[Tutor] Code/Style Review of Data Validation Code

[Sean Abrahams]

The following is some code I wrote to validate certain types of data  
that is passed into a python script via a web form. However, the way it  
is implemented now you can pass in any set of rules and any set of data  
and get back some results on wether the data passed the tests.

The style of the resulting dict helps with redisplaying the results  
back onto the web page.

I'm interested in improving the code overall and perhaps working  
exceptions in, instead of using a specific dict format. Anyone have any  
arguments for creating a class for this type of stuff? etc?

Thanks,
---Sean

------
def validateData(rules, data):
     """
     Validates {data} according to {rules}.

     Datatypes
     ---------
     alpha - can only contain alpha letters
     alphanum - can only contain alpha letters and/or numbers
     num - can only contain numbers
     email - must conform to email regexp recipe
     phone - must conform to phone regexp recipe

     Usage
     -----
     data = {
     'firstname' : 'John',
     'lastname' : 'St. Claire',
     'email' : 'jsn.com',
     'phone' : '415-333-3333'
     }

     rules = {
     'firstname' : {
         'dataType' : 'alpha',
         'minlen' : '2',
         'maxlen' : '64',
         'isRequired' : '1'
         },
     'lastname' : {
         'dataType' : 'alpha',
         'minlen' : '2',
         'maxlen' : '64',
         'isRequired' : '1'
         },
     'email' : {
         'dataType' : 'email',
         'minlen' : '5',
         'maxlen' : '30',
         'isRequired' : '0'
         },
     'phone' : {
         'dataType' : 'phone',
         'minlen' : '7' ,
         'maxlen' : '32',
         'isRequired' : '0'
         },
     }

     @returns dict of the format:
         results = {
         'name' : 'John'
         'name_error' : '', # Empty because no error
         'lastname' : 'St. Claire',
         'lastname_error' : '',
         'email' : 'jsn.com',
         'email_error' : '* Invalid email address. Please enter a valid  
email address. (Ex: yourname at sfsu.edu)',
         'phone' : '415-333-3333',
         'phone_error' : ''
         }

     @param data: dict of data
     @type  data: dict

     @param rules: the rules that will be applied towards the data
     @type  rules: dict of dicts

     @returns: original data with _error keys added
     @rtype: dict
     """
     results = {}
     for key in rules.keys():
         try:
             if rules[key]['isRequired'] == '0' and data[key] == "":
                 pass
             else:
                 errorCheck = validate(data[key], rules[key]['dataType'],
                 rules[key]['minlen'], rules[key]['maxlen'])
                 results[key] = errorCheck[0]
                 try:
                     results[key+"_error"] = errorCheck[1]
                 except IndexError:
                     results[key+"_error"] = ""
         except KeyError:
             results[key] = ""
             results[key+"_error"] = "* Error"

     return results

def validate(input, dataType, minlen, maxlen):
     """
     Validate input, applying dataType, minlen, and
     maxlen constraints, and return results.

     @param input: the input of the form field
     @type  input: string

     @param dataType: the dataType the input must match to
     @type  dataType: string

     @param minlen: the minimum length input must be
     @type  minlen: string

     @param maxlen: the maximum length input can be
     @type  maxlen: string

     @returns: results in the format of:
         results = ['Jon'] if the data is valid
         results = ['invalidemail.com', "* Error Message"] if data is  
invalid
     @rtype: list
     """
     results = []
     if dataType == "alpha":
         if re.compile("^\D+$").search(input):
             results = [input]
         else:
             results = [input, "* Only letters are allowed."]

     if dataType == "alphanum":
         if re.compile("^([1-zA-Z0-1@#.,'/\-\s]{1,255})$").search(input):
             results = [input]
         else:
             results = [input, "* Only alphanumerics are allowed."]

     if dataType == "num":
         if re.compile("^\d+$").search(input):
             results = [input]
         else:
             results = [input, "* Only numbers are allowed."]

     if dataType == "email":
         if re.compile("^.+ at .+\..{2,3}$").search(input):
             results = [input]
         else:
             results = [input, """* Invalid email address. Please enter  
a valid email address. (Ex: yourname at domain.com)"""]

     if dataType == "phone":
         if  
re.compile("^1?\s*-?\s*(\d{3}|\(\s*\d{3}\s*\))\s*-?\s*\d{3}\s*-? 
\s*\d{4}$").search(input):
             results = [input]
         else:
             results = [input, """* Invalid phone number. Please enter  
the complete number. (Ex: 415-333-3333)"""]

     if len(str(input)) < int(minlen):
         results = [input, """* Must contain at least """ + \
         str(minlen) + """ characters."""]

     if len(str(input)) > int(maxlen):
         results = [input, """* Must contain less than """ + \
         str(maxlen) + """ characters."""]

     return results