Our Flask code resides in a "demo" directory that looks like this:
(base) C:\Users\ashish\Desktop\demo>tree /f
C:.
│ server.py
│
└───static
form.html
Flask Server Code (\demo\server.py):
import json, requests
from flask_cors import CORS, cross_origin
from flask import Flask, request, Response, jsonify
app = Flask(__name__, static_url_path='', static_folder='static')
cors = CORS(app)
app.config['CORS_HEADERS'] = 'Content-Type'
@app.route('/', methods=['GET'])
@cross_origin()
def root():
print("root() called.")
return app.send_static_file('form.html')
@app.route("/getresponse", methods=['POST'])
@cross_origin()
def getResponse():
print("Content-Type: " + request.headers['Content-Type'])
username = "There"
if request.headers['Content-Type'] == 'text/plain':
return "Request from client is: " + request.data
elif(request.headers['Content-Type'] == 'application/json' or request.headers['Content-Type'] == 'application/json; charset=utf-8'):
# For C#: request.headers['Content-Type'] == 'application/json; charset=utf-8'
# For Python: request.headers['Content-Type'] == 'application/json'
# For AngularJS due to the "Content-Type" headers == 'application/json'
print("request.json: " + str(request.json))
username = request.json['username']
elif request.headers['Content-Type'] == 'application/octet-stream':
f = open('./binary', 'wb')
f.write(request.data)
f.close()
print("Binary message written!")
# For JavaScript and jQuery:
elif (request.headers['Content-Type'] == 'application/x-www-form-urlencoded; charset=UTF-8' or \
request.headers['Content-Type'] == 'application/x-www-form-urlencoded'): # Our HTML client code from "form.html" is hitting here.
print(request.form['username'])
username = request.form['username']
else:
return "415 Unsupported Media Type"
#rtnVal = "Hello %s !!" % (username)
rtnVal = "Hello {}!!".format(username)
return rtnVal
if __name__ == "__main__":
app.run(host = "0.0.0.0", port = 9000, debug = True)
HTML Client Code (\demo\static\form.html):
<form action="/getresponse" method="POST">
<input name="username" type="text" id="username" />
<br/>
<br/>
<input type="submit" />
<form>
Way to start Flask server:
(base) C:\Users\ashish\Desktop\demo>python server.py
After starting the local server, view the HTML form in browser at: http://localhost:9000/
Fill in the "username" in the form and submit to get the 'Hello ${username}' message in the browser window.
Now we come to Scrapy:
Scrapy Spider Code:
import scrapy
def authentication_failed(response):
# TODO: Check the contents of the response and return True if it failed
# or False if it succeeded.
pass
class CustomSpider(scrapy.Spider):
name = 'customspider'
allowed_domains = ['localhost:9000/']
start_urls = ['http://localhost:9000/']
def parse(self, response):
return scrapy.FormRequest.from_response(
response,
formdata={'username': 'ashish'},
callback=self.after_login
)
def after_login(self, response):
if authentication_failed(response):
self.logger.error("Login failed")
return
# continue scraping with authenticated session...
return {'text': response.text}
Run Command:
(base) D:\exp_54\myscraper>scrapy crawl customspider
Every "crawl" request from Scrapy first tries to get the "robots.txt" file from the server.
Flask Logs:
127.0.0.1 - - [01/Jan/2020 20:11:43] "[33mGET /robots.txt HTTP/1.1[0m" 404 -
root() called.
127.0.0.1 - - [01/Jan/2020 20:11:43] "[37mGET / HTTP/1.1[0m" 200 -
127.0.0.1 - - [01/Jan/2020 20:13:23] "[33mGET /robots.txt HTTP/1.1[0m" 404 -
root() called.
127.0.0.1 - - [01/Jan/2020 20:13:23] "[37mGET / HTTP/1.1[0m" 200 -
Not getting the expected output. The request is not getting past the HTML form to make a POST request and show the success message.
