Difference between revisions of "MHTTP"

Latest revision as of 22:02, 10 June 2015

Often times you may want to download a web page from the internet using HTTP, but HTTP can be complicated. This script handles most of the basics for you including

• URL Parsing
• SSL
• Cookies
• Sending POST data
• Following redirects
• Handling CHUNKED encoding

Typical usage simply involves using the /http.open, save and close commands to download a file, and creating a signal event to do something with it once it is done.

Example

alias DownloadGooglesLogo {
 http.open google https://www.google.com/images/srpr/logo11w.png
 http.save -f google logo.png
}
on *:SIGNAL:http: {
  if ($1 == google) {
     if ($2 == SAVED) { run $3- | http.close $1 } 
     if ($2 == PROGRESS) { echo -atg Download progress: $bytes($3).suf $+ / $+ $bytes($4).suf downloaded }
  }
}

Script

; Ben's (ben@st0rm.net) HTTP for mIRC script (mHTTP)
; Used to download over HTTP
; Basic usage
; /http.open [name] <URL> 
;     Opens an HTTP handle for the given URL
; /http.save [-f] <name> <file|bvar>
;     Downloads a given HTTP resource to the given file or binvar
;     -f forces the file to be overwritten
; /http.close <name> 
;     Closes and HTTP handle for the given URL
;
; Here are some things you can do after opening a handle, but before saving it
; Manage POST data:
;   /http.addpost <handle> <variable> <value>
;   /http.delpost <handle> <variable>
; Manage cookies 
;   /http.addcookie <handle> <value>
;   $http.cookie(handle,N) - gets Nth cookie
;
; After a request completes (e.g. after a save) you can get some data:
;     $http.responseheader(handle, header, N) - Returns value of given responseheader, or $false. Only useful after a request is made
;
; You can mark a socket with data of your choice (it's a transparent write to a hashtable) similar to sockmark
; /http.mark <handle> [data] - Writes the data. Specify no data to delete the mark
; $http.mark(handle) - Reads the data
;
; Signals
;   In order to tell via script when something happens (your file is being saved, for example) use
;   on *:SIGNAL:http:
;   where $1 = Handle name, $2 = Event name, $3- = parameters
;   Events:
;        COMPLETED <statuscode>   -  when a request completes
;        SAVED <location>         - when a save completes
;        REDIRECT <location>      - when a request is redirected elsewhere 
;        PROGRESS <bytes> [total size] - When part but not all of the data is downloaded. Total size is not available for chunked transfer
;       
;
; Known issues:
;    POSTing arrays is not currently supported
;    Cookies do not respect attributes such as domain, path, expiration, or secure. They are always sent
;    Relative redirects don't work, only absolute
;    Redirects from insecure to secure links when you don't have SSL will not be handled well
; Creates a request that when completed is saved to a file
alias http.save {
  if ($1 == -f) {
    var %force = $true
    tokenize 32 $2-
  }
  else { var %force = $false }
  if ($0 < 2) { 
    echo -atg * /http.save: Use /http.save <http handle> <file>
    return
  }
  var %hashtable = http. $+ $1
  if (!$hget(%hashtable)) { 
    echo -atg * /http.save: No such HTTP handle exists. Use /http.open first
    return
  }
  if ($sock(%hashtable)) {
    echo -atg * /http.save: There is a pending request for this HTTP handle already. A connection is open the the remote host. Close it, or wait for it to complete 
    return
  }
  var %destination = $2-
  if ($exists(%destination)) {
    if (%force) {
      .remove %destination
    }
    else {
      echo -atg * /http.save: File already exists. Try /http.save -f to force an overwrite
      return
    }
  }
  if (&* iswm %destination) { 
    .hadd %hashtable bvarout %destination
