"""
The webapp part of Scriptform, which takes care of serving requests and
handling them.
"""
from SocketServer import ThreadingMixIn
import BaseHTTPServer
from BaseHTTPServer import BaseHTTPRequestHandler
import urlparse
import cgi
import logging
import tempfile
import os
import base64
import hashlib
from formrender import FormRender
HTML_HEADER = u'''
{title}
'''
HTML_LIST = u''''
{header}
{form_list}
{footer}
'''
HTML_FORM = u'''
{header}
{footer}
'''
HTML_FORM_LIST = u'''
{description}
{title}
'''
HTML_SUBMIT_RESPONSE = u'''
{header}
{footer}
'''
class HTTPError(Exception):
"""
HTTPError may be thrown by routes to indicate HTTP errors such as 404, 301,
etc. They are caught by the 'framework' and sent to the client's browser.
"""
def __init__(self, status_code, msg, headers=None):
if headers is None:
headers = {}
self.status_code = status_code
self.msg = msg
self.headers = headers
Exception.__init__(self, status_code, msg, headers)
class ThreadedHTTPServer(ThreadingMixIn, BaseHTTPServer.HTTPServer):
"""
Base class for multithreaded HTTP servers.
"""
pass
class WebAppHandler(BaseHTTPRequestHandler):
"""
Basic web server request handler. Handles GET and POST requests. This class
should be extended with methods (starting with 'h_') to handle the actual
requests. If no path is set, it dispatches to the 'index' or 'default'
method.
"""
def log_message(self, fmt, *args):
"""Overrides BaseHTTPRequestHandler which logs to the console. We log
to our log file instead"""
fmt = "{} {}"
self.scriptform.log.info(fmt.format(self.address_string(), args))
def do_GET(self):
"""
Handle a GET request.
"""
self._call(*self._parse(self.path))
def do_POST(self):
"""
Handle a POST request.
"""
form_values = cgi.FieldStorage(
fp=self.rfile,
headers=self.headers,
environ={'REQUEST_METHOD': 'POST'})
self._call(self.path.strip('/'), params={'form_values': form_values})
def _parse(self, reqinfo):
"""
Parse information from a request.
"""
url_comp = urlparse.urlsplit(reqinfo)
path = url_comp.path
query_vars = urlparse.parse_qs(url_comp.query)
# Only return the first value of each query var. E.g. for
# "?foo=1&foo=2" return '1'.
var_values = dict([(k, v[0]) for k, v in query_vars.items()])
return (path.strip('/'), var_values)
def _call(self, path, params):
"""
Find a method to call on self.app_class based on `path` and call it.
The method that's called is in the form 'h_'. If no path was
given, it will try to call the 'index' method. If no method could be
found but a `default` method exists, it is called. Otherwise 404 is
sent.
Methods should take care of sending proper headers and content
themselves using self.send_response(), self.send_header(),
self.end_header() and by writing to self.wfile.
"""
method_name = 'h_{0}'.format(path)
method_cb = None
try:
if hasattr(self, method_name) and \
callable(getattr(self, method_name)):
method_cb = getattr(self, method_name)
elif path == '' and hasattr(self, 'index'):
method_cb = getattr(self, 'index')
elif hasattr(self, 'default'):
method_cb = getattr(self, 'default')
else:
raise HTTPError(404, "Not found")
method_cb(**params)
except HTTPError, err:
# HTTP erors are generally thrown by the webapp on purpose. Send
# error to the browser.
if err.status_code not in (401, ):
self.scriptform.log.exception(err)
self.send_response(err.status_code)
for header_k, header_v in err.headers.items():
self.send_header(header_k, header_v)
self.end_headers()
self.wfile.write("Error {}: {}".format(err.status_code,
err.msg))
self.wfile.flush()
return False
except Exception, err:
self.scriptform.log.exception(err)
self.send_error(500, "Internal server error")
raise
class ScriptFormWebApp(WebAppHandler):
"""
This class is a request handler for WebSrv.
"""
def index(self):
"""
Index handler. If there's only one form defined, render that form.
Otherwise render a list of available forms.
