wemo_moonraker.conf

[power printer] # Recommend assigning a static or manual IP to Wemo plug before adding to configuration
type: http
locked_while_printing: True
restart_klipper_when_powered: True
restart_delay: 2
bound_services: klipper
on_url: http://192.168.0.43:49154/upnp/control/basicevent1 # Some Wemo devices might use 49153
off_url: http://192.168.0.43:49154/upnp/control/basicevent1
status_url: http://192.168.0.43:49154/upnp/control/basicevent1
request_template:
    # Keep in mind semicolons (U+003B) and hash signs (U+0023) must be escaped unicode literals
    # If \# is used instead to bypass the configuration comment interpreter jinja2 will still see \# in the string instead of #
    {% do http_request.set_method("POST") %}
    {% set content_type_bearer = 'text/xml\u003b charset=\"utf-8\"' %}
    {% if command in ["status"] %}
      {% do log_debug("Attempting to send Wemo status request") %}     
      {% set soap_action_bearer = '\"urn:Belkin:service:basicevent:1\u0023GetBinaryState\"' %}
      {% set xml_body = '<?xml version="1.0" encoding="utf-8"?><s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:GetBinaryState xmlns:u="urn:Belkin:service:basicevent:1"></u:GetBinaryState></s:Body></s:Envelope>' %}
      {% do http_request.add_header("CONTENT-TYPE", content_type_bearer) %}
      {% do http_request.add_header("SOAPACTION", soap_action_bearer) %}
      {% do http_request.set_body(xml_body) %}
      {% do http_request.send() %}
    {% endif %}
    {% if command in ["on", "off"] %}
      {% set soap_action_bearer = '\"urn:Belkin:service:basicevent:1\u0023SetBinaryState\"' %}
      {% do http_request.add_header("CONTENT-TYPE", content_type_bearer) %}
      {% do http_request.add_header("SOAPACTION", soap_action_bearer) %}
      {% if command == "on" %}
          {% do log_debug("Attempting to send Wemo power-on request") %}
          {% set xml_body = '<?xml version="1.0" encoding="utf-8"?><s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:SetBinaryState xmlns:u="urn:Belkin:service:basicevent:1"><BinaryState>1</BinaryState></u:SetBinaryState></s:Body></s:Envelope>' %}
      {% elif command == "off" %}
          {% do log_debug("Attempting to send Wemo power-off request") %}
          {% set xml_body = '<?xml version="1.0" encoding="utf-8"?><s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:SetBinaryState xmlns:u="urn:Belkin:service:basicevent:1"><BinaryState>0</BinaryState></u:SetBinaryState></s:Body></s:Envelope>' %}
      {% endif %}
      {% do http_request.set_body(xml_body) %}
      {% do http_request.send() %}
    {% endif %}
response_template:
  {% do log_debug("Got status code " ~ http_request.last_response().status_code) %}
  {% if http_request.last_response().status_code == 200 %}
      {% set start_tag = '<BinaryState>' %}
      {% set end_tag = '</BinaryState>' %}
      {% set start_index = http_request.last_response().text.find(start_tag) + start_tag|length %}
      {% set end_index = http_request.last_response().text.find(end_tag) %}
      {% set binary_state = http_request.last_response().text[start_index:end_index] %}
      {% do log_debug("Plug state binary is " ~ binary_state) %}
      {% if binary_state == "1" %}
          {% do log_debug("Plug marked as on") %}
          {"on"}
      {% else %}
          {% do log_debug("Plug marked as off") %}
          {"off"}
      {% endif %}
  {% endif %}

Seems to work well! Although my wemo smart plugs WSP080 seem to use port 49152 instead of 49153 or 49154. Found this out with pywemo!