从html表单获取整数

Question

I want to get the integer value from HTML form and I used the following python code:

    form = cgi.FieldStorage()
    if not form.has_key("id"):
        error_pop("There is no id in this form","The format of the request is not correct")
    id = form["id"].value    (*)

And in the HTML file, I make the input type as number :

id: <input type="number" name="id" /><br />

However, it seems that the id I get from line ( * ) is still a string.

How can I convert it to integer?

I tried use int(form["id"].value) , but python gave me the following error:

<type 'exceptions.TypeError'> : %d format: a number is required, not str args = ('%d format: a number is required, not str',) message = '%d format: a number is required, not str'

So, I gave up using int() .

If I try to print the value before parsing it to int() , then I will get the internal server error from the browser. Actually I'm always getting this error if I change something in the python file. I can see the error from the error_log.log:

/usr/lib/python2.6/cgitb.py:173: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
value = pydoc.html.repr(getattr(evalue, name))

Actually if I grep today's time from error.log, then it cannot show the current error..although it really exits some error that happens several hours ago...

I found something new: only if things involves the "id" thing, the internal server error will appear. If I do something like id = form["idid"].value , then it will give the error:

<type 'exceptions.TypeError'>: int() argument must be a string or a number, not 'NoneType' 
      args = ("int() argument must be a string or a number, not 'NoneType'",) 
      message = "int() argument must be a string or a number, not 'NoneType'"

Any help is appreciated.

Answer 1

I was having the same problem you were, not being able to convert values from a form to numbers. Here's another solution I adapted from this blog post . I have some values returned from radio buttons sets named q1, q2, q3, etc., and convert them using this dictionary.

 str2num = {"1":1, "2":2, "3":3, "4":4, "5":5, "6":6}

 val1 = str2num[ form.getvalue("q1") ]
 val2 = str2num[ form.getvalue("q2") ]
 val3 = str2num[ form.getvalue("q3") ]

The value of the form element "q1" was the string form of the digit, so this converts it to to the numerical form. Like you, int( form.getvalue("q1") ) just wasn't working. I still don't know why this does.

Answer 2

It seems the value of the element is form , that you pass to int is the error message returned from the http server:
"%d format: a number is required, not str"
For the sake of argument can you try the same thing without restricting the id field to type="number", but type="text". My guess is that this will allow the conversion to integer. And if you need to enforce the result to be integer, use something like

while not id:
  try:
    id = int(form["id"].value)
  except TypeError:
    error_pop("id should be number")