"""
form_config = self.scriptform.get_form_config()
username = getattr(self, 'username', None)
visible_forms = form_config.get_visible_forms(username)
if len(visible_forms) == 1:
first_form = visible_forms[0]
return self.h_form(first_form.name)
else:
return self.h_list()
def auth(self):
"""
Verify that the user is authenticated. This is required if the form
definition contains a 'users' field. Returns the username if the user
is validated or None if no validation is required.. Otherwise, raises a
401 HTTP back to the client.
"""
form_config = self.scriptform.get_form_config()
username = None
# If a 'users' element was present in the form configuration file, the
# user must be authenticated.
if form_config.users:
auth_header = self.headers.getheader("Authorization")
if auth_header is not None:
# Validate the username and password
auth_unpw = auth_header.split(' ', 1)[1]
username, password = base64.decodestring(auth_unpw).split(":")
pw_hash = hashlib.sha256(password).hexdigest()
if username in form_config.users and \
pw_hash == form_config.users[username]:
# Valid username and password. Return the username.
return username
# Authentication needed, but not provided or wrong username/pw.
headers = {"WWW-Authenticate": 'Basic realm="Private Area"'}
raise HTTPError(401, 'Authenticate', headers)
# No authentication required. Return None as the username.
return None
def h_list(self):
"""
Render a list of available forms.
"""
username = self.auth()
form_config = self.scriptform.get_form_config()
h_form_list = []
for form_def in form_config.get_visible_forms(username):
h_form_list.append(
HTML_FORM_LIST.format(
title=form_def.title,
description=form_def.description,
name=form_def.name
)
)
output = HTML_LIST.format(
header=HTML_HEADER.format(title=form_config.title,
custom_css=form_config.custom_css),
footer=HTML_FOOTER,
form_list=u''.join(h_form_list)
)
self.send_response(200)
self.send_header('Content-type', 'text/html')
self.end_headers()
self.wfile.write(output.encode('utf8'))
def h_form(self, form_name, errors=None, **form_values):
"""
Render a form.
"""
def render_field(field, errors):
"""
Render a HTML field.
"""
params = {
'name': field['name'],
'classes': [],
}
if field.get('hidden', None):
params['classes'].append('hidden')
if field.get('required', None):
params['classes'].append('required')
params['classes'].extend(field.get('classes', '').split())
params["style"] = field.get("style", "")
# Get field-specific parameters
if field['type'] not in ('file', 'checkbox'):
params['value'] = form_values.get(field['name'], '')
if field['type'] not in ('radio', 'checkbox', 'select'):
params['required'] = field.get('required', False)
if field['type'] == 'string':
params['size'] = field.get('size', '')
if field['type'] in ('string', 'password', 'text'):
params['minlen'] = field.get('minlen', '')
if field['type'] in ('string', 'text'):
params['maxlen'] = field.get('maxlen', '')
if field['type'] in ('integer', 'float'):
params['minval'] = field.get("min", '')
params['maxval'] = field.get("max", '')
if field['type'] == 'date':
params['minval'] = field.get('min', '')
params['maxval'] = field.get('max', '')
if field['type'] == 'text':
params['rows'] = field.get("rows", '')
params['cols'] = field.get("cols", '')
if field['type'] == 'radio':
if not form_values.get(field['name'], None):
params['value'] = field['options'][0][0]
params['options'] = field['options']
if field['type'] in ('radio', 'select'):
params['options'] = field['options']
if field['type'] == 'checkbox':
params['checked'] = False
if field['name'] in form_values and \
form_values[field['name']] == 'on':
params['checked'] = True
h_input = fr_inst.r_field(field['type'], **params)
return fr_inst.r_form_line(field['type'], field['title'],
h_input, params['classes'], errors)
if errors is None:
errors = {}
username = self.auth()
form_config = self.scriptform.get_form_config()
fr_inst = FormRender(None)
# Make sure the user is allowed to access this form.
form_def = form_config.get_form_def(form_name)
if form_def.allowed_users is not None and \
username not in form_def.allowed_users:
raise HTTPError(403, "You're not authorized to view this form")
html_errors = u''
if errors:
html_errors = u''
for error in errors:
html_errors += u'- {0}
'.format(error)
html_errors += u'
'
output = HTML_FORM.format(
header=HTML_HEADER.format(title=form_config.title,
custom_css=form_config.custom_css),
footer=HTML_FOOTER,
title=form_def.title,
description=form_def.description,
errors=html_errors,
name=form_def.name,
fields=u''.join(
[render_field(f, errors.get(f['name'], []))
for f in form_def.fields]
),
submit_title=form_def.submit_title
)
self.send_response(200)
self.send_header('Content-type', 'text/html')
self.end_headers()
self.wfile.write(output.encode('utf8'))
def h_submit(self, form_values):
"""
Handle the submitting of a form by validating the values and then doing
a callback to a script. How the output is
handled depends on settings in the form definition.