  }
  else {
    ;  Open file handler stream for writing
    .fopen -n %hashtable %destination
    if ($ferr) {
      echo -atg * /http.save: Could not use file. Error: $ferr
      return
    }
    ; Store fstream name in hashtable to indicate that we want to save this once it completes
    .hadd %hashtable fstream %hashtable
  }
  ; Set redirect counter to 0
  .hadd %hashtable redirects 0
  ; Start socket
  http.sockstart %hashtable
}
alias http.mark {
  var %hashtable = http. $+ $1
  if ($isid) {
    ; As an identifier, read the mark
    return $hget(%hashtable,mark)
  }
  else {
    ; As a command, set the mark
    if (!$hget(%hashtable)) {
      echo -atg * /http.mark - No such handle $1
    }
    elseif (!$2) { 
      .hdel %hashtable mark
    }
    else {
      .hadd %hashtable mark $2-
    }
  }
}
; Opens socket
alias -l http.sockstart {
  if ($hget($1,secure) == $true) {
    if ($sock($1) && $sock($1).ssl) { 
      http.sendrequest $1
    } 
    else {
      if ($sock($1)) { .sockclose $1 }
      if (!$sslready) {
        echo -atg HTTP Error - request $qt($right($1,-5)) would require you to use SSL but you are not SSL ready. Please see http://mirc.com/ssl.html
        http.close $right($1,-5)
        return
      }
      sockopen -e $1 $hget($1, host) $hget($1, port)
    }
  }
  else {
    if ($sock($1)) {
      http.sendrequest $1
    }
    else {
      sockopen $1 $hget($1, host) $hget($1, port)
    }
  }
}
; Sends the request. Assumes the socket is open and ready
alias -l http.sendrequest {
  if (!$sock($1)) { echo -atg HTTP Internal error. Socket not open in /http.sendrequest | return }
  var %inname = $1
  var %exname = $right($1,-5)
  ; Cleanup from previous requests
  .hdel %inname responseheaders
  .hdel %inname body
  .hdel %inname contentlength
  .hdel %inname chunkleft
  ; Get POST binvar
  var %postBV = $http.postdata(%exname)
  ; Use GET if there's no post data, POST otherwise
  if ($bvar(%postBV,0) == 0) {
    sockwrite -n %inname GET $hget(%inname,path) HTTP/1.1 
  }
  else {
    sockwrite -n %inname POST $hget(%inname,path) HTTP/1.1 
  }
  ; Send the host
  sockwrite -n %inname Host: $hget(%inname,host)
  ; Send the user-agent
  sockwrite -n %inname User-agent: $hget(%inname,user-agent)
  sockwrite -n %inname Connection: Keep-Alive
  ; Only plain-text supported
  sockwrite -n %inname Accept: text/plain; q=0.5, text/html
  ; Send cookies
  if ($http.cookie(%exname, 0) > 0) {
    sockwrite %inname Cookie: $+ $chr(32)
    var %i = 1
    while ($http.cookie(%exname, %i)) {
      sockwrite %inname $http.urlencode($ifmatch) $+ ;
      inc %i
    }
    sockwrite -n %inname
  }
  ; If POST send content type and length
  if ($bvar(%postBV,0) > 0) {
    sockwrite -n %inname Content-Type: application/x-www-form-urlencoded
    sockwrite -n %inname Content-Length: $v1
  }
  ; End request headers with empty line
  sockwrite -n %inname
  ; If POST, send data
  if ($bvar(%postBV,0) > 0) {
    sockwrite %inname %postBV
    ; sockwrite -n %inname
  }
}
; Just some bookeeping in case we miss it 
on *:SOCKCLOSE:http.*: {
  if ($fopen($sockname)) { .fclose $sockname }
}
on *:SOCKOPEN:http.*: {
  http.sendrequest $sockname
}
on *:SOCKREAD:http.*: {
  if ($sockerr > 0) {
    echo -atg * HTTP handle $qt($right($sockname,-5)) failed with socket error $sockerr
    http.close $right($sockname,-5)
    return
  }
  ;Read all the data into &bvTemp
  :read
  ; First, read this buffer
  sockread &bvThis
  if ($sockbr > 0) {
    ; If data was read, copy it to the on-going buffer and continue
    bcopy &bvTemp $calc($bvar(&bvTemp,0) +1) &bvThis 1 -1
    goto read
  }
  if ($bvar(&bvTemp,0) == 0) { echo -atg HTTP sockread called with no data to read... | return }
  ; Do we need to parse headers?
