Supports obtaining PDF documents from web pages (#1107)

### What problem does this PR solve?

Knowledge base management supports crawling information from web pages
and generating PDF documents

### Type of change
- [x] New Feature (Support document from web pages)

api/utils/web_utils.py

@@ -0,0 +1,82 @@
+import re
+import json
+import base64
+
+from selenium import webdriver
+from selenium.webdriver.chrome.options import Options
+from selenium.webdriver.chrome.service import Service
+from selenium.common.exceptions import TimeoutException
+from selenium.webdriver.support.ui import WebDriverWait
+from selenium.webdriver.support.expected_conditions import staleness_of
+from webdriver_manager.chrome import ChromeDriverManager
+from selenium.webdriver.common.by import By
+
+
+def html2pdf(
+        source: str,
+        timeout: int = 2,
+        install_driver: bool = True,
+        print_options: dict = {},
+):
+    result = __get_pdf_from_html(source, timeout, install_driver, print_options)
+    return result
+
+
+def __send_devtools(driver, cmd, params={}):
+    resource = "/session/%s/chromium/send_command_and_get_result" % driver.session_id
+    url = driver.command_executor._url + resource
+    body = json.dumps({"cmd": cmd, "params": params})
+    response = driver.command_executor._request("POST", url, body)
+
+    if not response:
+        raise Exception(response.get("value"))
+
+    return response.get("value")
+
+
+def __get_pdf_from_html(
+        path: str,
+        timeout: int,
+        install_driver: bool,
+        print_options: dict
+):
+    webdriver_options = Options()
+    webdriver_prefs = {}
+    webdriver_options.add_argument("--headless")
+    webdriver_options.add_argument("--disable-gpu")
+    webdriver_options.add_argument("--no-sandbox")
+    webdriver_options.add_argument("--disable-dev-shm-usage")
+    webdriver_options.experimental_options["prefs"] = webdriver_prefs
+
+    webdriver_prefs["profile.default_content_settings"] = {"images": 2}
+
+    if install_driver:
+        service = Service(ChromeDriverManager().install())
+        driver = webdriver.Chrome(service=service, options=webdriver_options)
+    else:
+        driver = webdriver.Chrome(options=webdriver_options)
+
+    driver.get(path)
+
+    try:
+        WebDriverWait(driver, timeout).until(
+            staleness_of(driver.find_element(by=By.TAG_NAME, value="html"))
+        )
+    except TimeoutException:
+        calculated_print_options = {
+            "landscape": False,
+            "displayHeaderFooter": False,
+            "printBackground": True,
+            "preferCSSPageSize": True,
+        }
+        calculated_print_options.update(print_options)
+        result = __send_devtools(
+            driver, "Page.printToPDF", calculated_print_options)
+        driver.quit()
+        return base64.b64decode(result["data"])
+
+
+def is_valid_url(url: str) -> bool:
+    return bool(re.match(r"(https?|ftp|file)://[-A-Za-z0-9+&@#/%?=~_|!:,.;]+[-A-Za-z0-9+&@#/%=~_|]", url))
+
+