Question

I’m interfacing a page that needs a login with mechanize. It uses some javascript on the front page making using mechanize straight-up more difficult. I know what form I have to submit to log-in – the one always generated by the js, the same every time. How can I make mechanize just submit a custom form that isn’t on the page? Basically equivalent to this perl problem but in Python.

Answer 1

(NOTE: This came up again recently and I actually got it to work now.)

This seems to work:

br.open(URL)
res = mechanize._form.ParseString(FORM_HTML, BASE_URL)
br.form = res[1]
#continue as if the form was on the page and selected with .select_form()
br['username'] = 'foo'
br['password'] = 'bar'
br.submit()

URL is the full URL of the visited site. BASE_URL is the directory the URL is in. FORM_HTML is any HTML that has a form element, e.g.:

<form method='post' action='/login.aspx'>
    <input type='text' name='username'>
    <input type='text' name='password'>
    <input type='hidden' name='important_js_thing' value='processed_with_python TM'>
</form>

For some reason, mechanize._form.ParseString returns two forms. The first is a GET request to the base URL with no inputs; the second, the properly parsed form from FORM_HTML.