  ; If response headers not set, this call has the headers
  if (!$hget($sockname,responseheaders)) {
    ; Find the response headers
    var %end = $bfind(&bvTemp,1, 13 10 13 10)
    if (%end == 0) { echo -atg Error: No headers found, but no content length so this can't be a subsequent call | return }
    ; Increase to include the 3 extra characters
    inc %end 3
    bcopy &bvResponseHeaders 1 &bvTemp 1 %end
    ; If there's still non-header data copy it over
    if (%end < $bvar(&bvTemp, 0)) { 
      bcopy -c &bvTemp 1 &bvTemp $calc(%end + 1) -1
    }
    else { bunset &bvTemp }
    ; If this is the first header response, save in hash table
    if (!$hget($sockname, responseheaders)) {
      .hadd -b $sockname responseheaders &bvResponseHeaders 
      http.OnHeaders $sockname
    }
  }
  ; there's no more to read, bail
  if (!$bvar(&bvTemp,0)) {
    ; If that's all this response has to offer, we're done
    if ($hget($sockname,contentlength) == 0) {
      http.ondone $sockname
    }
    return
  }
  ; Read body
  var %contentlength = $hget($sockname,contentlength)
  if (%contentlength == $null || %contentlength == $false) {
    var %chunked = $true
  }
  else {
    var %chunked = $false
  }
  ; Set bvBody to the body ready so far
  if ($hget($sockname,body)) {
    noop $hget($sockname, body, &bvBody)
  }
  if (%chunked) {
    :readChunk
    var %chunkleft = $hget($sockname, chunkleft)
    if (!%chunkleft) {
      ; If we've read all of a chunk, or this is the first one, get its size
      var %crlf = $bfind(&bvTemp, 1, 13 10)
      if (!%crlf) {
        echo -atg HTTP internal error. Handle $qt($right($sockname,-5)) is in chunked encoding but no chunk size found in data
        return
      }
      var %chunkleft = $base($bvar(&bvTemp, 1, $calc(%crlf - 1)).text,16,10)
      if (%chunkleft !isnum) {
        echo -atg HTTP internal error. Handle $qt($right($sockname,-5))  has invalid chunk size: %chunkleft
      }
      ; New chunk
      else {
        ; Save chunk size and remove it (plus its \r\n) from temp
        .hadd $sockname chunkleft %chunkleft
        .bcopy -c &bvTemp 1 &bvTemp $calc(%crlf +2) -1
        if (%chunkLeft == 0) { 
          ; if we just read chunk size 0, that was the end. 
          .hadd -b $sockname body &bvBody
          http.onDone $sockname
          return
        }
      }
    }
    ; read %chunkleft bytes
    var %bytesToRead = $iif(%chunkLeft < $bvar(&bvTemp,0),%chunkLeft, $bvar(&bvTemp,0))
    .bcopy &bvBody $calc($bvar(&bvBody,0) +1) &bvTemp 1 %bytesToRead
    hdec $sockname chunkleft %bytesToRead
    .signal http $right($sockname,-5) PROGRESS %bytesToRead
    if (%bytesToRead == %chunkLeft) {
      ; If this is the end of the chunk, consume crlf
      inc %bytesToRead 2
      ; If there's still stuff in this var, go back and read the new chunk
      if (%bytesToRead < $bvar(&bvTemp,0)) {
        .bcopy -c &bvTemp 1 &bvTemp $calc(%bytesToRead + 1) -1    
        goto readChunk
      }
    }
    ; End of this call, save body in hashtable for future calls
    .hadd -b $sockname body &bvBody
  }
  else {
    ; Copy everything
    .bcopy &bvBody $calc($bvar(&bvBody,0) +1) &bvTemp 1 -1
    ; Add read-so-far body to hashtable
    .hadd -b $sockname body &bvBody
    .signal http $right($sockname,-5) PROGRESS $bvar(&bvBody,0) $hget($sockname,contentlength) 
    ; Check if we're done
    if ($bvar(&bvBody,0) >= $hget($sockname,contentlength)) { 
      ; We're done
      http.onDone $sockname
      if ($bvar(&bvBody,0) > $hget($sockname,contentlength)) { 
        echo -qatg HTTP Warning: Read past content-length.
