Copy from wireshark

POST /smp_18_ HTTP/1.1
Host: 192.168.219.6:7676
Accept-Encoding: gzip
Content-Length: 725
Content-Type: application/octet-stream
SOAPAction: urn:schemas-upnp-org:service:AVTransport:1#SetAVTransportURI
User-Agent: haskell wreq-0.1.0.1

<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
  <s:Body>
    <u:SetAVTransportURI xmlns:u="urn:schemas-upnp-org:service:AVTransport:1">
      <InstanceID>0
      </InstanceID>
      <CurrentURI>
      </CurrentURI>
      <CurrentURIMetaData/>
    </u:SetAVTransportURI>
  </s:Body>
</s:Envelope>

<!--
POST /smp_18_ HTTP/1.1
Host: 192.168.219.6:7676
SOAPAction: "urn:schemas-upnp-org:service:AVTransport:1#SetAVTransportURI"
Accept-Language: en-us;q=1, en;q=0.5
Accept-Encoding: gzip
Content-Type: text/xml; charset="utf-8"
User-Agent: gupnp-av-cp GUPnP/0.20.12 DLNADOC/1.50
Connection: Keep-Alive
Content-Length: 1405
-->

Main.hs

{-# LANGUAGE OverloadedStrings #-}
-- {-# LANGUAGE ExtendedDefaultRules #-}
-- {-# OPTIONS_GHC -fno-warn-type-defaults #-}

import qualified Data.ByteString as BS
import Network.Wreq
import Control.Lens
-- import           System.Environment
-- import           Shelly
-- import qualified Data.Text as T
-- default (T.Text)

setURI = do
  xml <- BS.readFile "/home/dontdieych/SetAVTransportURI.xml"
  postWith opts  "http://192.168.219.6:7676/smp_18_" xml

opts = defaults & header "SOAPAction" .~ ["urn:schemas-upnp-org:service:AVTransport:1#SetAVTransportURI"]
                & header "Content-Type" .~ ["text/xml; charset=\"utf-8\""]

-- s  = shelly
-- sv = s . verbosely
-- ss = s . silently

SetAVTransportURI.xml

<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
  <s:Body>
    <u:SetAVTransportURI xmlns:u="urn:schemas-upnp-org:service:AVTransport:1">
      <InstanceID>0
      </InstanceID>
      <CurrentURI>
      </CurrentURI>
      <CurrentURIMetaData/>
    </u:SetAVTransportURI>
  </s:Body>
</s:Envelope>

<!--
Captured packet from gupnp-av-cp

POST /smp_18_ HTTP/1.1
Host: 192.168.219.6:7676
SOAPAction: "urn:schemas-upnp-org:service:AVTransport:1#SetAVTransportURI"
Accept-Language: en-us;q=1, en;q=0.5
Accept-Encoding: gzip
Content-Type: text/xml; charset="utf-8"
User-Agent: gupnp-av-cp GUPnP/0.20.12 DLNADOC/1.50
Connection: Keep-Alive
Content-Length: 1405
-->