"""
username = self.auth()
form_config = self.scriptform.get_form_config()
form_name = form_values.getfirst('form_name', None)
form_def = form_config.get_form_def(form_name)
if form_def.allowed_users is not None and \
username not in form_def.allowed_users:
raise HTTPError(403, "You're not authorized to view this form")
# Convert FieldStorage to a simple dict, because we're not allowd to
# add items to it. For normal fields, the form field name becomes the
# key and the value becomes the field value. For file upload fields, we
# stream the uploaded file to a temp file and then put the temp file in
# the destination dict. We also add an extra field with the originally
# uploaded file's name.
values = {}
tmp_files = []
for field_name in form_values:
field = form_values[field_name]
if field.filename is not None:
# Field is an uploaded file. Stream it to a temp file if
# something was actually uploaded
if field.filename == '':
continue
tmp_fname = tempfile.mktemp(prefix="scriptform_")
tmp_file = file(tmp_fname, 'w')
while True:
buf = field.file.read(1024 * 16)
if not buf:
break
tmp_file.write(buf)
tmp_file.close()
field.file.close()
tmp_files.append(tmp_fname) # For later cleanup
values[field_name] = tmp_fname
values['{0}__name'.format(field_name)] = field.filename
else:
# Field is a normal form field. Store its value.
values[field_name] = form_values.getfirst(field_name, None)
# Validate the form values
form_errors, form_values = form_def.validate(values)
if not form_errors:
# Call user's callback. If a result is returned, we wrap its output
# in some nice HTML. If no result is returned, the output was raw
# and the callback should have written its own response to the
# self.wfile filehandle.
# Log the callback and its parameters for auditing purposes.
log = logging.getLogger('CALLBACK_AUDIT')
cwd = os.path.realpath(os.curdir)
log.info("Calling script: {0}".format(form_def.script))
log.info("Current working dir: {0}".format(cwd))
log.info("User: {0}".format(username))
log.info("Variables: {0}".format(dict(form_values.items())))
result = form_config.callback(form_name, form_values, self.wfile,
self.wfile)
if form_def.output != 'raw':
# Ignore everything if we're doing raw output, since it's the
# scripts responsibility.
if result['exitcode'] != 0:
stderr = cgi.escape(result['stderr'].decode('utf8'))
msg = u'{0}'.format(stderr)
else:
if form_def.output == 'escaped':
stdout = cgi.escape(result['stdout'].decode('utf8'))
msg = u'{0}'.format(stdout)
else:
# Non-escaped output (html, usually)
msg = result['stdout'].decode('utf8')
output = HTML_SUBMIT_RESPONSE.format(
header=HTML_HEADER.format(
title=form_config.title,
custom_css=form_config.custom_css
),
footer=HTML_FOOTER,
title=form_def.title,
form_name=form_def.name,
msg=msg,
)
self.send_response(200)
self.send_header('Content-type', 'text/html')
self.end_headers()
self.wfile.write(output.encode('utf8'))
else:
# Form had errors
form_values.pop('form_name')
self.h_form(form_name, form_errors, **form_values)
# Clean up uploaded files
for file_name in tmp_files:
if os.path.exists(file_name):
os.unlink(file_name)
def h_static(self, fname):
"""Serve static files"""
self.auth()
form_config = self.scriptform.get_form_config()
if not form_config.static_dir:
raise HTTPError(501, "Static file serving not enabled")
if '..' in fname:
raise HTTPError(403, "Invalid file name")
path = os.path.join(form_config.static_dir, fname)
if not os.path.exists(path):
raise HTTPError(404, "Not found")
static_file = file(path, 'r')
self.send_response(200)
self.end_headers()
self.wfile.write(static_file.read())