      }
    }
  }
}
; Internal event called when we get the first header response from the server
alias -l http.OnHeaders {
  noop $hget($1,responseheaders, &bvResponseHeaders)
  ; First header is always the status response
  var %end = $bfind(&bvResponseHeaders, 1, 13 10)
  if (%end <= 1) {
    echo -atg Error: HTTP $qt($right($1,-5)) Server did not respond with HTTP status 
    goto cleanup
  }
  var %status = $bvar(&bvResponseHeaders,1,$calc(%end - 1)).text
  .hadd $1 responsestatus %status
  var %version = $gettok(%status,1,32)
  if (%version != HTTP/1.1 && %version != HTTP/1.0) {
    echo -atg Error: HTTP $qt($right($1,-5)) Server indicated unknown version: %version
    goto cleanup
  }
  var %statuscode = $gettok(%status,2,32)
  if (%statuscode !isnum) {
    echo -atg Error: HTTP $qt($right($1,-5)) Server indicated invalid status code: %statuscode
    goto cleanup
  }
  ; Check transfer type
  if ($http.responseheader($right($1,-5),Content-Length,1) != $null) {
    hadd $1 contentlength $v1
  }
  elseif ($http.responseheader($right($1,-5), Transfer-Encoding, 1) != chunked) {
    echo -atg HTTP Handle $qt($right($1,-5)) has no content-length header and is not chunked
    echo -atg $bvar(&bvResponseHeaders,1-).text
    return
  } 
  ; Add any cookies that were set
  var %cookie = 1
  while ($http.responseheader($right($1,-5), Set-Cookie, %cookie)) {
    inc %cookie
    var %cookieValue = $gettok($ifmatch,1,$asc(;))
    http.addcookie $right($1,-5) %cookieValue
  }
  ; Handle redirects
  if (%statuscode == 303 || %statuscode == 302 || %statuscode == 307) {
    var %location = $http.responseheader($right($1,-5), Location)
    .signal http $right($1,-5) REDIRECT %location
    http.seturl $1 %location
    hinc $1 redirects
    ; If the server doesn't promise us this connection is keep-alive, close it and use a new one
    if ($http.responseheader($right($1,-5), Connection, 1) != Keep-Alive) {
      if ($sock($1)) { .sockclose $1 }
    }
    if ($hget($1, redirects) > 5) {
      echo -atg HTTP Handle $qt($right($1,-5)) redirect loop detected
      return
    }
    http.sockstart $1
  }
  return
  :cleanup
  if ($sock($1)) { .sockclose $1 }
}
alias http.addcookie {
  var %hashtable = http. $+ $1
  if (!$hget(%hashtable)) {
    echo -atg * /http.addcookie: No such HTTP handle
    return
  }
  if ($0 < 2) {
    echo -atg * /http.addcookie: Usage: /http.addcookie <handle> <value>
    return
  }
  var %i = 1
  var %cookieNum = 1
  while ($hget(%hashtable,%i).item) {
    var %item = $ifmatch
    inc %i
    if (cookie-* iswm %item) {
      var %tmp = $gettok(%item,2,$asc(-))
      ; If the value is the same, overwrite
      if ($2- == $hget(%hashtable,%item)) {
        %cookieNum = %tmp
        break
      }
      ; Otherwise store max cookie num
      elseif (%tmp >= %cookieNum) { %cookieNum = $calc(%tmp + 1) }
    }
  }
  .hadd %hashtable cookie- $+ %cookieNum $+ -value $2-
}
; Gets an HTTP cookie for the given handle
; $http.cookie(<handle>, <index>)
alias http.cookie {
  if ($2 !isnum) {
    echo -atg * $!http.cookie invalid parameters
    return
  }
  var %hashtable = http. $+ $1
  if (!$hget(%hashtable)) {
    echo -atg * $!http.cookie no such HTTP handle 
    return
  }
  var %i = 1
  var %found = 0
  while ($hget(%hashtable, %i).item) {
    inc %i
    var %item = $ifmatch
    if (cookie-*-value iswm %item) {
      inc %found
      var %id = $gettok(%item,2,$asc(-))
      if (%found == $2) {
        return $hget(%hashtable, cookie- $+ %id $+ -value)
      }
    }
  }
  if ($2 == 0) { return %found }
}
; Returns the value of the given response header
; Case sensitive since it is binary variable operation
alias http.responseheader {
  if ($0 < 2) {
    echo -atg Invalid usage. Use: $http.responseheader(<handle>, <header>[, index])
    return
  }
  ; %index is parameter 3 - 1-N or 0 for number
  var %index = 1
  if ($3 isnum) {
    %index = $3
  }
