So, I'm making a Python script, that gets a webpages content and compares it to a previously saved version to see if the webpage has changed. I'm getting the raw content using this method:
def getcontent(url):
str = requests.get(url)
str = str.text
return(str)
after that I'm doing some cleaning up of the content and quote escaping and such, but that's irrelevant. The issue I keep running into, is, that the webpage has got some JavaScript code, that generates a unique key that my method downloads. Each time you grab the webpage content, the key is different. I have zero idea what that key is for. The issue is, that if the key is different, the new content, and the saved content aren't identical.
How can I disable JavaScript from running when I request a webpage?
The token is generated server-side and can be used for various reasons (for example CSRF-token)
The token will always be in the content of your response, there is no JavaScript needed for that.
You should find a way to ignore / remove the token.
Related
I've been trying this for quite sometime
My url has # tag
url = http://www.firstcry.com/search.aspx?q=blue%20jeans#q=####1#0#20##&gender=Unisex&PageNo=1
When I try request.get(url) method, it only fetches for results where url is upto # tag, but the actual url takes time to completely load and gives final set of results (which are different).
How can I avoid this?
Thanks a lot.
The fragment part of a URI (everything after the '#') is normally interpreted by the browser. That is, the retrieved document is everything up to the '#'. That's what request.get(url) actually loads: the single file (resource) with that URI.
Now, the browser then "does something" with the fragment -- scrolls to it, most commonly. The browser could do other things with the fragment via javascript.
What it sounds like you're seeing is requests gets the file which contains javascript which, on loading, gets additional information based on the fragment.
This is not much different from scraping a dynamic HTML, where the scraped page loads javascript which builds a different DOM.
You'll need to use something like Selenium, or you'll have to manually interpret the results and load additional URLs.
I'm working on a project using Scrapy.
All wanted fields but one get scraped perfectly. The content of the missing field simply doesn't show up in the Scrapy response (as checked in the scrapy shell), while it does show up when i use my browser to visit the page. In the scrapy response, the expected tags are there, but not the text between the tags.
There's no JavaScript involved, but it is a variable that is provided by the server (it's the current number of visits to that particular page). No iframe involved either.
Already set the user agent (in the settings-file) to match my browser.
Already set the download delay (in the settings-file) to 5.
EDIT (addition):
The page : http://www.fincaraiz.com.co/apartamento-en-venta/bogota/salitre-det-1337688.aspx
Xpath to the wanted element : //*[#id="numAdvertVisits"]
What could be the cause of this mystery ?
It's an ajax/javascript loaded value.
What steps did you take to determine there is no JS involved? I loaded the page w/o javascript, and while that area of the page had the stub content ("Visitas"), the actual data was written there with an ajax request.
You can still load that data using scrapy, it'll just take an additional request to the URL endpoint normally accessed via on-page ajax. The server returns the number of visits in XML, via the script at http://www.fincaraiz.com.co/WebServices/Statistics.asmx/GetAdvertVisits?idAdvert=1337688&idASource=40&idType=1001 (try loading that script and you'll see the # of visits for the page you provided in the original email).
There is another ajax request that returns "True" for that page, but I'm not sure what the data's actual meaning is. Still, it may be useful:
http://www.fincaraiz.com.co/WebServices/Statistics.asmx/DetailAdvert?idAdvert=1337688&idType=1001&idASource=40&strCookie=13/11/2014:19-05419&idSession=10hx5wsfbqybyxsywezx0n1r&idOrigin=44
So I've scraped websites before, but this time I am stumped. I am attempting to search for a person on Biography.com and retrieve his/her biography. But whenever I search the site using urllib2 and query the URL: http://www.biography.com/search/ I get a blank page with no data in it.
When I look into the source generated in the browser by clicking View Source, I still do not see any data. When I use Chrome's developer tools, I find some data but still no links leading to the biography.
I have tried changing the User Agent, adding referrers, using cookies in Python but to no avail. If someone could help me out with this task it would be really helpful.
I am planning to use this text for my NLP project and worst case, I'll have to manually copy-paste the text. But I hope it doesn't come to that.
Chrome/Chromium's Developer Tools (or Firebug) is definitely your friend here. I can see that the initial search on Biography's site is made via a call to a Google API, e.g.
https://www.googleapis.com/customsearch/v1?q=Barack%20Obama&key=AIzaSyCMGfdDaSfjqv5zYoS0mTJnOT3e9MURWkU&cx=011223861749738482324%3Aijiqp2ioyxw&num=8&callback=angular.callbacks._0
The search term I used is in the q= part of the query string: q=Barack%20Obama.
This returns JSON inside of which there is a key link with the value of the article of interest's URL.
"link": "http://www.biography.com/people/barack-obama-12782369"
Visiting that page shows me that this is generated by a request to:
http://api.saymedia-content.com/:apiproxy-anon/content-sites/cs01a33b78d5c5860e/content-customs/#published/#by-custom-type/ContentPerson/#by-slug/barack-obama-12782369
which returns JSON containing HTML.
So, replacing the last part of the link barack-obama-12782369 with the relevant info for the person of interest in the saymedia-content link may well pull out what you want.
