<post
  url = anyURI
  encoding = any ASCII compatible encoding : "UTF-8"
  readResponse = boolean : false
>
  Content: [ field ]+
</post>

<field
  name = Form field name (US-ASCII only)
>
  Content: value | file
</field>

<value>
  Content: xs:string
</value>

<file
  name = Path
  contentType = Content type
/>

Emulates an HTML form possibly containing input type="file" elements. More precisely, the post element implements HTML5 — Form submission — Multipart form data using emulated input type="text" and input type="file" form fields.

The body of the POST request is encoded as "multipart/form-data" if the post element contains at least one file descendant element. Otherwise this body is encoded as "application/x-www-form-urlencoded".

Optional attribute encoding specifies the ASCII compatible character encoding (ISO-8859-1, UTF-8, Windows-1252, etc) used by the form submission algorithms.

About special field named "_charset_"

When the POST request is submitted to the backend, a field element having its name attribute set to _charset_ and having an empty value: <field name="_charset_"><value></value></field> is automatically given a value corresponding to attribute encoding of element post (by default UTF-8). This way, the backend is informed of the character encoding used to encode the field names, values and file paths. See last example below.

An emulated form field has a name specified by required attribute name. There are two type of fields:

If attribute readResponse is specified with value true, this element returns the response of the server. Otherwise, this element returns no result at all.

Moreover, for this element to return a result, the server must respond to the post request with a success code different from "No Content" (204) and must send "text/*" data (e.g. "text/plain", "text/html", etc). If the content type of the sent data has no charset, the data is read as a string using charset "UTF-8".

Examples:

<post url="http://localhost:8080/measure/archive" 
      encoding="ISO-8859-1" readResponse="true">
  <field name="op">
    <value>add</value>
  </field>
  <field name="user">
    <value>%U</value>
  </field>
  <field name="interactive">
    <value>false</value>
  </field>
  <field name="data">
    <file name="1052_3_CO_3.1R" 
          contentType="text/xml; charset=ISO-8859-1" />
  </field>
</post>

<post url="http://www.acme.com/login" 
      readResponse="true">
  <field name="username">
    <value>admin</value>
  </field>
  <field name="password">
    <value>changeit</value>
  </field>
</post>

<post url="http://localhost:8080/upload_photos">
  <field name="_charset_"><value></value></field>
  <field name="file1">
    <file name="/home/john/photos/la belle &#xE9;quipe.jpeg" 
          contentType="image/jpeg" />
  </field>
  <field name="copyTo1">
    <value>la belle &#xE9;quipe.jpg</value>
  </field>
  <field name="description1">
    <value>Oh la belle &#xE9;quipe que voil&#xE0;!</value>
  </field>
</post>