  ; Veriy hash table exists
  var %table = http. $+ $1
  if (!$hget(%table,responseheaders)) { return $false }
  noop $hget(%table,responseheaders, &bvResponseHeaders))
  ; Set up parameters for the header search
  ; Offset is where we start searching from in the loop
  ; thisIndex is the number of matches found so far
  var %offset = 1
  var %thisIndex = 0
  ; The main search loop
  :search
  var %start = $bfind(&bvResponseHeaders, %offset, $2 $+ :).text
  ; If there isn't another match, either the index was too large or they want the count
  if (!%start) { 
    if (%index == 0) { return %thisIndex }
    else { return $false  }
  }
  ; Find the end of the header
  var %end = $bfind(&bvResponseHeaders, %start, 13 10)
  if (%end <= %start) { echo -atg HTTP Internal error ($http.responseheader), header $qt($2) for handle $qt($1) has no CRLF termination | return $false }
  inc %thisIndex
  ; If this not the one they asked for, try again starting from the end of this header
  if (%index != %thisIndex) {
    var %offset = %end
    goto search
  }
  ; Find the colon. If there isn't one we'll return the whole string
  if ($calc($bfind(&bvResponseHeaders, %start, $asc(:)) +1) < %end) {
    %start = $v1
  }
  return $bvar(&bvResponseHeaders,%start, $calc(%end - %start)).text
}
; Internal event called when a request is filled. $1 = internal handle name
alias -l http.onDone {
  if ($hget($1,responseheaders)) {
    noop $hget($1,responseheaders,&bvResponseHeaders)
  }
  ; Write out and close filestream if set
  if ($hget($1,fstream)) {
    noop $hget($1,body,&bvBody)
    if (!$bvar(&bvBody,0)) {
      .fclose $hget($1,fstream)
    }
    else {
      .fwrite -b $hget($1,fstream) &bvBody
      ; Save fname so we can use it in the signal after the close
      var %fname = $fopen($hget($1,fstream)).fname
      .fclose $hget($1,fstream)
      .signal http $right($1,-5) SAVED %fname
    }
  }
  ; If socket is still around, close it
  if ($sock($1)) { .sockclose $1 }
  ; Reset redirects for future calls
  .hadd $1 redirects 0
  .signal HTTP $right($1,-5) COMPLETED $hget($1,responsestatus)
  if ($hget($1, bvarout)) {
    noop $hget($1,body,&bvBody)
    var %bvarout = $ifmatch
    bcopy %bvarout 1 &bvBody 1 -1
    ; Need to use -n so that the binvar is still in scope
    ; So we need to do this last
    .signal -n http $right($1,-5) SAVED %bvarout
  }
}
alias http.open {
  var %hashtable
  ; If two parameters are given, $1 is the name, else create a new name
  if ($0 > 1) { %hashtable = http. $+ $1 }
  else { 
    var %h = $calc($ticks % $rand(1,1000000))
    var %hashtable = http. $+ %h  
  }
  if ($hget(%hashtable)) {
    echo -atg * /http.open: HTTP Request $qt($1) already exists
    return
  }
  ; Encode the octects of the URL. e.g.: foo bar,pie --> foo%20bar,%2Cpie
  var %url = $iif($0 > 1, $2-, $1-)
  var %urlEncoded = $http.urlencode(%url)
  ; Check the URL
  if (!$http.urlparse(%urlEncoded)) {
    echo -atg * /http.open: Malformed URL. Use /http.open [name] <url> 
    return
  }
  if ($http.urlparse(%urlEncoded).secure && !$sslready) {
    echo -atg * /http.open: URL is SSL but $!sslready = false. See http://www.mirc.com/ssl.html
    return
  }
  ; Everything checks out, let's store the relevent bits in a hashtable
  .hmake %hashtable 10
  http.seturl %hashtable %url
  echo -qatg * /http.open: Opened HTTP request $qt($right(%hashtable,-5))
}
alias -l http.seturl {
  if ($0 < 2) { echo -atg HTTP Internal error, seturl called with no url }
  var %hashtable = $1
  if (!$hget(%hashtable)) { echo -atg HTTP Internal error, seturl called with invalid handle }
  var %urlEncoded = $http.urlencode($2-)
  .hadd %hashtable host $http.urlparse(%urlEncoded).host
  .hadd %hashtable port $http.urlparse(%urlEncoded).port
  .hadd %hashtable secure $http.urlparse(%urlEncoded).secure
  .hadd %hashtable path $http.urlparse(%urlEncoded).path
  .hadd %hashtable user-agent mIRC $version