To implement:
You'll need to use urllib2 (or requests) to do the search via their Google API call, using urllib2.urlopen(url) or requests.get(url). Replace the Barack%20Obama with a URL escaped search string, e.g. Bill%20Clinton.
Parse the JSON using Python's json module to extract the string that gives you the http://www.biography.com/people link. From this, extract the part of this link of interest (as barack-obama-12782369 above).
Use urllib2 or requests to do a saymedia-content API request replacing barack-obama-12782369 after #by-slug/ with whatever you extract from 2; i.e. do another urllib2.urlopen on this URL.
Parse the JSON from the response of this second request to extract the content you want.
(Caveat: This is provided that there are no session-based strings in those two API calls that might expire.)
Alternatively, you can use Selenium to visit the website, do the search and then extract the content.
You will most likely need to manually copy and paste, as biography.com is a completely javascript-based site, so it can't be scraped with traditional methods.
You can discover an api url with httpfox (firefox addon). f.e. http://www.biography.com/.api/item/search?config=published&query=marx
brings you a json you can process searching for /people/ to retrive biography links.
Or you can use an screen crawler like selenium
I'm trying to get some data from a webpage, but I found a problem. Whenever I want to go to the next page (i.e. page 2) to keep retrieving the data on it, I keep receiving the data from page 1. Apparently something goes wrong trying to switch to the next page.
The thing is, I haven't had problems with urls like this:
'http://www.webpage.com/index.php?page=' + str(pageno)
I can just start a while statement and I'll just jump to page 2 by adding 1 to "pageno"
My problem comes in when I try to open an url with this format:
'http://www.webpage.com/search/?show_all=1#sort_order=ASC&page=' + str(pageno)
As
urllib2.urlopen('http://www.webpage.com/search/?show_all=1#sort_order=ASC&page=4').read()
will retrieve the source code from http://www.webpage.com/search/?show_all=1
There is no other way to retrieve other pages without using the hash, as far as I'm concerned.
I guess it's just urllib2 ignoring the hash, as it is normally used to specify a starting point for a browser.
The fragment of the url after the hash (#) symbol is for client-side handling and isn't actually sent to the webserver. My guess is there is some javascript on the page that requests the correct data from the server using AJAX, and you need to figure out what URL is used for that.
If you use chrome you can watch the Network tab of the developer tools and see what URLs are requested when you click the link to go to page two in your browser.
that's because hash are not part of the url that is sent to the server, it's a fragment identifier that is used to identify elements inside the page. Some websites misused the hash fragment for JavaScript hook for identifying pages though. You'll either need to be able to execute the JavaScript on the page or you'll need to reverse engineer the JavaScript and emulate the true search request that is being made, presumably through ajax. Firebug's Net tab will be really useful for this.
I'm on the middle of a scrapping project using Scrapy.
I realized that Scrapy strips the URL from a hash tag to the end.
Here's the output from the shell:
[s] request <GET http://www.domain.com/b?ie=UTF8&node=3006339011&ref_=pe_112320_20310580%5C#/ref=sr_nr_p_8_0?rh=n%3A165796011%2Cn%3A%212334086011%2Cn%3A%212334148011%2Cn%3A3006339011%2Cp_8%3A2229010011&bbn=3006339011&ie=UTF8&qid=1309631658&rnid=598357011>
[s] response <200 http://www.domain.com/b?ie=UTF8&node=3006339011&ref_=pe_112320_20310580%5C>
This really affects my scrapping because after a couple of hours trying to find out why some item was not being selected, I realized that the HTML provided by the long URL differs from the one provided by the short one. Besides, after some observation, the content changes in some critical parts.
Is there a way to modify this behavior so Scrapy keeps the whole URL?
Thanks for your feedback and suggestions.
This isn't something scrapy itself can change--the portion following the hash in the url is the fragment identifier which is used by the client (scrapy here, usually a browser) instead of the server.
What probably happens when you fetch the page in a browser is that the page includes some JavaScript that looks at the fragment identifier and loads some additional data via AJAX and updates the page. You'll need to look at what the browser does and see if you can emulate it--developer tools like Firebug or the Chrome or Safari inspector make this easy.
For example, if you navigate to http://twitter.com/also, you are redirected to http://twitter.com/#!/also. The actual URL loaded by the browser here is just http://twitter.com/, but that page then loads data (http://twitter.com/users/show_for_profile.json?screen_name=also) which is used to generate the page, and is, in this case, just JSON data you could parse yourself. You can see this happen using the Network Inspector in Chrome.
Looks like it's not possible. The problem is not the response, it's in the request, which chops the url.
It is retrievable from Javascript - as
window.location.hash. From there you
could send it to the server with Ajax
for example, or encode it and put it
into URLs which can then be passed
through to the server-side.
Can I read the hash portion of the URL on my server-side application (PHP, Ruby, Python, etc.)?
Why do you need this part which is stripped if the server doesn't receive it from browser?
If you are working with Amazon - i haven't seen any problems with such urls.
Actually, when entering that URL in a web browser, it will also only send the part before the hash tag to the web server. If the content is different, it's probably because there are some javascript on the page that - based on the content of the hash tag part - changes the content of the page after it has been loaded (most likely an XmlHttpRequest is made that loads additional content).