Scrapy Logs:
(base) D:\exp_54\myscraper>scrapy crawl customspider
2020-01-01 20:13:23 [scrapy.utils.log] INFO: Scrapy 1.8.0 started (bot: myscraper)
2020-01-01 20:13:23 [scrapy.utils.log] INFO: Versions: lxml 4.2.5.0, libxml2 2.9.8, cssselect 1.1.0, parsel 1.5.2, w3lib 1.21.0, Twisted 18.9.0, Python 3.7.1 (default, Dec 10 2018, 22:54:23) [MSC v.1915 64 bit (AMD64)], pyOpenSSL 18.0.0 (OpenSSL 1.1.1a 20 Nov 2018), cryptography 2.4.2, Platform Windows-10-10.0.16299-SP0
2020-01-01 20:13:23 [scrapy.crawler] INFO: Overridden settings: {'BOT_NAME': 'myscraper', 'NEWSPIDER_MODULE': 'myscraper.spiders', 'ROBOTSTXT_OBEY': True, 'SPIDER_MODULES': ['myscraper.spiders']}
2020-01-01 20:13:23 [scrapy.extensions.telnet] INFO: Telnet Password: c90a356ca81c1ae6
2020-01-01 20:13:23 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
'scrapy.extensions.telnet.TelnetConsole',
'scrapy.extensions.logstats.LogStats']
2020-01-01 20:13:23 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware',
'scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
'scrapy.downloadermiddlewares.retry.RetryMiddleware',
'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',
'scrapy.downloadermiddlewares.stats.DownloaderStats']
2020-01-01 20:13:23 [scrapy.middleware] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
'scrapy.spidermiddlewares.referer.RefererMiddleware',
'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
'scrapy.spidermiddlewares.depth.DepthMiddleware']
2020-01-01 20:13:23 [scrapy.middleware] INFO: Enabled item pipelines:
[]
2020-01-01 20:13:23 [scrapy.core.engine] INFO: Spider opened
2020-01-01 20:13:23 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2020-01-01 20:13:23 [scrapy.extensions.telnet] INFO: Telnet console listening on 127.0.0.1:6023
2020-01-01 20:13:23 [scrapy.core.engine] DEBUG: Crawled (404) [[ GET http://localhost:9000/robots.txt ]] (referer: None)
2020-01-01 20:13:23 [scrapy.core.engine] DEBUG: Crawled (200) [[ GET http://localhost:9000/ ]] (referer: None)
2020-01-01 20:13:24 [scrapy.spidermiddlewares.offsite] DEBUG: Filtered offsite request to 'localhost': [[ POST http://localhost:9000/getresponse ]]
2020-01-01 20:13:24 [scrapy.core.engine] INFO: Closing spider (finished)
2020-01-01 20:13:24 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 426,
'downloader/request_count': 2,
'downloader/request_method_count/GET': 2,
'downloader/response_bytes': 902,
'downloader/response_count': 2,
'downloader/response_status_count/200': 1,
'downloader/response_status_count/404': 1,
'elapsed_time_seconds': 0.166431,
'finish_reason': 'finished',
'finish_time': datetime.datetime(--14, 43, 24, 58867),
'log_count/DEBUG': 3,
'log_count/INFO': 10,
'offsite/domains': 1,
'offsite/filtered': 1,
'request_depth_max': 1,
'response_received_count': 2,
'robotstxt/request_count': 1,
'robotstxt/response_count': 1,
'robotstxt/response_status_count/404': 1,
'scheduler/dequeued': 1,
'scheduler/dequeued/memory': 1,
'scheduler/enqueued': 1,
'scheduler/enqueued/memory': 1,
'start_time': datetime.datetime(--14, 43, 23, 892436)}
2020-01-01 20:13:24 [scrapy.core.engine] INFO: Spider closed (finished)
Google Drive link to Flask code: https://drive.google.com/open?id=1s-mOCM0bJrX9X-TCjzBo9LmsnS-yOhRV
Ref 1: https://stackoverflow.com/questions/20646822/how-to-serve-static-files-in-flask
Ref 2: http://doc.scrapy.org/en/latest/topics/request-response.html#formrequest-objects
Creating an HTML form on Flask server and scraping it with Scrapy
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