}
alias http.list {
  var %i = 1
  var %numFound = 0
  while (%i <= $hget(0)) {
    var %table = $hget(%i)
    inc %i
    if (http.* iswm %table) {
      inc %numFound
      echo -atg * $right(%table,-5) $+ : Host: $hget(%table,host) Port: $hget(%table,port) Path: $hget(%table,path)
    }
  }
  if (%numFound == 0) { echo -atg * No HTTP handles opened }
}
alias http.close {
  var %i = 1
  var %numFound = 0
  while (%i <= $hget(0)) {
    var %table = $hget(%i)
    if (http. $+ $1 iswm %table) {
      ; Cleanup resources
      if ($sock(%table)) { .sockclose %table }
      if ($fopen(%table)) { .fclose %table }
      if ($hget(%table $+ .postdata)) { .hfree %table $+ .postdata }
      .hfree %table
      inc %numFound
      echo -qatg * HTTP Closed $right(%table,-5) 
    }
    ; Only inc if we didnt find a match
    else {
      inc %i
    }
  }
  if (%numFound == 0) {  echo -qatg * No matching HTTP handles } 
}
;
; Takes an encoded URL and returns based on the property
; .secure - true if https
; .host - the URL host
; .port - the port, 80 by default
; .path - The path to download, / by default
;  Returns $false is URL is malformed
;
alias http.urlparse {
  var %secure
  var %host
  var %port
  var %path
  var %pathIndex
  var %protocol
  var %regex = /^(https?://)?([a-z.0-9\-_]+)(:\d+)?(/.*)?$/i
  if ($regex($1, %regex)) {
    if (http*:// iswm $regml(1)) {
      %protocol = $lower($left($regml(1),-3))
    }
    %secure = $false
    if (%protocol == https) { 
      %secure = $true
    }
    if (%protocol) { %host = $regml(2) }
    else { %host = $regml(1) }  
    var %portIndex = $iif(%protocol, 3, 2)
    var %portfound = $false
    if ($left($regml(%portIndex),1) == : && $right($regml(%portIndex),-1) isnum) {
      %port = $right($regml(%portIndex),-1) 
      %portFound = $true
    }
    else {
      if (%secure) { 
        %port = 443
      }
      else {
        %port = 80
      }
    }
    %pathIndex = $iif(%portFound, $calc(%portIndex + 1), %portIndex)
    if ($regml(0) >= %pathIndex) {
      %path = $regml(%pathIndex)
    }
    else { %path = / }
  }  
  else { return $false }
  if ($prop == secure) { return %secure }
  if ($prop == host) { return %host }
  if ($prop == path) { return %path }
  if ($prop == port) { return %port }
  return $true
}
alias http.addpost {
  if ($0 < 3) { 
    echo -atg * /http.addpost: Usage: /http.addpost <handle> <variable> <value>
    return
  }
  var %maintable = http. $+ $1
  var %posttable = %maintable $+ .postdata
  if (!$hget(%maintable)) {
    echo -atg * /http.addpost: No such HTTP handle found
    return
  }
  if (!$hget(%posttable)) { .hmake %posttable 10 }
  hadd %posttable $2 $3-
  echo -qatg Post variable added: $2 $+ = $+ $3-
}
alias http.delpost {
  if ($0 < 2) {
    echo -atg * /http.delpost: Usage: /http.delpost <handle> <variable>
    return
  }
  var %maintable = http. $+ $1
  var %posttable = %maintable $+ .postdata
  if (!$hget(%maintable)) {
    echo -atg * /http.addpost: No such HTTP handle found
    return
  }
  if (!$hget(%posttable,$2)) {
    echo -qatg * /http.addpost: No post variable with that name exists
    return
  }
  hdel %posttable $2
  echo -qatg Post variable deleted: $2
}
; Usage: $http.postdata(handle)
; Returns a binvar with a post data style query string (x=y&z=a) or $false
alias http.postdata {
  ; Post data is stored in INNAME.postdata
  var %posttable = http. $+ $1 $+ .postdata
  if (!$hget(%posttable,0).item) { return $false }
  var %i = 1
  while ($hget(%posttable,%i).item) {
    var %item = $ifmatch
    bset -t &bvPost $calc($bvar(&bvPost,0) +1) $iif(%i > 1,&,) $+ $http.urlencode(%item) $+ = $+ $http.urlencode($hget(%posttable,%item))
    inc %i
  }
  return &bvPost
}
; Replace some commonly touchy URL characters with their hex-octect encoding
alias -l http.urlencode {
  return $replacex($1-,$chr(32),% $+ 20, $chr(44), % $+ 2C,+, % $+ 2B, $chr(37), % $+ 25)
}