"""
scrapple.commands.run
~~~~~~~~~~~~~~~~~~~~~
"""
from __future__ import print_function
import os
from colorama import Back, Fore, init
from scrapple.commands import command
from scrapple.selectors.css import CssSelector
from scrapple.selectors.xpath import XpathSelector
from scrapple.utils.config import (InvalidConfigException, extract_fieldnames,
traverse_next, validate_config)
[docs]class RunCommand(command.Command):
"""
Defines the execution of :ref:`run <command-run>`
"""
def __init__(self, args):
super(RunCommand, self).__init__(args)
init()
[docs] def execute_command(self):
"""
The run command implements the web content extractor corresponding to the given \
configuration file.
The execute_command() validates the input project name and opens the JSON \
configuration file. The run() method handles the execution of the extractor run.
The extractor implementation follows these primary steps :
1. Selects the appropriate :ref:`selector class <implementation-selectors>` through \
a dynamic dispatch, with the selector_type argument from the CLI input.
#. Iterate through the data section in level-0 of the configuration file. \
On each data item, call the extract_content() method from the selector class to \
extract the content according to the specified extractor rule.
#. If there are multiple levels of the extractor, i.e, if there is a 'next' \
attribute in the configuration file, call the traverse_next() \
:ref:`utility function <implementation-utils>` and parse through successive levels \
of the configuration file.
#. According to the --output_type argument, the result data is saved in a JSON \
document or a CSV document.
"""
try:
self.args['--verbosity'] = int(self.args['--verbosity'])
if self.args['--verbosity'] not in [0, 1, 2]:
raise ValueError
if self.args['--verbosity'] > 0:
print(Back.GREEN + Fore.BLACK + "Scrapple Run")
print(Back.RESET + Fore.RESET)
import json
with open(self.args['<projectname>'] + '.json', 'r') as f:
self.config = json.load(f)
validate_config(self.config)
self.run()
except ValueError:
print(Back.WHITE + Fore.RED + "Use 0, 1 or 2 for verbosity." \
+ Back.RESET + Fore.RESET, sep="")
except IOError:
print(Back.WHITE + Fore.RED + self.args['<projectname>'], ".json does not ", \
"exist. Use ``scrapple genconfig``." + Back.RESET + Fore.RESET, sep="")
except InvalidConfigException as e:
print(Back.WHITE + Fore.RED + e + Back.RESET + Fore.RESET, sep="")
def run(self):
selectorClassMapping = {
'xpath': XpathSelector,
'css': CssSelector
}
selectorClass = selectorClassMapping.get(self.config['selector_type'].lower())
results = dict()
results['project'] = self.args['<projectname>']
results['data'] = list()
try:
result = dict()
tabular_data_headers = dict()
if self.args['--verbosity'] > 0:
print()
print(Back.YELLOW + Fore.BLUE + "Loading page ", self.config['scraping']['url'] \
+ Back.RESET + Fore.RESET, end='')
selector = selectorClass(self.config['scraping']['url'])
for attribute in self.config['scraping']['data']:
if attribute['field'] != "":
if self.args['--verbosity'] > 1:
print("\nExtracting", attribute['field'], "attribute", sep=' ', end='')
result[attribute['field']] = selector.extract_content(**attribute)
if not self.config['scraping'].get('table'):
result_list = [result]
else:
tables = self.config['scraping'].get('table', [])
for table in tables:
if table.get('selector', '').strip() != '':
table.update({
'result': result,
'verbosity': self.args['--verbosity']
})
table_headers, result_list = selector.extract_tabular(**table)
for th in table_headers:
if not th in tabular_data_headers:
tabular_data_headers[th] = len(tabular_data_headers)
if not self.config['scraping'].get('next'):
results['data'].extend(result_list)
else:
for nextx in self.config['scraping']['next']:
for tdh, r in traverse_next(selector, nextx, result, verbosity=self.args['--verbosity']):
results['data'].append(r)
for th in tdh:
if not th in tabular_data_headers:
tabular_data_headers[th] = len(tabular_data_headers)
except KeyboardInterrupt:
pass
except Exception as e:
print(e)
finally:
if self.args['--output_type'] == 'json':
import json
with open(os.path.join(os.getcwd(), self.args['<output_filename>'] + '.json'), \
'w') as f:
json.dump(results, f, indent=4)
elif self.args['--output_type'] == 'csv':
import csv
with open(os.path.join(os.getcwd(), self.args['<output_filename>'] + '.csv'), \
'w') as f:
fields = extract_fieldnames(self.config)
data_headers = sorted(tabular_data_headers, key=lambda x:tabular_data_headers[x])
fields.extend(data_headers)
writer = csv.DictWriter(f, fieldnames=fields)
writer.writeheader()
writer.writerows(results['data'])
if self.args['--verbosity'] > 0:
print()
print(Back.WHITE + Fore.RED + self.args['<output_filename>'], \
".", self.args['--output_type'], " has been created" \
+ Back.RESET + Fore.RESET, sep="")