I have setup my own custom form for mechanical turk and am posting to their external interface.
<form enctype="multipart/form-data" action="https://workersandbox.mturk.com/mturk/externalSubmit" method="post" name="mturk_form" id="mturk_form">
<p>
<label for="turk_task_image_image">Upload an image</label><br>
<input type="file" size="30" name="turk_task_image[image]" id="turk_task_image_image">
</p>
<b>- OR - </b><br><br>
<p>
<label for="turk_task_image_url">Specify an Image URL</label><br>
<input type="text" size="30" name="turk_task_image[url]" id="turk_task_image_url">
</p>
<p>
<label for="turk_task_image_description">Description (optional)</label><br>
<textarea rows="3" name="turk_task_image[description]" id="turk_task_image_description" cols="80"></textarea>
</p>
<input type="hidden" value="ASSIGNMENT_ID_NOT_AVAILABLE" name="assignmentId" id="assignmentId">
<input type="hidden" value="200" name="task[storyboard_location_id]" id="task_storyboard_location_id">
<input type="hidden" value="36" name="task[turk_task_id]" id="task_turk_task_id">
<p>
<input type="submit" value="You must ACCEPT the HIT before you can submit the results." name="commit" id="submitButton" disabled="">
<img border="0" style="display: none;" src="/images/spinner.gif?1274319066" id="spinner" alt="Spinner">
</p>
</form>
When I go to retrieve the responses, all of the text field values are available but the posted file is not. According to the API docs, I should receive another url that should make the uploaded file available for download?
How do I go about getting the url of the file that is posted to the externalSubmit interface?
P.S. On a side note, I am using the rturk gem to build up these HITs. But I see nothing in the code regarding the support for posted uploaded files.