweetburner.com/links/$($twurl.match( $_ ).groups[1].value)"
         write-output $twurl.Replace($_, "$($doc.selectsingleNode(""//div[@id='main-content']/p/a"").href)" )
      }
      default { write-output $_ }
   }
}
]]> http://huddledmasses.org/get-web-another-round-of-wget-for-powershell/feed/ 1 WGet 2 for PowerShell http://huddledmasses.org/wget-2-for-powershell/ http://huddledmasses.org/wget-2-for-powershell/#comments Thu, 01 May 2008 17:00:26 +0000 Joel 'Jaykul' Bennett http://HuddledMasses.org/wget-2-for-powershell/ [new] Edit: Added -Passthru

Edit: I made a mistake … I wrote this a few weeks ago, and made an error in the script which causes it to not work properly with most binary files … I’ve fixed the script down below now, and while I was at it, I went ahead and added a download progress report ;)

About a year ago, I wrote a script to download files from the web using PowerShell, but it was so simple that you had to specify the url to download and the file to save to. At the time I knew there was a way to find the file name of the download in the header, but I couldn’t remember how to get to the headers, and it’s not possible using System.Net.WebClient so I just dropped it.

Then the other day I saw an old post from Script Fanatic about querying Http status codes, and it reminded me of my annoyance with my wget script. So I fixed it, and I’m letting you have it.

The new version of wget for PowerShell (or Get-WebFile) is on the PowerShell Repository and it’s been completely rewritten to use System.Net.HttpWebRequest and HttpWebResponse which gives us access to the the name of the file in those cases where the URL is something like .../scripts/?dl=417 (assuming the server puts the file name in the headers as it should).

It still doesn’t support authentication, and even though the headers include the size (and I have to do the streams myself so I could easily read a few bytes at a time and give you progress reports)


## Get-WebFile (aka wget for PowerShell)
##############################################################################################################
## Downloads a file or page from the web
## History:
## v3.6 - Add -Passthru switch to output TEXT files
## v3.5 - Add -Quiet switch to turn off the progress reports ...
## v3.4 - Add progress report for files which don't report size
## v3.3 - Add progress report for files which report their size
## v3.2 - Use the pure Stream object because StreamWriter is based on TextWriter:
##        it was messing up binary files, and making mistakes with extended characters in text
## v3.1 - Unwrap the filename when it has quotes around it
## v3   - rewritten completely using HttpWebRequest + HttpWebResponse to figure out the file name, if possible
## v2   - adds a ton of parsing to make the output pretty
##        added measuring the scripts involved in the command, (uses Tokenizer)
##############################################################################################################
function Get-WebFile {
   param(
      $url = (Read-Host "The URL to download"),
      $fileName = $null,
      [switch]$Passthru,
      [switch]$quiet
   )
   
   $req = [System.Net.HttpWebRequest]::Create($url);
   $res = $req.GetResponse();
 
   if($fileName -and !(Split-Path $fileName)) {
      $fileName = Join-Path (Get-Location -PSProvider "FileSystem") $fileName
   }
   elseif((!$Passthru -and ($fileName -eq $null)) -or (($fileName -ne $null) -and (Test-Path -PathType "Container" $fileName)))
   {
      [string]$fileName = ([regex]'(?i)filename=(.*)$').Match( $res.Headers["Content-Disposition"] ).Groups[1].Value
      $fileName = $fileName.trim("\/""'")
      if(!$fileName) {
         $fileName = $res.ResponseUri.Segments[-1]
         $fileName = $fileName.trim("\/")
         if(!$fileName) {
            $fileName = Read-Host "Please provide a file name"
         }
         $fileName = $fileName.trim("\/")
         if(!([IO.FileInfo]$fileName).Extension) {
            $fileName = $fileName + "." + $res.ContentType.Split(";")[0].Split("/")[1]
         }
      }
      $fileName = Join-Path (Get-Location -PSProvider "FileSystem") $fileName
   }
   if($Passthru) {
      $encoding = [System.Text.Encoding]::GetEncoding( $res.CharacterSet )
      [string]$output = ""
   }
 
   if($res.StatusCode -eq 200) {
      [int]$goal = $res.ContentLength
      $reader = $res.GetResponseStream()
      if($fileName) {
         $writer = new-object System.IO.FileStream $fileName, "Create"
      }
      [byte[]]$buffer = new-object byte[] 4096
      [int]$total = [int]$count = 0
      do
      {
         $count = $reader.Read($buffer, 0, $buffer.Length);
         if($fileName) {
            $writer.Write($buffer, 0, $count);
         }
         if($Passthru){
            $output += $encoding.GetString($buffer,0,$count)
         } elseif(!$quiet) {
            $total += $count
            if($goal -gt 0) {
               Write-Progress "Downloading $url" "Saving $total of $goal" -id 0 -percentComplete (($total/$goal)*100)
            } else {
               Write-Progress "Downloading $url" "Saving $total bytes..." -id 0
            }
         }
      } while ($count -gt 0)
     
      $reader.Close()
      if($fileName) {
         $writer.Flush()
         $writer.Close()
      }
      if($Passthru){
         $output
      }
   }
   $res.Close();
   if($fileName) {
      ls $fileName
   }
}
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