Is there any good design pattern for code to handle error or exception in beautiful soup?-CodePudding

I am using beautiful soup library to extract out data from webpages. Sometimes we have the case where element could not be found in the webpage itself, and if we try to access the sub element than we get error like 'NoneType' object has no attribute 'find'.

Like let say for the below code

res = requests.get(url)
soup = BeautifulSoup(res.text, "html.parser")
primary_name = soup.find('div', {"class": "company-header"}).find('p', {"class": "heading-xlarge"}).text
company_number = soup.find('p', id="company-number").find('strong').text

If I want to handle the error, I have to write something like below.

try:
    primary_name = error_handler(soup.find('div', {"class": "company-header"}).find('p', {"class": "heading-xlarge"}).text)
except:
    primary_name = None

try:
    company_number = soup.find('p', id="company-number").find('strong').text.strip()
except:
    company_number = None

And if there are too many elements, then we end up with lots of try and catch statements. I actually want to write code in the below manner.

def error_handler(_):
    try:
        return _
    except:
        return None

primary_name = error_handler(soup.find('div', {"class": "company-header"}).find('p', {"class": "heading-xlarge"}).text)
# this will still raise the error

I know that above code wouldn't work because it will still try to execute first inner function in error_handler function, and it would still raise the error.

If you have any idea how to make this code looks cleaner, then please show me.

CodePudding user response：

I don't know if this is the most efficient way, but you can pass a lambda expression to the error_handler:

def error_handler(_):
    try:
        return _()
    except:
        return None

primary_name = error_handler(lambda: soup.find('div', {"class": "company-header"}).find('p', {"class": "heading-xlarge"}).text)

CodePudding user response：

So, you are finding a way to handle a lot of element's exceptions.

For this, I will assume that you will (like any other scraper), use for loop. You can handle exceptions as follows:

soup = BeautifulSoup(somehtml)

a_big_list_of_data = soup.find_all("div", {"class": "cards"})

for items in a_big_list_of_data:
    try:
       name = items.find_all("h3", {"id": "name"})
       price = items.find_all("h5", {"id": "price"})
    except:
       continue